The ‘Ice Technologies’ rotor sounds like a great idea: stainless steel on the outside to resist abrasion and heat, aluminium on the inside to save weight and conduct the heat away. According to Shimano, an Ice rotor stays 100°C cooler than an all-steel rotor.

That can only be a good thing, until you consider that the melting temperature of stainless steel is 550°C higher than that of aluminium.

As far as I know, there are no mountains in Dorset. So it can only have been a hill that Richard and Anne Lewis were descending, on their lightly loaded tandem (no tent), when the rear wheel skipped over a bump in the road, giving the pads a chance to grab the hot rotor. They grabbed and bit, just like when you bite an ice-cream wafer sandwich! As melting alloy extruded from between them, the stainless wafers collapsed and distorted, jamming the disc in the calliper. Fortunately Richard kept control of the tandem during its rear-wheel skid and no one was hurt. Solid stainless rotors were subsequently fitted.

Admittedly this is not a standard bicycle and Shimano does not claim these brakes are suitable for a tandem (so Richard used the biggest available 203mm rotors). But neither is Dorset the Alps; and the energy to be dissipated on a descent is the simple product of weight and height.

Chris Juden


This was first published in the October / November 2012 edition of CTC's Cycle magazine.