Originally Posted by
ednotmilkman
So my questions are:
Originally Posted by
ednotmilkman
1) where might this wobble be originating from, bent crank, bent spindle on bottom bracket or BB shell frame out of exact line? I guess shell being out of line would require new frame, oh my, but thinking it through ............. shell out of line would make the whole thing out of line, but would not wobble!
ID where/what is causing the wobble, would take it apart, re-build and see if you can ID the exact cause of the issue (I'm thinking worn BB spindle)
Originally Posted by
ednotmilkman
2) Should I, or even can I, check each of these possibilities separately without buying or going to LBS to borrow, then install new crank and BB as a test?
Why not, you seem more than capable, if you have the tools, all it will cost you is time.
Originally Posted by
ednotmilkman
3) I am watching ebay for used cranks to upgrade to, but am not sure if keeping a square taper cartridge BB is wise vs. going to the newer external bearing systems like Hollowtech or GXP even though they are stiffer and should help with chain ring wobble. Looks like durability of these external bearings is much poorer than the $15 Shimano square taper inner cartridge bearings?
The frame, then crank determine the BB, you can't choose to swap BB type, this choice is made when you choose the crank.
For durability of external BB's, that's old news, they are reliable now, much more user friendly, and easier to work with than non-external types
Originally Posted by
ednotmilkman
4) if I purchase a newer crank designed for a 10-speed setup, are the 3 rings closer together than what my current 9 speed front shifter is set for, which would cause even more alignment problems unless I put little spacers in between the crank bolts?
8/9/10 speed cranks are close enough in spec that they can be used for the same application. The rings distances haven't changed, and if you look at Shimano 10 speed rings, they have 9/10 speed marked on them.
If your looking at getting a new crank Shimano currently offers Claris (8 speed) 2403, Sora (9 Speed) 3503 or Tiagra (10 speed) 4703 triple cranks, Other makes are available.
For the issue you had with the 10 speed FD, Shimano offer a triple version of these in Claris (8 speed), Sora (9 Speed) and Tiagra (10 speed) options.