Care of unidirectional tires

[bamaboxster]

I own a 99 Boxster. This is the first car that I've owned with unidirectional tires so I'm curious about how to care for the tires. Specifically, how do I rotate unidirectional tires? The rears are a different size from the fronts and there's nothing gained by flipping them from one side to the other. Sooo - what to do? Just keep them balanced?

[Bruce2010]

I own a 99 Boxster. This is the first car that I've owned with unidirectional tires so I'm curious about how to care for the tires. Specifically, how do I rotate unidirectional tires? The rears are a different size from the fronts and there's nothing gained by flipping them from one side to the other. Sooo - what to do? Just keep them balanced?

The directional tyres also known as unidirectional

tyres give the best preformance in terms of traction,

and grip in the one direction only.

It is not adviced to put them on the wrong way, as

you will seriously lose grip. In the case of a

puncture, and you have to use one the wrong way it

should be regarded as temporary situation in the same way

as a space saver

Just keep them balanced and in the correct direction.

[demick]

That's right. You simply don't rotate the tires. This means that you will wear out one pair of tires before the other. It is fairly common for Boxsters to go through 2 sets of rear tires for every 1 set of fronts.

[fltrplntman]

I own a 99 Boxster. This is the first car that I've owned with unidirectional tires so I'm curious about how to care for the tires. Specifically, how do I rotate unidirectional tires? The rears are a different size from the fronts and there's nothing gained by flipping them from one side to the other. Sooo - what to do? Just keep them balanced?

Have them unmounted from the wheels and placed on the opposite wheel. The both rotate the same direction, but the camber wear will now be on the outside and should even up after several thousand miles.

[N41EF]

Make sure the air pressure is correct, and that the car is properly alligned. They will wear on the inner edges of the rear, it's "normal". And yes you should go through two sets of rears to a set of fronts. Make sure when you buy tires it's not something discontinued, so you can buy another set of rears.

[mikefocke]

With proper alignment, they don't wear on the inside if you align within specs but on the edge that favors even tire wear at the expense of some grip at the limits. A mechanic who sets cars up for racing will know the effects of various settings and, if you tell him what you are looking for, he can set it up. I took off my Ribs after 5 years and 17K miles because of age and they were perfectly evenly worn...actually they had legal tread depth left and it was even.

[racerx169]

Hi Everyone, I really question the basis for not being able to mount the tires on in the counter rotation orientation if the vehicle is used only in the dry. I would be interested in everyone’s input on the technical reason for this.

As for the tread pattern, yes there is a high dependency on water clearing characteristics depending on the orientation.

Unless the tire manufacturer lists the uni-directional tires as “front only” or “rear only” the forces on the belts inside the tires are in completely opposite directions under high acceleration and braking. The front tires will take the majority of the braking forces while the rears the majority of the acceleration. Swapping the direction means that now when you accelerate you are stressing the tire as if you were braking. In either case, the tire has to be constructed to be able to bear these loads. As for side to side, uni-directional tires can be mounted on left or right so there is no lateral force dependency there. This is consistent with being able to dismount and remount tires from left to right as someone mentioned in a post earlier.

So while you would be sacrificing wet traction (possibly dangerous in the rain) I suspect the tires are constructed to handle forces needed to mounted in the counter-rotation direction.

Please understand that I by no means recommend you run your tires counter-rotation but this is simply a technical discussion.

Thanks

Edited May 5, 2011 by racerx169