JonathanGennick 

I am looking at some cranks like these:

https://www.danscomp.com/452538.php?cat=PARTS#

Is it possible to mount them to a mountain-bike frame? All the bottom brackets that I've been able to find to match the above style of crank seem to be sized for the really large shells that you find on BMX bikes. Is there a solution for mountain-bikes?

Eggywootah

I have no idea.... but if you're gonna spend that much money, why not get some nice mountain cranks? Is it for the singlespeed? There are plenty of singlespeed mountain cranks. And what about pedals? Do those cranks take 1/2" or 9/16"?

Retro Grouch 

What you're looking for is called a "Euro" crank and bottom bracket.

reptilezs

just need a euro bb. most 3 piece cranks have euro bb options

JonathanGennick 

What I'm really after is a way to run a single, small ring up front. I'd like to be able to run a 25-tooth (or less even) ring up front in a 1x9 configuration with a 12-28 cassette out back.

Every time I think I'm close to a solution, some compatibility issue jumps out at me. BMX cranks work, but not the ones designed around Euro bottom-brackets. Mountain-cranks don't allow me to run a low-enough tooth-count.

Colored would be really nice. I can only get colors in single-speed, track cranksets having chainrings of 44 teeth, but that's far too many teeth. I can also get colors in BMX cranks.

I just want a simple, 1x9 or 1x8 configuration with a small ring up front. Color is optional, but would be nice to have.

JonathanGennick 

Maybe I'm just not interpreting what I see correctly. None of the bottom-brackets at Dans comp that allow for those BMX spindles is listed as a "Euro". The Euro models seem to be all square-taper or ISIS.

I'll look again. Maybe I'm just not seeing.

JonathanGennick 

Oh, duh! I wasn't seeing. I think I've gotten it figured out now though.

Dan Burkhart 

All you need is a cup set like this.
https://www.gussetbikes.com/gusset/pr....php?id=BBGUXE
That one is for a 19mm spindle, but I believe they are also available for 22mm.

Greyryder

Dan's sells a number of European bottom brackets designed for BMX cranks. The Demolition BB is only available in Mid size, but BBs to fit 19mm spindles are a dime a dozen. I'd recommend either the Profile or Redline bottom brackets. Both are available to fit Euro style crank hangers.

One word of warning: I don't know that MTBs and BMX bikes have the same width bottom bracket shells. If they do, you should be golden. If the MTB shell is narrower, you can probably get by with extra spacers. If it's wider, the spindle may not be long enough to properly engage the spindle splines.

Jeff Wills

I'm pretty certain the BMX "euro" BB shell is the standard 68mm width. For BMX bikes, they're commonly used on Mini-BMX frames where the "stress" isn't as great.

Another potential incompatibilty: chain width. BMX chainrings are available in 3/32" and 1/8" width- you want 3/32". Since you're going for a 1x9 drivetrain, you should be OK. If it were some whackdoodle 10-speed setup (which uses a 5/64" thick sprocket) then you'd be SOL.

Greyryder

These days, they're running them on the full sized race bikes, too. They're just not using the standard MTB spindles, because they don't hold up.