Bike Forums - View Single Post - Trek frame builder's marks

12-02-23, 12:32 PM

#34

JohnDThompson

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Quote:

Originally Posted by SJX426

@madpogue - If the 60TSI is rare, then we have one each No mark on this one, 1984 760 needing cosmetic attention.

From the Vintage Trek site:

"Some early and mid 80s bottom brackets were marked with 58TSI or 60TSI. In the early 1980s Tim S. Isaac designed new lugs and a new bottom bracket shell for Trek. The new bottom bracket shell is typically marked with 58TSI (or more rarely, 60TSI). This designation is not part of the serial number but is a model number of the shell. The TSI are Tim's initials. The 58 or 60 refer to the angle between the seattube and the downtube."

The reason the 60TSI (60°) shells are relatively rare is that they were only used on 60cm and larger frames, which comprised a relatively small fraction of total production.

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