Warped rotors and inside tire cupping

[Big T]

Just got back from a 4,500 mile trip through 6 States, BC and Alberta. Fly fished in Fernie BC. Rotors on my wife's 2014 Toyota 4Runner warped. 75k miles when we got home. I replaced brake pads and had the rotors turned when I got home. I noted that the RF tire was worn on the inside with cupping and that is the side where I was real int the most wheel pulse while braking at highway speed. The LF tire was new as my wife cut a sidewall while off-roading over lava rocks in the CA desert before picking me up in SLC after the USC @ Utah game and going onward. Just shy of 20K on the rest of the tire, Cooper AT3s.

Question, would the pulsing from the warped rotor cause the described tire wear?

After having the rotors turned, the pulsing is gone.

 

[THEFERMANATOR]

I've never seen warped rotors wear tires myself, and just don't see how it could. You're really not on your brakes that much while driving is the thing, so I just don't see how it could wear a tire.

 

[Will L.]

Cupping is usually a bouncing tire like bad shock absorber, tire out of balance or out of round.

That can cause the rotor to warp because the tire stopping at a different rate while in the air on a bounce, then up to speed when it hots the ground, the stopping quicker in the air, over and over, a hundred times a minute. So that uneven force heats the rotor unevenly.

If it were the rotor/ caliper hanging up affecting the tire, it would be center of the tread pattern flat spotting, not edge of the tire cupping.

 

[FellowTraveler]

I'd say shocks on the cupping or saw-tooth issue & alignment issue could cause wear on the inside of tire in turns.

 

[Big T]

Saw tooth is the better description of the wear. Truck is totally smooth when not braking. After turning the rotors, it's smooth while braking.

She does a lot of off-road driving with the truck.

 

[FellowTraveler]

My take on saw-tooth wear on fronts usually is from a combination of soft compound tires w/big lugs, braking in turns and out of spec alignment.

 

[79jasper]

Well I was about to say I've seen bad ball joints do that on my F350. Didn't help any that I ran them at almost max psi for awhile.
But then I saw we're running the same tires.
Most seem happy with them though, with no out of ordinary wear.

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

[Will L.]

My experience in cupping is 2 places.
Semi trailer tires- which are almost always lack of shock absorbers. In a fuel fleet it took me a year to convince adding shock absorbers to fuel tanker trailers. Within 9 months the rest of the fleet had them. Cupping was completely eliminated.

The other is on my hummer, to the point made by Fellow Traveler- 37" x 12.50" x 16.5 soft compound military goodyear mt tires. The bigger the lugs, (especially without sipes) in the soft compound tires are way worse than my gsa tires were. My shocks are toast all the way around. Hummers are 4 wheel independent coil suspension, with all the parts interchangeable- so it is easy to compare trailing vs steering tire wear.

Yes the alignment has good, or everything can go bad quick. but my hummer can cup tires in the rear just as fast as as the front now while my shocks are toast, and which ever tire is out of balance the worst is which one cups first.

 

[WarWagon]

I have had worn out shocks wear tires like that - and they weren't off road tires. Factory shocks had 100K on them with a hole in the driver side rear shock. After 30K OEM shocks/struts are more or less done.

Warped rotors are from a panic or very hard stop causing uneven friction material transfer and the red hot cast iron to turn into cementite. After a hard stop you need to creep forward ever few seconds so the red hot pads are over a cooler spot on the rotor rather than heat treating just one spot. Shift it into reverse and give yourself some room and then creep forward if needed. Always creep forward as you do not want to take off in reverse at a green light.

The brake turning tools bounce off cementite leaving hard spots usually resulting in a quick return of the pulse esp. when driving style continues to get the brake system too hot. Due to CAFE most brake systems are undersized for weight reduction and this is a common problem esp on FWD GM and GM 1/2 ton pickups/SUV's of the 90's.

Our parts now made by slave labor in Communist China means you check new rotors and drums for warping out of the box. So it's 50-50 risking new parts or formed cementite continuing to cause problems. Don't even get me started on how much fun new out of round drums are as I already said enough about the fun on replacing our front rotors.

 

[Big T]

As noted, this was at 75k miles. Attached is a pic of the tire at 20k miles and of the old vs new pads. I estimated 10K to 15k left on the old OEM pads, but changed them anyway. I was getting brake feeler squeal on initial application at mid speeds, though no indicative scrub wear on the rotors.

Shocks are OEM. No bounce in the ride post brake job.

 

[schiker]

Does wife's daily route have a hard braking event with right turn and possible bad pavement? Maybe a short freeway /highway exit with sharp curve to right that lifts the inside tire? A daily pothole / bad spot does a lot of cumulative damage.

There is a bad spot locally down the road I am in such a routine of swinging out to avoid the wavy patch I am liable to run oncoming traffic off the road out of habit. Hit it sometimes and cuss a little.

 

[Big T]

Her commute is about 20 to 25 miles one way from Fullerton to Long Beach. However it is irregular and I don't follow her. Her work has her up and down the State of CA regularly. She also takes it off-roading regularly. I worry on the latter as her judgement as to what is make able may not be on the same level as mine. She popped the sidewall on the RF tire driving over lava scree fields before picking me up on this trip. I told her not to do that shit, at least not alone.

Speaking of which, I need to get her some sort of eletric torque wrench and an appropriate Jack so she can change a tire by herself off-road. She had to drive several miles on the flat over sand road to get to the highway where AAA would change the tire for her. She ripped the mud flap off in the process. I don't know what to do with this adventurous woman. Can't cage the elephant.

 

[WarWagon]

Lots of concrete freeway in CA and the expansion joints will make extended cab pickups a miserable choice over regular cab...

As said above your tire picture matches worn shocks. May even need to run higher (+5) PSI in them if both side treads are worn more than the center. Ball joints and other suspension wear deserves a fair test.

Yes! Yes! Yes! Good jack, other tire change equipment, and a ELB: Emergency Locator Beacon. Make sure you join her for the memories that sets that off. I suggest the bar is stuck so bad with a 2WD that Yellow Iron is required to get both you and the 4X4 tow trucks (that never reached us) out. My trailer was another $150 to get out... Dry sand...