rear tire wear

Henry V · 11-29-2007, 09:54 AM

I have an 06 Prius with 60K. The OEM tires had normal wear and were replaced with Nokia WRs last spring. The Nokias have a little over 20K on them and have not been rotated. The tire pressure is checked regularly (40/38 or so). The rear tires now have some serious cupping on their interior edge. The only time I have ever had this sort of tire wear in the past was when a car had bad rear struts. I just reviewed some of the other tire wear posts and have a few questions for the tire/alignment/suspension experts here:
1) The alignment will get checked tomorrow. Other posts suggest there are no alignment adjustments in the rear. If the rear toe is out of line what are the reasonable options to get this fixed?

2) Even if the rear toe is out of line, that should cause uneven wear and not "cupping" from what I have read. I really wonder if this car's suspension has issues. When you push down on any corner of the car car there is virtually no give or spring in the suspension. It moves a couple inches down and then just comes back up. Is this normal in a Prius? My other cars do not behave this way. They have more give and more spring back. We have also know that the car will get into a noticeable rocking rhythm motion on the flat highway at speeds around 50-60 sometimes. It seems to happen most often when it is cold. The car was at the dealer at 36K and I told them I thought that the struts were bad. They checked for leaks and did not find any and just said "the prius has a stiff suspension don't expect a very good ride". What should I tell my local mechanic to look for regarding the front and rear struts?

drees · 11-29-2007, 12:32 PM

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.

bwilson4web · 11-29-2007, 01:34 PM

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

Quote:

. . .
1) The alignment will get checked tomorrow. Other posts suggest there are no alignment adjustments in the rear. If the rear toe is out of line what are the reasonable options to get this fixed?
. . .
[/b]

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

Henry V · 11-29-2007, 02:13 PM

Thanks for the replies so far. If I need the shim kit I will let you know.

Yes, I know rotations should be done more frequently, but my wife and I have driven many hundreds of thousands of miles on vehicles and have never had a problem like this before on a car with or without the recommended tire rotations. The only time we had a similar situation was due to a bad strut. I get that the inside would wear more noticeably without rotations but the cupping would seem to indicate more of a problem. The cupping is readily noticeable when running your hand on the tires and it is rather loud at highway speeds.

Any good guess why the car gets into a very noticeable back and forth oscillation under highway speeds? It did this on the last set of tires and on this one. It seems to happen most frequently when temps are below 20F.

All this being said, I am not at all impressed with the handling and suspension on the Prius. If folks have other suggestions to improve it, please pass them along. The old VW Jetta TDI has a much better ride.

David Beale · 11-29-2007, 03:24 PM

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.

John in LB · 11-29-2007, 03:26 PM

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

Quote:

Thanks for the replies so far. If I need the shim kit I will let you know.

Yes, I know rotations should be done more frequently, but my wife and I have driven many hundreds of thousands of miles on vehicles and have never had a problem like this before on a car with or without the recommended tire rotations. The only time we had a similar situation was due to a bad strut. I get that the inside would wear more noticeably without rotations but the cupping would seem to indicate more of a problem. The cupping is readily noticeable when running your hand on the tires and it is rather loud at highway speeds.

Any good guess why the car gets into a very noticeable back and forth oscillation under highway speeds? It did this on the last set of tires and on this one. It seems to happen most frequently when temps are below 20F.

All this being said, I am not at all impressed with the handling and suspension on the Prius. If folks have other suggestions to improve it, please pass them along. The old VW Jetta TDI has a much better ride.
[/b]

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.

Henry V · 11-29-2007, 04:39 PM

Both rear tires are cupped to the same degree. If shocks are the place to start, any recommendations??

wyounger · 11-29-2007, 05:45 PM

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

Quote:

...
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.
...
[/b]

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!

FL_Prius_Driver · 11-29-2007, 05:55 PM

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

Quote:

Both rear tires are cupped to the same degree. If shocks are the place to start, any recommendations??
[/b]

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?

Henry V · 12-02-2007, 10:55 PM

Well, the rear alignment was as dead-on as possible and the shocks/struts seem to be in good shape all around.

The problem appears to be two bad tires. The mechanic showed me that the wear is most odd on the inner edge but that there are also some anomalies along the center of the tire. It appears that their is something wrong with the belts in the tire. Hopefully, free replacement is in line this week.

It is still odd to me that among four tires bought at the same time that both rear tires have problems and not the fronts.

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11-29-2007, 09:54 AM	#1
Henry V Junior Member Join Date: Sep 2005 Posts: 10 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I have an 06 Prius with 60K. The OEM tires had normal wear and were replaced with Nokia WRs last spring. The Nokias have a little over 20K on them and have not been rotated. The tire pressure is checked regularly (40/38 or so). The rear tires now have some serious cupping on their interior edge. The only time I have ever had this sort of tire wear in the past was when a car had bad rear struts. I just reviewed some of the other tire wear posts and have a few questions for the tire/alignment/suspension experts here: 1) The alignment will get checked tomorrow. Other posts suggest there are no alignment adjustments in the rear. If the rear toe is out of line what are the reasonable options to get this fixed? 2) Even if the rear toe is out of line, that should cause uneven wear and not "cupping" from what I have read. I really wonder if this car's suspension has issues. When you push down on any corner of the car car there is virtually no give or spring in the suspension. It moves a couple inches down and then just comes back up. Is this normal in a Prius? My other cars do not behave this way. They have more give and more spring back. We have also know that the car will get into a noticeable rocking rhythm motion on the flat highway at speeds around 50-60 sometimes. It seems to happen most often when it is cold. The car was at the dealer at 36K and I told them I thought that the struts were bad. They checked for leaks and did not find any and just said "the prius has a stiff suspension don't expect a very good ride". What should I tell my local mechanic to look for regarding the front and rear struts?

11-29-2007, 12:32 PM	#2
drees Senior Member Join Date: Oct 2007 Location: San Diego, CA Posts: 327 My Car: 2008 Prius Package: #2 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	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.

11-29-2007, 02:13 PM	#4
Henry V Junior Member Join Date: Sep 2005 Posts: 10 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Thanks for the replies so far. If I need the shim kit I will let you know. Yes, I know rotations should be done more frequently, but my wife and I have driven many hundreds of thousands of miles on vehicles and have never had a problem like this before on a car with or without the recommended tire rotations. The only time we had a similar situation was due to a bad strut. I get that the inside would wear more noticeably without rotations but the cupping would seem to indicate more of a problem. The cupping is readily noticeable when running your hand on the tires and it is rather loud at highway speeds. Any good guess why the car gets into a very noticeable back and forth oscillation under highway speeds? It did this on the last set of tires and on this one. It seems to happen most frequently when temps are below 20F. All this being said, I am not at all impressed with the handling and suspension on the Prius. If folks have other suggestions to improve it, please pass them along. The old VW Jetta TDI has a much better ride.

11-29-2007, 03:24 PM	#5
David Beale Senior Member Join Date: Jul 2006 Location: Edmonton Alberta Posts: 1,343 My Car: 2007 Prius Package: B Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	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.

11-29-2007, 04:39 PM	#7
Henry V Junior Member Join Date: Sep 2005 Posts: 10 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Both rear tires are cupped to the same degree. If shocks are the place to start, any recommendations??

12-02-2007, 10:55 PM	#10
Henry V Junior Member Join Date: Sep 2005 Posts: 10 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Well, the rear alignment was as dead-on as possible and the shocks/struts seem to be in good shape all around. The problem appears to be two bad tires. The mechanic showed me that the wear is most odd on the inner edge but that there are also some anomalies along the center of the tire. It appears that their is something wrong with the belts in the tire. Hopefully, free replacement is in line this week. It is still odd to me that among four tires bought at the same time that both rear tires have problems and not the fronts.