Those are impressive numbers. From the Porterfield web site it looks like they provide a reline service rather than supplying linings. Do you know if it's possible to buy their lining material so that those of us who live outside the US can use it? I have another couple of old bikes that need better braking. I'd also like to try it on my 600 MV which has pathetically small and ineffective Campagnolo mechanical calliper disk pads.
Bill,
I think that you may be able to buy material directly from Porterfield. Some was sent to someone in Australia a few weeks ago. RD-4 is the material that we have tested and I think it is an excellent performer. It works well cold, which is a must for the street and its coefficient of friction goes up as it gets hotter.
For the race track I will keep going up in the coefficient of friction, but I am now getting away from the good cold working linings. The next lining I will try has a coefficient of friction at .70 plus, but it needs to be 250 F to start working. I am guessing that this will not be a suitable street compound due to its poor cold performance. The final lining does not start to bite until it is 400 F. I don't think this lining would work for many racers because the warm temperature is so high, but it may be useful to a racer like Phil Canning who is routinely overheating his brakes with the Twin racer.
The biggest obstacle so far has been making the extra shoes to install new linings on. I just finished making a small batch of 8" brake shoes so we can swap out the front shoes on David Tompkin's racer.
For anyone making shoes for themselves, use a carbide cutter for the steel shoe face for the cam. I found them to be hardened steel which is cast into the shoe. I have had several failures of the stock shoe and 8" shoe faces, H48. It is used on both shoes. H48 appears to deform too readily and creates a depression in the metal where the cam pushes. I think that this cannot happen with the EBC shoes, which is a nice feature.
David