Micro 2X Cranks

These cranks are for Jake Harrell’s PodRacerOne.

Bombshell Velocity 155mm cranks drilled to accept 64mm rings so that he could have a 2×9 drivetrain on his bike. The little man needs some gears to get up those hills!

It’s hard to get high quality 165mm cranks for multi speedĀ mountain bike. Hell, it’s even harder to get lower quality versions. You pay a premium and you don’t have many choices. Add to that difficulty is needing a 104/64mm bolt pattern that allows the use of decent 2×10 chainring options. You are basically looking at Shimano XTR or XT, SRAM X0 orĀ Race Face Respond

Small people need even smaller cranks. For Jake, smaller than 165mm is a must, he’s 8 years old. That mean turning to the BMX world for a platform. We (Bryan and I) decided on 155mm. These Bombshell cranks are available in 150 and 155mm as well as other larger sizes. It would have been nice to have a 24mm spindle crank option but there is more difficulty finding the right casting in the BMX world.

It’s really too bad that the Sinz Expert cranks are a 110bcd. They are cheap, decent quality and range in length from 115mm to 180mm in 5mm increments. There is just no way to make a 110bcd decent for modern parts selection in multispeed mtb applications.

You will notice that for some reason the BMX world is a little stuck on ISIS crank compatability. It’s as if they didn’t get the memo 10 years ago that it’s just the worst thing ever. They are moving away from that in favor of 24mm, but just stay away from this kind of junk for mtb.

The lands for the ring had to be faced square. I also decided to reference the existing bolt pattern rather than the center of the crank so the rings would be concentric to each other. Plus, it made the math more fun. Simple chainring spacers will fix everything nice. Not sure of the bottom bracket length yet. Obviously, the goal is 50mm chainline between the two rings.