At 9:32 PM -0500 11/28/08, Harvey Sachs wrote:
>Mike's post evoked memories of some peculiar black, molded, plastic
>pads for Mafacs Way Back When. In my mind's eye, I can still see the
>very fine foam structure, I think. What I can't remember is why we
>hated them so much. Were they the super-squealers?
Mafac pads were super-squealers. They actually braked very well. Mafac brakes don't squeal, it's the pads. They'll make any brake squeal...
I suspect the issue with the NOS pads that melted is related to age. Rubbers age, and nobody would ride 50-year-old tires and expect the same grip as a new tire.
Some rubbers get harder with age, others release their softeners and can "melt" in the way Mike described. The latter happened to me once when test-riding a wonderful 1952 Rene Herse. Just blocks from my house, a car suddenly appeared at an uncontrolled intersection. I braked hard, the pad melted and the cantilever brake dove under the rim, rendering it useless. The car stopped in time, so both I and the Herse remain intact. It took a while to remove the brake pad from the rim, which now was coated with black rubber.
This was a one-time application of the brake, from a moderate speed of perhaps 20 mph, not some "cautious" descending that heated pad and rim to the boiling point.
I have not had this problem with original Mafac pads, which have "MAFAC" molded into the material. However, on bikes I truly ride a lot, I have replaced the Mafac pads either with Matthauser cantilever pads, or with the afore-mentioned slip-in Kool-Stops, which use the same pad compound.
Jan Heine
Editor
Bicycle Quarterly
140 Lakeside Ave #C
Seattle WA 98122
http://www.bikequarterly.com