Replacement rotors - need some advice and education

[Evo442]

Was bleeding my brakes over the weekend and noticed my rotors were getting worn down... I know that all rotors have a minimum width (depth?) inscribed on them, which means "change the rotors now", but how close to that number can I get before I should not do another track day before changing rotors?

Weights of stock rotors, front and rear?

Advantages/disadvantages of 2 piece vs 1 piece rotors? In general, whats heavier, 2 piece or 1 piece setups?

Any reccomendations for replacement rotors? Evo is my daily driver, and am hoping to track the car once per month. Currently running endless SSS pads.

Anyone know about or have experience with cryogenically treated rotors?

[vtluu]

Some info about 2-piece "floating" rotors here: http://www.norcalevo.net/forums/viewtopic.php?p=46186#46186

From the service manual; stock brake rotor thickness:
Standard value:
<Front> 32.0 mm (1.26 inch)
<Rear> 22.0 mm (0.87 inch)
Minimum limit:
<Front> 29.8 mm (1.17 inch)
<Rear> 20.4 mm (0.80 inch)

My stock brake rotors have seen 3 track days, around 40 autocrosses, and 27000 miles of road/street driving, and still have a bit material left. If you have reason to believe that your rotors may not last the full track day, the safe thing to do is to replace them. Keep the old rotors around as spares, if they have some material left.

You can replace rotors at the track between sessions, but don't forget to bed them in before really driving them hard.

[methods4]

Also,

If you want a cheap alternative to OEM rotors, RRE sells Powerslot rotors for $250/pr (fronts) and $220/pr (rears).

If you do a lot of trackdays, it would be worth spending extra for the PF 2pc floating rotors.

[Evo442]

thanks for the input guys. anyone know how much the replacement rotors would be on a 2piece rotor? (ie vs buying a new 1piece rotor every time)

[earlyapex]

I added a longer review of the PF rotors here:

http://www.norcalevo.net/forums/viewtopic.php?p=50370#50370

[Evo442]

I added a longer review of the PF rotors here:

http://www.norcalevo.net/forums/viewtopic.php?p=50370#50370

Bryan - nice writeup. Thanks.

I'm interested to hear what your longer term impressions are, and to find out how the rotors hold up to multiple track days. I wish that they had the rotors with a slotted design. I'm also curious to find out what the price would be for replacement disks/rotors. Called RRE yesterday and they didn't know yet.

[Matz]

I added a longer review of the PF rotors here:

http://www.norcalevo.net/forums/viewtopic.php?p=50370#50370


Boo, where did this writeup go? :?

[earlyapex aka jack ass]

hrm interesting.

[Matz]

hrm interesting.


yeah... I think I'm going to try DS2500's this time around, but I am looking into rotors so I'm prepared... gotta pull the wheels off and inspect them. Was thinking about the Stoptech slotted ones. SE might have them for $399 for all four.

[ReSin]

Dave...get some 2-piece rotors for the front, take off some rotating mass. I'm not that impressed with the DS2500's...I was expecting more, as far as initial bite, bite after they're warmed up...everything. I wasn't disappoint with the price, as I got them for the same price as the Hawk HP+'s...

Dennis

[Matz]

Dave...get some 2-piece rotors for the front, take off some rotating mass. I'm not that impressed with the DS2500's...I was expecting more, as far as initial bite, bite after they're warmed up...everything. I wasn't disappoint with the price, as I got them for the same price as the Hawk HP+'s...

Dennis


I guess initial bite is pretty important for those SCCA AutoX events where you have to be able to break really well from the get-go? So you like the Hawk pads?

[XVeloX]

I know people say the HP+ are a milder pad than the DS2500's, but my HP+'s with Motul and stainless lines lock up my street tires and my RT615's with very little pressure. I love these pads, and after redoing the shims for the third time they are finally silent. Lots of dust though.

For rotors, i am trying out www.rotorpros.com slotted in the rear. I was going to do them all the way around but Dennis gave me his old slotted stoptechs that are practically brand new. I think rich quoted me something like $260? for all 4 rotors :shock: :)

[Matz]

I know people say the HP+ are a milder pad than the DS2500's, but my HP+'s with Motul and stainless lines lock up my street tires and my RT615's with very little pressure. I love these pads, and after redoing the shims for the third time they are finally silent. Lots of dust though.

For rotors, i am trying out www.rotorpros.com slotted in the rear. I was going to do them all the way around but Dennis gave me his old slotted stoptechs that are practically brand new. I think rich quoted me something like $260? for all 4 rotors :shock: :)


Yeah, I got PM'd this info last night, so I have sent Rich a quote request! Thanks for posting it up for me!

How did you like the DS2500s?

[Matz]

Well, won't get the new rotors in time for the pads, and the pads have to go on this week because I can't drive to get tuned until then. It's generally a bad idea to change the rotors after using new pads on old rotors, right?

[ReSin]

Well, won't get the new rotors in time for the pads, and the pads have to go on this week because I can't drive to get tuned until then. It's generally a bad idea to change the rotors after using new pads on old rotors, right?


I would say it depends on the condition of the rotors...if they are tore up pretty bad, then yes...if they are smooth, but just worn down...no...but go with your gut feeling...
Also...how many miles to you plan on driving before you get the new rotors???

Dennis

[MarkSAE]

Well, won't get the new rotors in time for the pads, and the pads have to go on this week because I can't drive to get tuned until then. It's generally a bad idea to change the rotors after using new pads on old rotors, right?


Not really. You can use new pads on old rotors or new rotors w/ old pads. Just be sure to do a few hard stops after each pad change to bed them in. I've lost count of how many times I've changed pads on my car.. probably over 20 times.

[Matz]

Well, won't get the new rotors in time for the pads, and the pads have to go on this week because I can't drive to get tuned until then. It's generally a bad idea to change the rotors after using new pads on old rotors, right?


Not really. You can use new pads on old rotors or new rotors w/ old pads. Just be sure to do a few hard stops after each pad change to bed them in. I've lost count of how many times I've changed pads on my car.. probably over 20 times.


Ok. I knew you could change pads on the same rotor, but thought you couldn't do it the other way around. I guess my reasoning was that a pad that was worn on a different rotor would then cause the new rotor to wear the same way. hehe... well, thanks for clearing that up. We'll see where my current rotors are, thickness-wise. I'm sure they're good enough for another couple of weeks... but my pads are totally shot.

[MarkSAE]

I read that old pads could carry over a previous wear pattern onto a new rotor also. But from my own experience, I've never seen it. The pads I've used always wear way faster compared to rotors. I measure my rotor and pad thicknesses all the time w/ calipers.

A visual cue for front rotors that need changing is when a lip begins to form at the edge of the rotor.

[Matz]

A visual cue for front rotors that need changing is when a lip begins to form at the edge of the rotor.


yeah, I was afraid of that. I have had that lip for thousands of miles... :(

[MarkSAE]

yeah, I was afraid of that. I have had that lip for thousands of miles... :(


I wouldn't worry too much about it. My front rotors had that lip for a long time and were close to the service limit, but didn't go past it. As long as your rotors don't have any major cracks on it, you should be fine until your new rotors show up next week.

[homi mike]

Matz, what rotors did you end up getting??
My stocks pads were on the wear indicators and made some horrible grinding noise yesterday (even w/o using the brake!).

Don't want to spend all the money for 2pc rotors, and also heard enough disadvantage of those slotted 1 pc rotors. Only wish someone else besides brembo has the right to manufacture blanks....I guess stock take-off would be my best bet....

[Matz]

Matz, what rotors did you end up getting??
My stocks pads were on the wear indicators and made some horrible grinding noise yesterday (even w/o using the brake!).

Don't want to spend all the money for 2pc rotors, and also heard enough disadvantage of those slotted 1 pc rotors. Only wish someone else besides brembo has the right to manufacture blanks....I guess stock take-off would be my best bet....


I went with rotorpros.com (centric rotors, I think?) for $250 shipped for ALL FOUR rotors. Great deal. I picked up DS2500s from Speed Element. I am really liking the setup for autox so far, but I need some more time on the course to get a better feel for the different in braking.

[XVeloX]

Matz, what rotors did you end up getting??
My stocks pads were on the wear indicators and made some horrible grinding noise yesterday (even w/o using the brake!).

Don't want to spend all the money for 2pc rotors, and also heard enough disadvantage of those slotted 1 pc rotors. Only wish someone else besides brembo has the right to manufacture blanks....I guess stock take-off would be my best bet....


I went with rotorpros.com (centric rotors, I think?) for $250 shipped for ALL FOUR rotors. Great deal. I picked up DS2500s from Speed Element. I am really liking the setup for autox so far, but I need some more time on the course to get a better feel for the different in braking.


+1, Rich has some great prices and is a really nice guy. I just put on my rear set of slotted rotors from rotorpors.com and am very satisfied.

[ZK]

Most generic rotors are good enough unless you're doing lap days... even for those it should be good enough. They're cheap enough to replace often and resurface when they get warped if you're trying to save some money.

I used 2 sets of normal rotors before I got a set of 2 piece rotors and haven't looked back. They really do make a big difference and last longer at the track.

[dabaysevo]

I have heard good things about the Centric blank replacement rotors. What is the new consensus about 1pc slotted rotors? I thought the cross drilled rotors were the only ones that have been frowned upon?

[Matz]

I have heard good things about the Centric blank replacement rotors. What is the new consensus about 1pc slotted rotors? I thought the cross drilled rotors were the only ones that have been frowned upon?


Everwhere I've read, people say that the cross drilled rotors are prone to cracking around the holes, but I don't have any firsthand experience with cracking. I had cross drilled rotors on my Maxima, but am not even sure why I got them, since I never did any sort of hard driving or motorsports with that car.

[earlyapex aka jack ass]

Most generic rotors are good enough unless you're doing lap days... even for those it should be good enough. They're cheap enough to replace often and resurface when they get warped if you're trying to save some money.

I used 2 sets of normal rotors before I got a set of 2 piece rotors and haven't looked back. They really do make a big difference and last longer at the track.


I currently use the cheapies at the track since they are 100% centric (same as stoptech as centric owns stoptech) and they have actually held up better so far than some of the 2 piece I have used. Oh the horror!

[dabaysevo]

^That's because your car is fast enough to scare you now. :D


http://www.trancewave.com/novalounge/blog/images/chicken.suit.jpg

[MarkSAE]

I currently use the cheapies at the track since they are 100% centric (same as stoptech as centric owns stoptech) and they have actually held up better so far than some of the 2 piece I have used. Oh the horror!


haha.. me too. I've "downgraded" from 2-pc racing brake's to blank Centric fronts and they seem to hold up much better to track abuse. A lot less spider cracks.

[ZK]

haha.. me too. I've "downgraded" from 2-pc racing brake's to blank Centric fronts and they seem to hold up much better to track abuse. A lot less spider cracks.


Mark, I picked them up after your endorsement of the 2 piece rotors... oh well.

[MarkSAE]

Mark, I picked them up after your endorsement of the 2 piece rotors... oh well.


Well, my RB rotors did last 16 track days. So that is pretty good. hehe.. I don't think the Centrics will get that many.

[heeltoer]

^^ the centrics won't if you don't turn em. If you get them turned (~$10/rotor if you got the right place) they will last that plus plenty of street miles. Get them turned after the first track event with heavy scoring, probably in the 6-8 track days range depending on your driving.

[wilson1]

So how deep of a lip before rotor replacement, if the car is meant for a DD?

[heeltoer]

So how deep of a lip before rotor replacement, if the car is meant for a DD?


wilson,
oem brake rotor thickness is 32mm (1.26 inch) measured from one rotor surface to the other.
min limit according to factory manual is 29.8 mm (1.17 inch)
Since this is the width of both brake rotor surfaces together that means any lip greater than ~6mm on either side means replacement according to the factory manual.Â* You really ought to turn the rotor before a ~4mm lip though, you may remove surface but your rotor will be more even and get much better wear and more consistant braking.

I have gotten away with low 29 mm widths at the track but there will be plenty of vibration and judder in the steering wheel.

-edit-
above figures are for the front
rear is 29.8 mm (1.17 inch) to 20.4 mm (.8inch)

hope this helps.
-heeltoer

[tam@xperformance]

Your math is off. 32.0mm minus 29.8mm = 2.2mm. Meaning a maximum lip of about 1.1mm per face, assuming both faces are even (often, they're not).

Best way to check is with a caliper micrometer.

A 6mm (~1/4") lip would mean you've worn through almost all your rotor material. :shock:

[wilson1]

Just curious if the majority of the rotor wear is on the outer or inner surfaces?

[heeltoer]

^^ oops
yeah the way its formatted in the manual is kinda confusing, let me just copy paste everything
"
Using a micrometer, measure disc thickness at eight
positions, approximately 45 degrees apart and 10 mm (0.39
inch) in from the outer edge of the disc.
Standard value:
<Front> 32.0 mm (1.26 inch)
<Rear> 22.0 mm (0.87 inch)
Minimum limit:
<Front> 29.8 mm (1.17 inch)
<Rear> 20.4 mm (0.80 inch)
"

As Tam said, any lip of ~1mm should be worrysome, front or rear rotor.

As far as which side wears more, technically neither side should see more wear since the pistons push in from both directions.Â* My actual usage indicates there is slightly heavier wear on the inside since that is a closer path for the fluid to travel.Â* If this is a real concern you can always flip pads but ive never found this to be necessary on the evo.Â* When the piston only pushes in from one side like my integra flipping brake pads becomes more useful.

[tam@xperformance]

I think my OEM rear pads wore about 2x as fast on the inside as outside. The imbalance doesn't seem to be as bad with more aggressive pads. Interesting point about the fluid travel; I always thought it was because of better cooling on the outside surface.

In the front, things seem to be fairly even.

[KakimotoEVO]

I have gotten away with low 29 mm widths at the track but there will be plenty of vibration and judder in the steering wheel.
-

Slightly off topic but since we're on the topic of rotors....Â* Â*I was at Infineon this weekend.Â* After the 2nd session, my steering wheel starts to vibrate pretty badly after the brakes warmed up.Â* It gotÂ* to a point so bad that if I trail my brakes into a turn, it would try to pull my steering wheel to the other side (pull left on a right turn)Â*

I suspect my dr. side front rotor is warped.Â* But I can't be sure.Â* They have slight to no vibration on the street or before the brakes are warmed up on the track.Â* These are FP 2 piece rotors.Â* I am using Project Mu Max 900 pads (as recommended by bryan as a dual purpose pad)Â* Today, while exiting the freeway, I did a hard stop from 80 to 20mph.Â* No vibration.Â* I am confused!Â* Perhaps I am not generating enough heat for the rotor to expand to a point where the warping is noticible?Â*

I might switch to centric's next track day and see....Â*

Thanks,
Adrian

[MarkSAE]

Adrian, you drove to/from the track on those pads right? Those pads are abrasive enough when cold to scrape off whatever transfer layer you had on the rotors at the track. That's why they were smooth again.

I never had a good experience w/ those Project Mu Level Max 900 pads. They left uneven pad deposits when not heated up enough. Infineon is not a very hard braking track, so you probably couldn't get them hot enough to lay a good even transfer layer on the rotors.

It's the characteristic of those Project Mu pads. I experienced something similiar when I used them. You most likely