Tire Cupping Due to Uneven Weight distribution

[Overspent]

I'm about to buy my THIRD set of tires for a 2009 MS3 with 40K miles. My tire place tells me the cause of my "severely cupped" tires is that too much of the car's weight is up-front, allowing the rear wheels to "skip" off the pavement- the cupping happens when they return to the ground.

I don't drive the car hard (much), and the tire have been rotated regularly. I did yank-out the spare tire to make room for a sub, amp, and sound processor. I have also put maybe 15 lbs of Dynamat in it, pretty-evenly distributed fornt-to-back.

The dealer acknowledged that weight distribution was the probem. I said: "so it's a badly-designed car..." Of course the dealer blames my troubles on my sound system and D-mat.

So I'm wondering if anyone else has encountered the "cupped" rear tires issue, and what any of you would say about how to fix it (short of putting 180 lbs of sand in my tiny cargo area (the dealer's suggestion).

Thanks for any thoughts-

 

[CR3 Motorsports]

What kind of tires do you have? Cupping is known to happen on cheaper tires, also have you had an alignment done? (You may need one)

 

[MikeHTally]

Man, the BS meter is off the scale on this one! The weight distribution of these cars is not much (if any) different than millions of other FWD vehicles. My YK-520s are nearing 23K. They get rotated every 6K and there is NO cupping of the rear tires. There's no cupping of the tires on my daughter's Camry. Those tires are at ~24K and they don't get rotated as often as they should . For a guess, I bet your add-ons weigh more than the spare you removed.

 

[flatlander937]

I'm about to buy my THIRD set of tires for a 2009 MS3 with 40K miles. My tire place tells me the cause of my "severely cupped" tires is that too much of the car's weight is up-front, allowing the rear wheels to "skip" off the pavement- the cupping happens when they return to the ground.

I don't drive the car hard (much), and the tire have been rotated regularly. I did yank-out the spare tire to make room for a sub, amp, and sound processor. I have also put maybe 15 lbs of Dynamat in it, pretty-evenly distributed fornt-to-back.

The dealer acknowledged that weight distribution was the probem. I said: "so it's a badly-designed car..." Of course the dealer blames my troubles on my sound system and D-mat.

So I'm wondering if anyone else has encountered the "cupped" rear tires issue, and what any of you would say about how to fix it (short of putting 180 lbs of sand in my tiny cargo area (the dealer's suggestion).

Thanks for any thoughts-

Uhh... I'm just guessing that your sub and/or amp are in the back area? Technically that would HELP weight distribution, so you can tell the dealer they don't know their asses from their elbows.

You should probably have your alignment checked, excessive toe will wear tires out really quickly... the best advise I can give is avoid directional tires so that you can cross rotate tires.

In my experience -most- front wheel drive vehicle will have the tires cup if you never rotate them... the key is to rotate them every 3 to 6k miles. If you do it yourself, then it is probably worth it to do every 3k miles since it will cost you nothing but a bit of time. If you are paying for it... then probably more worth it to stretch that out to 6k miles so you're not spending $20-25 every single time to rotate them.

I see this crap every day on all makes and models of cars. Some cars just happen to do it more easily/quickly... some especially so with certain tires.

When you get the alignment done, make sure they do it to spec... which will change depending upon how much gas is in your tank... there are specs for 0, 1/4, 1/2, 3/4, and full tanks IIRC. This is because the toe and camber change as you jounce the suspension... your setting will be significantly different if it is not aligned at the right set of specifications.

Mini Coopers are also super notorious about tires cupping... as are many many many other vehicles. In my experience the lower profile the tires... the more likely/quickly it happens. This would explain why you don't have as -many- problems with stuff like Corollas and base model Civics... they're appliances meant for a cushy ride... not performance.

 

[chuyler1]

It is 100% because of the alignment. The acceptible range the dealer thinks is ok, is NOT. Research the correct specs for the alignment and bring it to them. I just went through the same issue with my MS6. I blindly accepted the "within spec" settings and 5,000 miles later my tires were cupped and loud as hell on the highway. Turned out they didnt bother to fix the camber which was over 1 degree past factory specs because it was still within their acceptable range.

 

[flatlander937]

Yeah... generally if the alignment is good... they will still cup a tiny bit... but they shouldn't be sounding like a bi-plane after only 5,000 miles.



They will always wear the trailing edge of each tread "block" and round them off while leaving the leading edge of each tread block pretty sharp still... keep driving on them without rotating and eventually you get the cupping as it starts wearing away at the tread depth of the rear of each tread block quicker and then each tread block is 1 to 2 /32nds shallower than the one before it. This is why it's super important to rotate side to side and why I hate directional tires personally. I see this every single day at the dealer I work at.

 

[ericrapp]

you will not have cupping unless you have at least one alignment issues. if i recall it's toe out. but the fun part is, any alignment shop usually has these telltales on a poster in the waiting room for us women to understand. but really go to tire rack and use the site to solve the problem. they have some very useful tools for us

 

[Sinfoman]

Hello all,

I too have had the dreaded cupping problem, and I believe I MAY have some insight to what's going on here. 1) As previously stated, rotate your tires. That said
2) I SUSPECT WEIGHT is an issue. I had a set of Bridge RE050's (OEM) that went 36k with ZERO cupping. I was so impressed, I bought another set (4 new) and have had a SIGNIFICANT cupping problem. I cupped RightRear and diagnosed with a bad shock (???) as my alignment was "within spec." I replaced BOTH rear shocks and now I have cupped the LeftRear. BUT (!) I suspect the issue is NOT with the shocks but the camber alignment that CHANGES DUE TO WEIGHT. I have recently been carting around four adults (where the first set saw barely any more than maybe two front seat passengers) and believe this increased load in the rear seats contributed to my cupping. I am riding out this set of tires for a new set in the summer. At that time I will reset camber, toe, etc. to factory spec (as per above) and do some load testing. After the first 5000 miles, I will post an update (look sometime around December 2013) to advise if this was indeed the case.

In the meantime, anyone else think weight is causing cupping of tires? I gleaned this from the above (and other) posts that talked about setting alignment based on gas tank measurements (E, 1/4, 1/2, etc.)?

Talk amongst yourselves...

 

[ericrapp]

its actually blown/overloaded struts that causing cupping. i was hoping someone would actually look it up .
spring hopping in the rough corners

 

[Overspent]

Thanks to everyone who replied. I've spent the last year nursing another 12K miles from these tires. Both the dealer and a respected local tire place say alignment on all 4 wheels is well within specs. They were rotated twice during that time, and I'm gonna have them rotated once more and hope they'll last until I get new ones before winter. They hammer like a stamping factory at high speeds. I've seen very little in the various MS3 forums about cupping as a particular problem on this car, so I'm figuring it's my choice of tires and maybe some overzealousness keeping the pressure up (filling to specs on cool summer mornings, for example). The two tires that cupped-out, btw, were Kumho Ecstas and Yokahama Avid Envigors.

My problem now is that virtually all of the tires I can find for this car are directional, including my two favorites: Bridgestone Potenza RE970AS and Continental Extreme Contact DWS. I'm told Michelin will soon offer a tire for the MS3, but at a cost of over $3oo per tire.

Does anyone have a line on a good non-directional tire for the MS3?

 

[ericrapp]

been a long time brother !
all the tire i have used are directional as i think most High performance tires are. I could be wrong.
may i suggest you email tire rack and ask them. I haved used them as a resource many times.
I also just purchased two tires that are a bit different than my usual fare of Nittos from them. great service and pricing imo.

 

[chimmike]

Conti DW are not directional. Rear toe is what causes the rear inner tire wear. That's a factory setting. Of course it's within spec, but that means it's within spec to wear.

When the 350z was first brought over, the rear alignment caused pretty bad inner tire wear issues such that Nissan had to recall and re-do how they attached the cars in the ships when they were brought over to prevent the issue, but the stock alignment settings still did it.

 

[ericrapp]

Conti DW are not directional. Rear toe is what causes the rear inner tire wear. That's a factory setting. Of course it's within spec, but that means it's within spec to wear.

When the 350z was first brought over, the rear alignment caused pretty bad inner tire wear issues such that Nissan had to recall and re-do how they attached the cars in the ships when they were brought over to prevent the issue, but the stock alignment settings still did it.

you are making that up !

 

[MSMS3]

Has anyone tried to address the rear cupping issue by using adjustable rear camber arms to reduce the stock non-adjustable negative camber? Negative camber places more of the vehicle weight on the inside edges of the tires.

 

[chuyler1]

Post the last set of alignment specs you were given. As mentioned above "within-spec" is a pretty broad range. Before you have a camber kit installed it might be good to know which end of your car is actually causing the problem. Are you 100% sure it is the rear? Or are you still stuck on the "weight distribution and the car hops" theory...which is total crap...your car's tires are not leaving the ground and a few pounds of audio gear in place of the spare shouldn't make a difference.

 

[MSMS3]

^ I'm not the OP. My tire wear is cupping on the insides of the tires and it absolutely happens only at the rear. I think you may be confusing two different people. I did not suggest that weight distribution or audio equipment or tire hopping had anything to do with.

Just squat behind your car and look at the rear tire contact pattern. The tires do not sit with the contact patch evenly distributed. The inside edge of each tire tread is on the pavement but the outside edges much less so. This is negative camber.

With independent rear suspension spring compression increases camber toward neutral, such as weight transfer under rapid acceleration. During heavy braking, the rear springs decompress or unload with weight transfer to the front, making the negative camber effect worse.

You can see the hood rise when launching hard and dive when braking hard. Weak original struts and shocks at almost 85,000 miles are a part of my issue and will be replaced at the next tire change. But, the rear inside wear and cupping has been going on from day one on three sets of tires.

I just think taking some of the rear camber out when I replace tires and shocks might help stop this abnormal wear. The only way I know to do this would be installing adjustable rear camber arms.

 

[ericrapp]

I would have thought that excessive toe in or out would be the culprit as the tire would be fighting against going straight and cause the tire to (hop ).
These setups cause extremely fast tire wear as they will "scrub " and are usually outside OEM spec for racing applications to control turn in.
IMHO : )

 

[MSMS3]

Thanks. Your guess is as good as mine or better. I'm ordering shocks now. I'm going to spring for the adjustable rear camber arms and see whether this could be the problem.

Attached are images from another forum which posted shots from the shop manual for alignment specs.