# Chronic tire "cupping"



## Guest (Nov 26, 2002)

I've had lots of problems with my 96 Sentra GXE suspension/tires/brakes. Most noticeably the brakes seem to wear irregularly and start pulsing pretty badly. I was told that this was caused by scalloping on the tires due to the light weight of the rear end of the vehicle (lots of driving, usually empty). I put on new tires and had the brakes cut down. I was pretty careful about rotating the tires after that, but they've started acting up again. I have a pretty good shimmy in the front end which I was told is from tire wear. I'm planning on replacing them and getting a balance/align, but before that I want to make sure everything else in the steering and suspension is OK. My questions are: Is this a typical problem with the Sentra? Is it possibly suspension related? If I disassemble the front and rear suspension, what should I check and how will I recognize if something is bad? Is there anything I can change from stock to help avoid further problems (and possibly get some better handling)? 

Sorry for the long post and load of questions, but I'd really like to get this fixed once and for all. I need this car to be healthy while I work on my beloved 89 Hardbody.

Thanks!
unclejoey


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## V i V i D 200sx (Sep 17, 2002)

tire cupping? that means the tires are wearing irregularly on the outsides, right? check your tire inflation... they might be under inflated. tire pressure is 33/29, i think... it should be on your inner driver side door. my rotors are warped too, thats the pulsating brake pedal. i dunno if its a common problem tho. never really asked, and ive only had it for 3 or 4 months


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## shane (Jul 10, 2002)

Cupping is caused by one of 2 things...either your tire pressure is off, or your camber is off. You should check both. The pulsating is, as Vivid said, caused by warped rotors. There are lots of things that could cause warped rotors. In fact, mine are warped as well. Mine were caused because the dealership over-torqued the lugnuts so badly that when the rotors got hot, they warped due to the pressure of the lug nuts. F*cking dealership.


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## morepower2 (Apr 19, 2002)

shane said:


> *Cupping is caused by one of 2 things...either your tire pressure is off, or your camber is off. You should check both. The pulsating is, as Vivid said, caused by warped rotors. There are lots of things that could cause warped rotors. In fact, mine are warped as well. Mine were caused because the dealership over-torqued the lugnuts so badly that when the rotors got hot, they warped due to the pressure of the lug nuts. F*cking dealership. *


Cupping can also be caused by bad shocks and an out of balance condition.

Mike


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## V i V i D 200sx (Sep 17, 2002)

yeah.... if you wanna check your shocks, push down on each corner (one at a time) w/ all your weight and when you left off, see how many times it takes to rebound and balance itself. i think 1-2 is good... anymore, you should get new ones. is your ride kinda bouncy when you go over potholes and stuff? the shimmy could mean your wheels need balancing. i think mine still need to be rebalanced, even tho they were just put on and balanced twice.


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## sethwas (Apr 30, 2002)

Hey,
Don't forget that warped rotors can also be from bad brakeing habits.

Seth


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## Guest (Nov 27, 2002)

OK, I'll bite...What do you mean by "bad braking habits"? (I think my braking habits are pretty good...I generally stop before I hit things!)


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## V i V i D 200sx (Sep 17, 2002)

maybe using them too aggressively, creating too much heat, which leads to warping. i know i dont use good braking habits. haha...


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## Wagon Wagon (Sep 20, 2002)

I'd check the struts. My struts were bad, and it cupped the tires BAD. The car didn't seem to ride bad, but it squatted under heavy acceleration. Also in the rear it failed the bounce test.... if you put your weight onto it and let go, it's supposed to bounce once. Mine bounced twice.

When I took the springs off the struts, the struts were so far gone that when I compressed them, it took them 6 hours to re-extend. 

I replaced my struts with KYB AGX units. Mmmmmmm... AGX...


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## Guest (Nov 29, 2002)

A garage that did some recent work for me told me that shock & struts were bad, but I was suspicious that they were trying to sell more work. I'm not sure if my car is capable of "heavy acceleration", but it sounds like I may be in the same boat you were.
A quick question (well, 2 quick questions) about checking things out...Does outside temperature affect the bounce test? (It's down in the 30's and I wonder if the cold would make the shocks appear stiffer than they are.) Also, how would I check to see if the struts are bad?
Thanks, all!


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## 88NissanB12 (Nov 5, 2002)

Look for oil leak or seepage on the struts, though not all of them will show it. Also if you have the strut off the car. push on the rod all the way down an see if it comes back up all the way.


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