rear tire wear - inside cupping

1. Rotate your tires more frequently. At a minimum every 10k miles, 5-7500mi is recommended.

2. Slight cupping is not that uncommon on FWD cars, especially when the tires aren't rotated often. See #1. How bad is the cupping?

3. Alignment is a good idea, but keep in mind cupping is usually caused by toe problems in the rear in my experience. Since the rear axle is fixed in the Prius, toe is not adjustable, it not too likely it is out unless you've hit something. An alignment will verify this.

4. The suspension sounds OK to me. It should not move that much and will smoothly return to level if you bounce on it. If the struts were bad it would oscillate a lot more. It sounds like the cars you are comparing it to have much software suspension than the Prius.

 

<div class='quotetop'>QUOTE(Henry V @ Nov 29 2007, 08:54 AM) [snapback]545636[/snapback]</div>

Be sure and post your results here. I can provide a shim-kit and instructions. It will be important to have some way to testing your alignment after putting in the kit and possibly a second alignment check if the shims are off. But we can discuss this when the results come back.

BTW, I agree with the wheel rotation and would suggest twice a year, the spring and fall, would coincide nicely with oil, filters and other preventative maintenance.

Bob Wilson

 

Cupping can be caused by rear toe-in or toe-out as well as camber out of spec. Ditto for the oscillation. If you go to a -good- alignment place (not one of the "big names" - rather one owned by the operator who cares about his customers), he can shim the rear hubs. It's not rocket science! They can even bend the rear "axle" or beam (forget what it's called in the Prius). There is a tool for that.

 

<div class='quotetop'>QUOTE(Henry V @ Nov 29 2007, 12:13 PM) [snapback]545767[/snapback]</div>

I don't think it is going to be an adjustment / alignment issue. either you have bad shocks or you hit the wheel (against the curb) or it is no longer aligned / true with the road. After 30,000 miles, rear wheels wear totally flat and front wheels wear on the outside....

when you put the car up on the rack, ask them to re-balance the wheels. If the wheel itself is bent, it will wobble on the balancer - and it will be VERY apparent. If that's not the issue, go ahead and rotate your tires anyway.

You did not say: but are both rear tires cupping, or just one? If its both, then its less likely that you have hit something. I would then focus on the shocks.

I agree with you regarding the ride of the prius - definitely not going to be as good as a VW. As such, if you need new shocks, consider something a little stiffer than the current unit to help you out.

 

<div class='quotetop'>QUOTE(John in LB @ Nov 29 2007, 03:26 PM) [snapback]545805[/snapback]</div>

In a perfect world. I've had two bent aluminum wheels over the years on two different cars (granted, neither a Prius) that annoyed me to no end with shimmies but whose causes were actually not simple to find and diagnose. Both times I took the cars back repeatedly complaining of a shimmy. Sometimes you end up having to use a dial indicator to measure how true the wheel itself is. Certainly don't accept that "it balances ok on the machine" guarantees that the wheel is true and round. In both cases mine would balance normally on spin balances and road force variation balancers, but still had a mild high-speed shimmy that would feel different every time you rotated the tires. The first time I went through that I finally just tried a junkyard wheel, which fixed everything after 75k miles of tinkering trying to slay the shimmy. The second time around, years later, I was more confident and held my ground!

My Prius wandered and was highly susceptible to crosswinds when I got it. I took it to the dealer and re-alignment improved both issues (though it's still no Mercedes that way). The interesting part is that it was within-spec before the alignment, but it got better when they got it closer to the "perfect" mark. And I know this wasn't because their machine was miscalibrated; I had to wait extra long because the alignment machine company technician was calibrating their rack when I arrived!

 

<div class='quotetop'>QUOTE(Henry V @ Nov 29 2007, 04:39 PM) [snapback]545844[/snapback]</div>

I had a cupping episode on my 2001 Prius.

http://priuschat.com/index.php?showtopic=3...mp;#entry499532

Also, what kind of tires did this happen to?

 

I bought two sets of Bridgestone G019 grids. One for my 2007 Prius and one for my 2002 Mazda Protege5. The left rear on the Prius was cupped at 5000 miles and I had it aligned at the dealer where I learned 1) that the rear is not adjustable and 2) that it was within specs anyway. It is now time to rotate again and the new one on the left rear is also cupped. I have had no problems at all with the set on the Protege5, so it has to be the car alignment.

 

Are you sure it is cupping or just uneven wear?
Can you see the cupping just by looking at it or you have to use your hand to feel it?
If you cannot feel the edges when you run your hand along the tread then it is uneven wear, most likely due to shifting or separation of the steel belts.

 

You can stand behind mine and see the negative camber and toe. Best fix is a full contact 30% alignment ring at your independent shop. I made these in the shop because I refused to pay those outrageous prices. Tin snips and a piece of sheet metal and a disk grinder will do a great job.

Also cupping is sometimes suspension related.

 

PS/ It is worse on my 2007 Civic Hybrid. They replaced the rear suspension parts and did an alignment and my new tires are slowley doing the same thing. Rotation has just moved the problem to the front and now I have 4 tires with noise instead of two. LOL
Other than a real alignment at a shop you can trust it may be a problem we just have to live with! There may be a better shock/strut/??? for the rear.

 

Cupped tire wear is caused by the tire oscillating or bouncing up and down. This type of wear is not normally caused by worn suspension parts unless they are worn so badly that they are about to come apart.
Most cupped wear is caused by 3 things:
Worn shocks/struts.
Tire out of balance.
Internal tire defect.
Combination of above.
High inflation pressures (over placard spec) can exacerbate any of the above.
My advise would be to change the shocks and rotate the tires to insure the problem has gone away before getting new tires.
Once tires are cupped, they do not usually wear evenly, even after the cause is corrected.

Hope this helps,
Joe

 

I have a 2007 Touring which cups the left rear badly. My alignment shop will install shims for me but can't find any. If you can supply them, how do I get them and how much do they cost? I need one (or some?).

Tom Stahl

 

Re: rear tire wear - inside cupping Nokian tires

I would take the car to a tire service that sells Nokian tires.

 

My 2007 prius, with 58,000 miles, front passenger tire cupping due to a bad strut.
Replaced the KYB strut took care all the road noise and the front passenger tire cupping issue.

 

My 2005 Prius came with Bridgestone G019 Grid tires when I purchased it used with 78,000 miles in March of 2009. Now after 15,000 miles with rotations the tires are cupped on the inside. I had the alignment checked and it was all good except one of the specs on one of the rear wheels, and it was not that far off.

A local tire shop told me the cupping was because the G019 tires are V speed rated and the prius needs a lower speed/temperature rated tire like a S or T rated tire.

Does this sound correct?

 

Your tire shop is crazy. Speed rating of the tire has nothing to do with the way the tire wears - though often higher speed rated tires are "higher performance" so they tend to wear faster in general. That said, V-rated tires are standard on a lot of typical sedans these days.