# 20" disc ready wheels?



## jewels (Mar 17, 2004)

Hi all, got a 20" scott voltage for my 5 year old, it has v brakes on it now but disc tabs. Where can I get 20" wheels? Don't want to spend a fortune, but don't want it to be super heavy either. I see some on ebay , will those work even though it's a 6 spd? I suppose we can build up, but what rims and hubs? Here's a pix of the bike. Would like to upgrade the fork eventually too. I like the bike because my son is short for his age and the standover and reach is shorter than some other 20" bikes, plus it's slack for safe DH'ing. thanks for your help.

MTB Bike Bicycle Wheel Wheelset 20 29" for Shimano 8 9 Speed Disk Disc Brake | eBay


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## Will Fisher (May 12, 2015)

Jewel, if it's the same as my son's Spark, the cassette won't fit on a new hub as it's a screw on 6-speed cassette. So if you went that route you'd need a new cassette, derailleur, shifter and chain and make it a nine speed. Considering they charge $90 for shipping you'd be better off buying a light hub and having Dans Comp lace it (for free) to a lightweight bmx rim.


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## jewels (Mar 17, 2004)

we have tons of parts, I don't care about putting on cassette, der, shifters etc. That's no biggie. I'm going to have to measure the front and rear spacing. assuming its a standard 135 rear and 100mm front spacing, then I could just get standard hubs and get rims and spokes to lace up? Do most 20" rims have 36 holes? and how wide should I get?


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## Erock503 (Oct 20, 2014)

I'm going to try some alienation 20's laced to some Koozer hubs. The ankle biter 32h from dans comp are only 20x 1-1/8, but they are also only $20 bucks a set on sale right now. I'm building them up this weekend so I'll try and report back.


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## GrayJay (May 16, 2011)

Beware, 20x 1-1/8 BMX rims are a different diameter (451mm ISO) than MTB 20" rims which are 407mm diameter. BMX stuff tends to be extremely overbuilt for kid MTB use too, watch the weight of the parts.

Jewels - consider just finding a set of disk hubs that fit your frame, unlace the existing rims and re-lace them to the disk hubs. If you have 36 hole rims, you can save considerable weight by lacing them as 12 spoke front, 18 spoke rear wheels that are still plenty strong for kid use. See examples at; 
http://forums.mtbr.com/families-rid...-wheel-build-40lb-rider-need-help-891768.html


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## Erock503 (Oct 20, 2014)

GrayJay said:


> Beware, 20x 1-1/8 BMX rims are a different diameter (451mm ISO) than MTB 20" rims which are 407mm diameter. BMX stuff tends to be extremely overbuilt for kid MTB use too, watch the weight of the parts.
> 
> Jewels - consider just finding a set of disk hubs that fit your frame, unlace the existing rims and re-lace them to the disk hubs. If you have 36 hole rims, you can save considerable weight by lacing them as 12 spoke front, 18 spoke rear wheels that are still plenty strong for kid use. See examples at;
> http://forums.mtbr.com/families-rid...-wheel-build-40lb-rider-need-help-891768.html


Hey thanks for the heads up, those are indeed 451 iso. I would have been tearing my hair out trying to get a tire on it. Too bad, there were soooo cheap. Guess it's back to hunting down some aeroheat 20.


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## NYrr496 (Sep 10, 2008)

I used Aeroheats on my son's GF Precaliber when he was small. They were great. 
Weren't disc wheels though. 

If the rear spacing on that bike is 135mm, it may be easier to convert it into a 9 or 10 speed so you can use a cassette hub. Only thing is, with the short chainstays, you may not be able to get all ten gears. I had that issue on a 24" wheeled bike I built for my son. 
8 speeds on the 20" worked fine.


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## jblockers (May 16, 2009)

I also have been looking into some 20" 406 disc wheels. The folding bike scene outside the U.S. has a lot more options for discs and cassettes. You do have to make sure that the rim is a 406, the front hub is 100mm wide, and the rear is 135mm for 20" MTBs (because many folding bikes use 451 rims, 74mm front hubs, and 130mm rear hubs).

I can't verify anything, but this wheelset on ebay is $190 (free shipping with skewers) and has a claimed weight of 1,630g.
Tailor Made 20" 406 Front Rear Wheelset Litepro K Fun Disc Brake 32 32 Spokes | eBay

These are much lighter at 'approx 1,280g' , but are rim brake only for $190 (free shipping with skewers).
Tailor Made 20" 406 Front Rear Wheelset Litepro K Fun Hubs 20 28 Spokes | eBay

There are also other more exotic wheelsets that are very lightweight. Also, I have seen many lightweight rigid forks. Anyone have any thoughts/experience/sources when buying folding bike wheelsets/forks?


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## jblockers (May 16, 2009)

*Folding bike wheelset compatibility/availability?*

Has anyone considered the folding-bike or mini-velo wheelsets? They make very lightweight wheelsets that are rated for adult riders, with or without disc hubs, plus they offer freehubs that can handle up to 11 speed cassettes. These are becoming very popular in Asia, but are available in the U.S. as well. I have a 20" Gary Fisher Pre-Caliber that I want to upgrade to disc brakes with more gears.

I think the gotchas are to be sure that you get the proper MTB rim and hub sizes. I believe a 20" MTB typically uses 406 rims, 100mm wide front hubs, and 135mm wide rear hubs. Folding bikes wheels do come in these sizes, but wheelsets with 451 rims, 74mm wide front hubs, and 130mm rear hubs are also common.

On ebay there are several decent options under $200 delivered, but I can't vouch for the quality or the vendors.
With disc hubs:
$190.25, free-shipping, disc brakes, supports 8-9-10 speeds, with skewers, stated weight is approx 1,630g (per pair).
Tailor Made 20" 406 Front Rear Wheelset Litepro K Fun Disc Brake 32 32 Spokes | eBay
Much lighter, but without disc hubs:
$185.30, free-shipping, rim brakes, supports 8-9-10 speeds, with skewers, stated weight is approx 1,280g (per pair).
Tailor Made 20" 406 Front Rear Wheelset Litepro K Fun Hubs 20 28 Spokes | eBay
Even lighter, more expensive, without disc hubs:
$340.30, free-shipping, rim brakes, supports 8-9-10 speeds, with skewers, stated weight is approx 1,080g (per pair).
Tailor Made 20" 406 451 Front Rear Wheelset Litepro Star Hubs 14 16 Spoke | eBay

Does anyone have any thoughts/experience/sources? Also, anyone tried using a folding bike fork rigid fork on a 20" MTB?


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## CJH (Apr 21, 2004)

jblockers said:


> I have a 20" Gary Fisher Pre-Caliber that I want to upgrade to disc brakes with more gears.


The geared Precaliber has 130 mm rear hub spacing instead of the typical 135 mm. There are some rear disc hubs with 130 mm spacing but they're not real common.


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## NYrr496 (Sep 10, 2008)

I fooled around with the spacers on an old 8 speed XT hub and made it fit the 130mm frame. 
Also, I built a set of 20" wheels for my Dahon folder. I used a Bike Hub Store rear hub and a Paul's front hub. Had to. They're the only ones that made a 74mm wide hub. Freakin' thing was 150 bucks. Anyway, I used Velocity Cliffhanger rims. I love these wheels. I would have used the Cliffhangers on my son's GF had I known about them or they had been available.


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## Erock503 (Oct 20, 2014)

GrayJay said:


> Beware, 20x 1-1/8 BMX rims are a different diameter (451mm ISO) than MTB 20" rims which are 407mm diameter. BMX stuff tends to be extremely overbuilt for kid MTB use too, watch the weight of the parts.


Wanted to say thanks again, would have wasted a lot of time on those rims. Now that I look at them, there is a big difference in diameter.

You were also right about the weights. Built up some Aeroheat. What a waste of time that was with these Koozer xd1700, lol. I only saved about 175g total, but did move up to 7 speed from 6. Also allows disc now, but I think these v-pull are lighter. After weighing the stock tires, I think that will make a bigger difference than the wheels. They come out to 570g, which seems kind of heavy for 20". All said and done, wound up with a 1585g 20" wheelset(w/skewers, valves, tape incl.), which still seems stupid heavy. At least it has more bling.


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## PinoyMTBer (Nov 21, 2013)

The Voltage Jr20 are heavy little bikes! But that didn't stop me from upgrading my lil guys 20" DJ/Freeride looking rig. Here is how it looks currently :thumbsup:


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## PinoyMTBer (Nov 21, 2013)

The upgrades:

SRAM X7 shifter/rear mech (1x9 setup, 34t chainring - 12-36t cassette)(X9 trigger shifter pictured)
20" Novatec Disk wheelset
Avid BB7 Mechanical disk brakes with 160mm rotors with Avid levers
Dangerboy 40mm riser bar (cut to 600mm)
Truvativ Hussefelt 40mm stem
Maxxis MaxxDaddy tires (the knobbiest 20" tires I could find, great for mud/loose/rocks..basically anything)

The wheelset's (and tires) color scheme with those rotors definitely enhances the look...IT LOOKS SO SWEET! My boy loves how strong the brakes are too, but he's friends keeps complaining about it, cus they get catapulted out of the bike as soon as they hit the brakes.


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