Reliability questions

MMC (metal matrix composite) material combined with plasma spraying may be one alternative to traditional vehicle disc brakes, but is the MMC solution all that reliable? Some of the users don’t think so.

Until now, the discs on disc brakes have been mostly made of cast grey iron, but these are heavy, which reduces acceleration and contributes to increased fuel consumption. MMC disks are half the weight and, although they cost more initially, are supposed to offer the benefits of reduced fuel costs and longer wear. However, real life users have some doubts on the usefulness of the new solution. Alan Green of Breadline Racing (Pilning, Bristol) is one such sceptic. He says that in 1996, Fernando Mendes, a top rider on the motorcycle scene, tried the discs in the early part of the season, yet returned to using a conventional item after complaining about the poor stopping power.

Steve Patrickson, another top rider, also used such a disc brake with some unfortunate consequences. Green recalls: ‘In the final British Championship round of the ’96 season, I was close behind Steve Patrickson when his disc shattered approaching ‘Goddards’ corner. Patrickson collided with Fernando, and both crashed; fortunately, both were unhurt.’

Development of the iron disc is still happening. Brembo has recently produced an iron disc manufactured using a new metallurgical process. The disc diameter has been reduced as the coefficient of friction with the pad is claimed to be higher, giving a weight saving.