Good point Nick. I will include a limit on the size of the spacer.

Call me anytime, if I dont answer, just leave a message. Thanks.

The rules allow the use of any tire manufacturer as you know so we don't write the rules around Hoosier even though many choose to use that tire make. The 305 was selected to allow those currently using 12 inch tires to have options up to that size without needing to buy new wheels. The choice is up to the driver which tire to use which differentiates the Cup rules from a true spec series.

As we discussed at Nationals, there are PCA GT cars that would like to move over to Super Cup/SP3 but may not if they need to go out any buy several new sets of wheels. We want to encourage new drivers to enter the series when we can without unbalancing the field with existing drivers in the series. 305's allow the 12 inch wheels to be used, though not fully maximizing the full 12 inch wheel, or larger wheel. And as stated, checking tire section width molded in on the side of a tire is much easier for PCA techs to check that determining wheel size or measuring fender mods.

Having said all that, if you are now saying 315 is an acceptable size for 11 inch ( currently a popular rim size in use) and 12 inch rims, regardless of manufacturer, than the 315 can be used as the limit vs the 305.

Thanks for including 315s, Here is a link to Hoosier Specs and prices. http://www.hoosiertire.com/pdfs/pricescr.pdf

Rules should reflect what is commonly in use and what's available in the marketplace if we want to continue to grow the series.

I will use the 315 as the standard. But as said previously, we have grown the series by being inclusive, not exclusive. Making rules to accomodate one brand is exclusive, whether that be a shock, wheel or tire, etc.

Were in super cup did any one run 305's never mind 315's. I dont think so. The class has grown this year .If you want kill it this tire size is going to kill it. Silly wide wheel spacers, custom wide wheels if you want to keep up with the "jones" plus the custom flared fenders. I suggest 295's max. lets not be a 2-3 year class of 944.

Ernie, I think you are right.

There was a car running at Daytona with 315s and fender flares (already allowed). It was converted from the GT3S class.

And I spoke at length with this driver about the subject issue. He had a problem with our proposed rule to limit wheels size to 11 inch. He and some of his fellow GT racers where planning to make the switch to SP3 full time next year but if we limit wheels to 11 inch, he and his fellow drivers would need to buy two or more sets of 11 inch rims to replace their 12 inch wheels which we were about to make illegal. They would not do it and woudl rather race elsewhere.

Instead this driver suggested we limit the tire size to 305 which he could still use on his 12 inch rims. This was a better solution to the 11 inch limit and still accomplished what we wanted to do with and we woudl be attractin another group of cars from another class to SP3. Win win.

Follow up email from the driver being referred to here:

Hello Dave,

It was nice meeting you at Daytona a few weeks ago. I had such a good time running with all the 944 guys and now that I would not have to make any significant changes like all new wheels, I am planning to switch from running mostly in SCCA next year and trying to make the full eastern schedule of your series. I also think I will have 2 buddies that are going to run it with me…

So, knowing this what is section width that will fit on a 12 inch rim, keeping in mind the narrower the cheaper the price of the tire? And keep in mind the competing objectives in making a change like this, i.e. place some limits on car width in particular wheels and/or tires to keep costs down; attracting new drivers to the series, not alienating drivers away from series by changes that are more restrictive, not disadvantaging drievrs already in the series.



The proposed changes for 2014 here are placing limits on on tire widths which for 2013 had NO limits. So now limiting the tire size is going to kill the class? Or does it make it easier to keep up with the Jones' ? In my eyes placing a limit on tire widths improves the rules and the series.

Fender flaring has been allowed for several seasons, backing up on that would cause real problems for guys to go back and remove and repair, so not a good solution. Same with wheels which had no limits. Limiting the tire width in effect limits the useful width of the wheel.

Limiting tire width is the best option at this point. So what size do we use as a limit considering we want to include the guys who already are using 12 inch wheels?


From what I can see the 295's may not fit the 12 inch rim, so is it a good solution?

I think you are making the rest of the class have to step up to 12" wheels to extract maximum benefit. The 305 tire will benefit from the additional inch of wheel width and so everyone else will need to upgrade if they want to keep up. A 315 tire allowance will make the need for the wider wheel even MORE necessary.
Also, I am still curious about a limit to the overall width of the car body or something that, even if you lengthen the control arms, etc, only allows the car's contact patches to get so far apart from each other. I think there really needs to be a limit there.

Hard to say what if any measurable performance gain there is using a 12 inch wheel vs a 11 inch wheel with the same tire mounted. Wider is heavier unsprung weight which could further impact performance negatively. And remember tire and wheel sizes have been unlimited for many years in the series for SC and fenders could be flared for years up to 2 inches. So I am not "making the rest of the class have to step up to 12" wheels" with this proposed changed, that "need for wider" was already there and has been for years. We are just putting a limit on it now to minimize the "need for wider", but while also minimizing the exclusion of cars/drivers.