Stupid Fat Bike Que...
 

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[Closed] Stupid Fat Bike Question

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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


 
Posted : 05/01/2016 1:58 pm
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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!


 
Posted : 05/01/2016 2:08 pm
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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.


 
Posted : 05/01/2016 2:09 pm
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While we are at it. If you use a square taper bb can you use any old crank set?


 
Posted : 05/01/2016 2:14 pm
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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.


 
Posted : 05/01/2016 2:24 pm
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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.


 
Posted : 05/01/2016 2:42 pm
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Ok, ta.

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


 
Posted : 05/01/2016 2:43 pm
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someone used a saint BB on a fatbike, but like has been said the crank won't work


 
Posted : 05/01/2016 2:47 pm
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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


 
Posted : 05/01/2016 3:00 pm
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Cheers RD


 
Posted : 05/01/2016 3:20 pm
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What HTII 100 mm cranks are there?

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


 
Posted : 05/01/2016 3:24 pm
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Shimano don't make any but race for cranks are compatible with HTII cranks.


 
Posted : 05/01/2016 3:33 pm
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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!


 
Posted : 05/01/2016 3:33 pm
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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.


 
Posted : 05/01/2016 3:54 pm
 JoeG
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On-One have a 100mm square taper BB available
[url= http://www.on-one.co.uk/i/q/BBOO100/on-one-100mm-shell-bottom-bracket ]http://www.on-one.co.uk/i/q/BBOO100/on-one-100mm-shell-bottom-bracket[/url]


 
Posted : 05/01/2016 11:45 pm
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There's also at least one person who's cut and welded shimano cranks to widen them, seems pointless though.


 
Posted : 05/01/2016 11:55 pm
 Alex
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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 😉


 
Posted : 06/01/2016 8:46 am
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Alex was that the 170 or 190 aeffect crank. And is it the cinch single ring you used? Ta


 
Posted : 06/01/2016 9:09 am
 Alex
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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.


 
Posted : 06/01/2016 9:23 am
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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


 
Posted : 06/01/2016 9:40 am
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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.


 
Posted : 10/03/2016 4:37 pm
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Aeffect is a 24mm version of their 30mm cranks. Works with standard Hollowtech BBs.


 
Posted : 10/03/2016 4:40 pm
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Oooorrsum. I've got a spare HT2 BB anyway.

Cheers!


 
Posted : 10/03/2016 5:10 pm

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