As the construction of my track bike comes to a finish (cinelli bars and stem. pictures to come soon), I'm looking through thrift stores for a cool road frame to convert.

I started thinking about cranks. I really like BMX chainrings and cranks, but what's the sizing of their bottom brackets? There are "euro" converters. What's the "euro" bb size?

I can't find much information. Does anyone know if BMX cranks (3 piece) fit on to regular square taper bottom brackets?

Euro is the standard British thread that 95% of us use, as opposed to the 'American' large 1 piece style BB.

There are a few BMX cranks that use a square taper, but which one I don't know (JIS/Shimano is more common, but ISO (Campag) is ISO and therefore the logical choice if you don't know better). Primo, Ares/88 and Bizhouse are the only brands I can think of that make them.

"Euro" conversion kits are good, but not great. Basically you get two cups with bearings pressed in and some spacers (and maybe a pair of bolts too); you just thread the cups in, with the spacer in between, and put the axle through the middle, no fancy cartridge stuff here (but Hollowtech II is similar, so it can't be that bad). Not all crank makers do a conversion kit, but some use the same spindle diameter as others (like the Odyssey cranks on my BMX that will take a Profile BB). Do your homework if your chosen crank doesn't have a dedicated conversion. (Some cranks are available off the shelf with British cups, others you'll have to buy it seperatley and have an extra set of useless cups, handy if you ever build a BMX or a Schwinn )

There's nothing wrong with the conversion kits, but they're not as good as even a cheap cartridge BB (no seals, more chance of misaligned bearings), but on the other hand, they do have infinately adjustable chainlines, very useful for bodge-job SSs. My advice is, pick the cranks you want, not the BB.

some of the bmx bbs that look like square taper are not actually tapered or are differnt sizes and wont work with non bmx cranks andvice versa... also many manufactures sell in sets, with the bb and cranks together soyou dont ahve to worry about compatability,but on the other hand, that bmx stuf is damn heavy. looks nice though!

BMX BBs are pressfit. You can get converters to go BMX->euro, but not the other way. The BMX BB shell is much larger, so if you've got a threaded BB, you're out of luck.

If you're just looking for some stiff cranks, just about any aftermarket MTB crankset will be plenty stiff.

[edit]

Looks like I spoke too soon. Turns out, the 2004 models of the S&M frames have euro BBs, and they make a BMX BB for it that fits 19mm or 22mm spindles. Ask your LBS for the S&M Alloy Euro BB kit.

Many 3-piece BMx cranks should be fine. I've got a set of BUlletproof cranks that work great, no fuss no muss. go to the bike shop and they should be able to help you. Just be clear that you're budgetarily constrain and that $80 is not a cheap crankset in your book.

there are alot of euro bmx cranks out there now.. dont know if bmx euro and road euro are different.. take a look at www.danscomp.com for cranks and size info.

if you're looking for 165mm bmx cranks, you're going to have to look at stuff for mini bmx race bikes. crupi makes 165mm square taper bmx cranks, but at their prices, it's bike jewelry. you could look for some cool vintage anodized alloy bmx cranks. almost all of those cranks will use regular square tapers. you may have to run a 107mm or 109mm spindle to get the chain allignment correct, so i've been told.

The Bulletproof cranks come in 165 and cost $35-$40.

Check out Profile cranks. They're $$$ and heavy as they're cro-mo, but honestly, they'll most likely last forever.

https://www.profileracing.com

ditto on the bulletproof cranks -- more affordable and fit fine. i have 155s, even! (they are actually the same cranks as the 160 or 165 but the holes are drilled further away from the ends so a little bit of it extends past my pedals, those cheap bastards )

Ha! They go all the way down to 140mm. Hopefully they don't use the same arms on the 140's as the 170's.

Another plug for the Bulletproofs...I had to mount the ring on the inside (fugly) to get good chainline, but for the price you can't beat 'em.

is this road frame going to become your "track" bike? what magic will ensue.

moving on, dotek bmx cranks would also work great for a "track" bike.

here are some nice cranks:

https://www.revolutionbike.com/crank_pic_&_info.htm

another affordable option:

https://www.sinz-racing.com/

supposedly they run around $40. available in tapered or isis spline