2-ring crank options?

[FishMan473]

I'm building my first "real" fat bike, I think I've worked through most of it, but I'm a bit stumped with the whole crank thing.

I'm looking for something that can run a 22t (or in a perfect world 20t) small ring, and a 32t big ring... maybe a 34t at most. I'm looking for something fairly light since this will be a race bike (I plan on buying a Beargrease frame), but certainly not going for all out blingiest item.... my build is currently pushing my budget as it is. Lastly, I'd like to have the lowest q-factor I could get away with for a fat frame.

It looks like E*13 and Middleburn might be options, but I'm a little foggy on how/what BB's I would run with them. The FSA Alpha Drive cranks look pretty cheap, and not much heavier... depeding on the BB I suppose. And for that price I could get a Phil Wood BB to go with it for something like $100 less than those other cranksets and just a few grams heavier... or am I missing something?

I'm sure there are others I'm missing... what else is out there?

[BjornS]

I read in another thread the other day that RaceFace have fatbike specific cranksets available now. That is with a 100mm spindle, and I guess they use the "standard" bottom brackets type you find on Shimanos and the other RF cranks.

Remember from the thread that the "usual websites" dont have them listed yet, but any LBS should be able to contact RaceFace and get them ordered.

Some of them RF cranks are both light and beautiful, FWIW.

Bj.

[bdundee]

Still one of your best and lightest bets is like you said get a Phil and a square taper crankset. I would look for an Old RF Turbine or something on that line, there's a reason that crank is holding it's value.

[nvphatty]

I read in another thread the other day that RaceFace have fatbike specific cranksets available now. That is with a 100mm spindle, and I guess they use the "standard" bottom brackets type you find on Shimanos and the other RF cranks.

Remember from the thread that the "usual websites" dont have them listed yet, but any LBS should be able to contact RaceFace and get them ordered.

Some of them RF cranks are both light and beautiful, FWIW.

Bj.

yup they are. I currently use one of these 24/32 setup by choice but i imagine a 22t spider could be had elsewhere.

Race Face 2012

[Dustin Mustangs]

How about the Surly OD?

[pursuiter]

Surly Mr Whirly can be had with the MWOD 20/33 set-up:
Universal Cycles -- Surly MWOD Chainring Set

[lostraveller]

I cannot afford the Middleburns yet. Can I get started with this Shimano square taper crankset ( FC-M442 triple 22/32/44) and upgrade to the Middleburn RS7 later. Think this crankset was designed for 50mm chainline on 73mm BB shell????
What Phil spindle lenght? 145mm spindle with with 5mm offset?
What chainline would this give?
Can I clear Husker Du's on 80mm rims in 9zero7 170mm frame? Do I need to loose a cog from 10sp SLX cassette?
Will the 10 speed chain be ok with 9 speed chainrings?

OR just wait a few more months!

Ideas.

[Scottytheoneandonly]

fatbikes.com has the eThirteen double in stock. $350. BB cups are $50. Shipping free in the lower 48. (I just ordered one)

QBP does NOT have them in stock and ready to ship at this time, so it's doubtful any shops could get them for you soon. No ETA at this point either.

If you order middleburn or white industries crank arms along with a square taper bb, plus rings it'll almost certainly cost you more than $400.

I priced all of those options a month ago. eThirteen is the lightest and best cost option for fatbike double.

[Lars_D]

I cannot afford the Middleburns yet. Can I get started with this Shimano square taper crankset ( FC-M442 triple 22/32/44) and upgrade to the Middleburn RS7 later. Think this crankset was designed for 50mm chainline on 73mm BB shell????
What Phil spindle lenght? 145mm spindle with with 5mm offset?
What chainline would this give?
Can I clear Husker Du's on 80mm rims in 9zero7 170mm frame? Do I need to loose a cog from 10sp SLX cassette?
Will the 10 speed chain be ok with 9 speed chainrings?

OR just wait a few more months!

Ideas.

Phil spindles go from 145-155. You can even get one with a 5 mm offset to the right. The 155 offset which can be adjusted an additional 5 mm to the right is equivalent to a 170 spindle and should allow you to fit almost anything. Here is a picture of my mukluk with a Shimano triple crank a phil 155 offset BB and clownshoes and husker dus. There is Plenty of clearance with the chain as close to the tire as it will go (on the little chainring and big cog).

[sryanak]

Check out Speedway's Fatback double crank. It is reasonably light, fairly inexpensive and easy to set up. Can't go wrong with Phil BB and a square taper Shimano, Race Face or Middleburn, but the PW bottom bracket costs almost as much as the Fatback Crank complete.

[bdundee]

Check out Speedway's Fatback double crank. It is reasonably light, fairly inexpensive and easy to set up.

+1 It's funny how people pass by the Fatback cranks. I really like mine plus it gives extra chain to tire clearance than most of the others.

[FishMan473]

Phil spindles go from 145-155.

So what size does one need to clear 4" tires on 80 mm rims? I'd like to get the lowest q-factor that I can.

I've decided that, for now at least, the Phil Wood BB is the right option for me. I found an old square-taper Deore crankset in my parts box. Once I took the 44t chainring off I'm left with a 22/32 that only weighs 573 grams, and that's with the original steel bolts. Coupled with the Phil Wood that's only 843 grams, not bad for a total of $160. I think that puts them right about the same weight as the e*Thirteen crankset, but I'm not sure if they include the BB in the cost and weight of those when listed.

[NYrr496]

Supposedly, Surly's OD Crankset will be available on the 15th.
That's the one I'm waitin' to see.

[Tipstall]

Supposedly, Surly's OD Crankset will be available on the 15th.
That's the one I'm waitin' to see.

I was thinking the e13 was the best option. What advantage does the Surly OD offer?

[sryanak]

So what size does one need to clear 4" tires on 80 mm rims? I'd like to get the lowest q-factor that I can.

I've decided that, for now at least, the Phil Wood BB is the right option for me. I found an old square-taper Deore crankset in my parts box. Once I took the 44t chainring off I'm left with a 22/32 that only weighs 573 grams, and that's with the original steel bolts. Coupled with the Phil Wood that's only 843 grams, not bad for a total of $160. I think that puts them right about the same weight as the e*Thirteen crankset, but I'm not sure if they include the BB in the cost and weight of those when listed.

Don't forget you need the wide bottom bracket mounting rings for another $60.00 and then at least access to a tool to mount the rings. Mounting rings add another 50 grams or so as well. Still not too bad an overall weight. But as I stated earlier you are getting very close in price and weight to an all new Fatback crank. I was planning on doing almost exactly what you are planning to do on my wife's bike but went with the FB crank as it was simpler and faster as I could buy the crank from the shop rather than waiting for Phil Wood to send something out.

[bdundee]

Don't forget you need the wide bottom bracket mounting rings for another $60.00 and then at least access to a tool to mount the rings. Mounting rings add another 50 grams or so as well. Still not too bad an overall weight. But as I stated earlier you are getting very close in price and weight to an all new Fatback crank. I was planning on doing almost exactly what you are planning to do on my wife's bike but went with the FB crank as it was simpler and faster as I could buy the crank from the shop rather than waiting for Phil Wood to send something out.

Pretty wide q factor with the Fatback crank though.

[GrayJay]

Seems to me that if you are using any crank originally designed for 3-ring but only using the inner 2 rings (middle and inner ring + outer bashguard), you are either giving up chain/tire clearance and/or producing a wider Q-factor than would be needed with a purpose built 2-ring crank like the surley OD. The one other option of using only the middle & outer chainrings of a triple could be done with correct length spindle to maximize width and minimize Q-factor, but this usually also limits you to using a fairly large ring on the middle position, not a granny size ring.
Important consideration for the OD crank is that it actually moves the granny ring to middle position without widening the Q-factor.

[Lars_D]

So what size does one need to clear 4" tires on 80 mm rims? I'd like to get the lowest q-factor that I can.

I would guess you'd be pretty safe with a 145 with the 5mm offset. If it turned out that you didn't need the offset, there is enough adjustability to center the spindle.

[FishMan473]

Thanks for the info on the Phil Wood set-up sryanak, but my parts-box cranks plus the Phil Wood BB still comes in at ~$150 cheaper and only about 65 grams heavier than e-Thirteen. But it does spell things things out better, I guess q-factor could be a deciding factor here.

Speaking of which, GrayJay you make a good point about chainline vs q-factor. The OD cranks seem like they make sense I would need to pony-up extra for the 33/20t rings though. Does anyone know any actual facts about them? Price? Weight? Q-factor?

[thesilversurfer]

Get an FSA afterburner from fatback. Brilliant crank and has a great selection of chain rings to chose from too. Also they are more outboard than the E13 cranks. Less tire rub.

[NYrr496]

I was thinking the e13 was the best option. What advantage does the Surly OD offer?

Well, being that it isn't available yet, I just think it looks perfectly simple and suited to the application.