I swear every thread i've posted lately (because it has been) has been about cranks and gears. Having been looking at many different kinds of cranksets, i've come to something that stumps me. Some cranks advertise that they're a road crank, or a mountain bike crank. Is there really a difference in them? or is it just that specific gear combinations are used more in these activities. i've noticed teeth counts like 53-38 being popular for rod cranksets and like 44-32-20 being a more popular mountain set up. I'm just curious if the quality, make, or anything else is an important difference.


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a sump is "a pit or hollow in which liquid collects" thank you spelling error teaching me a new word

It's mostly the tooth counts, the number of chainrings, and the style.

If you're looking for a singlespeed / fixed gear crank though (this being the SSFG forum), it's best to start with an actual track / fixed gear crank and the appropriate size bottom bracket.

You can make a road crank work, especially for singlespeeds, by taking one chainring off, and getting shorter crank bolts, and figuring out which side of the spider the chainring needs to be on for a straightish chainline, and doing the math on what bottom bracket you need if your existing one doesn't work, etc., etc., etc., but if you're shopping for a new crank for an SSFG bike, it's kind of a waste of time looking for road cranks or MTB cranks.

Just buy a Pake or Origin 8 crank for $50-60, and get a 107mm BB and call it a day.

You'll be a lot happier with the right stuff.

There are all sorts of differences--- ranging from Q-factor, to the fact that most mtn bike cranks need to accommodate much smaller rings, and thus have smaller bolt circle diameters. You cannot fit a 20T ring on a 144 BCD crank.

But why are you posting this in SS/FG?

You forgot the Eighth Inch for $50. Although it would seem that 103mm is more appropriate for the BB.

I'm posing this in the ssfg area because that is the kind of bike i'm building, and have been considering trying to modify other cranks.

yeah and i very well may just stick with getting a ssfg crank. another thing though. how do i know if a chain i have is 1/8" or 3/32" because it seems like there is two different sizes of cranks.

You measure the width of the rollers on the chain. Same as the distance between the inner plates.