When I put this crank (Middleburn RS7) onto this bottom bracket it hits this washer(?) before it engages enough of the taper to tighten down. What’s the issue here? Using the correct spindle width for this crank so not sure why it’s not working…
by 4tunabrix
4 Comments
It’s a 113mm? It looks a little shorter than that, but it’s kind of hard to tell from a photo
What is the bottom bracket? Does it have JIS taper axle as required by the RS7 cranks? Is it the correct axle length?
If it bottoms out you shouldn’t ride it. The crank will fit loosely and will deform when ridden.
Shimano calls the black ring a “chainline stabilizer”. It’s for throwing away.
You’re not having a spindle length problem. The whole thing is a badly conceived way of counteracting the fact that square taper bores naturally can enlarge over time with repeated tightening and/or re-installations, which in turn can cause the chainline and clearance situation to change (marginally) with it.
The form factor of the crank inboard of the taper is not part of the JIS standard, so in other words Shimano BBs that have this are not necessarily a match with any random crank out of the box, because you might get interference with it as you are now.
this is a JIS – ISO issue.