# Another 24" build thread. 07 GT Chucker 24 on a budget



## stew325 (Jan 3, 2011)

So, my 8 year old son and I are starting work on what was originally my older sons GT Chucker 24. I was going to buy him a new bike instead, but figured we would still end up with a heavy turd that would suck for him to ride on trails with fairly decent climbs. My older son had to push this thing up steeper hills. 
We have no "before weight on it yet, and it's already torn down. But I have been weighing parts, and can't believe how heavy they are. The fork is 3000 grams! So we are raiding the spare parts bin. 
Have a XT/slx 10 spd setup, China carbon bar, post, and seat for it. Got a hold of some SLX disc brakes. Swapped the stem on my fatbike, so now have a 110g 60mm stem for it. I have a 26" fox fork that I'm going to try to lower to 80mm or less if I can. I ordered a set of Rock-Bros mag/ti pedals on ebay. I also have a Deore crankset that I plan to cut and redrill at 152mm. 
We are also stripping the frame, as my son wants it lime green. Not sure yet whether to prime and paint it, or have it powder coated. It's $100 for powder coating, but I'd kind of prefer to put that money towards a light disc wheelset. If I can find or build something cost effective. Crests are kind of pricey, but we may go that route.

Here is my son doing the dirty work of stripping the original paint.


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## stew325 (Jan 3, 2011)

Having trouble sourcing 24 inch tires and rims. Everywhere has no stock on the rocket rons.
I did notice that specialized 24" bikes come with fast tracks in 1.8" I have used fast tracks for xc racing, and like them. Not sure if they are knobbie enough for this bike though. Anyone have any experience with those? 

Also, where are you guys finding the alex ace20, or the stans crest 24" rims?


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## POAH (Apr 29, 2009)

they don't make the ACE 20 any more and the crest 24 from any shop that stocks stans can get a set. in the UK a few shops have them in actual stock


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## GSJ1973 (May 8, 2011)

stew325 said:


> Having trouble sourcing 25 inch tires and rims. Everywhere has no stock on the rocket rons.


Great project! Love those older GT frames.

If you are in North America, you can order 24" Rocket Ron tires direct from Schwalbe. They are showing as in stock right now.

Rocket Ron HS 438 | Schwalbe North America

Stans 24" Crest wheels should be in stock as well on their website, though they are $650/pair. Crest rims a pair are $170 if you can find some cheap/light hubs you should be able to build a wheelset for about $400 or so.


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## jestep (Jul 23, 2004)

Just use a few coats of decent spray paint and follow it up with a few coats of clear spray sealant. The worse it looks, the less likely it is to get stolen anyways. 

The RR's are sweet tires. Great weight and volume and good grip. Probably not the most durable tire on earth, but still a completely usable tire for most biking.

We did around a 1800g wheel build for about $250 or so. Used koozer hubs and found some WTB 24" MTB rims on ebay. If I were to do a disc build, I'd go with the stans and some circus monkey hubs, but it would definitely be pushing $400 with higher end spokes if you aren't doing the build yourself.


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## stew325 (Jan 3, 2011)

Thanks!. Will try the LBS for the rims and tires. I'm starting to realize that this will be expensive. Will probably buys rims and cheaper hubs. Possibly XT or SLX depending on the weight. I also have an old specialized 28h front hub. May even find some spares and re-lace the old rims with disc hubs. I'm going to take them apart and weigh the rims to see how bad they are. 
I'm also wondering if the a-c on the fox fork will too much for it even after lowering it. The old fork was pretty short travel. The F1rst fork is an option I guess, but prices are high in Canada now because our $ is tanked.


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## chuckactor (Apr 11, 2013)

Ace20's are no longer made but I there is a guy who still might have some. Contact [email protected]. The guys name is Mizuhiro. I paid $43/pair + shipping.

Alex Rims ACE20 24" (507 x 17) 6061H-T6 material 32H black Presta valve hole w/ CSW (cnc side wall) w/ SSE (stainless single eyelet). Item price $23.99/ea or $42.99/pair (2 rims). H&S fee depends on your location.

I bought spokes through Danscomp, the BMX place they are cheaper than anyone and they cut them to length. $0.59/ea for double butted Sapin spokes with alloy nipples in your choice of color. Black spokes are $0.10 more.

You'll find most 26" forks aren't much longer than the 24". An older Rockshox SID works nice for the kids and are light.

Chuck


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## bytesiz (Sep 6, 2007)

Trail craft will be releasing a 1500g wheel set soon. <$400. 


Sent from my iPhone using Tapatalk


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## stew325 (Jan 3, 2011)

Thanks. I'll look into that chasertech place. That price is way better than the crests! 
I'm hoping the fox fork I have won't be too far off once lowered. 

Also, this frame has IS disc tabs. Not sure if the native rotor size of the frame is 140 or 160mm but would need an adaptor to post mount calliper anyway. Is there a way to measure to see which adaptor I need. Hopefully I can use a 140 rotor on the rear but doubt it with an adaptor in there


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## NYrr496 (Sep 10, 2008)

When I built my son's 24" bike a few years ago, I used Deore hubs, Sun Ringle Rhyno Lite rims and Maxxis Snyper tires. It wasn't the lightest combo ever but it worked really well. 
Last spring, I did some single wall Alex rims on Bike Hub Store hubs for a friend's son. Those wheels were light. 
We used a 26" fork on that bike as well. Worked fine. My son put lots of off road miles on that bike.


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## chuckactor (Apr 11, 2013)

For some reason the default IS tabs on most frames seem to be 140 so you'll be in good shape. You usually need a +20 adapter to run a 160 rotor on the rear.

This guide is helpful for getting things figured out.

https://www.sram.com/service/techdo...iper-mounting-and-spacer-configurations-rev-b


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## stew325 (Jan 3, 2011)

So we got the frame stripped. Trying to talk him into polishing it instead of paint. Pretty sure he'll want it painted though.

I don't have a bike/luggage scale, so never weighed the complete bike. I weighed all the parts tonight. 31 lbs / 14.11 kg. I guess it's about what I expected, but I still couldn't believe the weights on some of the parts. Here are some examples:
Frame. 1796g
Fork w/front v-brake. 2971g
seat and post. 795g
pedals. 657g
crank/bb. 1229g
stem/cap. 248g.
Both wheels complete with tires/tubes, and cassette. 4383g

Should be able to save huge weight on this thing. Not sure what it'll get down to yet.


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## stew325 (Jan 3, 2011)

Weighed all the parts that I have to swap onto the GT, plus using confirmed weights from these forums, I've already shaved 5.6 lbs / 2556 grams from this tank. So down to approx 25.5 Lbs 
That's without the wheels, or fork that will also be upgraded.
So my LBS has ordered the Rocket Rons for me, but can't get the crest rims in 24" from the distributor. He is looking into a F!RST fork for me as well. Doubt it will be available either though. Apparently not enough market for higher level 24" stuff for the distributor to bother with it.
Bike-Discount.de is the only online source I've found for the fork so far. 
Still looking into lowering the fox fork to 60 or 80mm. Has anyone here done that?


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## jestep (Jul 23, 2004)

stew325 said:


> Still looking into lowering the fox fork to 60 or 80mm. Has anyone here done that?


The only ones I've seen commonly lowered are older marz or manitou with the stanchion clamps on the crown and dropouts that aren't part of the lowers. There's at least a few DIY'ish guides on how to do them, but they do still require some very precision machining.

I don't think it would be easy on forks with fixed dropouts because shortening the whole fork typically requires both the stanchions and the lowers to be modified.

You might be able to reduce the stanchions by themselves, but it would hugely reduce the travel and would definitely require machining the lower end of the stanchions to fit, and you have to modify all of the internals to get it to work properly. If you look at how complex some of the fox internals are, I couldn't even guess where to start. It's probably possible, but I'm not sure it would be worth the effort for the reduced travel you'll end up with.


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## stew325 (Jan 3, 2011)

I know the fox float 100mm is able to be reduced to 80mm with a spacer, but mine is a talas. I wasn't going to reduce the lowers, just the travel. I still think the axle to crown will be too much. The 24" that the bike came with was 63mm travel I think, so the gain of 17mm plus the extra length of the lowers may be too much. Thinking of a light weight 24" air fork now.


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## chuckactor (Apr 11, 2013)

When I upgraded my son's 24" Hotrock to an old 26" Rockshock SID (80mm) it only raised the front end about 3/4". Run the Fox Float 100 as is or through a spacer in it to drop it to 80mm.

How to adjust the Travel Range of a Fox Talas System | ENDURO Mountainbike Magazine


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## stew325 (Jan 3, 2011)

*Parts are rolling in. Someone is getting excited! My son is happy about it too! Lol*









Thanks for the tip to find the rims chuckactor. Have 2 on the way.
Thanks for everyone else's input as well. 
Looked into lowering my talas. It's a 2010, 3 position, so apparently can't lower it with the spacer. Considered getting a float and dropping it to 80, but found this SID, that I can lower to 63 with a spacer. Something is up with the lockout on it. I'll have to take it aprt for the spacer, so I'll look into the lockout issue then. It weighs 1388g. That's quite a bit lighter than the talas, and wayyy lighter than the boat anchor 3 kg fork that came off that bike.


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## chuckactor (Apr 11, 2013)

Go with the SID. You can still find a rebuild kit for the "SID Classic". Don't bother lowering it. Leave it at 80mm. We run the exact same exact fork on my kids 24" dirt jumper and a close version on his 24" x-country.

http://forums.mtbr.com/families-riding-kids/another-hotrock-24-build-863040.html

Chuck


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## jestep (Jul 23, 2004)

The SID's are awesome. Besides the weight, if the seals are good, you can run them at super low pressure which works great for lightweight riders.

I think you'd still be better off using the spacer though, especially if you're already tearing into it. It should lower the A->C proportionately. These bikes end up really slack with a 80mm SID on them. When we did our build, a 80mm SID was somewhere around 445mm with the stock fork around 415mm. A full inch on a bike this size changes the geometry quite a bit. You could always mount it as is and see how it handles before reducing it as well.


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## stew325 (Jan 3, 2011)

When I order the rebuild kit, I'll order the spacer too. Cheap enough I think. I may need to keep the bb as low as I can so he can get on the thing. The carbon post I got can't be slammed like the original post I had with the seat clamp flipped upside down so it was above the seat rails.


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## stew325 (Jan 3, 2011)

*Deore cranks shortened*

Finally got around to shortening the Deore Hollowtech 2pc crank.



























Glad I went this route as opposed to buying a Trailcraft crank, as I prefer the Hollowtech design with external bb cups. These cranks are available used for as little as $20, and look identical to the Zee cranks. The shortening process is pretty easy if you have access to the tools, and take your time. 
No pics of drilling and tapping, as I used a friends drill press in his garage, but I bolted the crank arms to the table of a drill press with the outside facing up, so the hole would be perfectly parallel to the spindle. Started with a 1/8ish bit, and progressed up to the 13mm. Then put the crank taps directly into the chuck of the drill press and turned it in by hand so the threads would also be straight. Then I cut the ends off with a hacksaw with the crank arm in a bench vise. I laid the cut off end on the shortened arm and lined up the pedal holes and used red spray paint to mark the shape onto the arm. I then used the hacksaw again to cut off the square corners. I tried an angle die grinder, but had the best luck using a flat file to shape the rounded end. I'm happy with how they turned out. I'm painting them right now.


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## stew325 (Jan 3, 2011)

*Some progress*

Frame was powdercoated lime green. Got some frame decals on Ebay. Couldn't find the "Chucker 24" decals, so just got generic GT. The decals on the fork were pretty hacked up, so ordered new ones. Couldn't find the '05 SID decals, so picked up the newer style ones in matchy green. Painted the shortened crank, and the Ace20 rims are here. The hubs will be a month on the slow boat. Should have asked for express shipping. Wasn't an option on the ebay ad. Here are some pics. Sorry my phone is crap.





















The frame looks brand new. The powdercoater only charged me $50.00. The decals were $12. Well worth it!


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## jestep (Jul 23, 2004)

Looks great. Cranks look like they came that way out of the box.


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## stew325 (Jan 3, 2011)

Thanks jestep! I was lucky to have a coworker who once worked in a machine shop show me the proper technique to file the rounded end. Happy how these turned out. Can't wait for it to be finished so he can ride it!


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## blubayou (Dec 31, 2015)

Make any more progress on this? Liking the build and planning something similar for my oldest.

I wish I could find someone to PC a frame for $50 locally. They all want like $200, which is crazy, in my opinion


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## stew325 (Jan 3, 2011)

Life has been busy, but finally finished assembling my sons bike. Just need to trim the brake lines, and steerer. Sorry for the crappy pics. We were in a hurry to get him on it before it got dark. I'll get better pics up from a trail ride soon. He loves it. I'll get the final weight also.


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## stew325 (Jan 3, 2011)

This makes agonizing over every part worth while! He's having a much easier time pedaling this bike up hills than his old 40 lb 20" .


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## fabrice (Mar 27, 2006)

Hi,
I know the thread is one year old 

Very nice and clever build !
I might pick up a used Checker 24 (same as yours) and start such a project ...
I have a couple of questions :

The weight you quoted for the frame, I guess it is bare (raw), or is it with the original paint ?
Have you weighted you shortened crank arms ?
I see you shortened it to 152mm.
Do you think it could be shortened more (say 145mm) ? Because it looks like the arms are getting thinner towards the axle, so that means less threads...


Thanks


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## stew325 (Jan 3, 2011)

That was the raw frame weight. I had a list of the weight of every part. I think it got throw out because I thought I already posted it. You could probably get another 7mm off the crank arms. I can't remember the weight of the shortened crank. But it was very light. The deore and zee cranks are solid. So they can be shortened easily. I think anything better is hollow. (Slx/xt etc). Do some googling first. There's some good info out there. And elsewhere on mtbr. The seat is a fizik TT seat. 180 g. Was sort of cheap used. All the light parts are key to a light end result. The frame is a tank.


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## fabrice (Mar 27, 2006)

Thanks for your reply 
There have been some changes in my plans... I saw today a 2nd hand Orbea MX24, and I just picked it up !
Its the cheaper "dirt" version (with rigid steel fork, 1x7, etc.) but the frame is the same as the higher end versions, "hydroformed" tubing, it has the disk tabs, so that's a good starting point for a light build ! Lighter than the GT probably, but the GT is a nice and original frame IMO  BTW, If I were you, I would have filed the V-brake tabs and front mech cable stops... Not for the few grams saved, just for the cleaner look, but that's no big deal anyway.

So, for the crank, I think I'll have a go at shortening a Shimano Alfine (170mm) crankset that I have. The arms are not hollow and look similar to Deore & Co. Since the announced weight is nearly 1kg (with 45T ring + bash, and BB), I was a bit skeptical about the final weight... But if you say that the shortening saves a lot, we'll see 
Now it's fitted with a 38T ring, so that will be OK with a 10-42 XD spare cassette that I have too. 38-10, that will be high speed for my son, hum ! But on the other side, 38-42 on 24" wheels is OK though.
For the rest, my plans are : build a 1100g wheelset (Crest Mk3 24", Novatec light hubs, 24 thin spokes), buy a Chinese carbon 26" rigid disk fork (not far from the current axle-crown distance of 420mm), and 1x11 transmission (I think X5 mech + Apex trigger, to keep the budget under control). All this will probably take place after the summer... My son will ride the bike as is for now.


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## stew325 (Jan 3, 2011)

Don't know that shortening the crank saved much. But the steel ring and bash guards on some of the entry level stuff is pretty heavy. I definitely wish I filed off the tabs before powder coating. Good luck with the mods. Sounds cool.


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## jochribs (Nov 12, 2009)

I think you did a kick ass job on that build Stew. What did you end up doing with that fork btw? Step it down to 80? 63? What was the axle to crown on it at that point? I'm curious if one of those Sids can be set in the 70~range with a custom sized spacer. 

I'm waiting for RST to finally release the Snyper but it appears that it is going to be a pig which is a bummer. Like 1800 grams. So not sure if I'll grab one or not...


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## Steve-XtC (Feb 7, 2016)

stew325 said:


> That was the raw frame weight. I had a list of the weight of every part. I think it got throw out because I thought I already posted it. You could probably get another 7mm off the crank arms. I can't remember the weight of the shortened crank. But it was very light. The deore and zee cranks are solid. So they can be shortened easily. I think anything better is hollow. (Slx/xt etc). Do some googling first. There's some good info out there. And elsewhere on mtbr. The seat is a fizik TT seat. 180 g. Was sort of cheap used. All the light parts are key to a light end result. The frame is a tank.


Stew, which Deore series is it? 
I have a set I put aside . they are 175's and too long for me but I've been holding off as I don't know if they are hollow or not... he's currently running some cut-down Zee but the weight of the Zee spindle almost offsets the weight of the old sq taper BB


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## fabrice (Mar 27, 2006)

Don't want to reply for Stew, but from the picture, it looks like the travel of the SID is reduced to 63mm.
For heavy riders, its rigidity is not top notch, but for kids, this light 26" fork is just great !
BTW, the v-brake tabs can be filed off aswell on the SID ; but then it requires some paint job.
Some older Rock Shox forks are very light too (Judy SL, Mag 21, ...) and already have a limited travel, but disc brake tabs will be missing very likely.


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## stew325 (Jan 3, 2011)

jochribs said:


> I think you did a kick ass job on that build Stew. What did you end up doing with that fork btw? Step it down to 80? 63? What was the axle to crown on it at that point? I'm curious if one of those Sids can be set in the 70~range with a custom sized spacer.
> 
> I'm waiting for RST to finally release the Snyper but it appears that it is going to be a pig which is a bummer. Like 1800 grams. So not sure if I'll grab one or not...


Hey thanks! It was so worth it! That SID fork is an '05. It was 80mm, and I dropped it to 63. Pretty sure you could customize the length of the spacers. I actually had to file the spacer down around the outside so it wouldn't bind from what I remember. I can't remember if it was one 20mm spacer, or 2 10mm. But I read about people just using pieces of plastic tubing with a saw cut down one side to make a spacer. This SID is only 1388g. You can find them cheap if you look, and ask around. The advertised ones seem expensive. This one was donated by a friend. Also, the lockout works fine. It is just spring loaded , and requires the bar mounted lever to keep it locked out. So we do without it. I also like the dual air feature. You can use slightly more pressure in the negative side to make the fork actually work for a light kid. Don't remember the axle to crown off hand, but I think with it lowered, it is the same as the old 6lb boat anchor the bike came with.


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## stew325 (Jan 3, 2011)

Steve-XtC said:


> Stew, which Deore series is it?
> I have a set I put aside . they are 175's and too long for me but I've been holding off as I don't know if they are hollow or not... he's currently running some cut-down Zee but the weight of the Zee spindle almost offsets the weight of the old sq taper BB


The crank is an m542 from a 2010 stumpjumper fsr. Not hollow. The hollow ones can be shortened as well apparently. There were some web sites selling shortened cranks, and some will shorten cranks if you send them. I had this one, so it was worth a try. I think at the time, there was a set for sale on pink bike for $20. with no BB. so wasn't to worried if I wrecked it.


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## Steve-XtC (Feb 7, 2016)

stew325 said:


> The crank is an m542 from a 2010 stumpjumper fsr. Not hollow. The hollow ones can be shortened as well apparently. There were some web sites selling shortened cranks, and some will shorten cranks if you send them. I had this one, so it was worth a try. I think at the time, there was a set for sale on pink bike for $20. with no BB. so wasn't to worried if I wrecked it.


Thanks, 
I think some later ones are hollow .the ones I managed to get are M580/M581.. and to be honest I was actually thinking I'd just drill them and find out ... and was then considering even if I do drill into the hollow part I could fill it with some of the aluminium epoxy (the stuff can be used on engines etc. and can be drilled/filed after) and clean that up before tapping

His current pedals (some Aest titanium) the pedal thread doesn't go all the way through anyway as they are a bit shorter ... and he's only 45lbs (wet through)

edits: I've already shortened 3 sets (a SRAM S600, Alivio and recently a Zee) so I'm not worried about the actual shortening process so much as the hollow-bit and the "wisdom" if you drill into the hollowpart its wrecked...


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