Warped rotors

[Dreamer99]

Dealership is going to replace my rotors under warranty (at 30,000km). It sounded like they were only replacing rotors though, lots of depth left on pads. Should I get new pads at the same time (even if I have to pay for them)?

[Amirsm3]

Originally Posted by Dreamer99

Dealership is going to replace my rotors under warranty (at 30,000km). It sounded like they were only replacing rotors though, lots of depth left on pads. Should I get new pads at the same time (even if I have to pay for them)?

No. Just keep the pads on there if they're still good. No sense in wasting money at that point.

[Dreamer99]

Turns out they are going to replace the pads under warranty as well. All good!

[dparm]

Wow, very lucky. Generally speaking, rotors outlast the pads on these cars.

[Amirsm3]

Damn, nice.

[Dreamer99]

Being a track rookie I'm probably over using the brakes. Will a track pad help keep the rotors from warping?

[roastbeef]

I got a set of front and rear brakes from the dealer once I started tracking.

[Hawk Lax]

Most likely pad deposits. Unlikely that you warped the rotors.

[dbyrd]

Originally Posted by Hawk Lax

Most likely pad deposits. Unlikely that you warped the rotors.

This ^^^^

You will always get pad deposits when running the OEM pad after your second or third track day. The shaking/judder will be significant but the deposits will wear off within 100 miles of daily driving. Time for track pads.

[dparm]

Originally Posted by Dreamer99

Being a track rookie I'm probably over using the brakes. Will a track pad help keep the rotors from warping?

Not really.

"Warping" is not the problem, it's pad deposits. The deposits happen when the pad material overheats and starts to lay down huge chunks on the rotor face. As you press the brake pedal down, you'll feel these vibrations through the pedal and steering wheel. The OEM pads are not designed for sustained high temperatures, and there's only so much cooling available.

A race pad can handle higher temperatures, and for longer periods of time., meaning they'll be less likely to leave deposits.

And yes, novices do tend to overuse the brakes.

[1MOREMOD]

It's amazing how many service departments thing people are warping rotors. Practically impossible.

[dparm]

Originally Posted by 1MOREMOD

It's amazing how many service departments thing people are warping rotors. Practically impossible.

It might be a case of them simply using that phrase since the lay-person understands it. Then again, SAs are not always the most technical guys....they're salespeople.

[HP Autosport]

A runout check will reveal the if the rotors are indeed warped or there is uneven pad deposits.

[Dreamer99]

The BMW Tech said they measured the rotors and they were out of spec. I have no reason to doubt him as it's costing them money to install new ones. That being said is there visual clues of this pad deposits? I have a few hundred km's on pads and rotors since the HPDE event and there has been no change in the feel of the brakes.

[HP Autosport]

Originally Posted by Dreamer99

The BMW Tech said they measured the rotors and they were out of spec. I have no reason to doubt him as it's costing them money to install new ones. That being said is there visual clues of this pad deposits? I have a few hundred km's on pads and rotors since the HPDE event and there has been no change in the feel of the brakes.

Most of the tech will perform a minimum thickness measurement, but not a runout measurement. If it's under, at or near minimum thickness, the rotor will just get replaced without having to go to the next check.

If you start to see pad material being smeared across the rotor surface, that could be an indication of deposits. The rotor surface should be pretty consistent.

[Dreamer99]

So the dealership replaced the front pads and rotors under warranty, very nice! I'm going to order some PFC08 pads for the front and rear for future track day events. I'll get them on a week before the event to seat them properly. Will there be any issues city driving them in cold or wet weather? Also, if I upgrade my brake fluid to something like AP Super 600 or Motul RBF600 would there be any issues with this fluid in the winter months (daily driving)?

Thanks in advance for your input.

[dparm]

Originally Posted by Dreamer99

So the dealership replaced the front pads and rotors under warranty, very nice! I'm going to order some PFC08 pads for the front and rear for future track day events. I'll get them on a week before the event to seat them properly. Will there be any issues city driving them in cold or wet weather? Also, if I upgrade my brake fluid to something like AP Super 600 or Motul RBF600 would there be any issues with this fluid in the winter months (daily driving)?

Thanks in advance for your input.

You don't need them on a week in advance. Just install them before you leave for the track (the day before or whatever). They'll bed-in on the first lap or two. I wouldn't run them any longer than necessary around town, as they'll be noisy as shit and really increase stopping distances.

No problems running those fluids year-round. Consider Castrol React SRF -- highest wet boiling point of any fluid. There's a reason race cars use it.

[Dr.Mark]

PFC08's are great. If you ever get deposits, put race pads on and drive for 1-2 weeks. That will clean those rotors up and all judder will be gone. It's nice you got them replaced.