Flat spots on tires — How long before they smooth out

Learn how long it takes for flat spots on tires to smooth out

If you leave your car parked unused for a month or longer, it’s not uncommon for flat spots to form on your tires. Then, once you start driving you might feel a vibration as the flat spot touches the road. In most cases the flat spots on tires smooth out within about 20 minutes of highway driving. It’s the warm-up from driving that removes the “set” of flat spotting.

What causes flat spots on tires

Most modern tires have a nylon cap just below the tread. When drive for long periods and warm up your tires, then park for long periods, your tire cools in the flat position and the nylon cap takes a “set.” This happens more often in cold weather and on high-performance tires. Once you start driving and the tire heats up, the nylon cap resumes its normal shape.

How to prevent flat spotting on tires in storage

Many online experts recommend over-inflating tires or placing your tires in tire supports if you won’t be driving the vehicle for a month or more. But there’s a lot of disagreement over both of these practices. Here’s what the tire companies say:

Michelin says no to overinflation

” We do not recommend that you inflate beyond placard pressure and certainly do not over-inflate. Tires should not be stored loaded and over-inflated while subjected to heat.”  — Michelin Tire Company

Continental says yes to over-inflation

“Similarly, if you’re about to park your car for a long time without driving, then slightly increasing the inflation pressure of the tires by 3 psi (+0.2 bar) before parking will help to reduce the chances of flat-spotting.” — Continental Tire

Firestone Tire and Rubber Company says no to over-inflation

“Inflate your tires to the manufacturer-recommended levels and check the air pressure once a month. Make arrangements to move your car every couple of weeks if you plan on storing it for months to maintain the tires’ integrity and prevent tires from wearing. Take the weight off of the tires by properly putting the vehicle on blocks or jack stands.” — Firestone Tire and Rubber Company 

Goodyear says no to over-inflation except for high performance tires

“First, it’s ideal to remove the weight from the tires. This can be accomplished by resting the car on jack-stands or similar load bearing devices under the chassis of the vehicle. Tires should be inflated to the vehicle recommended inflation pressure(s) – including the spare tire; and high-performance tires with an overlay should be inflated to the maximum inflation pressure shown on the sidewall of the tire. — Goodyear

How about tire supports/tire cradles? Do they prevent flat spotting?

Not a single tire manufacturer recommends the use of tire supports or tire cradles to prevent flat spotting.

“Theoretically, tire cradles help to keep

No tire manufacturer recommends tire supports or tire cradles

a round shape for your tires and therefore help to prevent flat-spotting. The cradle curvature would have to match the tire curvature to be effective. Michelin does not have any data to verify that tire cradles help reduce flat spot. We do know that when you store your tires in a cradle or not, if they are over-inflated, exposed to chemicals or excessive heat, your tires are at risk of damage, including flat spotting.” — Michelin

In other words, If you’re going to leave your car unused for long periods, put it on jackstands.

©, 2024 Rick Muscoplat