Can you use 83mm DH cranks on a fat bike frame with a 100mm BB shell? Wondering if there’s enough clearance on the spindle and BB cup threads.

Cheers

No, I don’t think that would generally work. There might be some combination of BB & cranks which would allow you to get away with it, but I suspect not. 17mm is quite a lot!

What he said, it’s almost twice the difference between 73 and 83mm cranks.

x5 fat cranks a re cheap enough that you could sell the DH cranks and not be too out of pocket.

While we are at it. If you use a square taper bb can you use any old crank set?

While we are at it. If you use a square taper bb can you use any old crank set?

Yes and no.

Yes you can, you just keep getting bigger and bigger BB’s until you have clearance between chainring/chain and chainstay/tyre.

No you can’t, some fat bike cranks have the chainline shifted out but the arms are straighter to keep the Q factor sensible, a bit like the current ‘boost’ standard. This means that some fat bike cranks don’t fit on some fatbikes (the first batch of On-One Trail’s had issues IIRC and had to be sent back, as well as others). So while it may fit, some combinations may result in a ridiculous Q-factor if you’re building a 120mm BB for 5″ tyres, 100mm BB/4″ tyres the worst that’ll happen is the Q-factor is almost as wide as a 120mm BB.

That and Royce BB’s are as much/more than a cheap chainset. And niche enough that there’s probably a limited 2nd hand market so you can’t make your money back on them.

thisisnotaspoon – Member

x5 fat cranks a re cheap enough that you could sell the DH cranks and not be too out of pocket.

Though on the downside, you’ll have SRAM cranks and BB.

@Zippy, I should have a 100m square taper BB spare soon, it’s worth buggerall as I’ve damaged one of the crank arms so if you’re looking for one, give me a shout.

Ok, ta.

Could have sworn I’d seen someone post on here about using Saint cranks on a fat bike but hey ho.

someone used a saint BB on a fatbike, but like has been said the crank won’t work

you can use any HT2 BB on a threaded frame, I’m using a deore with a 100mm race face crank (24mm) it’s the spindle length thats important

Cheers RD

What HTII 100 mm cranks are there?

Have got some RF Ride XCs at the moment but you know how it is

Shimano don’t make any but race for cranks are compatible with HTII cranks.

you can also use 100mm FSA ISIS BB with middleburn cranks and so on as well, mine has lasted for 17months on the pug without any bearing death yet!

psycorp – Member

Could have sworn I’d seen someone post on here about using Saint cranks on a fat bike but hey ho.

I think that was in one of the Dune threads- if I’ve got the right post, it’s someone using a raceface 24mm fatbike chainset who found they needed a bunch of spacers on the driveside so is using a Saint BB as they have more thread ie more support for spacers.

On-One have a 100mm square taper BB available
http://www.on-one.co.uk/i/q/BBOO100/on-one-100mm-shell-bottom-bracket

There’s also at least one person who’s cut and welded shimano cranks to widen them, seems pointless though.

I think that was in one of the Dune threads- if I’ve got the right post, it’s someone using a raceface 24mm fatbike chainset who found they needed a bunch of spacers on the driveside so is using a Saint BB as they have more thread ie more support for spacers.

That was me. Race Face Aeffect cranks with a saint BB. I’m sure every fat bike will be maddeningly different in terms of what works. There something about offset that I don’t really understand either 😉

Alex was that the 170 or 190 aeffect crank. And is it the cinch single ring you used? Ta

99% sure it was the 170: http://www.wiggle.co.uk/race-face-aeffect-cinch-fat-bike-crank-arms/?sku=5360734568 – out of stock now. Had a cinch single ring in the spares box. Cranks don’t come with a BB so no great shakes having to buy a saint.

Thanks for info I was gonna buy the 190 bit the q factor is huge. But I’d like to possibly run a 28t front so options are limited it seems

alex,

I thought the race face aeffect had a 30mm axle, and the Shimanos were all 24mm? I woudln’t have thought they could work?

Looking at the aeffect myself, but put off by pony RaceFace BB at £42 a throw, or slightly better Hope BB at double that.

Aeffect is a 24mm version of their 30mm cranks. Works with standard Hollowtech BBs.

Oooorrsum. I’ve got a spare HT2 BB anyway.

Cheers!