Mr. Zero":j8mysn2w said:
In reality it was only the largest frame sizes of the 1990 model that failed. The failure occurred at the minimalist rear dropout. Aside from the differences you mentioned the frames are the same. I actually prefer the '90 to the '91 partly due to the minimalist dropouts and the absence of eyelets. I've got another 42cm 1990 Zip frame in reserve.
Any other Bridgestones in your stable? I've got a fairly substantial list: 3 MB-Zips, MB-1, 2 RB-1s, XO-1, XO-2, Radac, and a CB-Zip.