Sunday, December 28, 2008

35 x 1...

This older mid-70's road bike comes in recently. It's got a Campy NR crankset with 52/47 gears (from a time when men were men and rode man-sized gears). Pretty nice old road bike - a Swiss Super Mondia. The first time it was in the shop, I steel-wooled the rust off the chrome stays and fork, got some fatter tires on it - basically made it road worthy after spending many years in a wood shed.

A few rides on it and the owner was back in the shop. "How can I get easier gears to pedal because I like to ride on the dirt paths and some of the hills are just too darn steep for me?" There aren't many options when dealing with old Nuovo Record parts. The smallest chainring possible is a 42t and with a NR derailleur, the largest freewheel cog is usually a 26. My suggestion was to replace the crank with a Sugino compact 50/34.

When he dropped the bike off, I'm thinking worst case, the bottom bracket threads will be Italian and I do have Italian bb's in stock - no problem. I pull off the left crank arm and see this:
From Repair Bikes

Oh, poo - French threads. Close. Swiss threads! Swiss threads are the same as French (35x1), but the right cup is left threaded as opposed to the French right hand threading. At this point, my options are to tap the bottom bracket to Italian threads, which is permanent, or sell a Phil Wood bottom bracket, which is a great bottom bracket but puts the project at about $100 over budget.

Hmmm, think, there's got to be a solution. Aha! Mavic used to make a bottom bracket that used two lock-rings to secure the bb in place. I've got a Mavic bb in my bin-o-parts, but it's spendy and the wrong length. As luck would have it, there is a distributor in Oregon who sells a similar bottom bracket and it fits the budget and it is available in the correct length. Bingo!
I get the bb, chamfer the frame bb shell with my trusty Mavic tool,
From Repair Bikes

...get everything buttoned up and it turns out really nice.

Next time I get a bike with Swiss bottom bracket threads that needs a new crank, my time invested will be like any other new crank install.

(What's playing: Beat Farmers Big Rock Candy Mountain - Country Dick Montana rules!)

1 comment:

cyclofiend said...

ahhh! Country Dick... unfortunately, "ruled"... RIP, Country Dick!