Putting Bmx Cranks On A Trials Bike

[willdudeXD]

right, im getting new cransk for my bmx and i want to put nmy old ones on my trials bike, but will i be able to use a sealed bmx bottom bracket on a trials frame?

and i need to find a bmx sprocket in 22 with a bashring

[Skoze]

Why? They're heavy, you'll have a f**king hard job finding a 22T ring, and you'll need to dick around with bb's. You could do it, but are you sure you really want to do it?

Especially when i've got some beautiful Middleburns for sale

[willdudeXD]

Why? They're heavy, you'll have a f**king hard job finding a 22T ring, and you'll need to dick around with bb's. You could do it, but are you sure you really want to do it?

Especially when i've got some beautiful Middleburns for sale

haha, i duno cuz my bmx cranks are better than my stock cranks, i dont really mind about the weight, i just trust bmx bbs and cranks more. plus i know more about them,

[Luke Rainbird]

It's very doable - I ran 3 piece cranks on my old Ashton 24", but they sure as hell ain't light.

If you do, you'll need a Euro BB and some way of sorting gearing - I've got a DMR Ring Thing Elite going spare (for 3 piece cranks) if it helps - would let you run the right sort of gearing (22t ring) on your cranks without any issues

[rupintart]

I don't know why everybody thinks BMX cranks are heavy. Your AVERAGE (read, not light, not heavy) is 33oz which is 935g. A typical BMX euro bearing cup (the BB bearings) is around 8oz or 226 grams, and that's for heavy ones. That's a total of 1151g.

A TITANIUM Reset BB is 210, but your average isis BB is around 300g

Trialtech isis arms are 510. After you add a bash and a sprocket, you're sitting around the same weight and not NEARLY as strong. And that's with a standard a crmo axle in the BMX cranks. Don't forget you can also get a Ti axle for the BMX cranks.

If you run Middleburns, you're gonna be slightly heavier than the Trial Tech crank arms, and it puts you toughly in the same weight as BMX cranks.

There are lots of BMX companies who have 23t front sprockets now that a lot of people run 23/8 gearing. You won't be able to get a bash unless you run something that's a 25t and then you get a bunch of options like a Shadow Conspiracy Crowgora (what I'm using) or Odyssey MDS. The inspired one looks to work with BMX cranks as well and is 23t. There's a bunch of other options out there, but those are just off the top of my head.

Anybody who's recently built up a BMX knows, with todays light bmx parts you can build up a SOLID bmx that weights sub 20lbs. It will definitely be a lot more durable than any trials bike you can build up. Heck, KHE has a street bike that weighs 17lbs, and many companies are offering completely OEM bikes that are in the 23lb range with pegs for under $700!!!

Edited February 8, 2010 by rupintart

[Ben John-Hynes]

I don't know why everybody thinks BMX cranks are heavy. Your AVERAGE (read, not light, not heavy) is 33oz which is 935g. A typical BMX euro bearing cup (the BB bearings) is around 8oz or 226 grams, and that's for heavy ones. That's a total of 1151g.

A TITANIUM Reset BB is 210, but your average isis BB is around 300g

Trialtech isis arms are 510. After you add a bash and a sprocket, you're sitting around the same weight and not NEARLY as strong. And that's with a standard a crmo axle in the BMX cranks. Don't forget you can also get a Ti axle for the BMX cranks.

Yeah, but with BMX cranks, you don't get a bash/protection. I know what I'd rather have. Length is also an issue, is it not?

[Sponge]

Definitely possible.

All you'd need is a BMX Euro BB set... just two threaded cups and a tube spacer. The pros would include being able to upgrade your axle to ti freely, choose from a variety of crank lengths (Profile do 145mm to 180mm+), and very importantly, BMX cranksets are much easier to get a proper chainline with than a normal MTB/trials set up.

With the nano-drive system on some BMX cranks, you can run 16t sprockets to 44t srockets freely. Bashring-wise, it's actually not that hard to sort one out I don't think? Though it may take some custom jobs.

[Borgschulze]

I don't know why everybody thinks BMX cranks are heavy.

My crankset, including cog and bash, weighs in at 710 grams with Tarty weights. $360 roughly.

Profile arms with a Ti spindle weighs in at 714 grams with Dan's Comp weight. (Do note the lack of Sprocket/Bash) $250 + Sprocket/Bash

Sooo...?

My setup is Try-All cranks, Reset Ti BB, Trialtech Cog, and Trialtech Ti Half-Bash.

I checked a chainring quick... 65 grams no bash, and about $40...

So the trials setup is about $50-$75 more expensive, but it's also 18t not 23t, and has a bash, and is about 70 grams lighter, won't have issues with the chainring hitting the BB Yoke either.

EDIT: I forgot about a BB for the Profile setup.. so add another 150 grams? now it's a good amount over 900 grams... almost a half pound.

Edited February 8, 2010 by Borgschulze

[Greetings]

Got sand in your vagina? 3rd rant in a few days.

It has been done a few years ago, I think by Dave Cleaver? They were some sort of grey Profile cranks.

[davey1991]

The sayshells character on here also uses them, (Mad mod BMX guy that no one really likes.)

[willdudeXD]

I don't know why everybody thinks BMX cranks are heavy. Your AVERAGE (read, not light, not heavy) is 33oz which is 935g. A typical BMX euro bearing cup (the BB bearings) is around 8oz or 226 grams, and that's for heavy ones. That's a total of 1151g.

A TITANIUM Reset BB is 210, but your average isis BB is around 300g

Trialtech isis arms are 510. After you add a bash and a sprocket, you're sitting around the same weight and not NEARLY as strong. And that's with a standard a crmo axle in the BMX cranks. Don't forget you can also get a Ti axle for the BMX cranks.

If you run Middleburns, you're gonna be slightly heavier than the Trial Tech crank arms, and it puts you toughly in the same weight as BMX cranks.

There are lots of BMX companies who have 23t front sprockets now that a lot of people run 23/8 gearing. You won't be able to get a bash unless you run something that's a 25t and then you get a bunch of options like a Shadow Conspiracy Crowgora (what I'm using) or Odyssey MDS. The inspired one looks to work with BMX cranks as well and is 23t. There's a bunch of other options out there, but those are just off the top of my head.

Anybody who's recently built up a BMX knows, with todays light bmx parts you can build up a SOLID bmx that weights sub 20lbs. It will definitely be a lot more durable than any trials bike you can build up. Heck, KHE has a street bike that weighs 17lbs, and many companies are offering completely OEM bikes that are in the 23lb range with pegs for under $700!!!

lol, yeah i recently built a bmx wich is 23 lbs with pegs, all inned is a ti spindle and a new front wheel and it will be roughly 19

[Mark W]

Why? They're heavy, you'll have a f**king hard job finding a 22T ring, and you'll need to dick around with bb's. You could do it, but are you sure you really want to do it?

Especially when i've got some beautiful Middleburns for sale

Finding a 22t ring's not hard at all, to be fair...

I don't know why everybody thinks BMX cranks are heavy. Your AVERAGE (read, not light, not heavy) is 33oz which is 935g. A typical BMX euro bearing cup (the BB bearings) is around 8oz or 226 grams, and that's for heavy ones. That's a total of 1151g.

Not including spindle it isn't, which is a few 100g's more on top. If you mean some of the newer 2-piece ones most of them are utter shit, and even more are 22mm which - with a Euro BB - isn't ideal.

There are lots of BMX companies who have 23t front sprockets now that a lot of people run 23/8 gearing. You won't be able to get a bash unless you run something that's a 25t and then you get a bunch of options like a Shadow Conspiracy Crowgora (what I'm using) or Odyssey MDS. The inspired one looks to work with BMX cranks as well and is 23t. There's a bunch of other options out there, but those are just off the top of my head.

Inspired bashrings don't fit BMX cranks, in that they're bored out to fit over the threaded part of a FFW crank which is fairly significantly over 22mm. Anyways, you can get a few sub 25t bashring/sprocket combos in the BMX world now, so that wouldn't necessarily be so much of an issue.

Anybody who's recently built up a BMX knows, with todays light bmx parts you can build up a SOLID bmx that weights sub 20lbs. It will definitely be a lot more durable than any trials bike you can build up. Heck, KHE has a street bike that weighs 17lbs, and many companies are offering completely OEM bikes that are in the 23lb range with pegs for under $700!!!

Our definitions of 'solid' and 'rides well' might differ - most ultra light BMXs I've ridden have generally compromised fairly significantly on strength, functionality and general size/geometry just to get that lightness, and I don't really agree with that simply to have a light bike. Things like KHE tyres - they're total shit, but because they're light people run them. Same as those super light KHE completes. The Anchor bar/stem combo is a badly designed, totally needless product that attempts to solve a problem that doesn't exist and as a result creates more problems itself. Their cranks are also pretty weak, and most of the quality of their parts is sub par. So I wouldn't necessarily agree with it being 'a lot more durable', as trials design has moved on quite a bit. You could quite easily spec a pretty damn strong trials bike that'd weigh about that much with relatively little hassle, and probably less expense for more aftermarket components than you'd spend for the equivalent weight BMX parts. Before you think I'm just being biased to trials, I ride BMX more, and have been involved in BMX much more (up until starting to work for Tartybikes, anyway).

Definitely possible.

All you'd need is a BMX Euro BB set... just two threaded cups and a tube spacer. The pros would include being able to upgrade your axle to ti freely, choose from a variety of crank lengths (Profile do 145mm to 180mm+), and very importantly, BMX cranksets are much easier to get a proper chainline with than a normal MTB/trials set up.

Hmm, maybe. Especially with companies like Profile you're fairly limited to your chainline options unless you start spacing out your sprocket from your cranks a fair bit, which isn't really great if you're putting that much power down in trials. I snapped the spokes out of my Vermont sprockets and warped the shit out of a Primo sprocket, and that was just on BMX - if I'd been putting trials pressure through them, I doubt they'd have lasted long at all. Having said that, I'd definitely recommend the Tree splined sprocket I'm running now - they're pretty damn good, and do offer that adjustability.

As a side note, you could quite easily run your bashring on the outside of your Euro BB cup, between the lip of it and the shell of the BB, if that makes sense? So effectively spacing out your drive-side cup of your Euro BB. I know a few people who run that kind of setup on their trials bikes and it works, so I don't see any reason why it shouldn't with that kind of setup.

Anyway, the key thing is to work out where the balancing act is between a strong setup and a light one. Whichever way you cut it, a BMX setup IS going to be heavier than a trials setup unless you spend a fairly significant amount of money on it (things like a ti spindle which you'd need to bring the weight down are about £70 or so), and if you spent that comparable money on a trials setup you'd be able to get a lighter setup that'd probably still be reasonably strong.

A better solution to all this would probably be started if more people used the Spanish BB setup that Deng's used for his 24" bikes. The Ti BB from Echo weighs less than a Reset, yet has bigger, longer lasting bearings and a much more durable spindle. It's a really, really good setup and bearing in mind a Spanish bearing is only fractionally wider than the traditional diameter of a Euro BB (I know some people who machined out their threads on their Euro BB frames to run a Spanish, so you could theoretically do it on your trials bike), it wouldn't exactly impact on weight or looks. With that weight saved you could run a heavier crank like the Trialtechs that are still pretty bomb-proof.

In any case, it's that balance between strength and lightness, and I seriously doubt many people would really need to run a BMX crankset.

[Borat]

Got sand in your vagina? 3rd rant in a few days.

It has been done a few years ago, I think by Dave Cleaver? They were some sort of grey Profile cranks.

I f**king love you.

[Mark W]

Oh, and old T-Masters came with 3-piece tubular cromoly cranks.

[rupintart]

5.75in spindle and I have a perfect chainline. DK Social cranks. I have a bash and have a 25t ring. Light as well.

As for all the rants lately...yeah, sorry bout that. Some crazy shit going on lately.

Edited February 8, 2010 by rupintart

[Mark W]

How long have you had those cranks on for? Most people I know who had them didn't get much more than a few months out of them.

[Borgschulze]

I have perfect chainline with my 128mm BB and the cog in the middle of my King SS hub.

With BMX cranks, there is no way I'd be able to run a 22t and have a perfect chainline, the chainring would be too far out for the hub.

Not sure how the Fourplay is, but that setup, will not work very well at all on my Koxx Coustellier.

[rupintart]

How long have you had those cranks on for? Most people I know who had them didn't get much more than a few months out of them.

I've had them for over 2 years. They were on a BMW Parkbike before the Inspired, which saw trails and DJs. They're pretty much like profiles, they have the 19mm 48 spline axle. They have a lifetime warranty as well, so it's the last thing I'm worried about breaking. They typical BMX spindle is 5 inches or 5.25. I got a 5.75, which is what the profile "mtb cranks" come with and I get 100% spline interface on BOTH arms. Yeah, the crank arms are spaced out a bit to clear the BB yoke, but it's a perfect fit. I have the Hope SS hub on the rear and it lines up perfectly.

[Borgschulze]

You're lucky, there is no chance in Hell it would line up on my Coustellier.

[Mark W]

I've had them for over 2 years. They were on a BMW Parkbike before the Inspired, which saw trails and DJs. They're pretty much like profiles, they have the 19mm 48 spline axle. They have a lifetime warranty as well, so it's the last thing I'm worried about breaking. They typical BMX spindle is 5 inches or 5.25. I got a 5.75, which is what the profile "mtb cranks" come with and I get 100% spline interface on BOTH arms. Yeah, the crank arms are spaced out a bit to clear the BB yoke, but it's a perfect fit. I have the Hope SS hub on the rear and it lines up perfectly.

UKBikeCo Revolution frames had a lifetime warranty, and almost literally every single one of them broke within 6 months of being sold. Lifetime warranties don't really mean anything, apart from you theoretically not having to pay as much when you come to needing to replace them. Similarly, there's a difference between 'pretty much like' and being the same thing (although I've seen broken Profiles too).

Getting "100% spline interface" also doesn't mean anything with regards to chainline, whatsoever, which is what the main problem is with them.

[rupintart]

The 100% spline interface was referring to the Yoke, with the yoke being so wide, most people don't get complete spline interface after spacing out their cranks. Then they strip out the crank arms and axle interface. then again, most people don't do it correctly and order a longer axle so that you can space them out and still have a good interface between the axle and the crank arms. they just ride them with the axle in the crankarm only 30% or so.

Chain line is no problem. Mine lines up perfect. And BMX cranks are easier to line up to the rear anyways. A hassle initially to get set-up, but there's definitely more room. As compared to MTB bs where when you put the crank arm on the BB, that's pretty much it, the chain ring can't "float" to the correct spot, you have to play with the cog in the rear.

As for the lifetime warranty, DK is like Profile, you send them to them, and they send you another one no charge. So if they do break, I'm not worried about buying another set of cranks. Much like you guys in the UK, aren't too worried about buying another set of Burns if they break. I've seen broken burns as well, does that man I should be worried about them breaking as well?

Edited February 9, 2010 by rupintart

[Mark W]

No, but Burns are slightly less prone to breaking than other cranks are. I'd rather not have to worry about my cranks snapping in that having snapped the ligaments in my ankle before I'd be keen to avoid doing that. Although all products break, I'd rather get ones that'll break less even though the weaker ones would still get replaced. It's time and money (for sending them back) that I'd rather not waste. Never mind though...

EDIT: By "100%" interface, do you mean that you're effectively bottoming out your crank bolts on the end of the spindle or something?

[willdudeXD]

5.75in spindle and I have a perfect chainline. DK Social cranks. I have a bash and have a 25t ring. Light as well.

As for all the rants lately...yeah, sorry bout that. Some crazy shit going on lately.

there the cranks i got

[rupintart]

No, but Burns are slightly less prone to breaking than other cranks are. I'd rather not have to worry about my cranks snapping in that having snapped the ligaments in my ankle before I'd be keen to avoid doing that. Although all products break, I'd rather get ones that'll break less even though the weaker ones would still get replaced. It's time and money (for sending them back) that I'd rather not waste. Never mind though...

EDIT: By "100%" interface, do you mean that you're effectively bottoming out your crank bolts on the end of the spindle or something?

The reason most BMX cranks break is 1 of two things:

1. They're OLD. Meaning can you realistically expect a set of cranks that are 5+ years old, that have surface rust from them being grinded on daily, and them being used for dirt jumps, really expect to hold up much longer? I don't really ride ANYTHING hat's more than 5 years old, lifetime warranty or not, even if it looks to be in good shape. You know what they've been through and how you ride. be smart in knowing that things fail. Just because your chain works and looks fine, would you continue riding on it after 1 year of daily use? No, you'd be a little more smart about it and replace it before it injures you. Too bad most people are too cheap when it comes to the same kind of thinking when it's over $10 and just a chain.

2. They're not installed correctly. Most people ride them loose, or don't properly prep the surfaces (loctite or grease) and it results in failure.

When I was talking about spline interface, yes, I was talking about nearly bottoming out the crankbolts on the spindle. The only way you can do that, is the crank arm is COMPLETELY on the axle. With the axle being able to "float" back and forth between both arms, most people don't have the axle centered on both arms, let alone interfacing 100% with the crank arm. Most of the time, the spindle for the application is too short (usually due to spacing), and like only 30-50% of the axle is interfacing with the crankarm and usually interfacing more on one side than the other. i.e. they didn't take the time to even it out when installing it.

If you've ever rode on 3 piece BMX cranks, you'd know exactly what I was talking about. The axle isn't stationary like it is on a mtb, once the bearings are in, you can slide the axle back and forth.

[Borgschulze]

I spaced my rear cog by putting the wheel on, using no cassette spacers, then backpedalling it till it stopped moving.

After it floated to it's position, I added the spacers, and job done.

I can't say the same for BMX cranks. Not to mention most BMX cranks just hammer on and hammer off, kind of archaic.