Really Wierd Tire Wear After Multiple Alignments

[Airtraffic]

Hey there everyone! I have had my '95 SC400 for about a year and a half now. The car is great in almost every way, looks, acceleration, sound system rocks with the Nakanichi system, gobs and gobs of power!

There's only one problem I have over and over again.. I got about 10 - 15K on the first set of tires that the seller installed when he put the car on the lot before they started feathering and making a lot of noise. I bought a new set of Khumo's because they got good reviews for low ride noise of course, I also had the car aligned. They were good tires, but after about 5K they too started to wear unevenly. I took the car back to shop that installed the tires and they re-aligned it again. The wear seemed to even up a little.

Two weeks ago, I needed to replace the rear tires due to wear as they were down past the wear bars. I went ahead and purchased a new set (4) of the new Continental Contact DWS tires on the recommendation of the shop. They were great! Whisper quiet.. It was as if I got a new stereo system. The car was once again aligned when the tires were installed.

I drive 150 miles daily for work. After only 10 days and about 1,000 miles, the noise was increasing noticably and I could feel the tires had started feathering when I ran my fingers across the tread. I stopped back at the shop and they took a look at it. They declared all was well with the suspension components. They found no play in steering or bearings or anything else. They didn't seem to think it was struts although they said after 108,000mi and 14 years, the struts could indeed be a weak link. They did acknowledge that the tires were wearing unevenly and they aligned it yet again, saying they would try to get it even closer to dead on zero error than before.

Has anybody else had the same problems or know of a possible solution? I am sick of spending $500 on tires only to have them scraped up after a couple of thousand miles.

Thanks!

[eatingupblacktop]

Tell them how you drive so they can dial in for your type of driving. Makes a world of difference!

[Airtraffic]

It's all highway driving..

[chesnutlane]

Hi I am a master tech with certification from Hunter Alignment too and I hope I can give you a few pointers or at least some questions to ask your shop but more info is needed. When you say feathering is it all across the tire or does it have a heel and toe effect ? down certain parts or the entire tire ? 99% of the time its the struts as their primary purpose is to take out wheel osicalation.

Also are the factory size wheels installed ? The reason I ask is that will open up another ball of wax with rearspacing aka backspacing and posotive and negative offsets You naturally never want a "0" alignment because as you drive down the road the tires will push themselves outward if anything 1/16" toe in is ideal.

Feathed edges:

1. caused by incorrect toe setting

2. Feathered edges can be felt more than seen

3. sometimes can look like a camber wear

4. excessive toe in = feather point in

5. excessive toe out = feathers point out

6. feathered edges can also be caused by loose steering linkage

General tire wear charastics :

underinflation- will cause inner and outer edges of the tire to wear

overinflation- wears out the center rib of the tire

camber wear- (outside edge wear) can also cause a steering pull

excessive posotive camber = outside edge wear only

excessive negative camber = inside wear only

I can go on and on but feel free to say hello take care tim

[Airtraffic]

Hi Tim,

Thanks for the response.. Yes, the feathering is more felt than seen. It is primarily along the outboard edge of the tire. about 1/2 inch or so in from the sidewall. They are the stock size factory rims with no modifications whatsoever to the suspension, no spacers etc.. Fronts are worse than rears.

The tires are the new Continental Contact Extreme DWS tires.. I wonder if part of the problem is that the continentals are still very noisy as previous versions of the tire have been.

I wouldn't think tire pressures would be an issue as the tires were installed a little more than a week ago, but you never know, I'll check again today.

[smooth1]

Hi I am a master tech with certification from Hunter Alignment too and I hope I can give you a few pointers or at least some questions to ask your shop but more info is needed. When you say feathering is it all across the tire or does it have a heel and toe effect ? down certain parts or the entire tire ? 99% of the time its the struts as their primary purpose is to take out wheel osicalation.

Also are the factory size wheels installed ? The reason I ask is that will open up another ball of wax with rearspacing aka backspacing and posotive and negative offsets You naturally never want a "0" alignment because as you drive down the road the tires will push themselves outward if anything 1/16" toe in is ideal.

Feathed edges:

1. caused by incorrect toe setting

2. Feathered edges can be felt more than seen

3. sometimes can look like a camber wear

4. excessive toe in = feather point in

5. excessive toe out = feathers point out

6. feathered edges can also be caused by loose steering linkage

General tire wear charastics :

underinflation- will cause inner and outer edges of the tire to wear

overinflation- wears out the center rib of the tire

camber wear- (outside edge wear) can also cause a steering pull

excessive posotive camber = outside edge wear only

excessive negative camber = inside wear only

I can go on and on but feel free to say hello take care tim

Hi Tim,

Thanks for the response.. Yes, the feathering is more felt than seen. It is primarily along the outboard edge of the tire. about 1/2 inch or so in from the sidewall. They are the stock size factory rims with no modifications whatsoever to the suspension, no spacers etc.. Fronts are worse than rears.

The tires are the new Continental Contact Extreme DWS tires.. I wonder if part of the problem is that the continentals are still very noisy as previous versions of the tire have been.

I wouldn't think tire pressures would be an issue as the tires were installed a little more than a week ago, but you never know, I'll check again today.

When was the last time you, or the previous owner replaced the suspension components? I'm a little surprised by master technician chestnutlane as the fact that your car is now 15 years old and probably way past due for a complete suspension overhaul was completely overlooked. Your at a time when it's probably not going to be any one component that is causing your trouble. The control arms, struts, ball joints, bushings, bearings, steering linkage, boots, mounts, springs, etc, etc, are all worn together. When your car is sitting on the rack being aligned, there are no outside forces on the car. So putting the car in spec isn't the issue. As you begin to drive the car, the suspension as a whole is worn out, so it's sagging and flexing out of spec causing your tire wear issues. When the car comes back to a stop, LOL,, when it matters the least, the car is back in spec. Just replacing the struts might fix it for about 6 months, but the rest of the worn suspension will just wear that new strut out faster and you'll be right back where you started. If you putting 150 miles a day on your car for over a year and a half , then you've put an additional 55,000 miles on the car atleast just in the time you've owned it. So I would imagine that the overall mileage on the car is quite high by now. As metals flex they heat up and cool down, expand and contract. And can even become brittle. Weather conditions and road salts eat away at the polyurathane and rubber compounds. bearings begin to gap, and seize. Most of this isn't detectable by a visual inspection. And just measuring backlash alone won't tell you the overall state of your suspension. Your at the cost verses time crossroads. Are you going to keep the car for more years to offset the suspension replacement? or is it cheaper to just keep replacing tires until you get rid of the car? there are plenty of how to's here so you can probably save a boat load of money if you decide to do the work yourself. That is really the only cost effective way I can see doing this for a 15 year old car. But you could also be one of those people that will own a car for the rest of your life. If that's the case, then it's even more worth doing.

[Airtraffic]

For sure the suspension is a consideration.. the car has 108,000 miles, aside from the tire wear, the car has no driveability issues. No creaks, groans or pops as I have heard many others complain about. I love the car, but if I did have to put 2K into a new suspension, I don't know if I'd want to keep it. On the one hand I have a great performing car that I know is solid. On the other hand I have a car approaching 20 years old that gets 20 MPG highway and drive 150 miles RT every day. One thing I did notice today as I checked the tire pressure. The tech's had filled the tires to 30 PSI.. Seemed low to me. The sidewalls say max pressure on the Conti's is 51 PSI. I know underinflation wears the shoulders so I do suspect underinflation as a possibillity. I bumper the pressure up to 35 PSI all around.

[chesnutlane]

Hello again,

I do understand that a proper diagnose over a computer is not an easy task. I myself have a 1993 with now 112k miles on it and yes its true that I have "worn parts" but they are not shot actually far from it and mine is a Colorado car with mag chloride on the roads. If you do love the car keep it ! I'm sorry I dont know that tire model but I will tell you that any tire that has an open shoulder will cup/feather they just do. On most vehicles the tire placard is on the drivers door jam but on my Lexus its on the inside of the glove box lid and it too states that 30 psi is its value. Ignore what is stamped on the tire and I would recommend following what the engineers came up with as they do take ride and performance into consideration. As a side note the first task in an alignment is to make sure tire psi at all 4 wheels is correct. Also needs to be checked cold ( as in not driven ) unless you are like me and using nitrogen which never changes.

A few more thoughts or maybe a little more in site for you also.

A static imbalance will cause vertical oscillations ( aka wheel !Removed! or hop ) of the tire and wheel assembly.

A dynamic imbalance will cause horizontal oscillations of the tire wheel assembly (shimmy).

I have been around and seen some tire shops do some shoddy work if you see more than six ounces of weight; the tire and or wheel could be defective or they were using the wrong style weights . Also out of round tires/wheels cant be trued by balance ( curb checks ) and from my experience the lower the aspect ratio and the wider the tire the harder it is to balance.

Well I am sure I said enough and you mentioned the tires were one week old take them back and tell them you are unhappy and would like another brand if they are a customer oriented reputable shop they will do what it takes to make it right. The fleet I work for has deep discounts with Michelin and even though the mileage is not there I love the quiet smooth ride it gives me. Again take care tim

[Airtraffic]

They seemed to do an OK job with the weights.. Since I pumped the tire up to 35 PSI the ride is a bit firmer, but the wear seems to have evened out. There is a 60 day satisfaction ride guarantee on the Conti's. I may go back and ask for another set to be put on. Now that the alignment seems to be better dialed in, I think I'll be OK. I think next time, I'll try Michelin's.

[osucool]

I too had a pair of Kumho Tires that had some excessive outside wear a few years back.

It seems there is a range of alignment acceptability according to the folks at the tire shop.

They said something like...."we normally shoot for the ?negative? camber side of this range and it will give you a more sportier feel."

I mentioned (firmly) that the tires were just a few months old and the outside tread was half gone and they re-aligned it.

I do not drive the car much but there is at least another 20,000 on it since then and a few years later with acceptable wear.

Not sure if I can dig up the numbers they gave. It was inside the tolerance range before and after.

My opinion:

#1 Kumho's wear pretty fast in general especially when they are not happy.

#2 If you go back in...have them print off the actual number values where they are setting them along with the allowable range they shoot for. If they have a fancy Hunter machine they should be able to.

At least you can publish your alignment numbers or have them adjusted until you are good with the wear pattern.

I'm no tire expert but it sure seemed to help for my car.