Replacement Tire Sizes

[SailDesign]

Originally Posted by Kal-El

215 is width, not height. The 55 measurement is sidewall height.

So my 55's are lower than stock. If I were to go 215/65/15, they would be the same sidewall height as stock.

And as for the speedo, my smaller diameter didn't affect the speedo at all (I have a nav that reads the same exact speed).

Ummmm - please read Kimona's link. The "55" is the sidewall height, true, but as a percentage of tire width. So the actual height of a 215/55 is 118.25mm. and the height of the sidewall on a 215/65 is 139.75mm. That makes the 65-series 43mm (twice the difference above) taller than the 55-series.

Small differences in height won't show up on an analogue speedo (can't read it accurately enough) but a 10% diffence sure will.