[CC2018SS1LE]

Hi I just came off a track day, wiped out rear pads
Can these rotors get cut, or do they just recommend replacing. They only have slight groves in them
Thank you

[JSH]

Can't imagine that you cut them.

[SHRFT]

Originally Posted by CC2018SS1LE

Hi I just came off a track day, wiped out rear pads
Can these rotors get cut, or do they just recommend replacing. They only have slight groves in them
Thank you

They can be turned.

[cdb95z28]

it would be better to not cut them, because that makes them thinner. Not a good situation for a car that is tracked. If there is no deep scoring on the rotor surface you can use this to give a fresh surface for new pads:

https://www.amazon.com/dp/B007INTEMC...?ie=UTF8&psc=1

I've used this on multiple applications and it works great.

[cdb95z28]

How many track days did you get out of that set of pads?

If the rears are wearing prematurely, and you are using the car's nannies on track in combination with overdriving, it will wear the rear pads quickly.

[wnta1ss]

Originally Posted by cdb95z28

it would be better to not cut them, because that makes them thinner. Not a good situation for a car that is tracked.

I agree with him, because in the past I had tracked a car after having the rotors turned, and one of them cracked. Yep, got a WTF feeling in the pedal, visual then showed rotor had cracked.

[BlackbeastSS2]

Myself if I was going to get the rotors turned I would only use them on the street and when I planned to return to the track it would be with fresh rotors.

[samr350]

Yeah as long as they're over min thickness you can turn them. But personally if the scratches aren't too deep I would just slap new pads on and bed them in hard. And if the scratches are really deep then you're probably past min thickness anyways. Rear rotors are pretty cheap too.

Minimum thickness for the fronts is 32mm.

Minimum thickness for the rears is 24mm.

[CC2018SS1LE]

Thank you all for you input

The scratches are minor, I had 3 track days on car, but not sure if it was tracked before I got car with 12k on it.

I think I should have changed fluid after 2nd track day, I was getting pretty bad front brake fade, so that’s how I think back pads got cooked

I’m in NY now, my car is in Florida

I’m going to go back and assess the situation, before I take car to Sebring, at the end of January

I’m bringing new Oem pads, new fluid and rear rotors with me, I’ll figure it out then

[cdrptrks]

Originally Posted by samr350

But personally if the scratches aren't too deep I would just slap new pads on and bed them in hard. And if the scratches are really deep then you're probably past min thickness anyways. Rear rotors are pretty cheap too.

+1

I ran out of rear pad on one side near the end of my last session at an event last year and new pads almost completely evened out the rotor surface appearance during my next track day although I kept a close eye on it after each session and did some hard stops on an empty road beforehand to make sure it felt ok and didn't crack. I believe I found a maximum allowable scoring spec listed at 1mm for the rotors which was definitely deeper than the grooves caused by the backing plates in my case.

I'm surprised that I couldn't hear the grinding noise while on track driving with the windows down lol!

I think my case was caused by using a different brake pad manufacturer & compound front and rear...not recommended. I managed to use more rear pad thickness than front pad thickness that day when I usually see about 2x more front pad wear than rear pad wear.

[CC2018SS1LE]

Originally Posted by cdrptrks

+1

I ran out of rear pad on one side near the end of my last session at an event last year and new pads almost completely evened out the rotor surface appearance during my next track day although I kept a close eye on it after each session and did some hard stops on an empty road beforehand to make sure it felt ok and didn't crack. I believe I found a maximum allowable scoring spec listed at 1mm for the rotors which was definitely deeper than the grooves caused by the backing plates in my case.

I'm surprised that I couldn't hear the grinding noise while on track driving with the windows down lol!

I think my case was caused by using a different brake pad manufacturer & compound front and rear...not recommended. I managed to use more rear pad thickness than front pad thickness that day when I usually see about 2x more front pad wear than rear pad wear.

Funny I never heard grinding, until I was driving home. Never on the track!

[cdb95z28]

Originally Posted by CC2018SS1LE

Thank you all for you input

The scratches are minor, I had 3 track days on car, but not sure if it was tracked before I got car with 12k on it.

I think I should have changed fluid after 2nd track day, I was getting pretty bad front brake fade, so that’s how I think back pads got cooked

I’m in NY now, my car is in Florida

I’m going to go back and assess the situation, before I take car to Sebring, at the end of January

I’m bringing new Oem pads, new fluid and rear rotors with me, I’ll figure it out then

I've been running the original rear rotors on my Gen5 with ST43 race pads since 2016, street and track, so your rotors should last a long time with the OE Ferodo pads with respect to thickness, as long as they are not being abused.

Excessive heat that pushes the pad beyond it's operating temp thresholds will cause fade. Fade is a hard pedal with greatly reduced braking power. Fade is a result of the pad being overheated. Which, going back to my comment in post #5, about running with the nannies on, this will cause the rear brakes to run very hot, possibly overheating the pads. The nannies will use the rear brakes to settle the car. If the fronts were being overheated, then there are other things that need to be looked at concerning cooling.

If you boiled the fluid, you'd know it because the pedal would be soft with even less braking power. This is significantly more dangerous than fade.

Brake fade and fluid boiling are two different things. Brake fade is unrelated to fluid boiling except that continued fade may cause the fluid to overheat. But that should rarely happen as a good driver should start cooling down the brakes then coming off track at the first sign of fade.

Cars that are tracked should have the fluid bled before every track day. Not a full bleed/flush unless you suspect the fluid compromised. But cars that are in high humidity environments may need even more attention. I "burp" my calipers before each event. I end up bleeding out about a total of 1/4 to 1/3 cup of fluid. Just enough to push fluid thru the caliper. Castrol SRF, Endless or HTC64T FTW.

[CC2018SS1LE]

Originally Posted by cdb95z28

I've been running the original rear rotors on my Gen5 with ST43 race pads since 2016, street and track, so your rotors should last a long time with the OE Ferodo pads with respect to thickness, as long as they are not being abused.

Excessive heat that pushes the pad beyond it's operating temp thresholds will cause fade. Fade is a hard pedal with greatly reduced braking power. Fade is a result of the pad being overheated. Which, going back to my comment in post #5, about running with the nannies on, this will cause the rear brakes to run very hot, possibly overheating the pads. The nannies will use the rear brakes to settle the car. If the fronts were being overheated, then there are other things that need to be looked at concerning cooling.

If you boiled the fluid, you'd know it because the pedal would be soft with even less braking power. This is significantly more dangerous than fade.

Brake fade and fluid boiling are two different things. Brake fade is unrelated to fluid boiling except that continued fade may cause the fluid to overheat. But that should rarely happen as a good driver should start cooling down the brakes then coming off track at the first sign of fade.

Cars that are tracked should have the fluid bled before every track day. Not a full bleed/flush unless you suspect the fluid compromised. But cars that are in high humidity environments may need even more attention. I "burp" my calipers before each event. I end up bleeding out about a total of 1/4 to 1/3 cup of fluid. Just enough to push fluid thru the caliper. Castrol SRF, Endless or HTC64T FTW.

You are correct, I did not bleed brake after last 2 events. It was my fault the fluid boiled in my front brakes

I drove my car to Florida for the season, then went to PBIR, I did not have my jack or tools with me, so I gave it a shot and just went to the track. I have since purchased all necessary tools to work on my car in Florida

I have learned my lesson

My last 2017 1le I had 28k on car, did a bunch of track days and a few auto Xs, still had original pads and rotors when I turned car back to GM (was a lease)
Still had plenty of life left

I will go over entire brake system, before I go to Sebring and will bleed after every track day

Me like an idiot, chased down a really fast GT350 with slicks, past him, (with no brakes left) stayed ahead of him until session ended
That’s why I cooked my rears

[cdrptrks]

Bleeding before each track day on stock pads is overkill IMO.

I ran StopTech 600°F dry boiling point fluid with stock pads for just under a year and about 9 track days including the last one in 90°F summer heat without ever bleeding any fluid in between events and experienced no brake issues although I brought bottles of new fluid along to the last event just in case. But I would have done a full flush sooner for peace of mind if I was going to NOLA or COTA where there is sustained heavy braking from 140+mph.