Bottom Bracket and GT Xizang (1994)

Hey, I have one question... Since last year I have a 94er Xizang. I use this GT bottom bracket in the size 73/107mm with XTR 900 Crank Set



Since a couple of week I have problems to find the right setup for the shifting. When I shift from the mid-chainring to the big chainring my chain jumps over the big chainring very often. No I have my setup as well as possible. But it is not perfect: when I push the STI I have a bit contact between the crank and the front derailleur. In the worst case I could live with that littel contact, because that is only the case, when i push the STI (when I take my finger from it, there is enough space) ... But it is not nice.

No I am thinking about it, to have maybe the wrong bottom bracket. The Chainline looks nice. But someone told me that I need a 113 mm bottm bracket lenght. Could someone with the same setup tell me, what lenght he uses

Thanks guys

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is this the original BB? i have the original XT BB in my 1994 GT zaskar and its a 113. i wouldnt of thought the 3mm would make a lot of difference but i may be wrong.... i would like to see the bike if you have any pics (not that it would help to answer your question, i just wanna see it )

Sean

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I have this same BB in a dozen GT's with M900 cranks and have no issues.

My question for you would be... that the cups are removable from the BB, did you perhaps switch the right and left cups when you installed it so that the spindle is 180 degrees from where it should be, right side to the left and left to the right?

@Sean... Sure....







@gm1230126
Do you think that it is possible to swith the cups...? I can't tell you... I didn't install the BB.
I could only solve the problem of the falling down chain, when I twistet the FD a little bit, so it is not parallel anymore. But now I have a little bit contact with the FD and the crankarm...

A beautiful Xizang! What is the distance between the axis of the seat tube and the middle ring? Read this article, it may be helpful:

http://sheldonbrown.com/chainline.html

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Sorry for my late answer. But I needed my time. Couldnt see that bike anymore. Well the distance is about 50 mm. As I read your page the distance should be about 47,5 to 50 mm. So 113 mm BB would not solve the problem

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Can't help you but just wanted to say......
"Lovely bike!! "

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Thx mate

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that"s definitely 47.5 chainline

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So everything OK... ?