[Pcormier66]

Noob here. Just purchased a 2019 ZLE. It's waiting for me in Chillicothe, OH. I'm in Dallas. The drive home will be the perfect break-in. Super excited.

I've been reading about 18" wheels and brake performance degradation due to reduced caliper clearance. Is their actual data (empirical or anecdotal) to support that claim or is it theoretical? I'd like to get a set of 18" wheels in stock size/offset to increase my tire choices. I don't need to be a hero at the track every event. But brakes are the most important performance variable to me. I don't want to waste to a single brain cell worrying about brakes.

Thx

[Tim M]

Don't understand your question. The challenge with an 18 inch wheel is will it fit over the ZL1 caliper. If one does, the quality of tire will impact the braking distance...possibly even the diameter compared to OEM. Seems folks run a Michelin for better street performance.

[Msquared]

There is no brake degradation due to reduced caliper clearance.

[TrackClub]

Originally Posted by Msquared

There is no brake degradation due to reduced caliper clearance.

Not per se, but apparently brakes tend to run hotter with smaller rims. To what extend i dont know. Cheers!

[R3ctivision]

I think I have experienced what the OP is asking about actually. I've attached pics of my front brake pads which saw 3 track days. Two of them on old cup 2 tires on stock 19" wheels and one day with used Pirelli slicks on 18inch wheels. Almost all of the tapering seemed to have happened on the final day when I used slicks. The wheel barrel clearance was really tight. My thought is that the pads tapered poorly towards the bottom of the calipers because that seems to be the hottest part of the caliper (appears to get less airflow). Of course running stickier tires would wear brakes down more, but if the heat distribution was more even I'd expect fast but fairly even wear.

I could be wrong though. I had pad taper on my old SS 1LE too but never anything like this. IIRC it did taper more when I ran 18" wheels with RS4s mounted but I am not certain.

[TheRealJA105]

Originally Posted by TrackClub

Not per se, but apparently brakes tend to run hotter with smaller rims. To what extend i dont know. Cheers!

This i agree with, we don't have the data to prove how much difference, but there will obviously be reduced airflow with such tight clearances.

Originally Posted by R3ctivision

I think I have experienced what the OP is asking about actually. I've attached pics of my front brake pads which saw 3 track days. Two of them on old cup 2 tires on stock 19" wheels and one day with used Pirelli slicks on 18inch wheels. Almost all of the tapering seemed to have happened on the final day when I used slicks. The wheel barrel clearance was really tight. My thought is that the pads tapered poorly towards the bottom of the calipers because that seems to be the hottest part of the caliper (appears to get less airflow). Of course running stickier tires would wear brakes down more, but if the heat distribution was more even I'd expect fast but fairly even wear.

I could be wrong though. I had pad taper on my old SS 1LE too but never anything like this. IIRC it did taper more when I ran 18" wheels with RS4s mounted but I am not certain.

Wow that is some extreme pad taper. Do you flip pads? Everytime i have tried that I have gotten a bad result.

[7speed]

If the 18s you get are anything like the oems 18s you will need to cut about half inch off front brake ducts

[R3ctivision]

Originally Posted by TheRealJA105

This i agree with, we don't have the data to prove how much difference, but there will obviously be reduced airflow with such tight clearances.


Wow that is some extreme pad taper. Do you flip pads? Everytime i have tried that I have gotten a bad result.

Pads weren't flipped. I think it is the increased heat from running stickier tires and less airflow with 18s.