Can U - grind 140mm cranks from a spider?

I use cranks on my MUni that Steve Howard had ground down from a spider. These are 170mm cranks.

Are there any 140mm cranks out there, that you could do the same thing with?

Has anyone done this? Use would be for trials with drops less than three feet.

As most cranks with a spider belong on a bike, I doubt you will find any that short.

Even small sizes of bikes (that have chainrings on them) will have cranks of around 170mm

ANy cranks smaller than that…if you can find them with a spider…would be the made of the weakest steel, I bet, and not suitable for any trials

Why not just buy 140mm unicycle cranks? Why do you have to buy bicycle cranks and remove the chain ring spider?

the dotek cranks that roger at has are made from mtb cranks, and good strong mtb cranks at that.

however the dotek cranks are actualy lefthand mtb cranks cut down and rethreaded. no spider to grind off.

140mm bike cranks are very hard to find. i’m pretty sure that the 145 monty cranks are the closest you’ll get, and as we have heard they are expensive and weak.

i will definatly get myself a set of dotek cranks after christmas, and after i’ve paid off my overdraft.

I have some 140mm Dotek cranks. In fact they are on this unicycle here.

I didn’t know that they were machined down mtb cranks. I got them from in the US.


Most times, I try to figure out a cheaper alternative to some things. When, yes, I agree, sometimes it’s just easier to pay for it simply.

My response was based on my experience.

The Steve Howard cranks were bought through Bike Nashbar as one of their sales cranksets and then ground off the spider.

I just thought I might ask if something like that might exist for shorter cranks. I don’t have anything to loose in asking.

I am still at that stage in spending when i try to get a decent deal for cheap. Sometimes I “catch” something and sometimes not. Eventually, I hope to be able to not hassle with that.

I had posted a question in the Reviews Forum regarding the durability of Dotek Cranks (140mm) for light trials this morning. I am still looking for coments on them. I have no problem getting a set of those if they will suit my riding style. They seem like a good deal if they hold up.

Happy Holidays everyone!!:slight_smile:

I will never “hear the end of it” if I don’t fix this one…

The spelling police will be all over me. As a teacher, I should know better.

loose, should be l-o-s-e.

There, I fixed it.


140mm cranks

I was wondering the same thing. I found a pair of 140mm cranks
with a spider made by Bulletproof BMX. (Same company that make the replacement crank arms for the DM ATU splined hub.) I think should be good quality cranks, if going by the brand name is worth anything. They cost $31.

Curious thing is I couldn’t find out any more about these cranks (by doing a Google search) and nor could I find a website for Bulletproof BMX. Seems a bit strange that a high-end BMX component factory doesn’t have a website. Makes me think that they’re either too small to have one or that Bulletproof is owned by some other operation… I’d like to know a bit more about these cranks before I buy them…Help!

Desperately wanting strong 140mm square taper cranks.

Re: Can U - grind 140mm cranks from a spider?

In the days when the only unicycle cranks you could buy were 125mm or 150mm steel, I ground down a 145mm Miche Childs Racing bike crankset and a Hadley 155mm BMX alloy crankset.
I used them both for Muni originally and latterly off-road cokering.

Leo White

Profile 140mm

I’m almost positive profile makes a cnc’d or posibly forged aluminum trials crank for bikes. they are 150mm and are made to fit standard square taper bottom brackets. profile has no problems catering to custom orders on their chro-mo crank arms and may be able to help you out with the aluminum ones as well.
they have a removable 20 or 23 tooth sprocket that you obviously wouldn’t be needing, i think it’s held on by a couple of allen head screws. they are beautifully crafted and priced pretty reasonably.

also, if you have a splined bottom brakcet. profile makes cranks for mini bmx bikes that are thinner walled and have a treaded crank bore so you don’t have to beat them mercifully to get them off of you axle. they will fit the 48 splined profile uni axle.
i believe you can get these in a 140, if not. as mentioned above, they are very helpful when it comes to customer needs.

Re: Profile 140mm

They’re 155mm - I have a set on my Muni.

The chainring comes off okay once you can brake the threadlock on the bolts and they require no grinding.

They’re not cheap in the UK. I got mine for 75 ukp (half-price).

Leo White

Re: Re: Profile 140mm

I’ve also remembered I now have a digital camera…



Re: Re: Profile 140mm

I’m turning myself in (to the spelling police !)



Isn’t that a photo of the left crank? Even in the UK, isn’t it the right crank that carries the chain rings? What does the right one look like on the inside? That would be tough to photograph without removing the crank.

Also, it looks like you’re using Allen head crank bolts rather than the antiquated crank nuts that unicycles historically use.

no man, Im pretty sure it is a righty. look at the way the pedal is shifted forward, lets you know what side it is.

It is the right one, the Allen headed bolts were on the inside bolting on the solid 23 tooth chainring.

Yep !

It’s a DM tapered hub so it has an “innie” hole that takes bolts.