17" rear snow tires to replace 18" regular tires?

[monkeydust]

The dealership I bought them from said it would be fine and would actually do a better job on snow. Is this correct? Is it going to affect my odometer?

I haven't put them on yet and was thinking about getting it done this afternoon.

[wross996TT]

What you have to maintain is the same diameter front to back. Also it is not the diameter that helps in snow, but the width...the narrower the better. I personally would not run 18 in front and 17 in back.

[gandrade1]

What you have to maintain is the same diameter front to back. Also it is not the diameter that helps in snow, but the width...the narrower the better. I personally would not run 18 in front and 17 in back.

Agreed - The narrower and the higher the TIRE the better...Total diameters calculations however do not solely justify why you should keep the same wheel diameter for your front and rear wheels...even within the same wheel diameter (see calcs below), you will notice that the total diameter (with tires) changes slightly...Adittionally you might have different wheel diameters but very close total diameters - it is all a matter of the height ratio of the tire you choose. Best advice however, is to keep the same wheel diameter in the front and in the rear because the recommended tire widths (hence the contact surface) are very different across different wheel diameters, which obviously changes the handling of the car. In general, the higher the height ratio of the tires, the higher the 'sidewalls' and the lower the changes of you getting stuck in snow...

Additionally, winter tires and summer tires are made of different materials and tread designs, which have a direct impact on how the car handles.

Just my 2 cents...

Gus

Edited November 20, 2007 by gandrade1

[monkeydust]

Thanks, i'm going from all 18" to all 17" for my snow tires(not just rear as i said). Just wanted to make sure I'd be ok. Thanks for the insight!