[johnbryanpeters]

For 21-speed gurus:

The rear shifting on the Bridgestone MB3 Comp I rescued recently from a free pile has been imprecise. It's Deore 3 x 7 with thumbies.

I replaced the shifter cable, and it routes under the BB in a plastic tube with an o-ring arrangement at each end. Cable travel through that assembly is way tight. Are these bits replaceable or is there a better arrangement?

J

 

[w00dy]

If I'm understanding what you're asking, there is a little molded plastic bit screwed onto your bb shell, which can easily be replaced. Most shops should have that laying around.

 

[D_D]

The standard guide looks like this

Sounds like his frame is using another method. Depending on exactly how the cable is routed it might be replaceable with one of those guides. They generally work pretty well, as the cable moves in a channel rather than a tube the dirt tends not to get trapped.

 

[EBasil]

Some bikes used a "noodle" there, under the bottom bracket shell, instead of the plastic plate with cable guides like those still used on Specialized bikes.

If you have that deal, the noodle is a place where a lot of friction can develop. If you can fit a teflon liner in, this will help a lot. There are three sources for good liners:
--old sets of "Gore" Ride On housing came with a very thin, low profile liner
--Avid Flak Jackets come with a large diameter, red liner (ask shops or buddies for scraps left over from installations).
--the noodle for veebrakes as a liner hiding in there. If you don't have an extra, ask the shop for one (avid's are quite good) and extract the liner from the metal tube.

 

[johnbryanpeters]

Yeah, I have the noodle setup, and it's, well, tight. Thanks for the suggestions.

J