not all sizes are created equal

[Canawler]

While reading the current thread on non-stock tire sizes I remembered this picture I took when I got new tires for the SRT-4 last spring. I thought some might find it interesting to see just how different in actual dimensions some tires of the same spec'ed size can really be. In theory every 215/45/17 tire should be the same physical size but every manufacturer seems to have their own yardsticks.

The Michelin snow tire in the middle and the old Kumho one on the right are both 215/45/17 and are obviously very different dimensions. The new Sumitomo on the left is a 225/45/17.

 

[scoobie]

kumho are made in china, and as such the quality checks can be very wild. even two solus's of the "same size" will be extremely different, so make sure you ask the clerk to check that they are all the same before shipping them to you. that being said, the next tires i'm buying are kumho's: they're cheap, highly rated, and the solus kr21 actually has a decent tread pattern, unlike the exceptionally cheap pattern you're showing, they actually even work with snow.

 

[Dominic]

For the record my OEM bridgestone RE92As on my Subaru were always 2.5mph off at 60mph according to GPS. My new Michelin Pilot Sport A/S tires fully corrected the speedometer to such amazing accuracy that it's less than 1mph off at 110mph now. It's quite amazing what a little quality control can do for you

 

[ksJoe]

Did you check to see if the manufacturers all used the same width of rim for their official measurement?