I'm not sure when the rule was passed to allow all to update existing cars or build new cars with 18" wheels. I remember it being discussed a couple years ago. Just wondering did the weight of cars already classed/running 16" wheels change? (I believe Goughary has since switched and Davis has built his new car to run on 18") I only see a weight reduction allowed if you run 15" . Does this mean there is no weight penalty if you run 18" ?
That is corrrect there is no weight penalty as in GT2 there is no restriction to diameter of wheel or width only that it must fit within max dimensions. The exception to the rule are the spec cars like the Porsche Cup Cars and the Panoz they have specified wheels that they are restricted to.
Below is the wording in the 2010 GT Rules
"shall be of the same diameter except in GT2. GT2 cars may run any tire/wheel combination provided that the tire does not exceed a maximum cross section width of 12.0” in the front and 13.75” in the rear. GT2 cars using 15 x 7” wheels exclusively may reduce the listed weight by 50 lbs."
Thanks for the reply. That is how I read the rules also. Just wanted confirmation from a GT2 competitor. Any idea when 18" was allowed in? Also can't remember how long has the front of the grid been on radials?
The tire rule has been out there a while 5 years or more would be my guess. The issue is that the tire manufactures cut back production and so far 18" has not been that popular on the traditional GT2 cars. However Hoosier has entered the market and you may see more switch.
Radials have been around for quite awhile. Early 90's the tire of choice was the radials (former GTU tires). Speaking from my experience they are so consistent from set to set.
Because the change from 16" is limited by section width (based on the existing 16" section width) tire footprint does not improve with 18" rims. I think the idea was greater choice of tire manufacturers (reduced cost?) and the fact that all pro-series with similar size wheel/tire package were on 18" rims. After this change Goodyear stopped production of 18" radial slicks (which made no sense to any of us) therefore trying other tires became the only choice for the few of us on 18's. If I were building a new car I'd recommend 18's but don't expect a significant advantage vs. 16's due to the slightly higher rotating weight and no additional rubber on the ground.
18" wheels for all ?
Posted - 01/15/2010 : 09:36:55
