[othello]

The question of short cranks often comes up in threads, and quite rightly too.

I found a supplier of short cranks a while back and thought others might be interested in the details. I'm fairly new to the forums, so apologies if you already know of them.

Utah Trikes sell a 152mm triple chainset Utah Trikes Catalog - Trikes, Upgrades & Accessories

Price is pretty good, and they are OK weight-wise. Not the lightest, and you have you run a heavy square taper bb. But not too terrible and the main thing is the short crank lengths.

I've used these on both of my childrens 13" MTBs.

 

[thesmokingman]

Hey, thanks for sharing that. The prices are rather reasonable too.

 

[cyclo-phile]

Thanks for sharing that. I just bought a set of short Truvativ cranks from BikeSmith, but I searched for days for alternatives for short cranks with replaceable rings. I wish I had seen these.

 

[TwoTone]

While I'm please with the cranks on my son's bike that I got from BikeSmith, I too wish I had know about these when I purchased.

FYI, nice to know Cannondale seems to be getting a kids bike close to right for a reasonable price.

Just bought my daughter the race 24 for $500. Air fork, 152mm cranks

 

[othello]

Glad to hear people are finding the link useful. The only problem is I'm in the UK, so I get charged import duty and an unfavourable dollar to pound exchange doesn't help! Still, better to have the option of short cranks than not at all.

I have also picked up a pair of these 155mm cranks for my sons CX bike. 110 BCD though, but still hard to find usually and really good value Lasco Junior Short Crank Set - Black

 

[thesmokingman]

In the future you can try Thorn from Sjscycles which is in the UK as well. They have cranks from 150mm and up.

 

[thesmokingman]

I just got my thorn cranks and put some rings and a saint bash on. A few minutes with a dremel to mod the slx 32t ring and it looks good as stock.

 

[IdahoLee]

Check out Sinz cranks as well. 125mm and up.

 

[thesmokingman]

A 1x setup is fine for up to 20" but when you get to 24" a 2x crankset is really needed because the kids are capable of some real climbing. Thus BMX cranks even though they are easy to acquire and cheap, they're typically 110bcd, ie. single ring only. Climbing is a lot easier with double/triple rings (ie. 64/104 bcd) and thus worth the hassle to source the bits.

 

[POAH]

what did you have to do to the rings to make them fit.? I'm thinking about getting a the crank for my son and putting my slx rings on as I've switched to a 1x10

I just got my thorn cranks and put some rings and a saint bash on. A few minutes with a dremel to mod the slx 32t ring and it looks good as stock.

 

[clarkrw3]

Those are great!! One of the best things about them is they are 104bcd. I am a big believer in short cranks but also 1x setups for kids. Both my kids are now running narrow wide 30t with 11-42 in the rear and they work great. You can try out Bombshell cranks they work well for the application. My daughters bike needed to have a 24mm spindle and the only one I could find was the bombshell spinnergy cranks.

 

[thesmokingman]

what did you have to do to the rings to make them fit.? I'm thinking about getting a the crank for my son and putting my slx rings on as I've switched to a 1x10

If you look closely at the 32t ring, you can see how I ground the molded plastic covering the ring flat so that it could fit on the thorn crank.

 

[POAH]

If you look closely at the 32t ring, you can see how I ground the molded plastic covering the ring flat so that it could fit on the thorn crank.

cant see it wit my old eyes and iphone

what BB width did you use? chain line for boys bike needs to be 50mm on middle ring

 

[thesmokingman]

When you set the ring onto the crank, you will see how there is excessive plastic molding preventing the ring from "setting" into the spider arms. I basically ground the plastic down to a mil or two of the visible metal leaving just a hair of plastic.

BB... I used a 113mm. The crank is a double so it doesn't have to be 50mm. However a 113mm would give you 50mm or so if you went with triple.

 

[POAH]

cheers helps a lot

 

[IAmHolland]

Huge pictures! The web page goes nuts when in "wide" mode.

I used the Utah Trikes 152mm crank (Lasco) on my son's 24" bike. I replaced the rings with RaceFace Turbine rings. Well used now, but still ticking with no problems at all. I would probably use 36/22, if you could, though my son has no problems with 32/22, a bit higher top end on flats would be nice.

http://forums.mtbr.com/families-riding-kids/sons-24-bike-779684.html

 

[POAH]

When you set the ring onto the crank, you will see how there is excessive plastic molding preventing the ring from "setting" into the spider arms. I basically ground the plastic down to a mil or two of the visible metal leaving just a hair of plastic.

BB... I used a 113mm. The crank is a double so it doesn't have to be 50mm. However a 113mm would give you 50mm or so if you went with triple.

got the crank, clipped the plastic off fitted my old rings. just waiting on BB arriving.

 

[thesmokingman]

Looks good. Did you weigh yours? Iirc the thorn setup as 2x (22/32 with slx bash) ended up over 300g less than the stock parts. The stock crank/bb was ludicrously heavy. I weighed everything while during the swap but forgot to write it all down, doh.

 

[POAH]

its make a significant impact on his cycling. well worth it for smaller kids.

old
BB - 312g
Crank - 938g

new
BB - un55 304g
crank - 766g

 

[thesmokingman]

That's a sweet looking bike!