Wednesday, June 24, 2009

Clive's Cranks

Clive's cranks will be the venerable TA Pro 5 Vis, with 48- and 32-tooth chainrings, in a 170mm length. It would be hard to argue for any other crankset in a randonneur application: the TAs are exceptionally light, can take an incredible range of chainring sizes, have a very narrow tread, and are the nicest looking cranks ever made. That they have been made continuously since the 1930s (if we allow for a momentary confusion with the Stronglight 49d) doesn't hurt.

These particular ones are the "60th Anniversary" model, spruced up with crankarm decals and some NOS dustcaps. I bought the crankset from Mike Barry shortly after he officially closed Bicycle Specialties. They were the last pair he had. He didn't have any of the newer-production 48-tooth outer chainrings, so I got an older one, with holes for the cyclocross chainguards (these will be as close as Clive gets to "drillium"). The day that I picked these up there was a meeting of the "No Click Club" at Bicycle Specialties—a group of collectors and enthusiasts of vintage bikes. I somewhat shyly attended, using the crank-pickup as a pretext, and have been a regular ever since. Indeed, I'm going tonight!

The issue of which bottom bracket to use with this crankset has been a vexing one. I bought a 116mm TA Axix BB on eBay last year, assuming it would be fine. But on my Fuji, and with a 135mm rear hub, the clearances were very tight between crankarms, chainrings, and stays. I also got pretty carried away with the desire to use a "Singer-style" bottom bracket at one point. I was going to use the 116mm axle from my Mavic bottom bracket (it has locating areas for sealed bearings) and have Dan Polito make me a 74mm BB shell. Well, luckily a 35mm metric reamer (which was necessary) costs something like $1,200, so my plan was quickly made ridiculous. Now I have a cheap Taiwanese 118mm BB in my closet, which I'll use if the TA doesn't work. (By the way: during my lengthy deliberations over a BB for this crankset, the closest thing I've been able to get to an answer to the question, 'Do TA cranks take ISO or JIS BB spindles?' is 'Probably something halfway between the two.')


OAP said...

Yes spindle/crank compatibility is hard to decipher. While the taper angles is constant at 2°, the dimensions of the square varies, even within presumably ISO or JIS units. So when mismatching, trial and error prevails!

Jim said...


Why not use a standard cup and cone
TA bottom bracket? Pack it full of grease, put on the axle sleeve between the cups,adjust the cup and tighten it up. When you are done, slip a couple of O rings over the axle ends and snuggle them up close to the outer faces of the bottom bracket cups. With fenders keeping most of the gunk off the bottom bracket you will not have any contamination or compatibility issues.

AH said...

Certainly something I'll think about if the Axix and the Taiwanese BBs don't work out. Cup-and-cone BBs and I have not generally gotten along, but I'm always willing to give old things a shot!