The "ideal" rim size is not that -- it's the rim size that the industry says should be used to measure the tire. The recommended range *is* what it says, but you are using measurement numbers that are on a wheel size that Hoosier doesn't pick.
Quoting the
Hoosier website:
"
Why are the listed rim dimensions different than the recommendations?
Whenever a D.O.T. tire spec is published there are Tire & Rim Association guidelines for the specific rim size for a particular tire. This is intended to standardize the information so that it is possible to compare one brand of tire to another.
For performance uses these Tire & Rim Association recommendations may not reflect a best choice or the designed application."
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