Gary R.

Both are longstanding rules. No body modifications and shocks must be as available from the factory. 72's didn't have SC flares and SC's didn't have adjustable shocks. Apples to Apples.

sig_a

Regarding the use of 15" wheels to play with gear ratios, leave it alone. Others have the option of buying some 15s if they want to. ( I don't have a stake in this one since I have to run 17s to clear my brakes).[/QUOTE]

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I agree.

And with all due respect, how are 15's with low profile wide width tires viewed as "prep" where 17" or 18" wheels with even lower profile and wider tread considered "stock". Given low profile tire technology is a fact, allowing stock wheel sizing in a stock class seems a good thing.

Circuit Motorsports

So what's the point of wanting remote reservoir shocks not being allowed in stock? That rule usually just creates a greater disparity in price points as there are real pimpy non RR shocks that people might end up going after while others will go with off the shelf Konis. 1600/set vs. 1600/each.

Gary R.

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Sorry, you are missing the point. 15" wheels are not the real issue. It's the Hoosier R6 275/35/15's that are about 8" less in circumference than 16. 17, 0r 18" wheels with the same profile tire. There ARE R6's available in a 50(?) series that have the same rolling diameter as all the others and that's what the guys with 15's need to go to. I know for a FACT that Fred is almost a full gear different on all tracks now with his 15's. Hey, why not allow us to re-gear our 915's or run different R&P too!

Gary R.

Why should we follow ANY of the rules? Non-Adjustable as delivered from the factory.

Circuit Motorsports

I not talking about following rules as I think whatever they are they should be followed.

I'm talking more about making remote reservoir shocks illegal in a certain class. I was curious as the thought behind the reasoning. Mainly because the most used one "cost control" actually doesn't happen when it's limited to a certain type of shock.

Gary R.

Joe it's the stock class rules, we can't use a type that wasn't available to be ordered from the dealer at the time of manufacture. It's just the way it is. It is a prepared change and should simply be written that way. One class bump, no big deal.

Just got some info on STOCK SC 15" rolling diameter as delivered from the factory-
roughly 25.2"

"[2 * (tread width in mm * profile as a percentage) / 25.4] + wheel diameter in inches
185/70/15 ---> [2*(185*.7)/25.4]+15 = 25.197"

my 18" 275's are 25.5 and the 16's and 17's are withing 10ths.

The 275/35 15's are 23.0"

Chris M.

I agree and I hope you guys are letting PCA know as well.

Circuit Motorsports

Got it. Thanks Gary. I was reading that slightly differently than that as it was a bigger bump out of class.

FredC

I agree.

And with all due respect, how are 15's with low profile wide width tires viewed as "prep" where 17" or 18" wheels with even lower profile and wider tread considered "stock". Given low profile tire technology is a fact, allowing stock wheel sizing in a stock class seems a good thing.[/QUOTE]

Simple. The 275/35/15 rear tires on an SC or 3.2 are equivalent to improving the ring and pinion. As you know ring and pinion must be as supplied by the factory or it is a prep.... I went from 17s to 15s so to run these incredible tires... the difference in performance is mind boggling... 2:13.8 to 2:12.08 at WGI.... The improvement will be even greater at Road America...

Gary R.

Chris - I don't want the people that have 15" wheels to have to buy new wheels to stay legal, the choice is to use Hoosier R6 275/50ZR15's with the same 25.5" rolling diameter as ALL the other size wheels or stay with the 23" tires and go prepared. The same logic goes to the 95% of the rest of us, why should we have to buy new wheels to compete on a level field?

jscott82

Reducing weight of 993 to bring them in-line with 964… yes please… best rule in the proposal in my opinion

Bumping remote reservoir shocks to prepared. Im not sure I see what real advantage “remote reservoir” brings to the table (ok, yes more heat dissipation per un-sprung weight) . I think what we are talking about is allowing the replacement of stock springs and POS shocks with high quality adjustable racing ones. If this is implemented, the effect will be for those with high dollar remote reservoir race shocks to go out and buy high dollar non-remote reservoir race shocks. No real difference here…..

If the goal is to get close to stock, then it should require stock spring rates and non-adjustable shocks. Remote reservoir is a symptom not the disease…

sig_a

".....the difference in performance is mind boggling". I like that. And this is a interesting discussion.

Fred, I understand the final drive ratio effect having made a similar change as well. But then how does one answer the question of allowing various 17" and 18" wheel/tire diameters with no similar restriction. Technically speaking, isn't that also "effective R&P prep"? And how was it ever accepted as "stock" by PCA? In other words, the rule is already inconsistent, and is what it is. As it stands now, allowing these inconsistencies to remain part of the rules is in itself consistent.

Chris M.

Why should I have to build a $15K motor to compete on a level field? Having an effective ring and pinion advantage is no different than having a hp/wt advantage because of a custom motor.

Running a 275/50 tire would be like driving on marshmallows, and be a disadvantage. The 245/50 works fine.

flatsics

Simple. The 275/35/15 rear tires on an SC or 3.2 are equivalent to improving the ring and pinion. As you know ring and pinion must be as supplied by the factory or it is a prep.... I went from 17s to 15s so to run these incredible tires... the difference in performance is mind boggling... 2:13.8 to 2:12.08 at WGI.... The improvement will be even greater at Road America...[/QUOTE]


Fred---full disclosure-- you made many other significant changes to your suspension set up. Implying that all of your lap improvement came from the 15" tires is misleading.