Hi Everyone,

I am new to this board. And I have been looking through old messages, but I could not find a similar problem like the one I have with my 94 Q45.

The car currently has 77K miles. I just changed a set of new tires about a year ago and had about 10K miles on them. But lately, I start seeing that the tires are not wearing out evenly. There are little curve or lumps on the inside of the tires, especially the front ones. And the tires start to make noises, espcially at high speed. The alignment feels fine. The car does not pull to one side. Is this a problem with the shocks, tires, or balancing?

Thanks

Ted

Ted - In a temperamental (and heavy) car like the Q, you'll want to do several things, all of which the more experienced members can expound upon.

First, get the alignment checked. "Feels right" is probably of no use - get it on a machine. Second, a good wheel balancing on a Hunter 9700 balancer is in order (dual plane balancing). Third, you didn't mention the brand or size of tires - this is critical, as the Q can do serious damage to tires that are below the factory-spec load rating.

Welcome to NICO, and tell us more about your Q!

If you examine the factory/dealer recommendations along with 3,750/90 day oil change you are supposed to get a tire rotation and rebalance [which you pay for]!

"Q can do serious damage to tires that are below the factory-spec load rating."

The load rating [1521 pounds minimum] is the critical part but tire internal construction [related to speed V minimum rating] is germain.Tire sidewalls come in single and dual plys.

The oem tires wear rating [170 on 90-93 and 200 on 94 and +] meant that they expected the tires to be destroyed at 15,000 to 20,000 miles roughly the correct service life of the brake pads.

Unfortunately owners didn't understand the personal expenditures necessary for a HEAVY PERFORMANCE CAR......the brake pads got harder [to last longer], the tires didn't get rotated 4 times a year, they were replaced with cheaper/harder compound tires [by owners who were cheap]. And many of the performance attributes disappeared !

The 90-96 Q is unusal in that the amount of negative CAMBER is much more negative than any other 4 door production car to enhance handling.......only Michelin Premiums [V rated] are build well enough to survive. The Michelin Pilot XGTH in the 235 sizes does well also but its treadwear 400 is twice as hard as the oem spec so expect some diminuation of braking,handling and wet performance as a trade off for double life.

All tires are only designed to pass the 8,000 mile tests created back in 1968 [unchanged to this day] so many will become noisey and nosier still as the blocks wear down and the internal construction is destroyed.

Tires are a constant debate here with everyone trying to find the best or cheapest/best that will work for them.

Currently it appears that the Yokohoma AVS db in 215/65/15 @ $71 [from tirerack.com] is a good substitute for the Michelin as is the Bstone RE940 @$102

Be careful lots of junk tires which can't stand the weight.....think carefully about downgrading even to H rated as there is a significant reduction in strength and construction and not much savings in mile prorated cost...the Michelin Pilot H 235/60/15 @$115 is an exception.

Thanks for the feedback. The tires I purchased are Bridgestone Potenza RE930i. The size fis P215/65R15 95H. The max load is 1510 lbs. Orignally I wanted to purchased the Michelin XGT, but they were out. So I settled with these. I have them rotate once at arount 5K miles. But I have not rebalance them.

It appears that TireRack no longer carries this tire [found some decent reviews going back to 1995 on much lighter cars but nothing on an over 3200 pound car ---Miatas, small cars].Couldn't find it in the list of customer surveyed tires?

Generally Bstone increments numbers in the 900 series: 900,910,920.....940 as the quality increase. But the following picture shows the tread pattern to be very very similar to the noisey Eager bottom of the line tire.

I think 5 k rotation is too long at least they are not directional so x rotation is possible. You can flip them on the wheels so the inside is now the outside to equalize camber wear........this should be done prior to [and every] 10k to maximize life.

Measured a set of 235/60/15 Michelin Pilot XGT H4 on a Q with -1.5 degrees front camber negative 2.2 rear camber that were rotated every 3k now with 13k. The inner and outer / middle tread depth is exactly the same within 1/64"....less than 0.4 mm difference.

You get what you pay for! And if you don't follow the factory recommendations for a minimum V rated tire [and decide to resign the car] then at least go for a premium H rated.

But then again I see lots of ragged out Q with S&T rated tires......always good to look in the junk pile at dealers to see the old tires you learn alot about what works and what doesn't.

Is there any upper link issue related to this inside front cupping? The noise factor is getting to me, but the tread is still good. No pull on the steering wheel.

Noise cancellation is designed with all tread blocks and sipes level. Also the block/trad depth is calculated in the process! As the tread wears the noise cancellation goes away!

Cupping, heel toe wear scalloping, feathering from inside to out [unusal non even wear] are symptoms of alignment, shock, tension rod, and other suspension defects.

Heel to Toe [feathering sharp edges] wear is ALSO an indication that the tire structure/design is WEAK allowing the blocks to squirm as the load varies.

If your alignment is perfect not just in the tolerable range and doesn't change as you roll down the road then it is probably the tires fault. Alignment specs are created new with new rubber bushings so it is impossible to know how much change occurs while driving except on special rolling road dynos where the factory determines the appropriate bushing stiffness in the design process.

Tires are designed to look GOOD externally but you can only see the internal structure by Xraying them. Michelin Xrays all premium tires as a quality control step [ask the other manufacturers if they do so].....to my knowledge only air craft tires are all Xrayed per FAA regulations.

If a tire cannot handle internal stresses for more than 20,000 miles you are better off using a tread compound soft enough to wear away by then so the owner is forced to change the tires!

This is what the factory does, thus oem tires are always soft and wear quickly so there will not be unseen internal damage.

Softer rubber is more expensive to make than harder 40,000 mile rubber. Same with a softer tire!

On many tires 10,000 miles is good before problems start, some brands make it to 20,000 miles and a few to 30,000 miles!

Upper links generally last around 30k, tension rods around 60k, shock life varies depending on load and road roughness from 40k to 100k maximum. Bushing life is also variable 60k-120k.

Only oem tires are tested to see if they will live on a Q the factory picks the ones that will do the best vs cost. It is not unusal to see Michelins as the oem tire for many top of the line lux cars as there is a reason no other tire would hold up to big MB. BMW.

I have seen Michelins fail on Q but it is always the owners fault: low inflation or curb hits, or accidents! On even a badly aligned car they wear twice as well [even across the face] as any other brand even the softer premium V and Z series.....they just stay round longer and absorb the stress.

Owners want someone to blame for tire problems yet they never want to spend the money to correct the causes.

If one tire works and another brand doesn't that should tell you something!Just like depression, there are dozens of drugs [all with side effects] and doctors find one that you will tolerate after some painful trial and errors!

Eternal optimism is a fault sometimes as I like other members are constantly looking for a less expensive holy grail tire!