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Smoking brakes from a single emergency stop? Sounds like your car is defective and I'd get it checked out. Sounds like you were lucky this time and avoided the

Smoking brakes from a single emergency stop? Sounds like your car is defective and I'd get it checked out. Sounds like you were lucky this time and avoided the accident but get your brake pads changed and make sure the fluid is topped up as that isn't right. Potential issues are stuck calipers, worn out friction material, or boiling fluid. With a well maintained car (i.e. brakes that don't end up smoking when doing just a single emergency stop, even from 60-80mph...) you are less likely to avoid accidents by just a meter...

toss1 2y ago
It's a metaphor; I didn't actually smell any smoke (but didn't stay around either). But I guarantee those pads were momentarily very hot. Thanks for your concern, but no, the car's braking capability was fully up to snuff and not compromised, stuck, worn-out, or boiling; it hauled the car down to zero in a handful of car-lengths, and mildly injured the passenger — crappy brakes can't do that. And yes, perfectly good brakes, even race brakes, can be made to smoke in a single stop. It's done every time you take them out to bed them after install (many high-performance brake pads are 'transfer pads' that work best when some of their material is transferred at temperature to the rotor). Also, it is very common to see high-performance situations where the rotors are glowing-hot in a corner [0]. The reason it is so rare in ordinary street cars is most people not knowing how to use even 30% of the real braking capability. People either don't press hard enough, or just press mash the pedal and skid. Once the tire is skidding, the brakes aren't turning, so they aren't heating. Even ABS just splits the braking between the pads and the intermittently skidding tire. Threshold braking is a skill that both takes time to learn and practice to maintain. It is basically getting a feel for the exact maximum braking grip the tire has at that moment, and braking just below that threshold. It extracts maximum performance from the car (sliding friction is always less than gripping friction) and also puts maximum heat into the pads. And yes, threshold braking can really heat up the pads in one stop, and (depending on the car, track, and driver) completely burn down a set of pads in a single outing. OTOH, I had a set of pads last an entire race season on one car, or have to replace them every several sessions with other cars. Properly used, brake pads are just a wear item, but this is unfamiliar with street use, because you should typically almost never be threshold braking, so they'll last tens of thousands of miles. But the main point here is that the ONE situation I've had in the last 30k miles with "collision alarms", the car completely missed it. [0] https://www.youtube.com/watch?v=NBoMTYZAyJc https://www.youtube.com/watch?v=NBoMTYZAyJc edit delete stray chars

toss1 2y ago

It's a metaphor; I didn't actually smell any smoke (but didn't stay around either). But I guarantee those pads were momentarily very hot. Thanks for your concern, but no, the car's braking capability was fully up to snuff and not compromised, stuck, worn-out, or boiling; it hauled the car down to zero in a handful of car-lengths, and mildly injured the passenger — crappy brakes can't do that. And yes, perfectly good brakes, even race brakes, can be made to smoke in a single stop. It's done every time you take them out to bed them after install (many high-performance brake pads are 'transfer pads' that work best when some of their material is transferred at temperature to the rotor). Also, it is very common to see high-performance situations where the rotors are glowing-hot in a corner [0]. The reason it is so rare in ordinary street cars is most people not knowing how to use even 30% of the real braking capability. People either don't press hard enough, or just press mash the pedal and skid. Once the tire is skidding, the brakes aren't turning, so they aren't heating. Even ABS just splits the braking between the pads and the intermittently skidding tire. Threshold braking is a skill that both takes time to learn and practice to maintain. It is basically getting a feel for the exact maximum braking grip the tire has at that moment, and braking just below that threshold. It extracts maximum performance from the car (sliding friction is always less than gripping friction) and also puts maximum heat into the pads. And yes, threshold braking can really heat up the pads in one stop, and (depending on the car, track, and driver) completely burn down a set of pads in a single outing. OTOH, I had a set of pads last an entire race season on one car, or have to replace them every several sessions with other cars. Properly used, brake pads are just a wear item, but this is unfamiliar with street use, because you should typically almost never be threshold braking, so they'll last tens of thousands of miles. But the main point here is that the ONE situation I've had in the last 30k miles with "collision alarms", the car completely missed it. [0] https://www.youtube.com/watch?v=NBoMTYZAyJc https://www.youtube.com/watch?v=NBoMTYZAyJc edit delete stray chars