Saturday, October 30, 2010

Definitive Answers about TA Track Crank BB Length; and Jocelyn Lovell Bike: Third Look

First things first: let no one every again wonder what bottom bracket spindle length to use with a TA Pro 5 Vis "Cyclotouriste" Track/Piste/Pista cranks (abundance of words to help Googling.) The answer is: 107mm JIS. Using a Shimano UN72 bottom bracket, this gave me exactly 42mm chainline. Now, mine are newer-production arms with laser etchings, and from what I understand, the newer ones occasionally need longer spindles than the older production. But any shorter than 107 and the spider would bottom out against even the remarkably low-profile UN72. So I can confidently say: pretty much anyone with TA cranks, with the exception of some hypothetical people with laser-etched arms different from mine: use a 107mm JIS spindle. (So much for TA's recommendation of 111.5mm—maybe they were talking about ISO taper BBs to fit in their JIS-taper crank arms. They're a funny company.) And do use really low-profile BBs like the Shimanos. The SKF 107 would NOT work: the "fixed cup" side sticks out too far, and the spider would bottom out.

Well, that's settled. Here's a look at the first iteration of Jocelyn Lovell Bike's build. I'm happy with most of it except (a) the tape colour, which is too brown—I'm already about 15 coats of clear shellac in to fixing this problem, and (b) the Wippermann Connex chain has a lousy master link, which I had to remove since it severely messed up my drive train. Who needs master links anyway, though, on big fat healthy chains? More photos of the bike when I'm completely happy with it.

4 comments:

RMHampel said...

Outstanding look, Alan.
I'm looking forward to seeing the details of the build.

Anonymous said...

Remember that the Connex link does not work both ways. The deeper contour needs to be towards the sprockets.

Lee said...

The T.A. Arms I have are ISO along with all the other T.A. Pro 5 arms i have seen. The 111.5mm Spindle is rare but, has the correct ISO taper and also gives you the perfect chain line.

AH said...

That may be, but ALL of my TA arms are DEFINITELY JIS. The controversy goes on...