was told Struts could cause flat spots on both back tires(2 different brands and tread still good)cannot see them but can feel it with my hand,was told to replace struts,allign front and rear('99 corolla)than new tires and balance.Can bad struts actually cause this massive vibration from rear at 55 to 75MPH?
Yes.
You can also get flat spots on non-drive tires if the tires aren’t ever rotated. Some cars are a lot more prone to it than others.
[b]The Reason You’d Have To Rotate Them Is That Something Is Causing Them To Wear Unevenly.[/b]
I don’t rotate. I don’t get uneven wear. I’d stay away from cars that I knew suffered from a “phenomenon” of this nature.
Maintenance might be behind. Sandy needs to tell us how many miles on this 99, and whether this car has had regular maintenance, recent tires, etcetera. We’ll get a better idea as to what to recommend. Struts and a 4-wheel alignment and tires and/or tire balance might be what’s needed. She can try the struts/alignment, first
and see how she rolls.
CSA
Sandy, Here’s A Thought. I Hate To Second Guess Your Mechanic.
He/she is probably correct about needing struts. However, a tire or tires with bad belts in them or some other defect can cause both bad wear patterns and very definitely violent shaking (“massive vibration”)! Balancing, new struts, etcetera won’t fix that. Older tires often suffer this fate and some new ones as well.
Be sure that someone spins the tires by hand with the car on a hoist/lift and while holding a pointer staionary up to the tread area, check the tires for run-out and “roundness” (no lumps or buldges, side-to-side movement). This can also be done by removing each wheel and spinning them slowly while on a wheel balance machine, off the car. The amount of tread left is not an indicator.
On my car, I’d get that checked first. Been there, done that, more than once. For massive vibration in the rear-end, that’s the first suspect.
CSA
My 99 corolla has 117,000 but 3 tires (2 front,1 lft rear are 4mos old)and 1 tire,
(RT rear is a different brand is apprx 1yr old) both have the flat spots though! Tread is good,this where my mechanic said i could keep tires if i wanted to ride it out or replace.But he assured i need 4 wheel alignment and new struts,that that is whats causing the flat spots.of cours i will also get 2 new tires on rear and balance all4,i just never heard of STRUTS causing flat spots.Than you
In case there’s a misinterpretation here, a flat spot (singular) is often a sign of a badly out of balance tire.
Flat spots (plural) could mean tire cupping and that is generally caused by weak shocks and struts.
Since the problem seems to exist on all tires it’s not likely a tire balance problem.
Some vehicles don’t take well to not having the tires rotated and can develop odd tire wear problems but without seeing the tires I have no idea if this is the case.
Exactly…it is both back tires,and like i said the Tread is still good.You can’t even see the “flat spot” but i could rub my hand over it and actuslly feel it dip down.And you right about the balance problem.mechanic said not waste my money on that till i get new Struts and all 4 wheel alignment,then i will get 2 new tires and balance all 4.I just didn’t want to spend 8-900.00 dollars on something i had never had or heard of.he said it is commomn,so i posted here to see if anyone could shed light on Struts causing “Flat spots”.Thanx alot all!!!
Sandy,
If you rub your hand on the tire and feel a sharp edge at the start of every tread element - that is NOT flat spots. That is called “heel and toe wear” and in extreme cases “feathering” In some repects, this is normal as the tread elements will bend as they enter the footprint, then rapidly return to their original positions as they leave the footprint (and the result sort of looks like a foot, hence the term “heel and toe”.) However, toe in (or toe out) aggravates this, so excessive amounts of Heel and Toe wear indicate an alignment issue.
But I suspect you have a different problem - irregular wear: A wear pattern where every 3rd or 4th element (more or less) wears more - and this is commonly called “flat spots” or “cupping wear”. While struts and shocks are frequently cited as the cause, excessive toe in by itself will also generate this wear - and, of course, bad shocks will aggravate the situation.
So your first step would be to get an alignment - That will take care of what is generating the wear pattern, but to fix the vibration, would have to get rid of the wear pattern - by replacing the tires.