How on earth are fins on a pad going to cool a disc down?

Conduction then convection.

richmars – Member

How on earth are fins on a pad going to cool a disc down?

Conduction then convection.

^^ this.

When you are braking the disc, pad, caliper and fluid are effectively one unit, so conduction to the pads then convection between fins and air.
When not braking there will still be a small amount of conduction but mainly radiation and convection between rotor and pads then convection between fins and air.

🙂

Change to a 650B and all will be reet.

michaelbowden – Member
I wonder how many of you that have had problems were using shimano brakes with the finned pads? I’m going to have a stab and say that without the extra heat dissipation of the finned pads the rotors exceed their design heat range.

But, can’t you get these brakes without the finned pads? You can get Shimano replacement pads without the fins. Is there a warning on these that they shouldn’t be used on icetech rotors?
Aluminum on this type of component does seem to be a risky idea, given that all a brake does (at a basic level) is convert kinetic energy into heat.

If I were Madison I’d want to know as much about the cause as possible, Shimano will have to redesign them based on your info to an extent.

Shouldn’t Shimano be doing their own R&D under controlled conditions, not relying on third hand anecdotes?

Aluminium is a fairly soft metal, and enough force from the caliper could squeeze it out of the rotor even at room temperature.

An aluminium caliper?

I’m using a XT Shimano XT RT86 Ice-Tec 180mm 6-Bolt Rotor with finned Shimano pads/ XTR calipers and levers (trail flavoured)

Pads are less than a month old, rotors are a year old.

Including the OP, ive heard off one other instance of this happening (ie 3 instances). Still reckon its a defective disc (crack in alu?) rather than a design flaw. Have emailed Madison.