Quote:
Originally Posted by j-c-c
Your first comment here is cherry picked. It's extremely rare condition a drum or any brake will fade in its first application. Nobody is arguing a disc brake can have better heat dissipation, but a large drum brake has more thermal mass and both can eventually catch fire when abused. The point few here are noting, Drums by design have a hard time cycling when ABS is activated, which discs excel at. Rear wheel lock up is the most difficult skid for the average driver to control and can be where most skids begin. Proper rear wheel ABS control favors discs greatly and helps the driver driving beyond their skillset.
If somebody here is repeatedly overheating their brakes in familiar driving locations, they likely IMO have a driver issue of not knowing the limits of their vehicles braking system in whatever conditions they face and should correct that before focusing on a brake shortcoming.
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Nobody is talking about the first application except for you. Continually use of brakes will overheat them and cause them to fail. This is not uncommon - if it was we would not have runaway truck ramps all over this country and others.
A drum does have more mass. However, when a drum heats up it expands and the diameter gets larger. That moves the drum away from the shoe and reduces braking force.
I work for a manufacturer of commercial vehicles. I have told you why we switched from drums to discs as our standard offering. You can chose to believe me or not - but that doesn't change why we changed to discs on air brake Class 8 trucks.