Stu

When I sold my OEM 18s, I bought 17s for the summer and winter. If I was to get a flat tire and use my spare, I be driving on three 17" wheels and the 18" spare tire.

All tire sizes are stock sizes, but I was wondering if driving the car short distances and low speed ( to get the flat fixed ) will cause any serious problems.

thanks

Jabberwock

As long as total diameter of wheel/ tire combo is fairly close it would do no harm. It would be just like driving with one tire significantly under or over inflated.
Your TPS would throw a warning because one tire would be sized different and therefore rotating at different speed from others (assuming equal pressures).

warminwisc

It is alot more critical if it is AWD FWIW.

AlexusAnja

Problem isnt juat isolated to AWD, but same axle drive. If the 18" tire is on the same axle that drives, then the rotations will be slightly off and cause issues with the differential if driven long term, say a few hundred miles. If the 18" is on the front of the LS, then you might experience some uneven on steerinh or off center.