# The 20-pound Geared 20" Hardtail Project (Customized Marin Hidden Canyon)



## quasi888 (Mar 13, 2009)

Been quite a few threads on kids' geared mountain bikes lately, and ideas on how to get their weights down, so I thought I'd present my own project.

A little background: I have a 6 y/o son who started racing BMX shortly after his 5th birthday in 2008, and quickly accumulated local and state wins, eventually taking an ABA Northern California State Champion title/plate for his age class that year on an 11-lb. bike built and spec'd by myself. He used the very same bike (re-geared, and with slightly modified ergos) to earn a championship title for his age group in a local kids' triathlon series (50m swim, 4 mile bike, 1 mile run) in 2009. For these little guys (and gals!), bike setup can be every bit as important as how quickly they can spin those pedals -- especially when you have a little guy like mine, who at 46" and 45 lbs, is in the 15th percentile for his age.

So when he mentioned that he wanted to start MTB racing in 2010 (same club that runs the triathlons), I adopted the same (admittedly obsessive) approach that I had with his BMX and Tri racing. (He's grown tired of BMX, but will continue with Tri's for 2010.) After a fair amount of research, it became quickly apparent that even the respected manufacturers are not willing to put too much effort in spec'ing geared 20" mountain bikes (and perhaps, justifiably so). Some of my priorities were:

*Geometry* - This always comes first, whether it's my bike or my kids' bikes. If the bike doesn't feel right, they won't want to ride them. Fortunately, with experience from his BMX bikes, I had a ballpark idea of what types of numbers I was looking for -- around 17" top tube, and 12" or less of seat tube. The first MTB he tried was a Gary Fisher Precaliber, and while he was able to ride it, it was quite apparent that the top tube was too long -- his upper body was too stretched on it. (And the Fisher website confirms it -- 504mm top tube, almost 20"!) Most other bikes were in the more reasonable 16.5-18" top tube range. You also want to consider crank size -- you will see everything from 120mm to 160mm on these kids' bikes -- a 40mm range of variation! That's a huge range for an adult, let alone a young child. My son was spinning 135mm cranks for BMX and Tri's, but I wanted to focus on 140mm cranks for this project -- he's growing, and he can use the additional leverage when climbing bigger hills.

*Weight* - A high priority, but it seemed that everything was at least 25 lbs. Hmm, being somewhat of a weight weenie, I knew I was going to need to do some tweaking regardless of which bike I chose. Based purely on subjective feel, the Scott Scale JR 20 seemed the lightest (albeit not by much). The Kona Shred 2-0 (last year's model, with double chainring) was an absolute TANK -- in a bad way. I really wanted to like that bike, especially with its disc brakes and shorter frame, but its heft was undeniable.

*Gearing* - The types of riding we do locally require some climbing, so that ruled out single speed. Most of the bikes I was looking at were 2x6 or 2x7, but I was initially convinced I needed a triple up front (and for a while was looking only at the Ibex Alpine 320k, which fits that description). But for a 6 y/o with no previous multi-gear experience, I realized that managing gears front and back would be sensory overload at this age. So I was determined to come up with an optimal range of gears with a single chainring up front, even if it meant some customization.

*Suspension* - Unfortunately, at this price point ($300-400ish for a complete bike), they can't afford to spec a quality suspension fork for 20" wheels -- nor is there a market for one among the OEMs. In fact, you're pretty much going to find your choices limited to Spinner Grind, RST Capa, and SR Suntour -- all simple spring/elastomer designs. Make no mistake, these all pretty much work the same (which is to say, badly), and any differences you may see can be attributed to varying quality control (or lack thereof). I have seen a Spinner Grind on a one bike require my full weight to compress, but another Spinner Grind feel properly sprung on another bike. Similar results with RST Capas. So my advice is, don't let the fork model be a deciding factor in your choice of bike -- they're all crap, but it's what we are given, so once you've found the model of bike that suits your child's needs, make sure the fork can compress without Herculean effort.

With the above in mind, I was leaning toward the Ibex Alpine 320k, the Scott Scale JR 20, or the Marin Hidden Canyon. The Ibex was hands-down the best-spec'd out of the bunch -- and also unavailable, with Ibex now out of business. The Scott was nice, but nearly the same cost as the Ibex. Marin was not particularly a standout in any area, but it fit my son reasonably well, but my sister-in-law works at a local sporting goods chain that carries them, and I could get 25% off its $330 retail price. Knowing that I was probably going to spend some money customizing the bike, I decided that buying the Marin at discount was my most cost-effective choice.

Then fortune struck. The local sporting goods store had an unridden 2008 model onhand that they could not sell at retail because it had unusable cranks (long story). They were willing to sell me the bike for $100 (while signing disclaimers acknowledging it was not warranteed or returnable). I jumped at the opportunity to take the bike down to bare frame and fork, and start from scratch on a custom build.

Within hours of taking the bike home I was removing old parts, placing orders for new parts, and scrounging around for other parts from around the garage. Here are some of the key components that were replaced:


*Cranks* - Stock: with 42/32 chainrings, 773 grams. Replacement: Crupi BMX race cranks, 140mm arms, and a FORM BMX 36t chainring, 455 grams.

*Seat* - Stock: 297g (and way to big for a little kid's butt). Replacement: Odyssey Junior BMX seat, 186 grams.

*Seatpost* - Stock: 290 grams. Replacement: spare Ritchey Comp I had lying around, cut down to minimum, 180 grams.

*Stem* - Stock: 240 grams. Replacement: Race Face Evolve XC 70mm, 130 grams.

*Brakeset* - No real weight savings here, but the stock set was pretty bad -- almost "Walmart bike" bad. I replaced them with some Avid FR5 equivalents that my LBS had lying around.

*Bottom Bracket* - Stock: 311 grams. Replacement: Sinz Titanium Euro Square Taper, 166 grams. I was REALLY surprised here. The replacement came off his BMX race bike, and I was surprised by not only how much lighter they were, but much more easily the cranks spun compared to the stock BB.

*Wheelset/Tires* - Stock: front and rear, including hubs and 7-speed 13-28t freewheel, Kenda 20x2.1" tires, 3676 grams. Replacement: Custom build with Crupi/Rhythm BMX rims, IRC Siren 20x1.5" tires, SRAM PG-970 11-32t cassette, Shimano Tiagra hubs, 2911 grams. About a 1.7 lb. reduction in rotational mass, not the monumental reduction I was hoping for, but still quite significant, and with more oprtions for gearing than the stock drivetrain.

*Rear Derailleur/Shifters* - Stock: Shimano Tourney RD, SRAM MRX twist shifters. Replacement: SRAM X5 medium-cage RD, SRAM X7 twist shifters. No huge weight savings, but higher quality and more options for gearing / components.

*Front Derailleru/Shifters* - Stock: Shimano Tourney TY-22, SRAM MRX twist shifters, est. 250 grams w/ cables. Replacement: Completely removed.

*Fork* - Stock, but about 2" of unused steel cut from the steer tube.

*Handlebars* - Stock (and surprisingly light), but about 1.5" cut from each end for better ergos.


End result: a sweet 1x9 setup that weighs 20.2 lbs. sans pedals (20.8 lbs with), compared to its stock weight of 25 lbs., and has already provided the little guy with tons of grins on his first trail ride during winter vacation. Only changes I plan on making are going with a 34t chainring to give him some extra advantage for climbing, and a chain guide like the one from Paul Components.

I could have easily saved a bit more weight by going with SUN CR-18 rims (350g each, vs. my 410g Crupi/Rhythms) but I'm a sucker for blingin' white rims. Other areas for weight savings would come at significantly higher cost: SRAM X-0 short cage rear derailleur (100 grams ligher, $160); KCNC Scandium seatpost (40 grams lighter uncut,$90); Xpedo flat pedals (60 grams lighter, $80). But a combination of these could easily take the bike weight below the magic 20-lb. mark.

A few pictures below.


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## Just me (Apr 20, 2007)

That's awesome. Enjoy your time with your son.


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## NYrr496 (Sep 10, 2008)

That is awesome. Nice work.


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## yetipop (Jul 27, 2009)

*Sweet !!!*

I have a 4yr old and the bike you built is just what I would want for her. Sell it to me in two years, Please!!!!


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## quasi888 (Mar 13, 2009)

yetipop said:


> I have a 4yr old and the bike you built is just what I would want for her. Sell it to me in two years, Please!!!!


I may consider that! But it all depends on whether or not his (now) 3-year-old little sister has inherited the same 2-wheel passion!


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## DWDW (Oct 7, 2005)

Awesome build. I really like the 1 x 9 gearing. Looks great too!


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## Rum Runner (Feb 13, 2008)

Hey all,
Been thinking about doing some mods to my Daughters bike. 
Very awsome build 

I saw some Aeroheat 406 24mm width, 300 grams $ 65.50. These rims would save a further .5lb frm the curernt wheels  I am looking for even a lighter rim if anyone knows of one.

Hope you are having fun 

Cheers,
Paul


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## DiRt DeViL (Dec 24, 2003)

Put a chain device to avoid chain drops, other than that it's a great ride for a youngster.


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## quasi888 (Mar 13, 2009)

DiRt DeViL said:


> Put a chain device to avoid chain drops, other than that it's a great ride for a youngster.


Definitely was part of my original plan (I was looking at the chain keeper from Paul Component Engineering), but he has yet to throw a chain so far, knock on wood. I had shortened the chain to the point where there is a fair amount of tension (while still barely maintaining an "S" shape through the rear mech's pulleys in the largest cog), so that has helped.


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## m-dub (Apr 22, 2005)

Here is our version:
Rav-x carbon bars (22" wide)
Straightline 35mm stem
custom bent/tuned levers and XT V brakes (long levers and the right setup has him one finger braking)
Sram attack 9 speed shifter
Ame mini grips
King headset with +5 base
XT hubs laced to stock rims 
Intense tubes
Kenda Small block 8 DTC kevlar ( lost 2 lbs with just tires and tubes)
Sinz 135 cranks, 34 tooth ring and pro ISIS BB
BBG bash ring ( destroyed the stock big ring on the first ride)
Mod. to front der as guide until I build a new style using old MRP parts or someone makes a ST mount style.
Sram 990 12/34 cassette
Sram hollow pin chain
Ultragra rea 9 spd. short cage der.
Thomson post ( off an old Dh bike and was chopped short)
Oddyssy saddle ( may go back to stock for comfort)
Drilled out cable stops to run full cables
stock pedals
Sinz QR seat clamp
Hope QR's on the wheels
Custom fork mods by Push ( well stickers anyway and a bit of grease  )
21lbs I wasnt shooting for loosing weight as much as making the bike more functional.

Rode it stock for a few rides and found too many falts to not dive into it.
So far the gearing change has made a huge difference! He can climb all but the steepest climbs and bombs down everything. Hes only six and has been riding his 16" pitboss on the trails but just gets rattled. His riding pace had jumped by leaps and he does 10 mile rides with a smile. Worth every penny. Speaking of $. I have a total of $600 ( half being the original purchase) out of pocket. I started by robbing my old parts bin.Thanks to e-bay deals, friends in the industry that hooked the little guy up ( thanks LikinBikin.com) and my local shop, its really a small investment. with a 3 year old brother that is now riding his 16" bmx ( been on 2 wheels since 2 1/2) it should get well used. Mini MTB might not be for every kid but this one is loving every second of it. It takes "family rides" to a whole new level.


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## quasi888 (Mar 13, 2009)

Nice build m-dub! Would love to see more pictures of it.

I'm curious how you got an XT hub to fit in the rear. Did you modify it? Rear dropout spacing on this bike (like most other kid's 20" MTBs) is 130mm -- the same as most road bikes, which is why I went with a Tiagra (road) hub. Most MTB rear hubs are designed for the standard MTB rear dropout spacing of 135mm.


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## m-dub (Apr 22, 2005)

You sure? I thought I mesured it as 135? Well it works with no mods! I got a set of non-disc XT hubs new for $30 on flee-bay and built them up. Chain line works ( bike has long stays) and dish was fine. I wanted to go with a 34 in the rear for the sake of climbing and it has worked out much better. Still a bit tall at times but he does great. I also had the shifter, rear der. off my old 4X bike so that helped with the cost. The Sram Attack shifter has a indacator in the clamp to help in the gear selection confusion with the little guys and the pod style is easier to set up proper brake lever location with his little hands. I put a red sticker on the one shifter so he knows were the " fast button" is  I will try to get some more photos up.


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## m-dub (Apr 22, 2005)

Here are a few. I will try to get a shot of the rear for you also.


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## m-dub (Apr 22, 2005)

Sinz 135 cranks with their pro BB ( Ti was out of stock and I got impatient) The stock front der. is fixed in place to work as a chain guide. I have rubber just above the chain and it keeps its quiet and in place ( old school fix) also a piece in the lower part to eliminate chain slap. I plan on making one out of a use MRP guide but hope they come out with a X1 that is seat tubes mounted. He dropped his chain 10 times on the first two rides ( its rough and he likes little drops) but now with the new cranks and home brewed guide it hasent dropped yet.The bash ring is nice and keeps the chain in place and his pants out of the chain plus he crushed the stock 44 tooth on the first ride into a rock.


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## m-dub (Apr 22, 2005)

The XT brakes were new on fle-bay for $30 bucks, how can you pase that up? The levers were cheepies from someone upgrading and I bent the levers to fit his hand. Also filed the thickness out of the lever to help the fit and drilled "speed holes" for no other reason than looks Then painted black. All the cable stops were also drilled out to run full cable housing. I took all the tention out of the springs and the kid can do stoppies( endows) in the yard with one finger:thumbsup: I had to tell him to cool it before he slammed the der. into the grass one to many times. The Small block 2.1's fit with a ton of clearence and are aired at 18lbs. The float great in the soft and cushion on the rough but roll awesome on the pavement.


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## m-dub (Apr 22, 2005)

Here is a shot of the rear. its a 09 model and the 135 works awesome. A lot of people talk about running singlspeed is all kids need. Well I think it depends on the kid and the terrain your riding. Where we live that would mean a lot of walking.The extra gearing has made a huge difference on his riding.


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## m-dub (Apr 22, 2005)

Hey, nothing like a "pushed fork" The mod included custom stickers on both legs and a bit of greese  The fork and tire give almost 1.5 inches of cush and that alone has ended any sore hand complants and has me yelling at him so slow it down for that sake of my own nerves:thumbsup:


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## m-dub (Apr 22, 2005)

oops. This is a shot before the re-lace of the xt hubs.


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## quasi888 (Mar 13, 2009)

Great pics m-dub!



> You sure? I thought I mesured it as 135?


Well I measured the rear dropout spacing today, and got.......132mm!! LOL. Don't know if it's simply a loose tolerance during manufacturing, or an intentional effort to allow either size hubs to work (doubtful), but I can see how either 130 or 135 would fit.



> A lot of people talk about running singlspeed is all kids need. Well I think it depends on the kid and the terrain your riding. Where we live that would mean a lot of walking.The extra gearing has made a huge difference on his riding.


100% with you there. Recently we've been going up some real extended (for a kid at least -- about a mile at 6% incline on rutty dirt) hill climbs, and he's definitely in the big cog most of the time. In fact, there are some times I wish I had gone with a 12-34 cassette as you have...perhaps I'll swap it out later. If we're talking fairly flat trails with short elevation changes, sure, go for SS. But the types of trails we choose to ride out here mandate the gears.

Your son looks taller than mine. (Mine is now 7 y/o, but at 46" is short for his age.) If yours is taller than that, you might consider longer cranks than the 135s -- at least 140s or 145s. It'll give him the extra leverage for hill climbs. The nice thing about going 1x gearing as you and I have, is that we've got tons of choices in lightweight, square-taper mini BMX cranks. I've been through most of the brands during his (successful-but-short-lived) race career, and the lightest by far are Crupi and LDC (Little Dude Components).


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## m-dub (Apr 22, 2005)

My son is 48" and just turned 6. The reason I went with 135 was the BB is super low and his pedals were really close the ground. I love a low BB and as a DH racer / skills instructor, I swear by them. But his pedals were only 2 inches off the ground and he would clip them in the slightest turn. I even went with a +5 head set spacer/base to lift it up a bit. He has now gotten very aware of them and has no issues. 
Oh I know about the cranks! Tons of sweet stuff out there and almost pulled the trigger on some ( sucker for US made stuff) but my friends at LikinBikin sent him a set and that saved me some cash.:thumbsup: 
I had to keep myself in check as not to go overboard and drop a ton of money. The Sinz are farley light and I could of lost weight in other places as well ( XT hubs are anyontg but light) but $ is tight these days Also the shorter cranks alow him to sit and spin without his knee hitting him in the chin. If you do the math, compared to my 35" inseam, they are still on the long side.
Fun, isnt it?


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## rroadie (Aug 3, 2008)

Awesome thread. I just picked up a Norco Ninja for my 6 year old. He already had a 13 pound mini bmx and rides the track but wants to come with us on some trails too and needed gears. 
Stock was 28 pounds. removed the kickstand, QR's (lots of theiving at school) rear der guard and presto 26 pound bike. I'll be changing the cheap heavy seat post with a short KCNC I have lying around and some cut down carbon handlebars. The big change will be going to a single front chainring and crank. The wheels have fairly nice rims but a 5 speed freewheel. I'll swap out the tires and tubes to some IRC Sirens which I think are the lightest 20" knobbies. I would like to ditch the Suntour suspension fork as it is useless and throw on a lighter rigid fork. All the carbon BMX forks don't have brake bosses. Any fork sugestions?


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## DWDW (Oct 7, 2005)

rroadie,

Some of the 20" forks work reasonably well. It seems to be hit and miss, but you could get a new one for under $100.

Another option is a mod trials fork. They come with various brake bosses including disc tabs. I'm not sure of their weight though - probably nowhere near as light as the BMX models you mentioned.

Finally, on a more ridiculous scale, White Brothers sells a 20" air sprung fork for recumbents. I think it is in the $700 range.


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## NYrr496 (Sep 10, 2008)

DWDW said:


> rroadie,
> 
> Some of the 20" forks work reasonably well. It seems to be hit and miss, but you could get a new one for under $100.
> 
> ...


I mentioned swapping 20" suspension forks in another thread. The Suntour fork that came on my son's bike may as well have been rigid. It was useless. The LBS got me an RST that was way softer. Works much better.


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## quasi888 (Mar 13, 2009)

> I would like to ditch the Suntour suspension fork as it is useless and throw on a lighter rigid fork. All the carbon BMX forks don't have brake bosses. Any fork sugestions?


For a rigid 20" fork, look at flatland forks, primarily designed for stunts/tricks. Most don't have front brake bosses, but some do. Two that come to mind are the KHE Tanaka and Odyssey Pro Flatland (new model might be known as Freestyle Classic). (See, I had the same idea too, so I already did the research. ) Both of these come in at around 2 lbs; about twice the weight of a good carbon race fork, but roughly half the weight of the 20" suspended forks.

EDIT: Hmm, just found out that both of the above forks have "990" mounts, e.d. designed for U-brakes. V-brakes wouldn't mount on them unless you found some sort of adapter plate.


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## NYrr496 (Sep 10, 2008)

I just went through my parts bin and found an old Moby Post and it fits my son's GF Precaliber. I also Ebay'd a set of Sinz cranks and an Easton Monkeybar which I can cut down for him. This is fun.


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## wycough (Mar 9, 2008)

quasi888, what a beautiful bike, put me in line when you are ready to sale.


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## Demo9 (Nov 20, 2006)

Quasi888, m-dub, what spindle length did you use for the bottom bracket?


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## quasi888 (Mar 13, 2009)

Sorry for the late reply, MTBR usually emails me when somebody posts in this thread, I guess I must have missed it.

Demo9, I used a 113mm spindle length for the BB -- fairly middle-of-the-road. As you probably know, the type of cranks you use generally dictate the spindle length. The Crupi cranks don't flare out very much (low Q-factor), but the 113mm spindle was enough to allow several millimeters of clearance between crankarms and chainstay. 

wycough, that day may come sooner than later. My son rode with me on a handful of singletrack rides this past spring, but he never ended up racing. Right now he's focusing on his triathlons (for which I have built a different bike), so the MTB is currently decommissioned from duty. If his interest level in MTB doesn't pick back up, I may end up selling this one.


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## quasi888 (Mar 13, 2009)

The bike is for sale now:

http://classifieds.mtbr.com/showproduct.php?product=54359


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## BunnV (Sep 7, 2005)

Now that the Marin is sold, I'd love to see his new road/tri bike. Based on how nice you made his Mtb, I know the roadie will be equally as awesome if not better.

Something like this maybe?


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## DWDW (Oct 7, 2005)

I bet the girl on the pretty blue bike kicked his butt.


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## yzblue242 (May 3, 2008)

Are those carbon "Lightweight" wheels on that bike? You know, the ones that go for $5K a set?


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## quasi888 (Mar 13, 2009)

BunnV said:


> Now that the Marin is sold, I'd love to see his new road/tri bike. Based on how nice you made his Mtb, I know the roadie will be equally as awesome if not better.
> 
> Something like this maybe?


LOL, what a great photo. Your child? I'm having a hard time figuring out what kind of bike that is. The only kids/junior road bike I'm aware of (at least in the US) with such a sloping downtube is the Blue 2Four. Or possibly it's a custom build based on a mountain bike frame, with road fork and carbon 650c wheelset? (Carbon in 650c is not uncommon; I doubt that's a 24" wheelset -- hard enough as it is to find a decent alloy wheelset in that size, much less carbon.)

After the heartbreak of selling the Marin, the road bike I got my son is a Felt F24. For the price (about $700 new) it's fairly well spec'ed. Of course, it's over 19 lbs. stock, so the closet weight weenie in me already started whittling ounces off once I brought the bike home.  Saved 200 grams alone in replacing the steel 50/36 chainrings with a lightweight FSA 46/36 set that came off my cross bike. Salsa Poco handlebars shortened his reach to the levers, and saved another 127 grams. Other functional (although not necessarily weight-saving) upgrades were shorter cranks, Shimano SPD pedals (same pedals/shoes as when he was racing BMX) and a 11-28 cassette. So, I haven't gone too crazy.......yet.  (Fizik saddle and a zero-offset carbon seatpost will take another 300 grams off, as well as shorten his reach to the bars a bit further, so I hope to get those soon.)

I took him to our local American River Trail (paved urban multi-use trail in Sacramento) last weekend and we did a 19-mile out-and-back on our road bikes. We had a blast.

I should probably start a new thread over on RoadBikeReview.com.


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## BunnV (Sep 7, 2005)

Not my kid. In fact, I'm pretty sure the picture is photoshopped because Lightweight doesn't make wheels that small (I don't think they are 650's).

Anyway, as usual I love your ideas. My son has a Specialized Allez Jr. So far all we've done is add Crank Brothers "Candy" pedals (not shown in the picture). It weighs 19.5 pounds as is. He's not as excited about road riding as your son is right now so we've turned our attention to his mountain bike.

We are working on his 13" Hotrock 24. I just had some lighter hubs laced to the stock Alex rims. The stock rear hub was actually lighter than the new one but, it was a freewheel instead of a cassette. The freewheel was 515 grams! I have a SRAM PG 850 on order that is a claimed 220 grams. Even if it comes in at 300 grams I will still save a ton of weight. 

Keep posing your builds and mods! :thumbsup:


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## Rhinofly (Aug 30, 2010)

I have a question about the two Marin builds...what size bottom bracket did it use?


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## quasi888 (Mar 13, 2009)

Rhinofly said:


> I have a question about the two Marin builds...what size bottom bracket did it use?


Standard 68mm shell. Stock (garbage!!!) BB had a 115 mm spindle as I recall; the Sinz unit I replaced it with had a 113mm spindle -- close enough.


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## m-dub (Apr 22, 2005)

I used the Sinz 113 as well.


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## Rhinofly (Aug 30, 2010)

I picked up a used 2009 model (the silver one) and am now in the process of building it up for my 7yo daughter. At this point the only thing left from stock is frame, fork, seat, seatpost. The wheels are currently being laced by CycleMonkey in Berkeley. When I get it all done I'll post some picks with a description.


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## m-dub (Apr 22, 2005)

Awesome! Its funny how that works out. We only have the stock frame fork and hoops ( rebuilt with new hubs) He is still loving it and impressing me more every day. We just did a little family vacation and he rode some tough stuff.


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## Rhinofly (Aug 30, 2010)

Actually the stock rims don't look like too bad a choice from a functional perspective. But I don't like they way they started to look after being used a while ( the black rim brake surfaces look scruffy as the black paint/whatever wears off). I went with Sun Rhyno Lite 20x1.5 rims. Neil at Cycle Monkey is gonna lace the wheels with 18 spokes in the front and 26 in the rear. It should have a real custom look. This is almost as much fun as was building my new RFX. 

Now I just gotta find a used White Bros RC80


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## DWDW (Oct 7, 2005)

Rhinofly said:


> Actually the stock rims don't look like too bad a choice from a functional perspective. But I don't like they way they started to look after being used a while ( the black rim brake surfaces look scruffy as the black paint/whatever wears off). I went with Sun Rhyno Lite 20x1.5 rims. Neil at Cycle Monkey is gonna lace the wheels with 18 spokes in the front and 26 in the rear. It should have a real custom look. This is almost as much fun as was building my new RFX.
> 
> Now I just gotta find a used White Bros RC80


I saw one on Ebay on the weekend - from the UK - starting bid $700 cdn, if I remember.


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## m-dub (Apr 22, 2005)

Rhinofly said:


> Actually the stock rims don't look like too bad a choice from a functional perspective. But I don't like they way they started to look after being used a while ( the black rim brake surfaces look scruffy as the black paint/whatever wears off). I went with Sun Rhyno Lite 20x1.5 rims. Neil at Cycle Monkey is gonna lace the wheels with 18 spokes in the front and 26 in the rear. It should have a real custom look. This is almost as much fun as was building my new RFX.
> 
> Now I just gotta find a used White Bros RC80


You could always just sand the pant off the side walls. I ran the stock because I got a new set of XT hubs for $40 on flebay and they were 32 hole. My little rat smacks them pretty hard so Im glad I went with more spokes.


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## William_Cannon (May 5, 2009)

there's some spoiled kids on this board with nicer bikes than mine!! HA HA


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## Rhinofly (Aug 30, 2010)

William_Cannon said:


> there's some spoiled kids on this board with nicer bikes than mine!! HA HA


I know it can kinda seem that way. But the truth is the same requirements I have for a bike holds equally true for my kids. Even more so in some ways considering how little the kids weigh. Here they are starting out, building confidence on the trails and strength on the hills. I don't want to burden my girl with a bike that weighs as much as she does and equipped with brakes that require more effort to activate than the ones on my bike. Its just wrong. The way I see it, I am just building the bike the way kids bikes should be to begin with: light and easy to use. I WANT my kids to ride with me so I am just doing everything I can to make it happen.

Besides, there is a real (albeit small) market for well built kids 20" bikes. When she outgrows it I can always sell it easily on the marketplace for a decent amount. That is more that can be said for the run-of-the-mill chinese assembled crap from REI.


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## paddler28 (Apr 4, 2010)

Rhinofly said:


> I know it can kinda seem that way. But the truth is the same requirements I have for a bike holds equally true for my kids. Even more so in some ways considering how little the kids weigh. Here they are starting out, building confidence on the trails and strength on the hills. I don't want to burden my girl with a bike that weighs as much as she does and equipped with brakes that require more effort to activate than the ones on my bike. Its just wrong. The way I see it, I am just building the bike the way kids bikes should be to begin with: light and easy to use. I WANT my kids to ride with me so I am just doing everything I can to make it happen.
> 
> Besides, there is a real (albeit small) market for well built kids 20" bikes. When she outgrows it I can always sell it easily on the marketplace for a decent amount. That is more that can be said for the run-of-the-mill chinese assembled crap from REI.


I couldn't agree more. My kids (aged 5 and 8) have got pretty pimped bikes, but now ride proper MTB trails, with my boy riding the hilly terrain with my husband. Getting a kid to ride a bike up hill for 1,2 or 3 hours with a bike that weights 2/3rds of their weight is not going to happen. Heck with my boys first bike (stock Avanti bike hence good quality but heavy) he couldn't even ride the hill home from school! At the end of the day this is maybe not so much about them riding, but also about me being able to go out and do what I enjoy, and us doing so as a family.


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## NYrr496 (Sep 10, 2008)

William_Cannon said:


> there's some spoiled kids on this board with nicer bikes than mine!! HA HA


I know what you mean... At my local trail, everyone knows my son as the kid on the little Fisher.


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## BOONER (Sep 19, 2008)

m-dub,
When you relaced the wheels to the XT hubs, what model number hub did you use and did you use the stock spokes? My son has a 20" Specialized Hotrock that I want to relace a front hub with a QR to the wheel. I've seen front hubs with a spoke hole circle of 38 mm or 40 mm. I can't tell for certain what the spoke hole circle is on the stock hub. Does a difference of 2 mm matter?


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## m-dub (Apr 22, 2005)

BOONER said:


> m-dub,
> When you relaced the wheels to the XT hubs, what model number hub did you use and did you use the stock spokes? My son has a 20" Specialized Hotrock that I want to relace a front hub with a QR to the wheel. I've seen front hubs with a spoke hole circle of 38 mm or 40 mm. I can't tell for certain what the spoke hole circle is on the stock hub. Does a difference of 2 mm matter?


I used XT M-750 The flange is pretty small, not sure on the hole circle and couldn't tell you if 2mm matters or not? I didn't use the stock spokes because my local wheel builder will not build with used spokes so I just cut new ones, laced them up 3x and he did the rest. They turned out pretty stout and much lighter thatn stock. Not super light by anymeans but I wanted them to last through two kids Sorry I don't have more wheel build knowledge for ya.


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## jacobhartsoch (Dec 17, 2010)

*Specialized Hotrock*

Just a note to say how much I appreciate the thread. I checked out the Marin but went with the new Specialized HotRock, which has a pretty sensible spec. The shock actually works pretty well, the levers have reach adjustment, it's got reasonably light tires and good geometry. The biggest drawback in the range on the 6 sp freewheel. It's already set up single front ring with a chain guard, so a new rear wheel build and shifter should do the trick for making this a very useable kids bike. It was 24 lbs new, but if you're interested in losing some weight the bars are steel (570 grams) and the seat post are good places to start. Rear spacing is 135mm.


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## m-dub (Apr 22, 2005)

*Little update.*

The little hidden Canyon has been taking a beating and was getting a loud clunk on compression (only during larger hits like in the photo) I took the fork apart and added more bottom out bumpers. they are in the middle of the coil spring. Just picked up some rubber grommet like bushing from Ace and popped in another 1/2" worth. Problem solved. I have been surprised with that little fork, it has been getting a solid 1 3/4 of travel out of it and being coil sprung, its works pretty well. I need to come up with a new chain guide idea also. He has been dropping the chain a bunch. I may try to mod an old MRP.

We bought him a BMX for thrashing on with the neighborhood kids but it just sits in the corner because hes all about his mini MTB and says the BMX hurts his hands on landings  I have no regrets on the money spent, I would rather him use the crap out of it, than it just sit looking pretty.


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## Broccoli (Jun 11, 2008)

I was not sure about suspension forks, so build up Giant XtC 20 for my daughter. Red colored one, so it would work for my son as well.

Raceface stem, cut down Easton carbon bar, Sinz 140mm cranks and ti BB, some light 34t front chainring with BBG bashguard and Token bolts, shortened Ritchey seatpost, lighter tubes and folding Kenda 8-block, road derailleur, light platform pedals, got the weight down to around 20lb. 

I have parts to convert it to 9speed, needed Dahon rear wheel, but she rides the current build quite well, so I never got to it. Next size. I am thinking if I can skip and go to the smallest 26" frame - was looking at those XXS Yeti AS-R on sale, but could not justify buying one so far in advance. I will find something.


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## will1596 (Mar 5, 2011)

Very interesting thread. Researching the options for my son. Seems like Ibex is still in business contrary to the first post.


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## Broccoli (Jun 11, 2008)

will1596 said:


> Very interesting thread. Researching the options for my son. Seems like Ibex is still in business contrary to the first post.


In the name only. New owners.


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## TwoTone (Jul 5, 2011)

I wish I had seen this tread along with http://forums.mtbr.com/showthread.php?t=719481 a year ago.

Many of the parts used to upgrade the 20 inch, could be reused in the build a 26 XS with 24 inch wheels as in the linked thread. That would help justify the cost. You could even get disk hubs for the 20 inch to be reused in the 24 inch wheel etc...

As it is now, my son will probably need a 24 after this season, so I'm on the wait and see.


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## t135 (Jul 11, 2011)

Cool story


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## NYrr496 (Sep 10, 2008)

I test fitted my son on a 24" wheel Hotrock last week and it fits perfectly. I'm gonna try and pass on the 24" wheels and find a 13.5" or 14" 26er frame. I think if I can get the rest of this year out of the 20" bke, He'll fit a real small 26" bike next spring.


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## m-dub (Apr 22, 2005)

NYrr496 said:


> I test fitted my son on a 24" wheel Hotrock last week and it fits perfectly. I'm gonna try and pass on the 24" wheels and find a 13.5" or 14" 26er frame. I think if I can get the rest of this year out of the 20" bke, He'll fit a real small 26" bike next spring.


 I thought about doing the same but the shorter stays on the hotrock over the xs 26er is very noticeable when lifting the front end for the little guy. He rode a 24" wheeled XS 26 and it was tough to get the front wheel up but had no issues on a friends Hula ( kona.) we ride with a lot of curb size up and overs and small drops so every bit helps.


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## TwoTone (Jul 5, 2011)

m-dub said:


> I thought about doing the same but the shorter stays on the hotrock over the xs 26er is very noticeable when lifting the front end for the little guy. He rode a 24" wheeled XS 26 and it was tough to get the front wheel up but had no issues on a friends Hula ( kona.) we ride with a lot of curb size up and overs and small drops so every bit helps.


So did you get him on a 26 XS at first then move him to a 24? I ask because this is exactly the feed back I need. I wish I had found this forum before spending all the time trying to get a FD working well for him.

I'm think 26xs, but I want him to learn to ride properly. I want him to be able to lift the rront wheel to get over objects etc...

Does anyone know of a 24 inch frame sold separately?


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## m-dub (Apr 22, 2005)

TwoTone said:


> So did you get him on a 26 XS at first then move him to a 24? I ask because this is exactly the feed back I need. I wish I had found this forum before spending all the time trying to get a FD working well for him.
> 
> I'm think 26xs, but I want him to learn to ride properly. I want him to be able to lift the rront wheel to get over objects etc...
> 
> Does anyone know of a 24 inch frame sold separately?


I have a friend who has build a xs 26 with 24" wheels for their daughter and he has put a ride or two on it. It depends on your child and their riding. My son rides "a lot" we live feet from a trail head) and not to sound like one of those dads but....he rides above his years, so for him I want something that works and works well. He also has a little brother not far behind to grow into it. If your child isn't really into it I would think giving yourself some growing room would be good idea and the XS 26 would be sweet. I haven't bought anything yet. Im looking for a used one because I'm only going to use the frame. I haven't seen 24 frames sold alone but you can get a complete for around $300, a lot cheaper than most xs 26er frames, and you have a few parts you can use.


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## TwoTone (Jul 5, 2011)

m-dub said:


> I have a friend who has build a xs 26 with 24" wheels for their daughter and he has put a ride or two on it. It depends on your child and their riding. My son rides "a lot" we live feet from a trail head) and not to sound like one of those dads but....he rides above his years, so for him I want something that works and works well. He also has a little brother not far behind to grow into it. If your child isn't really into it I would think giving yourself some growing room would be good idea and the XS 26 would be sweet. I haven't bought anything yet. Im looking for a used one because I'm only going to use the frame. I haven't seen 24 frames sold alone but you can get a complete for around $300, a lot cheaper than most xs 26er frames, and you have a few parts you can use.


See I'm going back and forth on what I want to do, but have all winter. After reading your comment I did some research. I just used Specialized to keep the brand the same.

The chainstay is only 16mm longer on the 13 Rockhopper than the kids 24 inch Hardrock.

I may just look for a used higher end 24 like Specialized or Marin, and build the rest.


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## NYrr496 (Sep 10, 2008)

I recently missed out on a 13.5" frame GF 26er on Ebay. Sette has a nice 14" frame. I showed it to my son and he likes the flat black. He said he wants all blue ano parts on the build.


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## m-dub (Apr 22, 2005)

TwoTone said:


> See I'm going back and forth on what I want to do, but have all winter. After reading your comment I did some research. I just used Specialized to keep the brand the same.
> 
> The chainstay is only 16mm longer on the 13 Rockhopper than the kids 24 inch Hardrock.
> 
> I may just look for a used higher end 24 like Specialized or Marin, and build the rest.


I like the hotrock for the low bb. I measured one out and if I run a 80mm 26" fork the head angle goes 67 and the bb is still lower than most 24" The plus of running a real fork appeals to me. Most 24" forks are heavy and really low end. I find used 26 forks all day on fley bay that would be way more functal and lighter.


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## pitbullandmtb (Jul 31, 2011)

Great action shot...Tried to get my kid doing that but dropped the camera when he dropped on his helmet...Not my proudest moment...But if he pulled it off, would have been awesome!!


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## dbutler (Aug 2, 2011)

Thanks to everyone who's contributed to this thread! Lot's of great info. My son is 7 and ready to move up from his 16"er. He's not accustomed to the trails yet but I plan on getting him out there this Fall. I just picked up a new 2011 Raleigh Rowdy with rigid fork for $220, and thought I would share some details.

Weighed on the shop's Park scale, 23lbs stock, not a bad start!

Has a steel one piece crankset with 40t front ring. It will stay that way for the forseeable future.

Steel pillar seatpost/clamp weighs an astounding 420gms! Should be able to drop at least 200 gms here.

Stock seat is at 333gms. Odyssey Junior seat replacement would drop another 145gms. How much padding does this seat have…will it be too hard?

Comes with Kenda Kwick 2.0 tires and Kenda standard BMX tubes. Can probably lose another 200gms on 2 ultralite tubes. Nice light hardpack style tires though.

Not sure about the weight of the bars and stem but they "look" heavy…will get to those later.

There is no immediate need, and it may never happen…but can someone tell me what is required for the rear wheel/hub to convert to a lower gear freewheel/cassette such as the 9spd setups seen here? I realize I am looking at all new drivetrain components to do this and any specific part recomendations are appreciated. I'd also like to hear from anyone who's converted one piece crankset.


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## m-dub (Apr 22, 2005)

The rear hub has to be replaces with a 8/9/10 speed compatible cassette style plus a shifter, chain and most likely derailleur.

The parts you mentioned sound like smart choices. The seat is ok but my little guy says he feels it after a long ( over 6 miles) ride.

I would ditch the steel cranks and 40tooth for something like a set of Sinz and a 32 tooth. You would loose a bunch of weigh and achieve much better gearing. 40 tooth is great on a BMX track but forget it on any trails (well just our experience, yours may vary  )

The one piece crank usually is mid style or "Big BMX" bottom bracket. Their are a few adapters to convert to euro ( standard mtb) style. Or you could go with a set of profile cranks that have the option to run any style bb but they will cost you as much as your bike.

Another option is to just replace the 40 tooth. DansComp.com has a house brand "poverty" that make a great priced alloy ring in any size. Poverty Econoline Chainwheel at Danscomp
I slapped a 28 tooth on a bike and it made it work really well with a 7 speed. Climbs much better and still plenty fast for little dudes.Plus, they actually have some clearance. That 40 tooth will smack everything you go over.

Fun hu?


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## boysan1968 (Feb 10, 2011)

sounds like you found a nice bike. You might want to pass on the Odyssey junior seat, my kids didn't like it and went back to the original seats. I have 2 in the parts bin, so let me know if you want one.

I agree with m-dub on the cranks, my kids never used the big ring. Their bikes had 34 and 42 tooth steel rings. I cut the big ring off, and replace it with a bash.


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## dbutler (Aug 2, 2011)

First let me say thanks again for the advice and second, I will confess my ignorance towards spec'ing out crank parts. I understand the removal/installation of the standard 1-piece crank and I've swapped out chainrings on my mtb. I just don't want to buy the wrong parts in this case.

Because the budget is tight, I love the idea of replacing the chainwheel on the 1-piece with a smaller one (28, 30 or 32) but i'm unclear on setting it up with a guard. The stock 40t is a double-sided guard/chainwheel....it looks like I will need to spec a guard and bolts for 110WCS? Any way to do it double sided?


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## NYrr496 (Sep 10, 2008)

dbutler said:


> First let me say thanks again for the advice and second, I will confess my ignorance towards spec'ing out crank parts. I understand the removal/installation of the standard 1-piece crank and I've swapped out chainrings on my mtb. I just don't want to buy the wrong parts in this case.
> 
> Because the budget is tight, I love the idea of replacing the chainwheel with a smaller one (28, 30 or 32) but i'm unclear on setting it up with a guard. The stock 40t is a double-sided guard/chainwheel....it looks like I will need to spec a guard and bolts for 110WCS? Any way to do it double sided?


I bought a Sinz crankset off Ebay and installed a 34 tooth chainring with a Spot guard on the outside. I put a crankstop or something on the inside to prevent the chain from coming off to the inside. It works pretty well. OR you could go with one of these...
The Widgit - Single Chainring for MTB and Road bikes


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## dbutler (Aug 2, 2011)

I've been looking all over for a small chainwheel and guard that I might be able to change out on the 1 piece cranks on the 20" bike I have for my son. M-dub...The Poverty Econoline chainwheel you linked to...are you saying that you have used one on a 1 piece crank? If so, would I still be able to install something like a BBG guard on it?

BBG comes in 32T 110 but Econoline chainwheel is 30t or 28t.

I'm not too concerned about saving weight on the cranks right now but I would like to give him a lower gear option for riding the hills in the neighborhood and eventually some trails. Replacing the existing chainwheel would be much more budget friendly right now and may suffice until he is ready for 24". However, if modifying the 1 piece seems like it's more trouble than it's worth then I suppose I would just wait and consider the conversion kit and new cranks down the road.

Thanks for all the help guys.


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## m-dub (Apr 22, 2005)

Yes, The Poverty chainwheel is made for one piece cranks and I have one on my sons bmx. As far as a bash ring goes.....you would have to do some DIY mods to make it work. Maybe get a 32 bbg and drill holes in the 30 chain wheel then just space it out ( washers or?) to clear the chain. Totally doable and budget. FYI: the smaller 28 and 30 chain rings don't have as many holes in them as the pictured 44.

You could always put some 155 sinz and then swap them over to the next 24" bike. My problem is I have a younger son also so I cant swap parts because little brother is next


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## dbutler (Aug 2, 2011)

Awesome, thanks for the reply...I think I will take a shot at the poverty/bbg idea as soon as I can commit some time to it. I'm assuming I'll need to shorten or replace the chain also?


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## m-dub (Apr 22, 2005)

Ya, Put the chain and chain ring on, put the derailuer to the largest rear cog and you can see how much extra chain you have (you can pull the derailuer almost tight, give it a little slack) and cut. I love the sram quick links for the ease of chain removal but not sure if they make a 6 or 7 peed version. If you don't have a chain tool, I would have a local shop do it or purchase one.


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## dbutler (Aug 2, 2011)

I should be able to manage the shortening the chain, thanks for the advice. In looking a little further at this...do you think the "Redline Spider for One Piece Cranks 110 x 5mm" would be a good way to go? I think the smallest chainring available would be 34t but I think that would be fine until he's ready for a bigger bike and much better than the stock 40t. It would cost just a few dollars more but saves me the trouble of drilling the Poverty chainwheel for a guard.


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## m-dub (Apr 22, 2005)

I think it would work but........the smallest ring you can run is a 34 tooth ( 110 or 5 arm spiders) and then purchase a chain ring, spider and bolts. Are you using the bash for "bashing" or for chain retention? You could run one of these: Paul Components Chain Keeper at JensonUSA.com or just go without. Simply drilling 4 holes is going to be your cheapest option, really not to hard. Just set in on top and mark some holes.


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## dbutler (Aug 2, 2011)

Really just want the bash to keep his pants off of the chain and to help keep the chain on. He spends quite a bit of time tooling around on the street with friends so I'm a little concerned with taking it down from 40t to 30t before we really get into some trail riding. The Poverty chainwheel only comes in 30t or 36t, I thought 34t might be a good compromise. Any thoughts on the Animal Lite v2 chainwheel? OPC compatible? Comes in 31t, 32t, 33t and also available at DansComp and other sources.

Always appreciate your insight, thanks.


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## alex_sdca (Apr 6, 2009)

dbutler said:


> Really just want the bash to keep his pants off of the chain and to help keep the chain on.


superlights

I don't have any experience with this but it looks like it is what you want and the price and weight are both low. At that weight it is probably not much of a "bash".


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## m-dub (Apr 22, 2005)

My son is running the poverty 28 front and 16tooth rear on his bmx that only sees street thrashing and its fine. 40tooth is even big for BMX track use. I dont have any experience with the animal stuff. The only neg to the superlight bash is its so thin its almost sharp but a lot less than a chainring


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## TwoTone (Jul 5, 2011)

When I was searching ebay for some parts I saw these. Not sure if they're any good, but thought I'd post them since I know some of us are looking for chain guides
DOWNHILL,MTB FREERIDE BIKE CHAIN GUIDE,TENSIONER | eBay


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## dbutler (Aug 2, 2011)

I have to ask where you got the 20" kevlar Small block 8's...? Only ones I can find online are wire bead. Kenda tells me I should have a shop order them. Thanks, D


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## boysan1968 (Feb 10, 2011)

I ran into the same issue and Kenda was kind enough to ship the tires directly to me. They did tell me to inform my LBS that even if the tires don't appear in the distributors list of Kenda products that they can still order them, just use the Kenda part number. Good luck.


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## dbutler (Aug 2, 2011)

Thanks, and what kind of pricing did you get? There is a Performance near me and they carry the 26". I guess I'll check with them.


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## alex_sdca (Apr 6, 2009)

If you search for small block eight 20 folding and hit the shopping link in google a place back east pops up. Price per tire looks good but they charge a lot for shipping. I have not ordered so I cannot attest to their service. Looks like 2 tires with shipping to CA is 95 bucks.


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## boysan1968 (Feb 10, 2011)

I think that I paid about $35 each, without the shipping fee. 
The Kenda website no longer has the wire bead version in 20" 1.95 or 2.1. Maybe the folding bead will be easier to find once shops sell through the existing stock of wire bead models?


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## dbutler (Aug 2, 2011)

Magic google terms combo...I didn't go straight to the Google/Shopping tab but went down through a few links and found a price of 2 for $65 shipped (to Atlanta) at bicyclespleasanton.com. $25/tire plus $15 shipping. I had searched all over with lots of other term combinations but never found this place!


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## bme107 (Jul 23, 2008)

Amazon has the wire bead version for $18+6.95.

I ordered 2, needed the express shipping and paid about $55 back in august.


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## skylinedrive (Apr 25, 2012)

awesome ideas from this thread


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## sledz (Jun 27, 2012)

*New Owner of the Marin Tangerine Speedo !*

I'm a newbie to the forum, and noticed I'm the new owner...after 3-4 weeks of looking for a new bike, getting upset about the cheap components, and having a low parts bin at home. I stumbled across the used this bike 2 weeks ago and picked it up !! has some wear but mechanically sound... I need a bottom bracket but cant detrmine the size? 103 or 108mm and idea? so i can order alonlong with a BB extractor!


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## IAmHolland (Jul 8, 2010)

sledz said:


> I need a bottom bracket but cant detrmine the size? 103 or 108mm and idea? so i can order alonlong with a BB extractor!


It's in the thread. You can also determine the size by measuring the spindle.



quasi888 said:


> Demo9, I used a 113mm spindle length for the BB -- fairly middle-of-the-road. As you probably know, the type of cranks you use generally dictate the spindle length. The Crupi cranks don't flare out very much (low Q-factor), but the *113mm spindle* was enough to allow several millimeters of clearance between crankarms and chainstay.





quasi888 said:


> Standard 68mm shell. Stock (garbage!!!) BB had a 115 mm spindle as I recall; the Sinz unit I replaced it with had a 113mm spindle -- close enough.





m-dub said:


> I used the Sinz 113 as well.


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## sledz (Jun 27, 2012)

*spindle size*

thx....reminds me need a crank puller as well... well my kids are young so time to invest in a bicycle tool kit now as well... I can see mods going on for the next 6 years.. thx for the help! better answers here than my LBS... they have no interest answering tech questions especoilly with no skills bike building quest!!


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## sledz (Jun 27, 2012)

I believe quasi888 built the Orange Marin I currently own, this thread seemed to circler back to Quasi... Bike seems to match up with the Sinz Ti BB and Tiagra shimano hubs takled abot... seems I'll give him a poke in the future !! I maybe taking the front Spinner shock apart...


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## wycough (Mar 9, 2008)

gonna be a 113 or 118.


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## Grubster (Jul 22, 2012)

Another option for crankset for a lightweight 20" mountain bike build is the profile mini cranks. My boys have had good success with 135mm version. Besides being as light as you want to pay for(they have one that is aluminum w/ ti bb and hardware) the coolest feature is the low gearing you can get. I have found that a 1x9 setup with a 26t or 28t works best. You can go lower if you want. It allows for a truelly low climbing gear so the little guys or girls can spin there way over anything. The gearing of the 20" wheeled mountain bike offerings is too high imo. Of course, I live in the mountains and have lots of climbing to do.


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## IAmHolland (Jul 8, 2010)

Grubster said:


> I have found that a 1x9 setup with a 26t or 28t works best. You can go lower if you want. It allows for a truelly low climbing gear so the little guys or girls can spin there way over anything. The gearing of the 20" wheeled mountain bike offerings is too high imo. Of course, I live in the mountains and have lots of climbing to do.


I agree with this. I have my daughter on a 28T running 1x9 with a 12-36T cassette. It helps. I'm using shortened cranks, I don't care much for the Q-factor and may look at the profile cranks. It's expensive though, $260 for the cranks and BB and another $60 or so for a sprocket @ J&R. 

Do you have the weight of your crank set, by chance?


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## Grubster (Jul 22, 2012)

No, I didn't actually weigh it before I installed it. They seemed pretty light. I have the tubular steel ones with a Ti BB. I even installed one on my older son's xxs Lynskey Pro26. Total bike weight on the Lynskey is 17.5 pounds. I was more conscerned about getting competitive weight with the "right" gear and crank length. They are pricey but sometimes you can find one on ebay. The only negative about the profiles to me is that they are a bit of a pain to get the spacers just right and removing them is not really fun either, but other than that I have been very happy.


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## Vxc961 (Apr 20, 2013)

*Disc brakes...still heavier than I'd like though!*

This thread inspired me! I just picked up this Hidden Canyon on craigslist. It came with click-shifters, upgraded hubs w/quick release, quick-release seat post, and mechanical disc brakes too! I'm planning more customization, but haven't figured out exactly what. Momma-bear is going to kill me for spending $300 on the bike, but I'm more excited than my son (he's sick today). Looking forward to hitting the trails with him!


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## Rondo (Oct 14, 2011)

I've never seen that disc conversion bracket before. Any ideas what it is or where to get one?


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## TwoTone (Jul 5, 2011)

Rondo said:


> I've never seen that disc conversion bracket before. Any ideas what it is or where to get one?


I'm going to hazard a guess he got extremely lucky and bought from a parent that works/owns a machine shop


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## Vxc961 (Apr 20, 2013)

Amazingly, the front shock had the tabs for the brakes, the rear part of the frame had two tabs (I think maybe for a luggage rack?). The previous owner (who took those pictures btw) had that aluminum machined, but I believe he designed it. Bruce, you did a great job, and thanks again for letting us have a turn with it!

I'm looking forward to softening/increasing travel on the fork, I may cut down the handlebars a few inches, I'd like to change the seat/post, and I'm thinking of painting the bike. Or, maybe just painting the fork so it doesn't match the frame. 

Once I find the time to dig into the bike, if anybody cares, I'll try to get the measurements of the rear disc brake adapter and post them. Thanks again to the forum members--we're really exciting about getting my middle son out there, and it's even worth hearing my youngest scream about how mad he is that he can't go yet!


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## Rondo (Oct 14, 2011)

Thanks for chiming in there TwoTone. I was hoping you , LP, or Holland would have some advice as I think you three know these threads better than anyone. I want to do the same for my kids bike and unbelievably I actually work for a metal fabricator but unfortunately we only deal with steel, (galv, hot roll, stainless, etc.) as in building construction, so I don’t think I can get anything to fit the bill. 

I am surprised with for how long hydro brakes have been out that no one makes these things with a shim kit for sale to market? Quite depressing. Someone should really be marketing these mounts. 
Thanks to the OP for posting up the cool bike, pics, and info!


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## TwoTone (Jul 5, 2011)

Rondo said:


> Thanks for chiming in there TwoTone. I was hoping you , LP, or Holland would have some advice as I think you three know these threads better than anyone. I want to do the same for my kids bike and unbelievably I actually work for a metal fabricator but unfortunately we only deal with steel, (galv, hot roll, stainless, etc.) as in building construction, so I don't think I can get anything to fit the bill.
> 
> I am surprised with for how long hydro brakes have been out that no one makes these things with a shim kit for sale to market? Quite depressing. Someone should really be marketing these mounts.
> Thanks to the OP for posting up the cool bike, pics, and info!


It's more about the frame fitting a rotor. I bought the ING Marin 24 inch for my son while making a bad assumptions. When I got the bike I had an adapter ready, but even a 140mm Rotor wouldn't clear the chain stays.

I'm amazed it worked on a 20 inch version.


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## dirtdawg21892 (Jul 20, 2009)

wish i had a bike like this when i was that age...


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## quasi888 (Mar 13, 2009)

I don't visit MTBR very often (more of a roadie nowadays) but I'm glad to see this thread I created nearly 4 years ago is still inspiring folks to build some killer bikes for the li'l ones. Stay tuned for a review (and the inevitable weight-loss project) of my son's current bike, a KHS Alite 24.


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