# 24" air fork



## Hallett6103 (May 9, 2010)

Looking for what to use on my daughters new Shred.The Spinner is decent but would love her to have a more adjustable plush ride.I know some of you have been using 26" forks,what have you been using and or modifiying to work,Thanks.


----------



## GrayJay (May 16, 2011)

I am working on adapting a RS mag21 for 24", see within thread;
http://forums.mtbr.com/families-riding-kids/novara-pixie-20-project-853041.html

Also see Tigs method of lowering the brake post (without shortening the fork ends).


----------



## yellowdogx (Oct 31, 2006)

Hallett6103 said:


> Looking for what to use on my daughters new Shred.The Spinner is decent but would love her to have a more adjustable plush ride.I know some of you have been using 26" forks,what have you been using and or modifiying to work,Thanks.


My son is running a standard 26" RS Tora air. Raises the front end a bit but at least it slackens out the head angle a bit.


----------



## slapheadmofo (Jun 9, 2006)

If you can't hunt down an air fork, you can also just completely remove the spring from one leg of a coil fork on many models. This worked out great on my son's bike.


----------



## TigWorld (Feb 8, 2010)

Early model RS SID's with the 28mm stanchions are a good air sprung fork that work well for lighter riders. You can put spacers on the air spring rod to lower them down to 60mm (or less). If you have disc brakes then easy mod. For v-brakes you will need to lower the v-brake mounts using some sort of bracket. xc71 did this.


----------



## jh_on_the_cape (Jan 12, 2004)

I found an air fork for 24" for sale, but in the end decided to remove the spring from one side. Made a huge difference, but still not awesome.
IMHO this is the ultimate lameness of 24" wheel bikes: the forks.
I have decided to just wait another year or so and totally do up a great 26" wheel bike.
A disc front wheel in 24" is either $$ to have someone do it or a big sink of time if you DIY.
Moving the canti mounts down seemed doable, but I tried and just could not get it to work using readily available (not custom) stuff.
the guy at lilshredder.com has some 24" air forks, but for how and where my son and I ride, I am going to just hold out for the real deal in a year or so.

Someone should make the V brake adaptor and sell them.



slapheadmofo said:


> If you can't hunt down an air fork, you can also just completely remove the spring from one leg of a coil fork on many models. This worked out great on my son's bike.


----------



## GrayJay (May 16, 2011)

It is a shame that the 24" forks that are available are so rediculously overbuilt. Much better options if you can re-use a modified 26" fork. Latest project I have been working on is to adapt a '97-'99 era manitou spyder 26" fork as a 24" fork. I found one of these for dirt cheap at local coop and thought it had potential as a kid fork. The spyder is V-brake only, no disks. Reasonably lightweight construction with 28mm aluminum stanchions and uses an aluminum steer tube. This fork uses elastomers and coil springs stacked together for around 65mm of travel, and it also has a separate primitive dampening mechanism in one of the legs to provide some degree of dampening for the spring. 







1450gr total weight for all orignal parts as found. I removed the elastomers and springs from one leg to soften the fork for my 65 pound rider, a much more suitable stiffness for her to compress. I will probably do a bit further tuning to dial it in by changing/modifying the elastomers or by converting to a coil spring in place of the remaining elastomers since there is also separate dampeing mechanism to keep it from becoming a pogo-fork.








One of the reasons I selected this for was for the configuration of the fork ends which are directly inline with the stanchion tubes (instead of protruding forward from the fork). Started my 24" wheel conversion by drilling small holes through the fork that are 25mm upward from center of the original axle location.








Original fork end detail.








I used a carpentry spade drill bit that was same outer diameter as an axle nut, centered it in the pilot hole previously drilled and roughed-in a new dropout from the existing metal, hacksawed the excess length off and then used dremmel and hand files to finish the new dropout.








Resulting 390mm Axel-to-crown fork length correctly lines up a 24" rim with the brake post and is shorter than a 26" fork so doesnt jack-up the front end and slacken the headtube angle.








No excess clearance between tire and the arch.








Resulting weight after shortening and removing the elastomers & springs from one leg was 1283gr, approx 1 pound lighter than sourcing a new (and expensive) 24" air fork, nearly 2 pounds lighter than the junk coil-spring forks that most 24" bikes come with. Staying with V-brakes also saves weight and expense over a disk brake conversion and in my experience V's are plenty strong.

In hindsight, if I were to convert another of these forks I would not shorten it by a full 25mm. When shortened by 25mm, there was still plenty up upward brake pad adjustment range left on the V-brakes I am using. Shorteing by 25mm started to place the new axle location up in the fat tapered portion of the slider casting and made it more work to produce a new flat fork-end for the axle to securly bolt into. It would have been easier fabrication work if I has setup to have the brake pads fully upward on the arms, so that I could get away only shorteing the fork by around 15-20mm instead of 25mm, this would keep the new fork end down on the flatter, skinny section of the casting, reducing the need to carve out so much of the tapered portion of the casting to produce a new flat dropout.

Later edit- the manitou spyder fork was not a huge seller BITD, might be a bit hard to find a decent used one. Another good option for this same approach is to use a rockshox indy fork, similar construction style but the Indy forks were much more numerous. I cut-up a broken Indy fork and confirmed that the lower part of the slider casting is solid, so is amenable to this shortening modification approach unlike the similar looking hollow casting RS mag21. The cheapest OEM indy models that came stock on lower end bikes were fairly heavy (steel stanchions and steerer) but there also were nicer, lighter models available.


----------



## TigWorld (Feb 8, 2010)

Nicely done.


----------



## GMF (Jan 10, 2004)

Kudos to you. I can appreciate a dad willing to cut up a fork for their kid...


----------



## TwoTone (Jul 5, 2011)

I just ended up buying a Spinner Air 24. I shopped Ebay for a long time and never ended up finding a used SID for a decent price.

I'm and more importantly my son is really happy with the Spinner.


----------



## xc71 (Dec 24, 2008)

1283 grams is an excellent weight, very nice.


----------



## NYrr496 (Sep 10, 2008)

Good job. I built my son a disc wheel and used a 26" Manitou fork. Works fine but looks a little odd.


----------



## veryavgwhtguy (Jul 31, 2008)

I use a 115mm (or maybe 120mm) 26" Reba with dual air, and just pump the negative reservoir up enough to reduce travel to about 80mm. The 24" disc wheel works fine in it.


----------



## jh_on_the_cape (Jan 12, 2004)

How big of an improvement is the spinner fork? What did it replace?



TwoTone said:


> I just ended up buying a Spinner Air 24. I shopped Ebay for a long time and never ended up finding a used SID for a decent price.
> 
> I'm and more importantly my son is really happy with the Spinner.


----------



## jh_on_the_cape (Jan 12, 2004)

GrayJay said:


> It is a shame that the 24" forks that are available are so rediculously overbuilt. Much better options if you can re-use a modified 26" fork. Latest project I have been working on is to adapt a '97-'99 era manitou spyder 26" fork as a 24" fork.


You rock! Do you use a wheel like that with so few spokes? Or is it a mockup?


----------



## TwoTone (Jul 5, 2011)

jh_on_the_cape said:


> How big of an improvement is the spinner fork? What did it replace?


It replaced the stock Suntour XCT-JR, 50mm, 24 on the a 2013 Bayview Trail Disc. I may miss a bike but it will be better than any stock 24 inch fork, except the few bike that come with air already, but those are 1k plus bikes.

It's a 1000x times better. It was such an improvement I almost spent the money on a 20 inch version for my daughters bike. The only reason I didn't was she had a growth spurt and I Knew the bike was going to be done this year.

I figure there are enough dads looking for an 24 inch air fork, that when it's time to sell the Marin, I'll put the old fork back on and sell the air fork and recoup some of the money, so it'll end up like renting, well worth it to me.


----------



## GrayJay (May 16, 2011)

jh_on_the_cape said:


> You rock! Do you use a wheel like that with so few spokes? Or is it a mockup?


The 12 spoke wheel is no mockup. I started with a 36 hole rim and re-laced using every third spoke hole. The rim itself is 430gr, way overkill in strength for a 70 pound rider so I tried saving weight on the wheel by reducing # of spokes. Only reason I can see for using >24 spokes on a kids 24"wheel is if you could source rims that are well below 400gr each but these dont seem to exist, 24" rims are made from same heavy extrusions as 26" rims for adult bikes. After I built the 12-spoke wheel, I strength tested by popping it into my own bike and riding it around to see if it would withstand my 200 pounds. It stayed completely true and felt no-less laterally stiff than a standard MTB wheel, I am confident it with hold up fine for a kid rider. I also built an 18 spoke rear wheel for same bike, see last entry (#27) with pictures in thread;
http://forums.mtbr.com/families-riding-kids/novara-pixie-20-project-853041.html


----------



## jh_on_the_cape (Jan 12, 2004)

Thanks super helpful. I had decided not to get the spinner... but I just changed my mind! I bought my son's 24" wheel bike for $100 in mint condition on CL. That's how I am justifying it....



TwoTone said:


> It replaced the stock Suntour XCT-JR, 50mm, 24 on the a 2013 Bayview Trail Disc. I may miss a bike but it will be better than any stock 24 inch fork, except the few bike that come with air already, but those are 1k plus bikes.
> 
> It's a 1000x times better. It was such an improvement I almost spent the money on a 20 inch version for my daughters bike. The only reason I didn't was she had a growth spurt and I new the bike was going to be done this year.
> 
> I figure there are enough dads looking for an 24 inch air fork, that when it's time to sell the Marin, I'll put the old fork back on and sell the air fork and recoup some of the money, so it'll end up like renting, well worth it to me.


----------



## jh_on_the_cape (Jan 12, 2004)

Go for it! I would be concerned that if one spoke broke (due to a branch getting caught or something) the wheel would self destruct. Most 32 spoke wheels will get home on 31 or even 30 spokes.
What about 6 spokes? 
In any case, I appreciate your tinkering...



GrayJay said:


> The 12 spoke wheel is no mockup. I started with a 36 hole rim and re-laced using every third spoke hole. The rim itself is 430gr, way overkill in strength for a 70 pound rider so I tried saving weight on the wheel by reducing # of spokes. Only reason I can see for using >24 spokes on a kids 24"wheel is if you could source rims that are well below 400gr each but these dont seem to exist, 24" rims are made from same heavy extrusions as 26" rims for adult bikes. After I built the 12-spoke wheel, I strength tested by popping it into my own bike and riding it around to see if it would withstand my 200 pounds. It stayed completely true and felt no-less laterally stiff than a standard MTB wheel, I am confident it with hold up fine for a kid rider. I also built an 18 spoke rear wheel for same bike, see last entry (#27) with pictures in thread;
> http://forums.mtbr.com/families-riding-kids/novara-pixie-20-project-853041.html


----------



## Mark194 (Mar 3, 2012)

Where did you buy it from? I am lookin for 1 for my daughters bike. I will do the same as you and sell it later!



TwoTone said:


> I just ended up buying a Spinner Air 24. I shopped Ebay for a long time and never ended up finding a used SID for a decent price.
> 
> I'm and more importantly my son is really happy with the Spinner.


----------



## jh_on_the_cape (Jan 12, 2004)

I bought mine on ebay.... from lilshredder. He was selling them pretty cheap so I got the impression that he was just getting rid of them.

I cannot seem to get full travel on the spinner air fork... is there a spacer to remove or something?



Mark194 said:


> Where did you buy it from? I am lookin for 1 for my daughters bike. I will do the same as you and sell it later!


----------



## Mark194 (Mar 3, 2012)

What model is it? Grind?


----------



## TwoTone (Jul 5, 2011)

Mark194 said:


> Where did you buy it from? I am lookin for 1 for my daughters bike. I will do the same as you and sell it later!


lilshredders bikes- Home Page . Not sure if he still has any left. There is also a German site I know some people have ordered from, but I don't have the link.


----------



## Mark194 (Mar 3, 2012)

Thanks guys, I will give him a call


----------

