ayceejay
Guru
- Location
- Rural Quebec
I want to change the bb on my fixed wheel bike. At the moment the chain is in perfect alignment and the bb is 103mm, the Phil Woods I want to change it for is 110.5mm. How do I get back to my perfect alignment?
Change bottom bracket change chain alignment
- Thread starter ayceejay
- Start date
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RecordAceFromNew
Swinging Member
- Location
- West London
Not much detailed info to go with there but if you are talking about a Sugino RD chainset, which is probably the most common use for a 103mm BB (for a 42mm chainline), then the general consensus is that a Shimano 107mm BB will deliver a ~45mm front chainline. The Shimano 110.5mm BB is identical to the 107mm on the drive side so same ~45mm chainline.
However, it appears the only 110.5mm Phil BB currently is ISO not JIS, so if I were you I would contact Phil and ask.
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ayceejay
Guru
- Location
- Rural Quebec
Thank you: yes the existing BB is the Sugino. Are you saying that I could use a either of these BB's without any further adjustment? I will contact Phil Woods as suggested.
RecordAceFromNew
Swinging Member
- Location
- West London
Not exactly. If I have to guess I would say a 110.5mm ISO BB, assuming the spindle is more or less symmetric, would deliver a ~40.5mm front chainline with a Sugino RD. But even if my guesstimates are correct whether they are any good to you depends on what your rear chainline is and how straight you want it to be. Where there is a chainline reduction from present you could also find the crank arms swinging a bit too close to the frame for comfort.
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ayceejay
Guru
- Location
- Rural Quebec
I really appreciate the time you have spent on this. The frame is Masi the wheels are Mavic Ellipse the chain/crankset is Sugino Messenger. I like the frame and wheels but I want to upgrade the Messenger. I have looked at Sugino 75 and Campag Pista and the possibility of keeping what I have with an upgrade in the BB only, leading to my question. I guess one way would be a 103mm BB of better quality.
RecordAceFromNew
Swinging Member
- Location
- West London
Fwiw the RD2/Messenger and a Sugino 103mm BB (which is JIS) should deliver a 45mm chainline supposedly, which should be just about right for the Ellipse. But if you are thinking of getting a 75 then you will have to be aware that the chainline is only 42mm with a Sugino 75 BB (which is ISO... 
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