Warped rotors?

willimo

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Honda strictly forbids dealers from resurfacing Type R rotors in the service manual.
It's probably because of the service limit then. For years BMWs have manufactured their rotors almost exactly to the service limit, requiring owners to change the rotors with the pads. It's likely a similar situation. Slots or holes don't make any difference.
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Type R 761

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Most shops won't resurface cross drilled rotors because it damages the blades so the OP has 3 options. 1- if braking is not affected, issue is only esthetic and you can live with it do nothing it's normal. I have been doing track days for 12years, and have seen grooving across many cross drilled rotors. My Porsche 993 + CTR included. 2- by new discs, replace yourself. 3- pick up some really aggressive track pads, like DTC60, ride them as you usually (to work, in traffic, etc) for 1 to 2 weeks and they will look new since pad material never reaches optimum temp on street, the wear off disk material. I know because I had some grooving + deposits (causing vibrations) on a disk after multiple track days (leaving TC full on). After a track weekend and driving around for 3-4 days on DTC60 (my track pads at the time) deposits/grooving were gone. Switch back to OEM and they braked like new and discs looked like new.
 

Speed9117

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Thanks for all the responses here.

Car has 5000 miles. It’s on the original pads and rotors. Properly broken in. No aggressive braking.

A few facts:
1. Drilled rotors can’t be resurfaced.
2. I don’t have any vibrations
3. I don’t have any decreased performance

4. Thanks for sharing photos of other R rotors. I have found quite a few with the same “issue”
5. Grooves might be the better term. I can f
“feel” them with my finger.
6. Groves do seem to line up with a drilled part of the rotor at one point.
Sounds like you don't have an issue. Just keep driving the car until the pads need to be replaced and then buy new rotors when you do pads. Centric has a cheap OEM drilled alternative if you don't want to spend $400 in rotors front and rear.
 

Gansan

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False. Places don't like doing it because if you're not careful you'll break the bits on the brake lathe. We did it all the time.



Also false. A resurfaced rotor isn't any more prone to warping than it was before you resurfaced it. The only thing you really need to worry about is if you have to cut it pretty deep, because then you'll be getting close to the service limit, which will make it easier to damage and you won't be able to cut it again. A lot of times rotors are "prone to warping againg" because a shop uses a brake lathe that cuts it flat to itself, not the hub. A good shop should have an on-car brake lathe which will cut the rotor flat to the plane it spins on relative to the car. This is best practice and Honda dealers have been required to use on-car lathes for some years now.
Saw this randomly and although it's from a year ago, I thought I would chime in. I personally don't think the second point is false. The reason is that when you machine down a warped rotor, whether it is on the lathe or on the car, you are planing the surface flat while not straightening the underlying disc. The result is you end up with the rotor having varying thickness in different areas, and it seems to me that this will exacerbate problems from thermal expansion in track driving.

Mind you, I think it's only an issue on the track. For street driving, it will be fine.
 


OP
OP

garoto

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Sounds like you don't have an issue. Just keep driving the car until the pads need to be replaced and then buy new rotors when you do pads. Centric has a cheap OEM drilled alternative if you don't want to spend $400 in rotors front and rear.
Car has been fine thousands of miles later. And almost every CTR I see manifests the issue as well as other high performance brands. Zero concerns. (I also don’t do aftermarket)
 

amurciano

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Someone mentioned to change rotors when you change brake pads, is this true? Also if it is true why, is it because the older brake pads will also be grooved and not work well with a smooth new rotor, and vice versa a grooved rotor with new brake pad will also be bad?
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