I feel like I might be missing something.
We all know that reducing unsprung mass and rotational inertia is great for improving handling and acceleration. But at the same time, you also want your brake disks to have enough mass to act as a heat buffer to avoid brake fade during heavy braking. Sure, lighter brake disks can absorb the same heat than heavier ones if cooled more efficiently. But in that case they will experience higher thermal stress due to wider temperature fluctuations.
Given how much effort Toyota put into weight management on the GR Yaris, I have no doubt they carefully balanced the brake disk mass to optimize braking performance/handling/acceleration.
Some aftermarket manufacturers offer lighter brake disks emphasizing better handling. Are these really so advanced that they shed heat faster and use materials strong enough to handle the added thermal stress? It could be true, but I feel like if that were the case, manufacturers would highlight it more boldly in their marketing.
Maybe the real answer is more practical, perhaps the people buying lighter disks know exactly how they'll be using them. Maybe they don’t push their cars hard on track, or they drive on circuits that aren’t particularly brake intensive. Or maybe they’ve added extra cooling to compensate for the reduced mass.
In my mind, lighter disks aren’t clearly beneficial unless you’ve carefully weighed your priorities.
Am I overlooking something here?
