Out of round tires

Way back when, it wasn’t uncommon for a customer to come back, complaining of vibration after getting new tires. We’d clear the suspension, take the tire off, check the balance then stick it on the tire lathe, shave off 1/32nd of an inch, put it on the car and problem solved.

Now those were all bias tires, I never saw or had to do this with radials.

Fast forward 30 years, I hear, over the past 2-4 years or so a lot of out of round tires.

What gives?

The out of round tires I run into are not new, and I’ve never even heard it suggested that shaving the tread would fix them. The out of roundness is in the form of either a bump or a flat spot. My understanding is that it’s typically caused by a broken or slipped belt in the casing, and the only cure is tire replacement. In my experience it’s not rare, but not all that common either. I would guess I run into maybe 10-12 cases a year at my one-man shop.

Back in 1999 or so I picked up a couple of those very week for return to the tire wholesaler I was working at. All radials. It was one of the more common defects we encountered.

I purchased four Goodyear tires a couple of years ago, one of which was defective. I don’t know if you would call a bulge “out of round,” but it was definately bad. This has got to be pretty rare.

I sure would if it was on the circumference (tread surface), but not if it was on a sidewall.

I am having a problem at the moment with some brand new Pirelli P5 tires on my Lotus Esprit Turbo. They have been re balanced 5 times now and still give a shimmy at 85 kph through to 100 kph. Below and above that speed they are fine. The local rep. tried to tell me it was the rims so we had those checked and they were perfect. I kept telling him that the old tires I took off were 18 year old Pirelli P600 and they were fine. I only changed them as everyone told me I was stupid to drive with 18 year old tires even though they had 80% tread left and no cracks in them.

They are now going to replace the P5s and I hope that we can find some good ones.