Rotors Warped after two track days! (Video)

JDM_BMW

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More problems with the stock brake system on track. I'm thinking its my fault but if anyone has any input on how to keep this from happening again your help would be appreciated.

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nibble

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Here's my take on this.

MKV supra's front brake tend to make those grooves with hard braking during track days. Of 10 students I had past 3~4 months, all student's rotors were forming grooves as well as mine. One of my guess of this characteristic on rotor is that once it forms that grooves, it marries with pads creating larger contact surface area between the rotor and the pad. This might be far fetched idea and might not be true but looking at everyone's rotor behaving same, this cannot be just mine that's defective. Rear does not show this behavior.

For that reason, when winter comes and if I equip with more street friendly pad, I plan to store these rotor and pad marked left, right, inside (L&R), outside (L&R) etc.
what I see you may have done wrong, possible theory, is that when you re-surfaced the rotor, there may have been very slight difference of width between left & right side. this will definitely cause warp on rotor and I had this issue with other car and took me long time to figure it out. since then I use brand new rotors and never re-surface. also, Supra's rotor has left & right side which has to be installed on proper side dissipate heat properly.

If my speculation is true, what you should've done was getting new rotor specifically working with XP10. and now a days, you can get cheaper rotor from Dynamic Friction.
 
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JDM_BMW

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Thank you very much for taking the time to share your information on this. It was very informative and helpful!

Follow up question; if I buy new OEM front rotors am I ok to install them with the XP10 I already have a track day with? Or will this cause any weird bedding issues?

Thanks again!
 

nibble

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Thank you very much for taking the time to share your information on this. It was very informative and helpful!

Follow up question; if I buy new OEM front rotors am I ok to install them with the XP10 I already have a track day with? Or will this cause any weird bedding issues?

Thanks again!
That's a very good question. first of all, you cannot just replace one. you will have to replace both. otherwise, you will encounter same problem due to difference of the width. having said that, I'm not sure if brake pad has worn out evenly on both side. it is possible that pad width are equal on all 4 pads and will that matter is another question. however, I have somewhat mix/match XP10 on my s2000 before and had no issue. will this occur on supra, I'm not sure. further more, these rotor compound might be specifically designed to work with pad that was supplied and harder compound on XP10 may eat up more of rotor than pad. This too, I haven't tried yet.

Eventually, I will be using G-LOC pads (as same as carbotech) since I know this was the best pads I used on track. when I do change, I plan to change rotor to steel also.
 
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JDM_BMW

JDM_BMW

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That's a very good question. first of all, you cannot just replace one. you will have to replace both. otherwise, you will encounter same problem due to difference of the width. having said that, I'm not sure if brake pad has worn out evenly on both side. it is possible that pad width are equal on all 4 pads and will that matter is another question. however, I have somewhat mix/match XP10 on my s2000 before and had no issue. will this occur on supra, I'm not sure. further more, these rotor compound might be specifically designed to work with pad that was supplied and harder compound on XP10 may eat up more of rotor than pad. This too, I haven't tried yet.

Eventually, I will be using G-LOC pads (as same as carbotech) since I know this was the best pads I used on track. when I do change, I plan to change rotor to steel also.
I just ordered two new front rotors and I am going to give them a go with the XP10s I have.

I will measure the pad thickness just to know but they look even and almost new still.

Thank you again for the advice and information. I will update after I get the new rotors on and hit the track!
 

handsoffsam

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full disclosure I didn't watch your video, but from a quick read over all of this -- and my opinion:

1- they're iron rotors, nothing magic or special about them. any of the aftermarket pads out there are designed for iron rotors. rotor widths relative to the other side are irrelevant for the most part, that's why the cylinders in brakes compress with fluid -- to make up that space. same with pad shape, irrelevant barring total uneven wonky wedges. that's why over the course of a 12 hour race, the pedal feels mostly the same (ignoring fade or air) -- the fluid braking system and cylinders inside each caliper take up that gap. a mm or two difference is going to matter absolutely zilch.

2- carbos and glocs are incredibly sensitive to the bedding process. if you didn't properly bed these, it's possible you bunny hopped the transfer layer on the rotor which is cumulative as you cycle through adherent and abrasive frictions. again, my opinion, but I've only ever had that issue running carbs/glocs -- not saying they're not amazing when things are working well.

3- going from carb/g's to any other brake compound on same rotor has never been an issue for me, but doing the reverse absolutely has. see #2 - transfer layer dependent pad.

next time you have the rotors off, sand them / resurface it and start the process over. I'm biased, I've always had a love / hate relationship with them but always had less issues running pagid / pfc / or even old ass hawks for what its worth.
 

Rocksandblues

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Had another track day again yesterday. 40 2mile laps. no warping- bone stock brakes.
I don't ride the brakes, do all my braking before the turn, and i drive around the paddock and parking lot slowly not using the brakes after each session for 5 mins.

Looking at brake upgrades but i am really liking the stock brakes so far. I am trusting them more and more and braking later and harder. I am no Jackie and driver mod the is still the top mod i need. But i am learning and lap times are coming down.
 
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JDM_BMW

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Had another track day again yesterday. 40 2mile laps. no warping- bone stock brakes.
I don't ride the brakes, do all my braking before the turn, and i drive around the paddock and parking lot slowly not using the brakes after each session for 5 mins.

Looking at brake upgrades but i am really liking the stock brakes so far. I am trusting them more and more and braking later and harder. I am no Jackie and driver mod the is still the top mod i need. But i am learning and lap times are coming down.
No offence but if If you are truly on stock pads and fluid and not having any issues you are simply not driving the car hard enough.

To follow up on my post for those that watched the entire vid I replaced the rotors (brand new fronts) and have not had any more warping issues.

The problem now as some have told me I may run into is after about ten mins Im getting some fade from the XP10s.
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