Originally Posted by coachboyd

You should definitely change out brake brakes when you swap between alloy and carbon wheels. Some of the slivers can be very small and hard to see by just looking at them, but they can chew through a carbon brake track. It takes all of 90 seconds to swap out 4brake pads, it's worth it.

The TG that you are talking about is the glass transition temperature. It's the temperature at which the resins will reach a melting point and begin to soften. When this happens (especially on a carbon clincher rim) the walls can bow outward from the pressure of the tire pressing against the hook of the rim. There is a big difference however in peak TG temperature vs. continuous. A lot of the cheaper Chinese brands are now claiming 240degrees Celcius as a TG temperature, and this may be true for small bursts. I have used the comparison to cheap speakers before. They may say they are rated to 1000 watts power, but if you look at the RMS rating it'll be like 85-100 watts. Whereas a nice speaker that has 1000 watts max, can be run continuous at 500 or more watts (or until you get pulled over by the cops).

You also have to look at continuous braking, and also not so much a goal of resisting the highest possible temperature, but doing things to prevent the rims from ever getting up to those temperatures (which is why brake pad development has been such a major part of carbon wheel). Most wheel manufacturers provide their own brake pads with carbon wheels, and they have been developed specifically for the types of carbons and resins in that particular rim.

Keep in mind that as the TG point of the resins goes up, so does the brittleness. The past couple years we have seen a lot of advancements in resins that can handle heat, yet won't be brittle (you don't want the wheel to crack upon every small impact).