How wheel width affects tire width

Back to Wheels, Tires

From http://www.tirerack.com/tires/tiretech/tirespecskey.jsp:

The industry rule of thumb is that for every 1/2" change in rim width, the tire's section width will correspondingly change by approximately 2/10".

For example: a tire in the P205/60R15 size is measured on a 6.0" wide wheel and this size tire has an approved rim width range from 5.5" to 7.5" wide. The tire has a section width of 8.23" (209mm) when mounted on a 6.0" wide wheel. If that tire were mounted on all of the rims within its range, the tire's approximate section width would change as follows:

Difference from Measuring Rim	Rim Width	Approximate Tire section width
0.5" narrower	5.5"	8.03"
Measuring Rim	6.0"	8.23"
0.5" wider	6.5"	8.43"
1.0" wider	7.0"	8.63"
1.5" wider	7.5"	8.83"

Because of the different wheel widths used in the above example, there is a 8/10" projected difference in tire section width when comparing a tire mounted on the narrowest rim to the widest rim within its range. This may affect fenderwell and frame clearances when selecting optional aftermarket wheel and tire packages.