RichBinAZ

The lad has managed to put over 30K miles on the Xb this past year, since he put a set of Yokohamas on from Discount tire. He got a nail in the front tire and Discount fixed it and did a tire rotation - first one on these tires.

He then had to go to yet another wedding about 150 miles away and he had a harsh vibration all the way up and back. So much so that his hands were numb when he stopped for lunch near his destination.

Upon his return, we jacked up the front end to see if the brakes were dragging (they weren't) and while spinning the tires by hand I noticed a few oddities in the tire tread. The left front had a few bumps in the tread in one zone. Not an out and out bubble, but I thought it was the beginning of the tire going bad. Checked the right one and it too had just a couple of tiny bumps in one spot.

Checked the rears (which had been on the front for the last 30K miles) and they were fine, perfectly round and no dragging brakes. So I popped the rear door and bounced each corner to check the shock action - perfect, no rebounding at all (other than a controlled return to normal ride height).

The tread itself was smooth, no cupping or ridges or signs of misalignment wear, just the bulges.

So he took the car to discount tire and the manager said that he too could see these "defects" and went on to say that this sometimes happens when you don't rotate the tires and they should be good again in another 3000 miles. They did not replace the tires.

What do you think? Is Discount blowing smoke, or is this real? I have had tires do this to my other cars before, but we always replaced them. So odd that it would be the ones from the rear also.

I told the lad to try another discount tire store and e-mail Yokohama, don't know if he has done that yet.

cmcpride

iTrader: (3)

a few things will cause uneven wear pattern , over inflated tire will have lumps in the center and more tire wear in the center, bad shocks will also cause this pattern but much more spread out now if your having both over inflated and bad shocks you will get vibration, cupping and choppy tires all together. and or loose suspension components. rotating tires will just cause newly rotated tire to wear in the same pattern. one more, its a long shot but if your tire wear rating is to high it will also cause uneven wear pattern, due to the tire being to hard .

moonray

With out seeing the tires first hand I have a feeling the tires that are now on the front have some cupping from not being rotated on a regular basis. The tires should have been rotated about every 5-6k. I have an '04 xb and my rear tires show slight signs of irregular wear even after 5k. Something to do with how Toyota set up the rear end suspension. It may take awhile for the tires that are now on the front to "true" up a bit.

RichBinAZ

Thanks for the input.
He brought the car around yesterday (1 week and another 200 miles later). He said the "wub-wub-wub" noise is much better than last week, but we jacked up the front tires for another look.

I thought the left front tire looked a bit better, with less obvious rippled tread. Again the ripples were not all the way around the tire, just in one zone. The right front tire looked worse if anything, with the ripples in the tread in 2 zones, occupying about 25% of the tread each.

Checked one of the rear tires (old fronts before the rotations). No problems, perfecty round.

So the plan is to keep driving them and check them each week. I'll report in if anything dramatic happens.

Jan06xB

You might want to swap the front tires to opposite sides in front. My 2006 xb ran the factory tires in the rear for 50,000 miles with plenty of tread left and perfect wear for over 6 years, they just were getting cracked on the sidewall and needed replacement. The rear alignment is pretty much fixed and should wear the inside tread slightly more than the outside. Driving with that bad a vibration is definitely not good for the suspension, I would have the front end alignment checked.

yelotoxbop

Sounds like tire tread seperation Or if the tires are directional did he put the one tire on backwards after repaire Or did he put a plug in tire Vibration is usualy caused by balance or tread seperation You did say ther was bubbel thats tire seperation is the bubble in the same place the repaire was made Its not caused by overinflation or cupping The center will wear out if over filed The tire will cupp if shocks are bad because it bounces. If you have wher in the front end parts you will most likley wonder around on the road

RichBinAZ

Well, he has put about 3000 miles on these tires now and he said the vibration is almost gone. I want him to bring the car over at thanksgiving so we can jack it up again and have another look.
Tread seperation was the worry I had, and I have seen it before on other tires on other vehicles, but it does appear to be a lack of rotation of the tires. Very odd. Perhaps it has something to do with how light the car is and how little load there is on the rear, specially when compared to the width of these tires.
The tread that was slightly rippled was spread over about a 30-60 degree arc and about 1/4 of the way in from the inboard side of the tire. Not the edges or the center.
Shocks in the back are good, no dragging brakes, even wear on the old tires he removed so no alignment issues

Anyway, I'll add to this when he brings the car back over

onyxxtreme

i had that exact problem on an older car of mine, i never rotated the tires since it was a complete beater of a daily driver Ford Taurus.
I learned my lesson about rotating tires after that though

RichBinAZ

He brought the car over for it's 75K sevice this xmas week (oil & filter change, engine & cabin filter change) and the tires look perfectly round now, so it must be due to lack of rotation. We will switch them back at 80K and every 10K after that.