FAQ: Vibration under braking: warped rotors? NO!

[Kimberly Lazarski]

Quick question: when are rotors considered too hot for your car to be washed? I know that sudden changes in temperature can cause warping?
If I can touch and keep my hand on the (warm) rotor, is it fine to pressure wash the wheel? Or should pressure washing the wheel be totally avoided?
Thanks!

You may wash the car immediately after parking it. Think about it; if rotors actually did warp under less severe conditions than Merlin mentioned, they would be encased in a sealed module with an active cooling system rather than installed outboard at the hubs where they _WILL_ be subjected to splashing and even immersion in very cold water while driving (rain, snow, and puddles are things). Any time you think your rotors might be warped, remind yourself that vented rotors rarely if ever warp. They are more likely to deform from a BJs/Sam's Club/NTB tire tech using a half inch impact wrench on the lug nuts than by street-duty heat cycles. _Do_ go for a 15-20 minute drive after washing&drying the car to also dry the rotors to prevent surface rust.

Don't stand on the brakes while stopped after hard stops from 140mph+ (use park or the parking brake instead), and if forced to creep in stop&go traffic jams or city driving, do the bedding procedure periodically. And, if you park the car outside a week or longer and the rotors develop surface rust, re-bed to strip the rust and prevent deposits.

 

[StingertimeNC]

I too am interested in a good brake solution. Was just thinking about pairing the EBC Yellowstuff with the stock rotors, and upgrading the fluid to Motul 600. Ran two Track days so 80 20 minute sessions in total, speeds in excess of 120-130 mph with turns at the end of those high speed areas. I experienced no problems with only upgraded front pads to hawk HPS, everything else stock. However, I did not test the outer limits of the brakes. After each session I would drive around the complex parking area and access roads for about 5 or 6 minutes at about 30 MPH to cool the brakes and the turbos. also, once parked, I would move the car up a few feet a couple of times to continue to move the pads to a different area of the rotor. Knock wood, I've never had a brake issue with pad deposits. 6000 miles on the car and two hard track days and so far so good. I am still interested in an upgrade though. I want overkill, so I just don't have to worry about hauling down from 145+ mph.

 

[MerlintheMad]

I've been having fun trying to find discs and pads that don't get warped after track days. Have some RDA 4000 series slotted front discs and replacement rear discs with HD pads. Used some EBC yellow stuff pads on the front and they barely lasted one track session, about 25 laps, 5 sessions of 5 laps. Had to have the discs skimmed flat again. Then tried some Project MU pads on the front. Was a little better, got 2 track days in, but discs are warped again. I think the 4 pot brakes just maybe aren't enough to pull up such a heavy car in a track scenario. Tempted to upgrade to some even better brakes, something 2 piece but not sure the extra expense will fix the problem and I've spent waaay too much on new pads/disc skimming already really. Would be interested to hear if anyone else is doing a lot of track work and what brakes solutions they've come up with.
The annoying thing is I've put all the 'standard' discs/pads back on that have never seen a race track and I still have vibrations or pulsing under braking! Haven't done many kms/miles since putting them back on so hoping it's just everything bedding back in maybe. I tried to keep the discs and pads locations all the same but may have got the rear discs wrong way around.
Might like into a on car disc machining, always done skimming with the discs off previously. Would also like a way to test the discs for warpage.

I'm going to say this again: the driver is the main component in all of this. Several performance drivers did the Stinger during Speed Week: only Randy Pobst said nothing about the brakes being deficient: that's because (near as I can tell) none of the others are a Randy Pobst. This line of reasoning has an earlier comparison (as dramatized clearly in "Ford vs Ferrari"), where Ken Miles literally burns brakes up and loses them: historically, Dan Gurney, after his lost brakes at Zandvoort, never recovered his previous confidence in late braking and referred to himself as a graduate from "the chicken shit school of braking": but he never burned through brakes or lost them either.

In order for you to get max braking out of this car and not lose the brakes at the same time, I'm guessing that the next step is a dedicated track/race spec set. Here's where I am not a car guy: I do not know if any of those brakes that you've listed are already race spec: but I'm guessing that the most they are is a combo street/track set. So, either don't push the brakes as hard as your capabilities, or suck it up and go full on race spec.

 

[RogueIV]

I've been having fun trying to find discs and pads that don't get warped after track days. Have some RDA 4000 series slotted front discs and replacement rear discs with HD pads. Used some EBC yellow stuff pads on the front and they barely lasted one track session, about 25 laps, 5 sessions of 5 laps. Had to have the discs skimmed flat again. Then tried some Project MU pads on the front. Was a little better, got 2 track days in, but discs are warped again. I think the 4 pot brakes just maybe aren't enough to pull up such a heavy car in a track scenario. Tempted to upgrade to some even better brakes, something 2 piece but not sure the extra expense will fix the problem and I've spent waaay too much on new pads/disc skimming already really. Would be interested to hear if anyone else is doing a lot of track work and what brakes solutions they've come up with.
The annoying thing is I've put all the 'standard' discs/pads back on that have never seen a race track and I still have vibrations or pulsing under braking! Haven't done many kms/miles since putting them back on so hoping it's just everything bedding back in maybe. I tried to keep the discs and pads locations all the same but may have got the rear discs wrong way around.
Might like into a on car disc machining, always done skimming with the discs off previously. Would also like a way to test the discs for warpage.

Have you attempted to just rebed the brakes after having the shuddering issue? Did you bed the brakes at all? I highly doubt your physically warping the rotors but you are probably getting a lot of uneven pad deposits.

 

[laynevans]

D

Have you attempted to just rebed the brakes after having the shuddering issue? Did you bed the brakes at all? I highly doubt your physically warping the rotors but you are probably getting a lot of uneven pad deposits.

Definitely warping the discs. When I get them skimmed the warpage is pretty clear when they're on the lathe.
The street ones I've got on again now I will try rebedding them. In the past I've even tried some water based abrasive compound to try to remove deposits with not much success.

 

[laynevans]

I'm going to say this again: the driver is the main component in all of this. Several performance drivers did the Stinger during Speed Week: only Randy Pobst said nothing about the brakes being deficient: that's because (near as I can tell) none of the others are a Randy Pobst. This line of reasoning has an earlier comparison (as dramatized clearly in "Ford vs Ferrari"), where Ken Miles literally burns brakes up and loses them: historically, Dan Gurney, after his lost brakes at Zandvoort, never recovered his previous confidence in late braking and referred to himself as a graduate from "the chicken shit school of braking": but he never burned through brakes or lost them either.

In order for you to get max braking out of this car and not lose the brakes at the same time, I'm guessing that the next step is a dedicated track/race spec set. Here's where I am not a car guy: I do not know if any of those brakes that you've listed are already race spec: but I'm guessing that the most they are is a combo street/track set. So, either don't push the brakes as hard as your capabilities, or suck it up and go full on race spec.

Yeah, the EBC and Project MU are considered race spec pads that can still be used for general street use though they don't work so good until they're warmed up. The discs are approaching race spec but not quite. I do have to 'detune' my driving to get the brakes to last longer which is real shame as I love improving my lap times at events and beat a lot of higher dollar and more 'exotic' brands. Going full race spec discs is the next possible option but I'm concerned its still only 4 piston braking. Would love to know if anyone else has gone full race spec brakes AND actually using them at a track.

 

[laynevans]

I too am interested in a good brake solution. Was just thinking about pairing the EBC Yellowstuff with the stock rotors, and upgrading the fluid to Motul 600. Ran two Track days so 80 20 minute sessions in total, speeds in excess of 120-130 mph with turns at the end of those high speed areas. I experienced no problems with only upgraded front pads to hawk HPS, everything else stock. However, I did not test the outer limits of the brakes. After each session I would drive around the complex parking area and access roads for about 5 or 6 minutes at about 30 MPH to cool the brakes and the turbos. also, once parked, I would move the car up a few feet a couple of times to continue to move the pads to a different area of the rotor. Knock wood, I've never had a brake issue with pad deposits. 6000 miles on the car and two hard track days and so far so good. I am still interested in an upgrade though. I want overkill, so I just don't have to worry about hauling down from 145+ mph.

I haven't done a fluid upgrade but have never had pedal fade so not thinking the fluid is insufficient. All of my racing gives us a cool down lap where we don't use brakes at all and when I get back to the pits I generally just put the handbrake on so the pads don't touch the rotor again.
First couple of times at a track I was braking so hard I would get the hazards on sometimes due to the ABS activating but generally try to keep it just under that braking level and turn off the computers now anyway.
My EBC yellow stuff pads got way too hot and basically fell apart (attached). Project MU were way better but still not great. So I either brake earlier/run slower lap times or find a better brake solution without spending a fortune hopefully and no more trial and error. Would love to hear someone has already found a solution.

 

[StingertimeNC]

Stinger is not a hard core track car so we probably don't have a ton of folks going all out on their brake setup. I think it would be fun to make the car as track capable as possible. It's just different. I want to do something just not sure.

 

[NS_Stinger]

I haven't done a fluid upgrade but have never had pedal fade so not thinking the fluid is insufficient. All of my racing gives us a cool down lap where we don't use brakes at all and when I get back to the pits I generally just put the handbrake on so the pads don't touch the rotor again.
First couple of times at a track I was braking so hard I would get the hazards on sometimes due to the ABS activating but generally try to keep it just under that braking level and turn off the computers now anyway.
My EBC yellow stuff pads got way too hot and basically fell apart (attached). Project MU were way better but still not great. So I either brake earlier/run slower lap times or find a better brake solution without spending a fortune hopefully and no more trial and error. Would love to hear someone has already found a solution.

Yikes you shredded those, I've heard of other people having the same results from the yellow stuff pads after a track day. Apparently the blue stuff pads are supposed to hold up much better on the track.

 

[laynevans]

Stinger is not a hard core track car so we probably don't have a ton of folks going all out on their brake setup. I think it would be fun to make the car as track capable as possible. It's just different. I want to do something just not sure.

No, you're right. More of a grand tourer of course. I'm defintely pushing it beyond it's limits but wonder how far the mods must go to get it track ready or if I just don't bother. The i30N is more track ready but would still prefer the Stinger any day.

 

[laynevans]

Yikes you shredded those, I've heard of other people having the same results from the yellow stuff pads after a track day. Apparently the blue stuff pads are supposed to hold up much better on the track.

Hmmm...might look into the Blue Stuff. Thanks.

 

[StingertimeNC]

so, do you think part of the problem with the yellow stuff was going in you already had some deposits on your rotors, so the aggressive braking just made it much worse than if your rotors where clean and smooth? One thing I did note is the description on the Yellow stuff pads (khartunerz website) says it's a good track pad for cars up to 3500 lbs, or something along those lines.

 

[BadTrainDriver]

so, do you think part of the problem with the yellow stuff was going in you already had some deposits on your rotors, so the aggressive braking just made it much worse than if your rotors where clean and smooth? One thing I did note is the description on the Yellow stuff pads (khartunerz website) says it's a good track pad for cars up to 3500 lbs, or something along those lines.

As someone who has auto crossed and tracked cars for the last twenty years, I'm skeptical of any "track" brake pad that doesn't list the operating temperature. In my experience, blank rotors(rotors without grooves or holes) is the best, with a proper track pad that covers the operating temperature you're likely to see. Knowing the max brake temperature is a must, and can be easily found with a $30 infrared thermometer. I've dealt with Ken at KNS Brakes for years, and his website lists the operating temperatures of the race pads he sell. If you're hitting 130+MPH, I'd get a pad with a minimum 1200 degree operating range. I've had very good luck luck with G-LOC pads, FYI.

KNS Brakes

KNS Brakes DBA Rotors Hawk Brake Pads

www.knsbrakes.com

 

[StingertimeNC]

Great info. Thank you. Wondering if our current rotors would be sufficient. By the way, someone at cars and coffee mentioned Ken and KNS to me just yesterday.

 

[BadTrainDriver]

Great info. Thank you. Wondering if our current rotors would be sufficient. By the way, someone at cars and coffee mentioned Ken and KNS to me just yesterday.

I'd trust an OEM blank rotor for high speed track usage over ANY other rotor option I've seen...to include the expensive, fancy two piece rotors. I've seen first hand failures of that type of aftermarket rotor, and it causes a ton of damage! That's my opinion, but Ken could probably answer that question better than I can. I do see he sells a two piece rotor option.

 

[RM7]

I'd trust an OEM blank rotor for high speed track usage over ANY other rotor option I've seen...to include the expensive, fancy two piece rotors. I've seen first hand failures of that type of aftermarket rotor, and it causes a ton of damage! That's my opinion, but Ken could probably answer that question better than I can. I do see he sells a two piece rotor option.

There are good aftermarket rotors, but too many people go for what looks cool and not what has the best heat capacity. MB is guilty of going with what "looks cool" on a lot of cars, vs. what is functional.

 

[StingertimeNC]

Good to hear. I will ask Ken for his opinion. My rotors are in great shape so if I can get great braking with just pads that would be awesome.

 

[laynevans]

so, do you think part of the problem with the yellow stuff was going in you already had some deposits on your rotors, so the aggressive braking just made it much worse than if your rotors where clean and smooth? One thing I did note is the description on the Yellow stuff pads (khartunerz website) says it's a good track pad for cars up to 3500 lbs, or something along those lines.

No. Definitely no deposits at the start of the day. Freshly skimmed rotors and brand new pads. I did have to run off through the sand trap once so I looking back I guess some stuff could have got in there... Def thinking the yellow stuff isn't quite high spec enough.

 

[laynevans]

As someone who has auto crossed and tracked cars for the last twenty years, I'm skeptical of any "track" brake pad that doesn't list the operating temperature. In my experience, blank rotors(rotors without grooves or holes) is the best, with a proper track pad that covers the operating temperature you're likely to see. Knowing the max brake temperature is a must, and can be easily found with a $30 infrared thermometer. I've dealt with Ken at KNS Brakes for years, and his website lists the operating temperatures of the race pads he sell. If you're hitting 130+MPH, I'd get a pad with a minimum 1200 degree operating range. I've had very good luck luck with G-LOC pads, FYI.

KNS Brakes

KNS Brakes DBA Rotors Hawk Brake Pads

www.knsbrakes.com

Good info. Thanks. The Project MU pads that I've maybe had best success with list operating temperature as 0-800 C. The RDA discs have colour paint spots that change colour according to temps they've reached so I know they have reached 620 C from memory. That's the highest marker so could easily have been higher.

 

[Terrorz75]

Hi everyone,
Got a question. Do I have to resurface my rotors before putting new brake pads on? My car has that shuddering issue when braking. I'm only asking because I normally take my car to Mavis tire for brake and tire work, I don't think Mavis resurfaces rotors at there shops. Unless someone on this forum knows a good place in Nassau county Long Island. Thank you!
I only have 6500 Miles on the car and I drive about 11 miles a day on average and speeds don't exceed 50-60 mph. I do drive hard rarely given the chance.