Sunday, February 27, 2011

Rebuilding a "bike-boom" era Peugeot

After working on bikes over time, you may encounter recurring situations requiring an inordinate amount of patience.

French bikes always present their challenges, mainly with their obsolete threading. Most recently, it's been on rebuilding a 70s bike-boom era Peugeot UO-8 sport/touring bike. Although Peugeot has made great bicycles such as the renowned PX-10 racing bike, the UO-8 was one of the lower-end models, typical of the large volume of Peugeots sold in the US in the 70s for the mass market. I brought it home and considered how it could be best rebuilt. It made sense to make it a single speed, as the older, heavier steel frame would be well suited to a stripped down utility bike.

French bikes have unique threads that are difficult to deal with when you want to replace bearings. The steel cottered crankset and bottom bracket were pretty much obsolete. Once I actually was able to remove one side of the crank (extracting the pin that holds the crank arm) I found that trying to replace this with a square taper bottom bracket spindle wasn't going to work because the cottered bb spindle has different dimensions.

So I retrofitted it with aftermarket French thread bb cups and a modern sealed IRD bb. It turns out I managed to somehow cross thread one of the bb cups—no matter how much I tried, this just wasn't going to work.

Next stop: machine shop. I had the bottom bracket shell reamed and re-tapped.

Since spray can paint isn't very durable not being heat cured, I took the frame to a powder coater and had them redo the frame in a dark metallic blue. They did an excellent job and applied a clear coat that gives the normally dull powder coat finish a high luster.



I built the frame up as a single speed with a track wheelset. I chose to keep the original centerpull MAFAC Racer brakeset that has it's own history. Based near Auvergne region of France, MAFAC is an acronym for Manufacture Auvernoise de Freins et Accessoires pour Cycles.

More races have probably been won using on MAFAC Racer model brakes than any other brakes ever made. They present a mechanical challenge to adjust. The pads need to be exactly perpendicular to the rim when they come in contact and doing this is a feat by itself. Getting the right amount of gap between the rim and the pads is also somewhat of an art—enough gap so they don't rub, but tight enough so the brakes have enough grab, that has to do with the length of the brake straddle wire and where the center cable yoke is positioned...

The old black pads these came with have long since dried out and end up squealing and leaving deposits on rims. I replaced these with Kool-stop salmon pads. Also, the bushings for the bolts that hold the arms can wear over time and the slop can contribute to break squeal. If the brake assembly isn't lubricated this can rust and bolts can break. Although I lubed everything before reassembling and readjusting the brakes on this bike, I still managed to snap one of the brake arm mounting bolts and a center yoke bolt. Fortunately I had an extra set and I'll drill-out the broken bolt on the old pair sometime with a drill press. Once you get these brakes dialed in though they work well.



A general rule of thumb with all older brakes sets: you must lube all of the parts because these will surely break when you try to retighten things if they get corroded.

Once I retrofitted the Peugeot with new wheels, a new single speed drivetrain and new brake levers, I was having a really hard time with getting the rear brake to not squeal. I tried to "toe-in" the brakes and tighten the brake arms (why I broke one) to no avail. Eventually I reverted to a tip a mechanic gave me who's worked on cyclocross bikes "Sometimes all you can do is toe 'em in backwards".




After assembling the bike, I relettered the Peugeot logotype script from a vintage 50s catalog and had decals made. This old Peugeot is now transformed to a new life as a single speed and looks and rides fantastic.

The bike was too large for me and I ended up selling to a buyer in San Francisco. So if you see this bike around SF, you'll know this was rebuilt by someone who appreciates French bikes no matter what grade.