Replace rotors before track day?

[PACarGuy]

Howdy all. I am thinking about doing my first track day at the end of August or Sept, and my rotors are the original OEM rotors with almost 60K miles. I measured them this morning with calipers and they are still at about 28.5-28.6 mm (min is 28.4). I measured them back in October, 2017 as well (had ~55.6K miles at the time) and they were about 28.6-28.7mm then, so the wear rate hasn't been too bad. They do have a slight lip, but there's no cracking and no deep grooves, etc. and there is no vibration.

I have a new set of OEM rotors ready to go on the car, but I am looking for thoughts from those who have tracked on OEM rotors as to whether I should replace the original rotors before the track day, or just go and use the originals up and then replace them after the track day. Is 0.1-0.2mm enough meat left to do a track day? I have bought a set of PFC08 pads up front to use for the track day, but obviously haven't installed them yet.

If it matters, while I've never done a track day in a street car, I do have some experience on track. I did the Skip Barber 3-day Formula Ford racing school in 1993 and did a few formula ford lapping days that same year. I also autocrossed for a handful of seasons in some prior cars, with my last auto-x done in 2005. I do spend some time on my iRacing simulator these days as well. That being said, I assume I would start in the beginner run groups. So, presumably I won't be pushing too hard, but would like to get a little bit of speed up to see what this car is all about nearer the limit.

Thoughts? TIA.

[roastbeef]

i'd run your first day on those old rotors. i don't think you'll kill them, but if you get pad deposits or whatever, just toss 'em and put the new ones on.

[PACarGuy]

Originally Posted by roastbeef

i'd run your first day on those old rotors. i don't think you'll kill them, but if you get pad deposits or whatever, just toss 'em and put the new ones on.

Thanks! That's what I was thinking, but wasn't sure if I'd kill them in one day.

[tdott]

Yea i'd run your current ones until there is a reason to replace them, I wouldn't even bother changing the pads yet, just make sure you have fresh brake fluid and you should be fine until you start getting faster.

[PACarGuy]

Originally Posted by tdott

Yea i'd run your current ones until there is a reason to replace them, I wouldn't even bother changing the pads yet, just make sure you have fresh brake fluid and you should be fine until you start getting faster.

I'm a bit leery of running stock pads for a track day and cooking them...you think it's OK to start out on those?

[macdude357]

Originally Posted by PACarGuy

I'm a bit leery of running stock pads for a track day and cooking them...you think it's OK to start out on those?

I got deposits on my rotors with stock pads on my 4th track day. Given that you are not a total novice, I'd go ahead and throw those PFC08's in since you already have them.

[ayao]

As a beginner on the track, stock pads on the rotors you describe will be perfectly fine.

[PACarGuy]

Originally Posted by ayao

As a beginner on the track, stock pads on the rotors you describe will be perfectly fine.

Thanks. Again, I'm not a total beginner and do have track experience; it's just been a while.

[tdott]

Originally Posted by PACarGuy

I'm a bit leery of running stock pads for a track day and cooking them...you think it's OK to start out on those?

Unless it's a track that is very hard on brakes, of course i'd say you will be fine with fresh fluid, they are not delicate pieces of paper like some make them out to be. Worse case you might get some fading or start to feel the pedal change towards the end of a session, at that point you just back off a bit, do a cool down lap or head for the pits.

In the beginners group which you'll probably be placed, i doubt you'll get a ton of hot laps enough to cook the brakes, most likely you'll have traffic and learning the course/lines to deal with.

[VictorH]

It sounds like you are going to be running track pads up front. If you are going to run new track pads in back, then I would replace the rotors. If you are going to use either street pads (not generally advisable) or some used track pads, then I would agree with everyone else and just run this rear set. Only condition if you want to put new pads on back then best to also start with new rotors.

[bigjae1976]

I'd recommend starting on track pads unless you want to work on managing your brakes. Managing brakes is an unnecessary distraction for a novice.

Still, OEM pads are fine.

[PACarGuy]

Originally Posted by bigjae1976

I'd recommend starting on track pads unless you want to work on managing your brakes. Managing brakes is an unnecessary distraction for a novice.

Still, OEM pads are fine.

Thanks for the recs folks. If I run track pads up front, is it ok to run stock pads in the rear or should I pop in some stop tech sport pads, etc.?

[ayao]

Originally Posted by PACarGuy

Thanks for the recs folks. If I run track pads up front, is it ok to run stock pads in the rear or should I pop in some stop tech sport pads, etc.?

Answer is that it sort of depends. Biggest issue will be the difference in mu between axles which will lead to greater front brake bias and the potential effects on stability under braking. The front axle will also do a greater proportion of the work which could lead to more heat and wear.
All that being said, on track I run race compound up front (BBK) and aggressive street (DS2500) on the rear because I try to reduce track prep work and as a result leave the same pads on rear for street/track. It's a compromise.

[bigjae1976]

Originally Posted by PACarGuy

Thanks for the recs folks. If I run track pads up front, is it ok to run stock pads in the rear or should I pop in some stop tech sport pads, etc.?

Better to install track pads fr and rr but you'll be fine. The front pads will take more of a beating.

[PACarGuy]

Originally Posted by ayao

Answer is that it sort of depends. Biggest issue will be the difference in mu between axles which will lead to greater front brake bias and the potential effects on stability under braking. The front axle will also do a greater proportion of the work which could lead to more heat and wear.
All that being said, on track I run race compound up front (BBK) and aggressive street (DS2500) on the rear because I try to reduce track prep work and as a result leave the same pads on rear for street/track. It's a compromise.

Yeah, been thinking about the change in bias, though after reading some other threads, I got the sense that a number of folks do this hybrid approach, and the idea would be to reduce track prep work as much as possible.

[PACarGuy]

Originally Posted by VictorH

It sounds like you are going to be running track pads up front. If you are going to run new track pads in back, then I would replace the rotors. If you are going to use either street pads (not generally advisable) or some used track pads, then I would agree with everyone else and just run this rear set. Only condition if you want to put new pads on back then best to also start with new rotors.

Sorry - not 100% sure I understand what you're saying - are you saying that I should replace the front rotors if I run track pads front and rear, or replace both front and rear rotors if I run track pads all around? I haven't measured the rears yet to know how worn they are, but I have to imagine they've got more meat left than the fronts...

[ayao]

I think what he's trying to say is that if you have heavy worn rotors that are grooved, etc, that you might benefit from replacing them preemptively if you are going to simultaneously install -new- track pads so that the rotor/pad combo wear evenly, rather than potentially introducing uneven wear patterns into new pads. If the track pads are used, then maybe it's not quite such a big deal as their lifespan will be more limited than a brand new set.

[PACarGuy]

Originally Posted by ayao

I think what he's trying to say is that if you have heavy worn rotors that are grooved, etc, that you might benefit from replacing them preemptively if you are going to simultaneously install -new- track pads so that the rotor/pad combo wear evenly, rather than potentially introducing uneven wear patterns into new pads. If the track pads are used, then maybe it's not quite such a big deal as their lifespan will be more limited than a brand new set.

Gotcha. Yes, the pads are new, though I only have fronts at the moment. As mentioned, the rotors are not heavily grooved, though they are obviously not new.

[roastbeef]

you'll be perfectly fine running race pads on your existing rotors, with oem rear brakes. go have fun. if thats not enough for once or twice a year, we can talk about the next step.

[PACarGuy]

Originally Posted by roastbeef

you'll be perfectly fine running race pads on your existing rotors, with oem rear brakes. go have fun. if thats not enough for once or twice a year, we can talk about the next step.

Thank you sir!

[PACarGuy]

Just to follow up on my thread, I ended up flushing the fluid w/Brembo LCF600, replacing the front rotors and putting on some ST Sport pads all around (got em cheap from Rockauto!) before the event and the setup did very well.

The track (NJMP Thunder) wasn't overly tough on brakes but I was in the intermediate run group and ended up picking up speed throughout the day, and through 4 sessions the brakes worked well with no fade. The pedal got a bit softer towards the end of the day but I had no loss of braking power. Still some decent life left on the pads as well.

As this was probably the only event I'll do this season, I'll do a flush before winter w/some street fluid to firm the pedal back up, and maybe put the Textar OEM pads back on for the cold weather, though I will say the ST's have pretty good cold bite on the street so far.

[roastbeef]

so now that you got your first trackday done, how do you feel about it? is this something that you feel like you're going to do once or twice a year, or are you shopping for track wheels and a helmet? lol