91Toyota

This is on my brothers truck...so the exact info might not be well...exact...but close. He bought the truck from my step dad. My step dad put mickey thompson baja claws on it (31") and had to get rid of the tires before they were all the way down. Les Schwab told him that he needed to replace his shocks. He replaced his shocks and bought some Wild cat ext tires from Les Schwab (there brand of tire) Now, 10 to 15k miles later we are noticing the same cupping. It is like 1/4 difference in the tread at some places. We can't figure out what could cause this? Is this because my step dad put heavy duty shocks on?...it feels like a 1-ton going down the road....Thanks!

1990Runner

pictures???

stormin94

Check tire pressure???

MMA_Alex

probably alignment or pressure

91Toyota

His tire pressure was set at like 25 or something from Les Schwab...so he bumped it up to about 30-35...maybe even 40. I don't have pics since he is gone right now and will be gone til 2-3 in the morning. I can get them later if necessary

The alignment is fine. Drives straight...better than my truck actually. It is smooth.

stormin94

too many burnouts??? How often does he check pressure?

CJM

Chalk test:

Air up tires to what you think they need, draw a line ACROSS the tread and drive a bit straight down the road. Get out and check, wear should be even. Outsides wore down then to little pressure, insides worn down to much pressure.

sdstud212001

^^will that work on tires that are already cupped?

I have also hear that driving on the same roads all the time casues the vehicle to kinda bounce causing the cupping. Think of how a washboard road forms, well the asphalt won't give like a dirt road so the tires give.

muddpigg

iTrader: (1)

check wheel bearing torque. and regrease bearing while you at it.

MMA_Alex

I beg to differ...ever seen the roads in maine? the asphalt collapses where the tires go lol

CJM

I dunno for sure, probably so.. The tires are already ruined tbh.

desertyodaboy

Rotate the tires??? how often

91Toyota

Wow...didn't even think about that...thats a good idea!

91Toyota

He drives on the same roads all the time. He has had the tires for like 10k miles and has been off-road for maybe 20 miles total. Doesn't burn out...or anything like that. He has topped out at 90mph though. And the tires were sipped for longevity and better mpg...not sure if that is true or not???

Forgot to mention that his last tires (mickey thompson baja claws) he had he had to get rid of because of the same issue...cupping!

Matt16

Siping increases longevity and wet /ice traction. It increases longevity by dissipating heat faster. Wet traction is improved by increasing the amount of edges exposed to the road which grip better than smooth rubber.

I doubt very much siping increased mpg as it allows the tire to conform better to the road's irregularities. That is conducive to better traction, but not mpg.

CJM

Sounds to me like the truck has front suspension issue or he doesnt have the proper air pressure.

booth.st

What's Happening to the tire, causes, corrective actions:
http://www.kaltire.com/commercial/medium_truck_tires/cupping.php

General Tire Problems
http://www.partsamerica.com/Maintena...reProblem.aspx

It also seems to be most common in certain vehicles, such as sport-trac for example
Ref:http://www.topix.com/forum/autos/for...TPQ2FDOFIHJJU8


My 2 cents is, do the chalk test as mentioned before and check the balancing of the tires. I have Trxus tires (heavy for there size) and the shop that originally balanced them tried to screw me by throwing as many weights as they could on and saying it was balanced . I knew a little and checked them out to find they were way off and I had to powder balance. To sum up, check out all possibilities before you ruin another set. You'll save in the long run.

Hope I could help. Good luck.

motorhead

I had the same problem with the same size of the same brand of tire, even fewer miles...they are directional so I was "rotating" them front to back. Had been told that dismounting and remounting tires more than 3 times or so would cause the bead to be harder to seal. Been told since then that it's not a big deal. I have them on aluminum sr5 wheels, so my guess is that they were not balanced correctly, and the tread design masked any problems I might have felt with ATs or something less aggressive. Truck tracked straight, never wore any of the 225s or 235s that were on it, so I was not thinking front end, but want to redo everything after I put the 7m in. Will be going to ProComp ATs next, on old American racing aluminum wheels. Trying to trade all my Toy wheels (2 sets of sr5s, one chrome steel) for aftermarket to get rid of the lug-centric balancing issues...

J

Yoda

What kind of truck?

The wildcats are schwabs cheap brand. The cat muds we had didn't wear for crap.

motorhead

Mine was a stock 86 4runner...while it's down for a motor I have a low-km (111k when I got it), high-cancer 86 pickup...found out later I got bent over on the rubber, so now there is only one place in Ottawa I'd go for tires...