# Need help with 24" Hotrock



## Slow poke (Jul 23, 2013)

Well I just picked up this 24" hot rock, looks like a 2009 model for $70 off craigslist. My son is currently riding a 20" hot rock coaster. I wish I had gotten that one with gears because he rides his sister's more because of the gears. :madman: Well, we are starting to hit trails and definitely want to build something decent for him. I got the idea to build instead of buy from you guys and your excellent write ups. But my dilemma is I don't know where to start or how to do it myself so I might take the parts in to get them installed if I can't do it on my own. As you can see in the pictures it has rust on the gearing area and the fork area. The seat is torn as well. I would like to change out as much as possible without breaking the bank because his next bike is where I would like to spend a bunch. 

So please help me decide what parts to get and where to get them. The best bang for the buck. I don't mind spending top dollar on the fork since it seems normal to spend the money here. I would like him to have mechanical disc brakes, since I'm guessing the hydraulic ones will cost a lot more. I definitely need to change the gearing system as you can see the rust. I would also like to change out the wheels and handle bar. I think some of the wheel sets you guys have been putting on your bikes really stand out. Please keep in mind best bang for the buck unless you note that I should just buy it. Thanks again for your time.


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## watts888 (Oct 2, 2012)

So many things. If that seat is the right height for him, that bike is just too big for him right now. If it's just lowered for transportation, and the 24" is appropriately sized, I'd do the following.

IMO, I'd ride the drivetrain as is. Just clean it up with some lube and ride it. Rust isn't necessary a horrible thing on the chain and freewheel, as long as they're not sharktoothed and stretched. If needed, grab a new 8-speed chain and Shimano freewheel for about $20 total. Set of new derailure cables/housing. Clean up the rear derailure and redo the drivetrain. 

Rip any of that plastic stuff off the crankset. It doesn't look that bad, except the plastic stuff. If the chain rings are bolted on instead of riveted, I'd consider removing the front derailure and big ring. The small ring and middle ring should be plenty, and shift the chain by hand if it's really necessary for a long climb.

New lightweight tires and tubes. A new 24" wheelset would be nice, but not really necessary if the rims are aluminum. Especially if they're single wall aluminum. Should be light enough.

Discs are nice, but kinda overrated for a kid. As long as you're not riding in the rain, a good set of new rim brake pads will do wonders. Might want to invest in an alloy set of brake levers if the stock brake levers are plastic and flexy. New brake cables and housing too.

Fork. For now, I'd tear it apart and re-grease it and assemble it properly. The seals have popped off and the fork is probably flexy as all hell because of it. It's heavy, but it works well when operating smoothly. If weight is a real concern, alloy rigid fork or there are some acceptably lightweight 24" forks. RST spinner I think. If you wanted to go all in, relace the front wheel with a disc hub and get a used rockshox sid 26" fork and adjust the travel down to 80mm.


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## Slow poke (Jul 23, 2013)

Thanks for the reply. Disc brakes are not a must and can go either way. I wouldn't know how to tear the forks apart so I would have to take it into the bike shop to get it done. I really like how that 1x10 set up looks. I can probably raise the seat an inch but your right it is a lil big for him right now. But he still has his 20" and I want this to be ready for when he is ready which should be soon. He turned 9 last month.


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## Erock503 (Oct 20, 2014)

I bought a 24" hotrock for my son. Easiest things to swap first are handbars, stem, and seatpost. They are steel and swapping to Al or carbon saves a lot of weight. If you aren't changing wheels, you'll probably want to keep the drivetrain and just lube it up if it's not roached. Looks like someone already upgraded the freewheel with a mega range. This is a good opportunity to learn about bike maintenance with the cables/housings, drivetrain, forks, etc. It's pretty easy to do, and you'll save a lot compared to taking it to the LBS.

If you are thinking to going 1x, I would keep the 7 speed and upgrade the crankset. Than just remove the fd. Spawn makes a great single chainring 32t 127mm crank arm, and trailcraft makes an awesome 30t 155mm crank length single chainring crankset. The trailcraft is pricey though.

I looked at forks for a whille, and like mentioned, there is the 24" rst first air, and spinner grind air as the top contenders. I got the rst, and it saved almost a pound and a half over the stock fork. Modding a 26" is also an option.

Tires is another place to save some weight and add some volume. I got the Schwalbe racing Ralph, and they work great in the 24". You can do a lot with those frames, I got my sons down to 22lbs with a lot of upgrades, ie. Wheels, tires, cockpit, 10x drivetrain, disc, etc... It can get spendy though, and lBS labor would have made it way too cost prohibitive for me. The bike works great now though, and my 9yr old is progressing rapidly on the trails.


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## Slow poke (Jul 23, 2013)

Erock that is a great looking pic. Your sons bike looks sharp. I think I am definitely buying the rst air fork 24". Just seems easy to install and I can just upgrade the v brakes as they look old and rusty. I looked at the tail craft crank shaft. Is that what you have? It costs 130$. Would that be all I have to buy or is there more? I really like the look of the single.


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## Slow poke (Jul 23, 2013)

Also where can I find the best deals on the stem, bars and seat post for our particular model? Thanks erock.


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## Slow poke (Jul 23, 2013)

Those wheels are sweet. Saw them on the trail craft websight. If I buy their crank set it says compatible with 9/10 speed. Will I still be able to use the 7 speed shifters?


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## Erock503 (Oct 20, 2014)

Thanks man, yes I'm using the trailcraft crankset with a 10 speed cassette, and zee shifter/derailluer. The bike takes pretty standard size parts, 1 1/8 straight steerer fork, square tapered bb, 27.2 seatpost. As for the crankset, if it works with 7 speed, you would just need a new chain fit to the right length. I would email trailcraft and ask their opinion on it working correctly with a 7 speed freewheel first though. Also, if the bottom bracket is shot, IIRC I used a shimano 68/ 113 spindle sealed cartridge. Didn't save much weight, but it's sealed bearings instead of the open style. 

i built my wheels using the Stans crest rims and cheap hubs, but IIRC trailcraft offers built ones. They also have their own rims/wheels which look pretty sweet. For deals, I had the winter to scour eBay for deals, so I had some time. You're gonna need to shop around, but the parts are pretty standard, so you should be able to find deals.

watts888 has good advice in his post. You may be able to just convert that to a single ring if you can find the right bcd chainring, then put a chain guard where the big ring is. That or just leave it like watts said. That would save some loot. You might be able to leave just the front derailluer itself as a chain guide too if you go single. There are a lot of threads on th conversion if you search the boards.

for tools, you will need a crank arm puller to remove cranks, but that's cheap. A decent torque wrench with some metric Allen sockets is invaluable too. If you need to remove the bb, the socket is pretty cheap also. They are good tools to have anyway if you ever have to work on your own bike.


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## bendermike (Oct 17, 2011)

I have enjoyed building up a hotrock for my son. I went with the Rst first air fork and Stans Crest wheels with Racing Ralph. I did have an old set of SRAM x9 1x drive train and Elixir brakes to out on as well.









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## NYrr496 (Sep 10, 2008)

I did a 24" Gary Fisher Tyro that I got on Craigslist for my son a few years ago when he needed a larger bike. I had stripped it to the bare frame and made it into a 1x10, disc brake hard tail. I used a 26" fork at the time since there were very few quality 24" forks. Built nice wheels for it and good quality tires. Really upped his game. 
None of what I did was really cheap but I knocked a ton of weight off the bike and he really enjoyed riding it. 
Sinz cranks are fairly inexpensive and lighter than what's on there now.


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## watts888 (Oct 2, 2012)

Slow poke said:


> I wouldn't know how to tear the forks apart so I would have to take it into the bike shop to get it done.


Quite simple actually. There should be a nut at the bottom of the fork by the axle. Remove the nuts, and the tops and lowers should slide apart. Clean off all the grease, use a high grit sandpaper to remove any rust, try to re-attach the seals to the lowers (should just press in), throw grease at it (automotive grease works fine), and put the uppers and lowers back together.


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## Slow poke (Jul 23, 2013)

Watts888 thanks. I've been looking at some videos so I now know what your talking about. I think I'm just going to buy the rst fork and then move onto the crank setup. The wheels I've been looking at seem to only come with disk brake option only so I'm going to see what is involved in switching to disc brakes. Will I have to drill into my frame to add disk brakes?


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## Erock503 (Oct 20, 2014)

They do make adapters, although I don't know if it's worth the trouble. Like watts said, v brakes are fine for kids bikes unless you're riding in the rain or through streams a lot. Like he also mentioned, the stock ones might not be too bad depending on construction.

I built a set of 20" wheels for my youngest using velocity aeroheat rims with the machined sidewalls. They work great. I contemplated using them for the 24" build too, but had some extra hydros I wasn't using.

Velocity Wheels - Hand Made in USA










Edit: I remember looking at these a long time ago, no experience with them. DM UNI or something

www.a2zcomponents.com


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## Slow poke (Jul 23, 2013)

Sinz cranks are fairly inexpensive and lighter than what's on there now.[/QUOTE]

I'm looking at sing cranks and they are 60$ without the ring. The tailcraft crank set comes with ring for $130.


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## Slow poke (Jul 23, 2013)

Erock503 said:


> They do make adapters, although I don't know if it's worth the trouble. Like watts said, v brakes are fine for kids bikes unless you're riding in the rain or through streams a lot. Like he also mentioned, the stock ones might not be too bad depending on construction.
> 
> I built a set of 20" wheels for my youngest using velocity aeroheat rims with the machined sidewalls. They work great. I contemplated using them for the 24" build too, but had some extra hydros I wasn't using.
> 
> Velocity Wheels - Hand Made in USA


Those look nice. Thanks. I might stay with the v brakes after all. Just have to get a nice set of wheels to accommodate them.


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## NYrr496 (Sep 10, 2008)

Yep. My son's 20" GF Precaliber had Aeroheats and XT Vee brakes. 
His 24" bike had Sun Ringle' Rhynolites with black sidewalls since that was a disc brake bike. 
I wish Velocity would make the Cliffhangers in 24".


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## Slow poke (Jul 23, 2013)

Maybe I'm looking for the wrong wheels. I can't seem to find a wheel set to use with my current brakes. I'm not changing to disc. Can someone point me in the right direction for the best bang for the buck wheels. The ones I look at all say that they are for disc only. Also, does anyone know where they have the best price for the rst airfork. Probably going to order that this week. Thanks for your help.


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## Steve-XtC (Feb 7, 2016)

Swapping components is mostly pretty simple.

Finding the right components that work/fit together is more of a challenge. 
Bottom brackets and headsets are a nightmare as there are so many combo's but your BB should be square taper... (not the lightest but rugged and simple and lots of options)

We got the RST F1rst Air forks and they are pretty darned good. I say that from a perspective of expecting they would be OK ... but they actually REALLY work and way exceed my expectations.

Don't worry about shifters, mechs etc. .... they are both cheap to buy new and cheaper used .. and even unused if you get 9 or 10 speed where people have bought a new bike and then upgraded to a 1x11. The real bonus is you can use them on the next bike as well and sticking with the low end stuff you'll end up replacing often anyway... In my experience a good SLX or XT outlasts several Tourney's... whilst being way nicer to use. In my experience (again) a kid getting a stick stuck in the rear mech will wreck a Tourney but snap in the XT.... (Again with kids power and weight they become nearly indestructible) (Orr you could use a Zee etc.

You really have 1 main choice (excluding forks) ... what you decide will dictate the rest. 
Basically: Wheels & Brakes (disc or not)

You can buy an adaptor for the rear disk.... I'd not recommend this for an adult downhill bike but on a kids bike I'd not see a problem. The difference between an adult weighing 220lbs and a 60lb kid as wells as a 203mm vs 140mm or 160mm rotor is huge! Also buy the right forks and they will come with disc mounts....

There is a lot of debate of if kids need or can use disc brakes .... well my 6yr old uses hydraulic no problem. Does he "need" them ? I'd say he wouldn't ride half what he does with rim brakes....

So you need a different rear hub for a cassette and your fork will if you chose come with disc mounts.

I tried some cheaper wheels with disc hubs.... as an interim to change to disc whilst trying to find some used on eBay.... to be honest I mightest well have been searching for a mint set of hens teeth.

*In the end *I bought some Stans Crest and some Novatec D711/712 hubs and this coincided with a sale of spokes so I ended up getting CX-Ray spokes at GB£1 each instead of the normal GB£3 each.

In the end the wheels aren't transferable to the next bike so you gotta choose and if your going to spend money do it early and get the use out of them!

I got some cheap carbon bars of eBay and a very cheap but light stem .... pedals of ebay are superlight but not that cheap....

Crank wise I bought a set of new SRAM S600's and cut the ends off and redrilled/taped at 140mm ... I'd thought this would be a lot harder than it was. Beauty is its standard 104 BCD which means a huge choice of chainrings and we ended up with a NarrowWide Oval 34T with a 36T XT casette with a 40T expander stuck on and the smallest cog taken off. (Instead of replacing the 15T and 17T with a 16T) ... it goes fast enough....


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## Slow poke (Jul 23, 2013)

Steve-XtC said:


> Swapping components is mostly pretty simple.
> 
> Finding the right components that work/fit together is more of a challenge.
> 
> I am probably going to get some velocity wheels since I found a good price on them. They are disk compatible but Gonna stay with the vbrakes. Found a stock set that is like new that I will put on a new carbon bar. Also going 1x10. Gonna get the tailcraft crank set. Oh I have to replace the seat since its torn. I think these upgrades should be enough to give it a good look and a hell of a bike that he will have fun with. I'll post pics afterwards. Thanks for your help.


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## Steve-XtC (Feb 7, 2016)

Keeping disc/v brake options on wheels is a good idea. Those velocity rims are probably bombproof but they are quite heavy (485g compared to the 310g Stans) That's a fair difference x2. (It's Worth thinking about as its pure rotating mass but *even if* you just counted it as 350g you wanted to save elsewhere how much would it cost)

From the saddle height in the first pic I'd question if the 152mm trailcraft cranks are the correct length. (also based on it being $170 - it's not something you want to buy and not be correct)

It's worth a check:
Crank Length Calculation - Highpath Engineering Ltd

US Shortening .. Crank Arm Shortening

Quite honestly though I found this very easy to do myself. I'd thought it would be a really difficult task and half expected to mess it up but it was actually really simple and easy. (I have a good battery powered drill and a vice in my garage but otherwise it just meant buying the 13mm drill and then the taps) I drilled 5mm, 10mm and then 13mm as being in the UK my drill bits are mostly metric ... I just used bike grease when tapping....the only "hard bit" was actually drilling slowly enough ...

I repeated this with some used Alivio cranks (something like $10 off ebay) and the whole thing took me 30 minutes start to finish once I'd done it once.

All I can say is it makes such a HUGE difference that you wonder why we all don't do it (adult bikes as well).... one of the other members here also said something similar.

With the correct length cranks you also find the saddle can go higher.

Whilst your at the cranks I'm pretty impressed with the narrow wide oval chain-rings.. bought on for the kid then ended up buying myself one. The kids was an impulse buy ... there was a 50% sale.... but I was so impressed I paid full whack for mine. I'd certainly buy oval in future so if you are buying one it's well worth considering.

Most noticeably it smooths out climbing over rough rocks/roots. Whereas before he would get rear wheel slips and then lose momentum now he never seems to.

I got carbon bars off ebay for $15.... I was sceptical but they have turned out to be strong. The stem I got a Wake (<$5 delivered) ... and again certainly strong enough for kid weights and very light.

*Links are just examples of the models... if you take some time you'll find much cheaper*

WAKE CNC ANODISED MTB STEM 31.8MM 50MM RED GOLD BLUE GREEN BLACK DH XC

These pedals are so light I spent a day just picking them up.....
The alloy platforms are a bit soft.... (Not Saint strength) and they are good for a UK shoe size up to perhaps a 1-2 (US 2-3 I think) I also took out the pins and filed them down to half height and more rounded to preserve skin on his shins!

New AEST Titanium Spindle TI Axle CNC Road Bike MTB BMX Flat Platform Pedals Red | eBay

Seatpost I ended up with a Titanium one used off eBay (when people have cut them they go cheap). The saddle ended up being really cheap ($15 or so) BMX race saddle with Kevlar sides and its yet to rip despite serious abuse.... and pretty light... bought from a UK based BMW shop...

*Brakes .... really preference and local riding conditions.*
We ride through a lot of mud and it rains a lot here.(even if you don't ride in the rain the trails are still wet).. if nothing else the mud was really annoying on v-brakes as soon as rims were even slightly out of true .. once you adjust for small hands you end up with little slack.... but they have worked out really well and the stopping power gives him confidence. He has XT front and SLX rear ... as far as I know* the calipers are functionally identical*.... the only difference is colour and the SLX come with a split pin for the pads BUT it actually has the thread for the bolt for the XT.... For the levers the XT is better and importantly (for smaller hands) more adjustable than SLX.

Either way *its well worth thinking about now* as in our case the shifter and brakes are both i-spec B so its much cleaner on the bars. (So if you think you might change to discs later worth considering)

I went with 160mm rotors simply because it meant no adaptors... I'm sure a 140 would be more than enough but the 160's are "cleaner mounted" and easier to get rotors etc. Finally the brakes are all identical to mine so same bleed kit, oil, pads etc.

In other words I carry a set of spare pads, keep a single bleed kit in the trunk etc. and the mineral oil is safe for kids... (I wouldn't want him to drink a bottle but way safer than DOT fluid)
If you do go disc .....
ROTORS .... choose carefully poking fingers inside the disc whilst wheel is spinning = lost finger (not much you can do about that except talk to them but the cassette would be the same) but I have ones with smooth outsides and sand off any burrs with some emery as its more way likely they might grab it than try and poke a finger in.... (think the number of times you might almost grab a spinning wheel)

He has the alligator aries rotor on the front....and its pretty good and light and strong enough for his weight and then some.


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## Erock503 (Oct 20, 2014)

Steve makes some good points. Those velocity 24" are actually 455g, but it's still a significant difference over the stans. The crank arm length is a consideration too. I like the idea of shortening an adult set, but there is also the option of the 127mm spawn crankset for $60 if he's the right height. I used that for my youngest son's 20". 

The only issue I see with the disc conversion is the rear frame tabs. I did link that a2z adaptor up a few posts, but no experience actually using or fitting it.

I used the wake stem too, just like the one Steve linked. Be careful with the other wake style, that has a straight face instead of angled. I have 2 of them that must have been formed slightly off, as one corner will dig into carbon bars no matter how carefully you evenly tighten the clamp.


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## Slow poke (Jul 23, 2013)

My son is 49" tall. Yeah I know- short for age 9. I measured ground to crotch and its roughly 21 1/2". So what crank is recommended. He will get plenty of use of the bike since he is just growing into it.


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## Slow poke (Jul 23, 2013)

Erock503 said:


> Steve makes some good points. Those velocity 24" are actually 455g, but it's still a significant difference over the stans. The crank arm length is a consideration too. I like the idea of shortening an adult set, but there is also the option of the 127mm spawn crankset for $60 if he's the right height. I used that for my youngest son's 20".
> 
> The only issue I see with the disc conversion is the rear frame tabs. I did link that a2z adaptor up a few posts, but no experience actually using or fitting it.
> 
> I used the wake stem too, just like the one Steve linked. Be careful with the other wake style, that has a straight face instead of angled. I have 2 of them that must have been formed slightly off, as one corner will dig into carbon bars no matter how carefully you evenly tighten the clamp.


Is this the right one?
Wake Cycling Bicycle MTB Bike Aluminium Alloy Handlebar Stem 31 8mm Black CS316 | eBay


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## Steve-XtC (Feb 7, 2016)

Yes .. The other is straight not angled up


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## Steve-XtC (Feb 7, 2016)

Slow poke said:


> My son is 49" tall. Yeah I know- short for age 9. I measured ground to crotch and its roughly 21 1/2". So what crank is recommended. He will get plenty of use of the bike since he is just growing into it.


Take a look at the link I posted.

You can do it crudely on height but the 'outside leg' measurement method in the link is better and to be honest better to do it right ...I'm 5'10 but short legs so I end up being 165-170 rather than 175 and when I jump on my other (commuting bike) with 175mm it feels uncomfortable and I get more issues with knees and hips.. Despite not doing half or even 1/4 the hard exercise I do on my MTB - just a ride into town...

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## LewisQC (Jul 3, 2013)

Slow poke said:


> My son is 49" tall. Yeah I know- short for age 9. I measured ground to crotch and its roughly 21 1/2". So what crank is recommended. He will get plenty of use of the bike since he is just growing into it.


I wouldn't go bigger than 130-135cm. I did swap crankset on two bike this summer (Trailcraft for my 56" daughter ans Sram S600 shortened for my 54" son) for my kids and it did a lot of difference. I had to change BB as well. My nephew is really really short for his age but love to bike and my brother wanted to upgrade his bike. My brother took the S600 route cause even the stock 130mm crankset on his 20" was too much. He was skeptical but his climbing capability improved on the first ride, his balance and mouvement on the bike as well. He's riding exclusively offroad. I think he went for 105mm crank!!


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## Steve-XtC (Feb 7, 2016)

LewisQC said:


> I wouldn't go bigger than 130-135cm. I did swap crankset on two bike this summer (Trailcraft for my 56" daughter ans Sram S600 shortened for my 54" son) for my kids and it did a lot of difference. I had to change BB as well. My nephew is really really short for his age but love to bike and my brother wanted to upgrade his bike. My brother took the S600 route cause even the stock 130mm crankset on his 20" was too much. He was skeptical but his climbing capability improved on the first ride, his balance and mouvement on the bike as well. He's riding exclusively offroad. I think he went for 105mm crank!!


Yep I did 142mm first time being what I thought was conservative and being a bit longer - in the back of my head was nah all these bike manufacturers can't be that wrong ... But when you see the effect they are or simply cut costs ....

With experience id say conservative is actually shorter not longer As I've yet to see anyone say cranks are too short.

If I lock the forks and add extra air to my kids tires his 142mm actually feel fine for me at 5'10" ... Strom I think also said the same on his kids bike .... Your cadence goes up a bit but it feels fine ... On the other hand just going up 5mm to 175 feels bad for me (I do have some joint issues) and realistically I should try some 160 or 165mm

When people say "that bikes too big" usually think ... "Not really the cranks are way too long though" .... If they can step over the bar comfortably then the next thing is crank length and this usually means you can put the saddle higher ... Improves the position on the bike and balance and manoeuvrability they don't need to get out of the saddle etc

It's amazing just how much difference it makes when you think how little we think about it compared to saddle height or stem length ....

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## Slow poke (Jul 23, 2013)

So it looks like a 120- 130 crank set. Who makes them in this size. Erock mentioned spawn? Thanks for the help. I would have ordered a 155.


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## jestep (Jul 23, 2004)

Some good info here: Determining Crank Length for Children

They sell cranks and do shortening as well, but they're pretty expensive, but some good info on the site. I don't think any of the custom ones get down below about 150mm. I haven't been able to verify it all, but it sounds accurate based on a number of other articles and discussions I've read about crank length.

_Edit, just now seeing that someone did post a link here earlier. _


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## Erock503 (Oct 20, 2014)

Slow poke said:


> So it looks like a 120- 130 crank set. Who makes them in this size. Erock mentioned spawn? Thanks for the help. I would have ordered a 155.


This is the one I ordered. 
Alloy Cranks - 127MM - Parts - Gear - Born to Ride | The World's Best Kids Bikes!


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## Slow poke (Jul 23, 2013)

Where do they sale Stan crest 24" wheel sets to be sold or shipped in USA? Thanks


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## Steve-XtC (Feb 7, 2016)

Slow poke said:


> So it looks like a 120- 130 crank set. Who makes them in this size. Erock mentioned spawn? Thanks for the help. I would have ordered a 155.


Back on computer not phone
Do the height calc but also try this "outside leg" method.
Crank Length Calculation - Highpath Engineering Ltd

It's not an exact science but if you're going to the trouble of finding the right cranks or having them shortened then it's worth doing the measurements as well as possible or the old measure twice/cut once. If they are the same  if not you might split the difference or prefer one over the other.

There isn't much problem going a bit smaller than "ideal" but going a bit too long can quickly mess up the riding. In an ideal world you'd be able to test different lengths... if you have a 6-8 speed 20" you can try those cranks just as a starting point!

When my kid got his 24" we spent the first few weeks with his cranks from the old bike. These were really short ... perhaps 110mm? but between those or the supplied 155mm? the old ones were MUCH better and he was actually able to pedal properly not his body being moved about as he tried to pedal!

The SRAM-S600's are cuttable down to VERY short. Visually to the same size as a 32T/34T chainring.... they are also not a bad weight and cheap and cheaper used.

The Alivio's I shortened you can't get much shorter than 140mm easily because they have a groove in the back.

A set of pedal taps is cheap ..... and once you have them you can always change to a different length just by getting a new sacrificial set of used cranks of eBay...

If you have a local bike CoOP or Local Bike Shop you might borrow them or pay them to do it... (if you don't feel confident yourself) or buy the taps and find a local engineering shop...

It sounds really complex but it's actually not... drill/hacksaw/file and taps + tap wrench... it's certainly much easier than fitting new forks and star spangled nuts etc. or servicing a fork... and you are doing it on something cheap to replace should it go wrong (the only bit that really could go wrong is getting the first pilot hole in the right place and straight or drilling at to fast RPM which will melt the soft alloy...) though the SRAM's are big enough to mean you don't need to be exact to the 1/16th" and the hole is short enough that 1 degree or so won't be noticeable

Eitherway, buy, make, have made.... the reason I emphasise the DIY is once you have done a set you can make new lengths really cheaply and easily. Basically in less than an hour you could make some cranks 10mm longer, fit them and give the kid a try.... if they are too long keep them till the next growth spell....


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## Slow poke (Jul 23, 2013)

Thanks for your reply Steve. I measured again and he is sitting at 63.5 cm which is between the 140 and 145 but closer to 140. He will probably grow some while using this bike since he is just growing into this bike. Should I go 140 or 145?


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## Steve-XtC (Feb 7, 2016)

Slow poke said:


> Thanks for your reply Steve. I measured again and he is sitting at 63.5 cm which is between the 140 and 145 but closer to 140. He will probably grow some while using this bike since he is just growing into this bike. Should I go 140 or 145?


You'd guess best if he's due a growing spell  
Either is obviously going to be much better than 155....

If you are buying pre-made then it would be what's available at length (bearing in mind the BCD and availability of chain-rings) ... bear in mind you were going to end up with much longer.

If you are having made or going to DIY then I actually split the difference ... no reason you can't have 142.5mm 
FYI: My kid *was *1m25 and inside leg 51cm (I had this info when buying frame so it's written down... but I don't have the outside leg) and I made his cranks at 142.5mm.
*In retrospect I should probably have made them shorter .... * but they make a HUGE difference all the same! I didn't measure him for a while but the saddler has gone up so he's grown a bit and they are probably spot on 6 mo later.


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## Slow poke (Jul 23, 2013)

Going to have them made. Thanks for the idea. Never thought about that. 142.5mm is what I am going to order. Thanks for your help.


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## NYrr496 (Sep 10, 2008)

As much as I love Velocity's rims, I'd also look at Sunringle's CR18 and Rhynolite. 
Good rims and a little wider than Aeroheats. 

Like I said above, if they made the Cliffhanger in 24", I'd use that.


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## watts888 (Oct 2, 2012)

Steve-XtC said:


> A set of pedal taps is cheap .....


This piqued my interest, so I had to look around. Under $15 isn't too bad for taps, plus the cost of some cheap crankarms. Going to have to try this. And I know Park tools are better, but they're also $50 for their tap&die. If I'm spending that much, once you account for the cost of cranks, worth it to just buy pedals the right length.

2X Right Left Hand 9 16 20 TPI Unified USA Standard Threads HSS Right Hand Tap | eBay


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## Slow poke (Jul 23, 2013)

NYrr496 said:


> As much as I love Velocity's rims, I'd also look at Sunringle's CR18 and Rhynolite.
> Good rims and a little wider than Aeroheats.
> 
> Like I said above, if they made the Cliffhanger in 24", I'd use that.


These were the only ones I could find

https://www.bikeparts.com/BPC109763...ar-wheel-36h?gclid=CPf_1vGSqM4CFREoaQodO8EIOQ

These are the ones I was looking at

http://www.perennialcycle.com/productcart/m/viewprd.asp

Also saw these stans for a good price if anyone is interested. You have to build them up though.

https://www.raceviewcycles.com/stans-notubes-ztr-crest-rims-24-inch-32h?language=en&currency=USD

Maybe I'll just put front only disc for one of these. They look awesome.


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## NYrr496 (Sep 10, 2008)

I bought the rims and laced them to Shimano disc hubs myself. Kinda opens up lots of options.


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## Steve-XtC (Feb 7, 2016)

watts888 said:


> This piqued my interest, so I had to look around. Under $15 isn't too bad for taps, plus the cost of some cheap crankarms. Going to have to try this. And I know Park tools are better, but they're also $50 for their tap&die. If I'm spending that much, once you account for the cost of cranks, worth it to just buy pedals the right length.
> 
> 2X Right Left Hand 9 16 20 TPI Unified USA Standard Threads HSS Right Hand Tap | eBay


Parks tools are great (real quality stuff) .... but alloy is really soft.... the cheap ones I used still go through like butter and it's not like you want to do 100 of them or you had steel cranks.

I got the cheapest from CRC (based on delivery time) ... I could probably have got them cheaper... but I paid <$10 for both....from memory.


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## Steve-XtC (Feb 7, 2016)

Slow poke said:


> Where do they sale Stan crest 24" wheel sets to be sold or shipped in USA? Thanks


They are made in the US so you have a whole load of choice including the easy option at trailcraft (pre made) from stans direct or any local bike shop that sells stans.

The Crest rims are to my knowledge identical in metal/quality etc regardless of size and they make 29" that hold up as a string XC rim for 200lb adults so a 60lb kid with much smaller 24" rims are much stronger ... If you get them in 28H it should be bullet proof ... Lots of 24" rims are made for adult size jump bikes so way way overspecified for kids with heavier rims and more holes for spokes ... I screwed up (a bit) in that I was planning to use some existing 32h rims so I'd bought 32h hubs so I added 8 spokes I didn't really need but they still come in at 1100g for the pair with spokes, hubs and rims ... And some of the jump type rims weigh nearly that a pair by themselves ...

Anyway .... Truth is I spent more than i planned but they turned out to be with it IMHO ... And I'm glad I did.

They are also ridiculously easy to go tubeless (which shouldn't be a surprise as that is Stans big thing) but by really easy I mean really easy... Just a cheap track pump and rocket ron tires


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## Slow poke (Jul 23, 2013)

If I had stans I would definitely have them tubeless as well.


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## Steve-XtC (Feb 7, 2016)

Slow poke said:


> If I had stans I would definitely have them tubeless as well.


If you can afford it I'd just go for it TBH.

You might want to just try one of these first (sorry UK link but you can find easy on google).

Wiggle | A2Z Universal Disc Mount | Brake Spares

I haven't personally tried them but they are fairly cheap and if you mail order you can return it if you decide against it. If you google you can see how they fit










Much wheels are the biggest cost item on the bike and you only paid $70 for the frame you're pretty stuck until you decide on the wheels.

I didn't and bought some cheap interim wheels but these still cost a fair bit anyway. 
I had thought I'd bag some used on ebay or pinkbike but 99% of 24 wheels were always the heavyweight jump bike ones.

Looking in the UK (where we have less choice anyway) I can find a few places do the Stans for 25% less than retail.


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## Slow poke (Jul 23, 2013)

Thanks for the link. Yes I've been stuck on which way to go because of the wheels but will probably be deciding here soon. In the process of getting the crankset though.


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## Steve-XtC (Feb 7, 2016)

Slow poke said:


> Thanks for the link. Yes I've been stuck on which way to go because of the wheels but will probably be deciding here soon. In the process of getting the crankset though.


Good luck 

I'm speaking from experience in dithering on wheels though 

Remember your new crankset will still be stuck with your current back wheel which is a freewheel not cassette.

If you get a modded S600 then you can keep a granny ring for now which you'll need as you won't be able to get a big enough freewheel to go 1x unless you live somewhere really flat. (Whereas if you have a cassette rear you can go 40T or 42T on the back)

So from making my own mistakes I'd say try the disc adaptor then you know if you can or can't (or will or won't) go discs. * If you decide no then you can return it  * but at least you'll know.

Once you know you can start looking on eBay etc. for shifters, mechs and brakes etc. and also take advantage of special offers (lots of the older M780 stuff being sold cheap)

Apart from the wheels I didn't pay retail price for anything on the kids bike. 
The difference for me was I had a frame with disc mounts AND a good reason to go disc  (local conditions) but my learning was I should have just decided on the wheels and stumped up the cash instead of waiting.

TBH I wouldn't bother with mechanical discs to save money if you aren't in a rush but decide on the groupset/fixings.... The reason being if you take your time on ebay etc. there are really good used and even unused good ones going

(Just one example but the kids rear mech is XT780 which I got "used" for about $20 but it will probably outlast 2-3 cheaper end ones)

Anyway .... just trying to help others learn from my mistakes


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