Originally Posted by
Papa Tom
Some time ago, I got the bug to order a spare bottom bracket for my 1996 GT Outpost so I could replace the current one (getting old) in my spare time. Well, now that I have nothing BUT spare time, I put on my "shop" clothes this morning and set out to do it.
The problem is, the folks here on this forum insisted that a Shimano UN55 would be the replacement for the impossible-to-find UN72, so I bought the 55. So far, it ain't workin'. I can't screw either side of the bracket all the way into the frame. On each side, there is about 1/2" of protrusion.
Is there a trick to making this work, or is my brand new UN55 a doorstop now? And is there a better replacement for the UN72? The only details printed on the UN72 are ""LL113." The 55 reads "73 BC1.37 X 24."
I'm full of grease, and I am lost.
You have the 73mm version of the UN55, but you need the 68mm UN55. Here is a link to a listing for either (use the drop down list to see all available sizes). You could sell the 73mm, which I think would be in use in a vintage Raleigh, among other bikes (with a wider shell).
https://www.jensonusa.com/Shimano-UN55-Bottom-Bracket