Cross-Drilled Brake Rotors & noise / pulsations

[i_hate_autofraud]

I wonder how many people had experienced drilled / slotted brake rotors that begin
to make noise or pulsate badly after just 1 or 2 years?

"Extreme Stop" brake rotors are drilled and slotted and are beautiful to look at,
but just under 2 years they started pulsing badly when stopping from hiway speeds.

I noticed that some of the slots loaded up with hard deposits from the brake pads
and some of the drilled holes plugged up.

So I took the rotors off and drilled out the holes a little bigger on a drill press
and manually scrapped out the slots but the pulsation is back again, this time the
drilled holes and slots are NOT loaded up!.....What’s next?

I'm thinking I'll have to go back to plain rotors next time!

 

[WobblyElvis]

I just had a similar experience. The cure was plain rotors. I would suggest you don't waste any more of your time.

 

[spasm3]

Originally Posted By: i_hate_autofraud


So I took the rotors off and drilled out the holes a little bigger on a drill press

I'm thinking I'll have to go back to plain rotors next time!


I think drilled rotors are more trouble than they are worth. I have tried them and they only seem to improve braking in the rain, no where else.

I hope you chamfered the holes you drilled or you could be prone to cracks from heat and cooling cycles.

 

[dan_erickson]

Same with drilled rotors. I might go back to plain rotors if this set of warranty drilled rotors acts up.

 

[bmwtechguy]

A friend heard some brake squeaking noise, so for some reason he ordered a set of cross-drilled rotors and new brake pads from Amazon for his 09 1500 Silverado. He had another friend replace the front brakes, but still heard the squeak, esp in reverse. Turns out that actually his rear drum brakes badly needed replaced, which we did together. A few weeks later his newish front brakes with fancy rotors started to squeak. He wishes now he had kept the old front brakes/rotors, which were nearly new and actually noise-free when replaced. Some people....

 

[Johnny2Bad]

There is a place for drilled / slotted rotors, but not on a daily driver. A proper example will be made of special material and employ special processes and if you're not paying $300 a disc (or more ... the pretty discs on that Ferrari are $2000 to $4000 a copy), you didn't buy that type.

Race teams replace these parts regularly; you don't want to be having to do that on a road car or truck.

They WILL develop cracks over time, they warp easier with temperature shock (like hitting the brakes hard before or after driving through a puddle) and in general are an appearance item, not a performance improvement on a non-race use application.

If you must use fancy discs, the slotted ones are a bit more durable than drilled. Drilled is just asking for trouble, actually. They work OK on motorbikes because they don't see water much and get plenty of air cooling, they also typically will be full floating rotors which you don't see on cars, although often on bikes you see stainless rotors which don't stop as well as iron, but iron can rust. They can get away with it because a bike will out-stop almost any vehicle on the road.

Again, it's an appearance item.

 

[tomcat27]

IMHO and from my experience - drilled rotors are for appearance. the people I know that race concur that sometimes slotted helps - but they prefer solid rotors. more mass and less chance of cracking. in fact - currently preparing for a 3.5 hour endurance race this weekend - solid rotors and a fresh set of Pagid pads.

of course, I'm sure that others have other opinions. it's great to live in America!

 

[tomcat27]

For some unknown reason I kept experiencing excessive runout on the rotors on my Toyota echo; usually within a year of installation. I tried a few different brands of rotors. when I tried drilled and slotted rotors, the problem went away and I never had a problem in many years. I'm not saying the drilled and slotted rotors fixed my problem - just that I chose a good brand of rotors and certainly the holes and slots did not cause me any runout problems. I always thought it was weird that the smallest/lightest car in the family had frequent brake issues - while my heavy Intrepid with AutoZone rotors never had a problem.

 

[Johnny2Bad]

Originally Posted By: tomcat27
For some unknown reason I kept experiencing excessive runout on the rotors on my Toyota echo; usually within a year of installation. I tried a few different brands of rotors. when I tried drilled and slotted rotors, the problem went away and I never had a problem in many years. I'm not saying the drilled and slotted rotors fixed my problem - just that I chose a good brand of rotors and certainly the holes and slots did not cause me any runout problems. I always thought it was weird that the smallest/lightest car in the family had frequent brake issues - while my heavy Intrepid with AutoZone rotors never had a problem.


Not saying it is the case, but it's possible the Toyota had brake biased heavily to the front rotors. Would be more likely if the Echo had 4-wheel discs.

If the Intrepid had drums in the rear, it's almost certain the bias would differ between the two models, because drums slow the car better than discs while discs stop the car better than drums. So early application typically will be biased towards the drums with the heavy application shifting to the front discs.

It's also typical to have that type of bias as the vehicle gets heavier, even with 4-wheel discs.

The switch to discs from drums in the rear is more about unsprung weight than overall stopping performance. Discs work excellently in the front.

 

[SF0059]

Drilled and/or slotted disks are not really necessary anymore. In olden times they helped brake pads off-gas during hard use. With the improvements in pad materials, off-gassing is not a concern with street pads. As previously mentioned in this thread, many performance applications have steered away from drilled/slotted as well. It is just simply not worth the reliability issues for almost no modern performance gains.

Get some solid, balance rotors.

 

[901Memphis]

I would never use cross drilled rotors, I have seen them crack before.

 

[HangFire]

So what was the disc's on-vehicle runout when mounted, and what is it now?

If you can't answer those questions, all discussion is [censored] in the wind.

Since checking parallelism and runout on all my brake jobs, all my pulsation problems (and "warped discs") have gone away. Squeaks have all gone away since I started a.) removing all rust and replacing all abutment clips on each brake job, and b.) replacing the pad ear, back, and slide/pin lube once a year with a proper brake lube.

See: https://bobistheoilguy.com/forums/ubbthreads.php/topics/4399642/Re:_New_brakes_rotors#Post4399642

 

[555]

If one has hot brakes coming down a steep hill(lets say San Francisco) and has to come to a full stop at the bottom at a traffic light with the pads clamped tightly onto a hot rotor while waiting for the light to change, the pad will leave some material on the rotor which will cause the pulsating/shimmy the driver feels through the steering wheel and brake pedal. Whew! Long sentence. Commonly referred to as a "warped" rotor,this is not the case as iron(yes I know there are ceramic rotors too) rotors are the most common and iron rotors will not undergo the required conditions on the street to actually warp.
Cross-drilled rotors can help if your vehicle has poor brakes, my Tahoe being an example. Yes the holes were chamfered but they still started to crack and by then most of the pad was gone anyway but the fade resistance increased significantly. Well worth it, but pads/rotors won't last very long, in my case approximately 20,000 miles. I moved to slotted rotors and twin piston calipers on the Tahoe.

 

[Lubener]

Originally Posted By: dan_erickson
Same with drilled rotors. I might go back to plain rotors if this set of warranty drilled rotors acts up.


I have found out that warranties don't mean much with rotors anymore.Unless they are flaking apart or something, distributors do not consider warpage as a defect and blame calipers as the cause. Unless it is detected out of the box as warped.

 

[Bgallagher]

Originally Posted By: WobblyElvis
I just had a similar experience. The cure was plain rotors. I would suggest you don't waste any more of your time.


+1 The cross rotors look fun and have great stopping power but last a fraction of what traditional rotors do.

 

[DriveHard]

Originally Posted By: Johnny2Bad

If you must use fancy discs, the slotted ones are a bit more durable than drilled. Drilled is just asking for trouble, actually. They work OK on motorbikes because they don't see water much and get plenty of air cooling, they also typically will be full floating rotors which you don't see on cars, although often on bikes you see stainless rotors which don't stop as well as iron, but iron can rust. They can get away with it because a bike will out-stop almost any vehicle on the road.



Absolute mis-information and garbage!

Even with modern bikes having ABS they still can't out-brake most cars. BIKES DO NOT STOP FASTER THAN CARS!!! Bikers are out there losing their lives because so many people think this way. PLEASE STOP SPREADING THIS!!! Even if a bike can stop as fast as a car on paper, it takes more skill...probably a skill the rider has not practiced. It doesn't take much skill to get a car to stop to its maximum ability with today's tech.

great article on real bike stopping capabilities
http://www.sportrider.com/sportbikes/abs-comparison-test-absolutely-brilliant-stopping#page-5

and some real braking numbers...

https://www.reddit.com/r/motorcycles/comments/33sun7/motorcycle_braking_distances/

You, on your bike, are highly unlikely to outbrake a car in an emergency stop on the highway.
If you brake at the bikes maximum capability and the driver brakes at their vehicles maximum capability there's quite a few cases where the car will stop faster and sometimes pretty significantly. Rarely does the combination favor the bike. In some cases maximum braking even favors a pickup more than a bike.
Some people are going to take issue with this statement so let's just go straight to the numbers: All are 60mph to 0mph stopping distances.
.
.
Minivans:
2015 Kia Sedona: 118 ft
2015 Toyota Sienna: 121 ft
2014 Chrysler T&C: 126 ft
2015 Honda Odyssey: 126 ft
Sedans & Hatchbacks:
2014 Honda Civic: 118 ft
2012 Kia Rio: 119 ft
2013 Honda Accord: 117 ft
2014 Mazda 6: 121ft
2013 Toyota Camry: 120 ft
2014 BMW i3 eDrive: 108 ft
2015 Honda Fit: 127 ft
Pickups:
2013 Ford F-150: 132 ft
2013 GMC Sierra 1500: 137 ft
2013 Chevy Silverado: 138 ft
2013 Ram 1500: 142 ft
2013 Nissan Titan: 144 ft
2013 Toyota Tundra: 150 ft
Cars that will always win:
2011 Chevrolet Corvette Z06 Carbon: 93 ft
2008 Ferrari 430 Scuderia: 93 ft
2012 Chevrolet Corvette Z06 Centennial: 94 ft
2012 Lexus LFA: 94 ft
2010 Porsche 911 GT3: 94 ft
2010 Ferrari 16m Scuderia Spyder: 96 ft
2009 Audi R8 5.2: 96 ft
2008 Audi R8: 96 ft
2009 Chevrolet Corvette ZR1: 97 ft
2008 Dodge Viper ACR: 97 ft
2003 Dodge Viper SRT10: 97 ft
2011 Porsche 911 GT3 RS: 98 ft
2010 Lamborghini Murcielago LP670-4 SV: 98 ft
2009 Chevrolet Corvette ZR1: 98 ft
2008 Porsche 911 GT2: 98 ft
2011 Nissan GT-R: 99 ft
2010 Chevrolet Corvette ZR1: 99 ft
2010 Ferrari 458 Italia: 99 ft
2010 Porsche 911 Turbo: 99 ft
2009 Porsche Boxster S: 99 ft
2007 Porsche 911 GT3: 99 ft
Superbikes:
2011 BMW S1000RR: 129 ft
2011 Ducati 1198: 141 ft
2011 Honda CBR1000RR: 134 ft
2011 Suzuki GSXR-1000: 140 ft
2011 KTM RC8R: 135 ft
2011 Kawasaki ZX10R: 129 ft
2011 Yamaha R1: 137 ft
Supersports:
2011 Yamaha R6: 124 ft
2011 Honda CBR600RR: 126 ft
2011 Ducati 848 EVO: 127 ft
2011 Triumph 675R: 126 ft
2011 Suzuki GSXR-600: 122 ft
Other bikes:
2015 Harley Street 750: 152 ft
2011 Harley StreetGlide: 129 ft
2011 Star Stratoliner: 142 ft
2011 Kawasaki Vulcan Vaquero: 144 ft
2013 BMW R1200-RTP: 144 ft
2013 Harley Electra Glide: 144 ft
2010 Star Raider S: 124 ft
2010 Harley Softail Rocker C: 125 ft
2010 Victory Vegas Jackpot: 129 ft
Don't become a statistic. Know the facts. Don't spread misinformation that could get someone hurt or killed. You probably won't outbrake a car. In the cases where maybe you can do you really want to bet your life on it?

 

[DriveHard]

I have drilled and slotted rotors on the front of my Silverado. They work fine, make no extra noise and have not given me any trouble. I haul and tow and don't baby my truck. I have done several practice panic stops from 60+ mph and never had an issue. I got them from rock auto, they are Powerstop brand.

 

[i_hate_autofraud]

Originally Posted By: spasm3
Originally Posted By: i_hate_autofraud


So I took the rotors off and drilled out the holes a little bigger on a drill press

I'm thinking I'll have to go back to plain rotors next time!


I think drilled rotors are more trouble than they are worth. I have tried them and they only seem to improve braking in the rain, no where else.

I hope you chamfered the holes you drilled or you could be prone to cracks from heat and cooling cycles.




Yeah, I chamfered the holes mostly to be sure there were no burrs to eat thru the pads or make things worse!
As far as heat cracks, not too worried, the way I drive (steady, easy) the max brake temps I got where under
150 F highway with a long stop, less then I thought!

Thanks,

 

[i_hate_autofraud]

Originally Posted By: 901Memphis
I would never use cross drilled rotors, I have seen them crack before.


How big were the cracks?