smb1234

I'm looking to pick up a slightly used tire to run on my 18" spare. My main tires are 255/35/18. For the spare, the closest I can find is either: (1) a 255/40/18; or, (2) a 245/40/18. I don't anticipate using the wheel except in an emergency situation. Am I safe covering a short distance in a different sized tire? If so, am I better off going with a taller version of the same width tire (option 1), or a narrower tire running similar dimensions (option 2)? For what it's worth, the spare has a slightly greater offset (5mm closer to the edge of the car).

2.7Twin

IMHO, for a short distance and in an emergancy situation anything close will do.

ArtsA6Q

So we know that smaller is okay. With the sizes you are talking about, there shouldn't be any problem.

Just be careful about getting directional tires. You don't want to end up with a flat on the wrong side in the middle of heavy rain, only to plop on a directional tire BACKWARDS and end up sucking water into the center groove of the tire instead of channeling it out!!

Most cheapo's are not directional anyway, and I doubt you will be shelling out massive bucks for a nice tire, right?

Also you may have more of an issue of fitting the darn thing into the spare tire well. You might need the longer bolt.

David in LA

I don't think those widths will fit in the tire well... you'll need something in the 205-225 range

DWP

ummm I think the OD on a donut is the same as the fullsize.

howdeeaudi98

I have a 245/17 inch and it matched up well with the old spare based on the 16 inch sport wheel package my car came with. Just upsize the donut if your car has larger diameter wheels than that. Get an inflator and deflate the spare 1/2 to fit it in the well. (That wheel well makes a handy hideout for subwoofer amp's etc..so consider the donut as a good thing).