BMX Conversion?

[TOMTRIALS123]

I was just wondering, could you convert a BMX into a trials bike for a more 'street' style of riding and if so would it could more than it would be worth?

[bing]

Not worth the hassle. The geo will be wrong, as will the brake mounts. Get rid and buy a proper trials bike

[dezmtber]

I brazed on a set of steel magura mounts i got from chain reaction cycles.

fitted them to a gt dyno bmx i found it quite fun to ride. I say give it a go

[*gentlydoesit]

Looking at a few videos, quite a lot of the street stuff I used to do a similar thing on my bmx.. a smaller drive gear and laid forward bars would be good enough, as long as you had good brakes

[Ash-Kennard]

that is the reason 20"s are referred to as mods

modified bmx

if you look HERE you will see the direction things look to be going

[AlexxRogers]

that is the reason 20"s are referred to as mods

modified bmx

I thought it was because Stocks were 26'', so you're modding a mountain bike, not a BMX.

[Ali C]

I think a long bmx with a disc mount and trials gear would be such fun! I'd love to try it but I'm scared I'd like it too much.

[Ash-Kennard]

I thought it was because Stocks were 26'', so you're modding a mountain bike, not a BMX.

20″ – 'Mod Bikes'

The first purpose made and commercially available trials bikes were manufactured by Montesa^[3] a mototrials company and were based on the modified bmx bikes that riders had been using. As a result of being based on BMX bikes, the rear dropout spacing is 116mm. These 20″ wheeled trials bikes have become known colloquially as Mod bikes. It should be noted that some mod bikes have a 19" rear wheel to make room for a bigger tyre, but the overall tyre diameter is similar regardless of the rim size, so this is mostly important as a compatibility issue for spare parts.

26″ – 'Stock Bikes'

Early mountain bikes were well suited to the trials riding and so a separate class was introduced for them. 'Stock Bikes' used to refer to a 26" wheeled mountain bike kept in original or 'stock' condition, i.e. not modified like a mod bike. Stock classed bikes were required to have at least six working gears and a seat. Now however, this designation is used to describe any trials bike with 26″ wheels, as current 26" trials bikes look about as similar to mountain bikes as 20" trials bikes look like BMXs.

Historically stock bikes all had 135 mm spaced dropouts to take a standard mountain bike rear hub. There is a subcategory of Stock trials bikes, sometimes called 'Modstock Bikes', which have 26" wheels but have horizontal dropouts spaced at 116 mm, similar to mod bikes. Horizontal dropouts at both spacings are becoming more and more common in stock bikes as they eliminate the need for a chain tensioner, making the bike lighter (The chain is tensioned by moving the wheel backwards in the dropouts; vertical dropouts are designed to hold the wheel in one position only and therefore require a separate means of tensioning the chain to accommodate wear).

Edited October 18, 2013 by Ash-Kennard

[TOMTRIALS123]

How could you put a trials sprocket on a BMX cause most of them are screw on? You would need to get new cranks as well wouldn't you?

[Ali C]

there are ways to get the correct gear

[TOMTRIALS123]

Ali C... What would you recommend?

[*gentlydoesit]

Smaller chain ring bigger sptoket is esay to find, and cheap.

[Ash-Kennard]

bigger rear cog

[*gentlydoesit]

Still don't know why you'd do it though

[Ali C]

because BMX is rad, and so is trials, bmx's have good geo (short chainstays, highish bb, steep head angle), an easier gear would allow more trials moves and so would brakes. A longer frame would be needed, maybe like a 21.3 or something. Most streety 20" bikes are still a bit too trialsy for my liking, long stem....why?

[Ben Cox]

a mate of mine Martin Murphy started riding on a schwinn bmx with a maxxis maxx daddy on the back.

Ben

[TOMTRIALS123]

Do any of you guys know if you can put a Trials sprocket (Splined or Screw on) on a American Bottom bracket and if so, how?

[Scott Gibbs]

Profile make a 18t imperial nano drive sprocket originally designed for flatland if that helps any?

[dezmtber]

I just ran a 18t freewheel on the back with a 25t front cog.

but you can get smaller front cogs now

[eskimo]

I just ran a 18t freewheel on the back with a 25t front cog.

but you can get smaller front cogs now

That's probably the best way. Run a decent trials freewheel on the back or run a Profile with a big driver.

As for turning an existing bmx into a trials rig, not worth it, in the sense of changing stuff. You'll need a long ass frame, 22" minimum if you want to sidehop anywhere near a reasonable height comfortably. And running a trials gear isn't going to benefit on a short bike.

You can happily hop up walls, do some back hops on a normal un-modified bmx. Just tweak them brakes, and if you get somewhere with gaping on the bmx then lighten up that gear slightly.

Though a 24" trials or bmx would probably be a nice inbetweener.