PCA SDR

I'm changing to run DOT tires for next year's time trial. When I went through the zone8 classification website, it put me in cc14 from cc16. I know I saved some points going from slicks to DOT tires, but didn't expect to move down 2 classes. I practically checked every modification boxes including all engine mods and the lower weight. And I went through the websites a few times and got the same classification.

Has the rules changed from 2 years back? I just want to make sure I'm not doing it wrong.

thanks

-Fred

Fred,
That doesn't sound unreasonable to me. If you go from the bottom of one class point range to the top of another, it's not that hard to drop two classes. Did you also change the tire size besides the type? The change from slicks to DOT tire with treadwear of 1-49 saved you 60 points, which is almost a whole class at that level (there is a 75 point spread between classes from CC12 on up to CC16). If you also ran wider slicks before, you saved a point for every mm in width reduction. You are showing 245 F and 295 R tire widths now on the classification site. How wide were the slicks you were running? You may have saved some more points there. The other place you may have saved points is in the weight calculation. There was a tweak to the weight reduction rule a couple years back. You used to get 50lbs. free, now you get a 2.5% reduction of stock weight free. This saved you a few points as well.

Your classification sheet looks totally reasonable to me. If you were at the bottom of CC16 (1051 points), you can drop to the top of CC14 (974 pts,) by shedding only 77 points. You are at 968, so you must have dropped at least 83 points, which is only 23 points more than the 60-point reduction you got in tire compound alone. A reduction of 10mm on each axle's tire width, plus 3 points for weight and you're there--a two class drop.

HTH,
TT

Very possible that you dropped two classes Fred. There were a lot of minor adjustments to the rules last year regarding tire points, weight, sway bars, shortened gearboxes, suspension geometry, and others that when added up on a full-dressed race prepared car might make a big difference. Always a good idea to run your car through the classification tool once the new rules are posted to see how the changes might affect you.

In other news there were very few rule change proposals this year and a brief look at results confirms that we are pretty close to our goal of a level playing field for all cars. There are no perfect rule sets but top drivers are finishing at the top of their class and lap time spread looks logical. Combine a top driver with a well optimized car and they are often found in the top 10 BRI if they ran a good lap. Also nearly every model of car has been represented at the top of the results page.

Yes I do plan to go down on tire sizes. I forgot what I put in before, something like 275F 315R maybe. I didn't bother to convert inch->mm from my slicks as I was at cc16 anyway. I ran some used Hoosiers 245/275 in the last TT. The car felt pretty good, just little more tail happy With the right alignment and wider rears it might just work.

The change is purely for economical reasons. The slicks are $400+ each plus they were in and out of production, making used tires supply scarce. Moving to 17" and DOT tires make sense $$ wise and tire choice wise. Just want to get the most fun for the buck

Thanks for the replies. Have a great Christmas and New Year. See you all next year.

-Fred

M-tinker wrote:Yes I do plan to go down on tire sizes. I forgot what I put in before, something like 275F 315R maybe.

That's 50 points more in tire width than you will have with the 245/295 combo. Combined with the 60 points less for compound, you had a 110 point reduction just in tire choice--easily enough to drop 2 classes without anything else, if you weren't too far into the CC16 range.

Cajundaddy wrote:Always a good idea to run your car through the classification tool once the new rules are posted to see how the changes might affect you...there were very few rule change proposals this year...

As far as I could see, there was only one change proposed for 2013 that is going to go through, and that had to do with tech inspection waivers--nothing in the final proposals for 2014 that would effect the TT/AX classification system. So whatever your class is in 2013 is the same for 2014, no?

TT

ttweed wrote:

Cajundaddy wrote:Always a good idea to run your car through the classification tool once the new rules are posted to see how the changes might affect you...there were very few rule change proposals this year...

As far as I could see, there was only one change proposed for 2013 that is going to go through, and that had to do with tech inspection waivers--nothing in the final proposals for 2014 that would effect the TT/AX classification system. So whatever your class is in 2013 is the same for 2014, no?

TT

In 2013 we had a lot of small changes that tightened up our new rules set and affected many cars. For 2014 it looks like no direct points change proposals but there are always a few administrative changes to clarify the language and add new cars so every model has a place in the sandbox. My suggestion as a competitive AX/TT driver: Run your car through the classification tool every January to make sure you have not overlooked something because changing classes mid-year can be painful if you are in a points championship.