Tire Size Calculator

As part of the research process behind my Matrix, I was pleasantly surprised to find that I could probably use the winter rims and tires from my Impreza on my wife’s 09 Corolla.

To make it interesting, and as you may recall, I used the ‘downsize’ approach when picking rims for my Subaru many many moons ago. Basically this calls for selection of narrower taller tires mounted on rims one size down. So, while my OEMs were 205/55s on 16 inch rims, I went with 195/65s on 15 inch rims as per Tire Racks recommendation. The result was tires that cut through the snow and give wonderful traction.

The fact that the bolt pattern is identical  (5 x 100mm) was a complete fluke and while one would think that seals the deal it does not. You have to be aware of offset as well. Offset is the distance between the physical center of the rim and the actual back plane of the center of the rim (where it mounts onto the wheel). If you choose rims with improper offset there may not be room between the rim and the caliper and junk like that.

Finding the offset can be troublesome but once again I used tirerack to do the work for me – simply using their winter package function and comparing 15 inch rims for the 09 Corolla and the 01 Impreza. The offsets are different (of course) with the Impreza calling for a 45mm offset for 15in rims and the Corolla requiring a 35mm offset. This means that the  Subaru tire will sit slightly further into the Corolla wheel well than is called for.

To the rescue comes another site which does a better job of explaining and illustrating:

Visit  rims n tires to explore for yourself.