Why is it hard to find 86mm crankset

[memeticmusic]

I've been looking for a x2 crankset for a 86.5 mm bottom bracket (30 or 24mm spindle) with a large chainring 60t if possible. Most cranksets Don't even specify the spindle length, why is that? Do I have to assume they're 68-73? I saw one #BB386evo I'm assuming it's 86mm but I need a bit more than 86mm, maybe 100mm total due to crankarm width.

 

[glennb]

You have an 86.5mm bottom bracket installed, and want to be sure the cranks you buy will fit them?

Square taper cranks? The width doesn’t matter, only the spline. There’s only two standards, JIS, and ISO. The BB will be JIS, and so will practically any “new” cranks you buy. Just avoid Campagnolo or any exotic sounding European names on the second-hand market.

There’s no guarantee about precisely what chainline you end up with though, that’s not so standardised, and with cheap soft aluminium it varies by how much you torque them, and reduces each time you reinstall them.

 

[bengxe]

We need to know what bb shell you have in your frame. 68, 73, and 86mm are shell widths, not spindle lengths, so they may already do what you need. BB386evo has a larger shell diameter than anything that would take a 24mm spindle, so it's not either/ or.

 

[memeticmusic]

We need to know what bb shell you have in your frame. 68, 73, and 86mm are shell widths, not spindle lengths, so they may already do what you need. BB386evo has a larger shell diameter than anything that would take a 24mm spindle, so it's not either/ or.

the shell is T47 threaded 84mm 2"OD.

 

[bengxe]

You probably need an internal t47 bottom bracket and a standard width crankset. You can add spacers to take up that difference and possibly add some clearance, but the q factor measurement might be more important for the clearance you need.

https://www.amazon.com/FSA-BB-6002-MegaExo-Hollowtech-Bearings/dp/B0BQJ84JKP/ref=sr_1_16?crid=3TURUFZK0OY30&keywords=t47+bottom+bracket&qid=1697117748&sprefix=t47+bottom+brac%2Caps%2C85&sr=8-16