Please help me out. First step on the new frame and first big issue.
I really wanted to take my Easton EA70 Cranks on my new Karate Monkey. The Cranks are for a 68mm bottom bracket with a 128mm spingle, so i thought i just get a new spindle (134mm) for the 73mm bb on the karate monkey. 50€ later and a new spindle the friggin driveside hits the frame while i have plenty of space on the non-driveside that the preload cant handle.
am i wrong or do i need spacers for the bottombracket and a even longer spindle?
already spend to much money to make that crap work that i propably cant return because of scratches from putting them in 🙁
by Striking-Jury2712
12 Comments
Looks like you need ~5mm of spacers on the drive side. There appears to be a gap on the non-drive side without spacers.
73mm BB still needs a 2.5mm spacer on the drive side. 68mm has 5mm on drive side and 2.5mm non drive side.
https://wheelsmfg.com/bb-standards
This should help with figuring out which spacer configuration to use.
Hard to tell from photo but it looks like you have spacer between the preload ring and bb. At a minimum that should be on the drive side I think but hard to tell without knowing all the specifics of your setup.
haha i’m dealing with the same thing on a CINCH equipped fat bike. You just need some spacers, but good luck finding them…
Are ea70 cranks intended for road/gravel bikes? If so, you likely need a very long spindle and a lot of spacers for the cranks to clear the chainstay, and then your chainline will be way off. Probably better off buying a crankset intended for use with boost rear spacing.
MTB cranks fit on a 73mm shell, yes, but they also have an additional 2.5mm spacer on the drive side which is a place holder for a BB mounted front derailleur or chain guard. So all else being equal, it’s not a jump from 68mm to 73mm but from 68mm to 75.5mm as far as the chainring is concerned.
Best to actually measure ideal chainline. [All About Bicycle Chainline](https://sheldonbrown.com/chainline.html)
One thing to note, you are trying to adapt Road/Gravel cranks to a Mountain bike frame. This generally does not work well, or at all. Chainline and q-factor need to also be considered when adapting these cranks.
Original chainline on the EA70 cranks was 45mm
New chainline should be ~48mm with the 6mm longer spindle
Boost MTN chainline needs to be between 51 and 53mm
Q-factor is a bit different and difficult to find. But generally, Road/Gravel Q-Factor is narrower than Mountain. A larger q-factor is needed for the crank arms to clear the chainstays. Road/gravel is more narrow as they have narrower chainstays.
SPACERS
Rad White Industries BB!!!!
You don’t have any spacers installed.
You need spacers on the drive side.
Forgot the bearings