Boone Ti middle ring and Shimano XT cranks
I just replaced my Shimano middle ring with a Boone Ti 32t ring. The Shimano ring fit flush against the grooves in the crank arm, which I'm sure helped take most of the shearing force since it prevented it from rotating. But, the new Boone ring doesn't fit flush, there is a few mm's between it and the grooves on the arm; so it's just kind of floating on the arm, relying solely on the chainring bolts to keep it in place.
I'm worried about my FSA alloy chainring bolts failing. Anyone think it might be problematic???
Last edited by dulyebr; 01-26-2006 at 05:48 PM.
Originally Posted by dulyebr
i'm afraid it could be fatal. it is just a slightly different size. have you marked it? can it be exchanged? i use an xt (hollow tech assuming the same or no difference) and it think the bolts will shear pretty quickly. the ring will also start to wobble...never good.
i broke the middle and outer rings that came with the crank. i replaced them with middleburn (don't know the model) and they are fine.
are you being serious?
Originally Posted by fstrthnu
Do It Yourself
I think you will be fine. The chainring nuts are what take the shear stresses not the bolt. The bolt just holds it in place.
on my crank there's a small grove where the arm comes out, and the chainring sits about 1 or 2mm in there. i fitted a ring that didn't sit in there and it sheared. 1/4 came off directly between the holes for the bolts. i guessed that's what caused it. was i wrong? i couldn't think of anything else.
Originally Posted by Homebrew
here to be educated... ;-)
It's really no different than the granny ring not having any support from the spider.
Here's an email from Brett Boone
"I know what you are saying. If you get a chance, shoot me a picture. The spider shelves really donâ€™t carry any load from the shear on the bolts, so I wouldnâ€™t be concerned. I, like you, just like the parts to fit snugly."