a possibly dumb question...

[dkois]

...but I'm going to ask anyway.

What is the point of the Road Tire classes?

My assumption was that PAX would account for the fact that someone was running with road tires. That is to say, I assumed that if two identical cars in the same class got the same time--one on road tires in road tire class, and one on R-compound tires in the stock class--that PAX would put the road tire car ahead in the results (eg, it is at a disadvantage on road tires so the same time=better driving).

It looks like my assumption is not correct (which is not surprising... for some reason this happens all the time!?!).

In our event last weekend, I registered as All-wheel drive B-stock ("ABS") in a 2011 Lancer Evo. In looking at the results, my times were adjusted in PAX by a factor of .843. A fellow competitor who was driving a 2010 Evo in straight B-stock also had times adjusted by exactly the same .843 factor... even though (theoretically... this is an example!) he could have been on R-compound tires in B stock, right?

What am I missing (besides actual driving skill!!)

Thanks for explaining this to me--try and talk to me like I'm 2, please!

Dennis

[pzahornasky]

The road tire classes are for people that want to compete against other people that are also on road tires.  So you are competing against other people in Stock Class AWD cars that do not want to run on R-Comps.

It does not give you a better PAX than the Open stock classes though.

[dkois]

So its a way to segregate road tire "only" in one class? Eg, in stock class you can run road OR r-tire, in road tire class only road tires, yes?

But I guess I still don't get the point of making it a special class then; if there is no PAX advantage for running road tire class, why not just stick with the stock class?  If the only point of road tire class is to allow apples-to-apples comparison, then wouldn't it follow that the stock class should become "r-tires only," to keep it segregated as well?

Not sure if my questions are making sense, but hopefully you get the idea. And not trying to beat the system--just trying to figure out the logic, since I thought the whole point of PAX and classes was to equalize the playing field based on equipment, of which tires are just about the most important.

Thanks for humoring me...

[pzahornasky]

The Road tire classes are there to serve those people that run Stock Class cars that do not want to run on R-Compound tires.  The classes are PAX classes which means that the times are adjusted by the appropriate modifier based on what Stock class your car falls in.

So in RTA, you were competing against a DS WRX.

On the overall scoring, there is no special advantage to running in Road Tire.  It is impossible to accurately predict how much slower a road tire car would be versus the same car on r-comps.

[madame_toussleau]

I'll add that normally the B stock cars have R comp tires so they would be faster than they showed this past weekend, but because no one showed up on R-comps, it's a wash.

Second - Some regions add in a modifier for the road tire classes.

Look at Milwalkee as an example:

http://www.scca-milwaukee.org/solo/2012/e1/event1finalpax.htm

A number like .975 is multiplied to the road tire time in addition to the PAX.  Doing that in these other regions makes the street tire drivers competitive in the PAX list for the day. In theory, this is where the difference is thaat had you question the classing (but the region doesn't support it currently).

Our region had a heated debate on adding the road tire classes. I'm pretty sure the road tire drivers would like the modifier to bring more validity to the whole "pax and street tire" thing, mainly because it affects the season championship and this year these classes are SCCA national office inspired.

If we set up the road tire classes the way those other regions do, the road tire cars would be competitive in PAX and would  have a shot at the Moss.  But we (NER) are only 1/2 way there and the road tire people are supporting the SCCA's initiative at their own expense - the year end Moss regional championship.  

I don't speak for all RT drivers, but I have thought, since RT was experimental, is supported by SCCA, and now seems to have a following, perhaps we should consider adding the modifier. Why not...?


-Barb Seeger- Road Tire Rear - B stock

[Gus Heck]

I'll add that normally the B stock cars have R comp tires so they would be faster than they showed this past weekend, but because no one showed up on R-comps, it's a wash.

Second - Some regions add in a modifier for the road tire classes.

Look at Milwalkee as an example:

http://www.scca-milwaukee.org/solo/2012/e1/event1finalpax.htm

A number like .975 is multiplied to the road tire time in addition to the PAX.  Doing that in these other regions makes the street tire drivers competitive in the PAX list for the day. In theory, this is where the difference is thaat had you question the classing (but the region doesn't support it currently).

Our region had a heated debate on adding the road tire classes. I'm pretty sure the road tire drivers would like the modifier to bring more validity to the whole "pax and street tire" thing, mainly because it affects the season championship and this year these classes are SCCA national office inspired.

If we set up the road tire classes the way those other regions do, the road tire cars would be competitive in PAX and would  have a shot at the Moss.  But we (NER) are only 1/2 way there and the road tire people are supporting the SCCA's initiative at their own expense - the year end Moss regional championship.  

I don't speak for all RT drivers, but I have thought, since RT was experimental, is supported by SCCA, and now seems to have a following, perhaps we should consider adding the modifier. Why not...?


-Barb Seeger- Road Tire Rear - B stock

It seems like a reasonable thing to do for next year, with some question as to the derivation of that modifer (how does PAX master RTP Rick feel about it for example, does it come from data?) but changes in scoring (or any rules) midway in a season don't seem like a good idea, and should be reserved for safety issues, or drastic problems. My $0.02...

[pzahornasky]

Arriving at a meaningful set of Index factors for each Stock class fitted with street tires will be very difficult, probably impossible.  Right now there are only 8 cars entered in the Road Tire classes at the Dixie Tour and that's split up among only a few classes.  That's a start, but not nearly enough to begin a whole new group of factors.  For regular classes I get hundreds of cars in each class.  Even if the Road Tire class is wildly successfull (say 10-15 cars in each group), that will still only be a few cars from each class.

This quote from Rick Ruth is from the Road Tire class discussion. 

I didn't pay a heck of a lot of attention to my statistics class in college but I remember that without a huge sample size, it is difficult to get a truly accurate number.  A blanket modifier doesn't work because some cars are not handicapped by street tires (vs R comp) as other cars.

[madame_toussleau]

This quote from Rick Ruth is from the Road Tire class discussion. 

I didn't pay a heck of a lot of attention to my statistics class in college but I remember that without a huge sample size, it is difficult to get a truly accurate number.  A blanket modifier doesn't work because some cars are not handicapped by street tires (vs R comp) as other cars.

\
Good point Paul. Thanks,

[Chang]

If I remeber correctly, Rick Ruth did post a couple of numbers for a RT modifier in one of our threads.  Cant remember which thread or what the numbers were.  We could use the more conservative number, it would be a start in the right direction.

[GrantR]

From what I've read about street tire PAX scalars over the years, 0.975 is pretty aggressive. The right cars on the right tires can totally make that up and win PAX easily. I've heard of 0.985 being a good conservative yet workable number. As PZ mentioned different cars respond differently to street tires vs R-comps.

Being a nerd, I have a spreadsheet for tracking the combined pax results for the whole season, and it already is set up to do a street tire scalar. After 3 events, Barbara and Bryan are the top two road-tire competitors. Using no street tire modifier, they are 29th and 30th. Using 0.985, they move up to 22nd and 25th. Plugging in 0.975 brings both drivers up to 19th and 20th.

[madame_toussleau]

After 3 events, Barbara and Bryan are the top two road-tire competitors. Using no street tire modifier, they are 29th and 30th. Using 0.985, they move up to 22nd and 25th. Plugging in 0.975 brings both drivers up to 19th and 20th.

Are you missing Ken Johnson? He seems formidable in  RTA class.

[newportroyal]

Are you missing Ken Johnson? He seems formidable in  RTA class.

Neither me or my co-driver made it to points #2 at NHMS, so we're going to be pretty far back in PAX points for a while.

I think Rick Ruth can be quoted as saying that .975 is the most realistic number.  In my opinion, .985 sounds incredibly harsh.  At .985, that is the same as saying I'd only pickup 1 second on a 60 second Devens course by switching from street tires to Hoosiers.  That doesn't seem plausible to me.  I wouldn't oppose meeting in the middle.

[GrantR]

Are you missing Ken Johnson? He seems formidable in  RTA class.

Well, technically I'm not missing him, he's only got the 2 events which blows his results out until we get to event #6

But if I look at the positions based on average, which includes those folks who have only done 1 or 2 events, so the averages are really sketchy with such a small dataset to work from:

at 1.0, Ken is 39th with 94.314, Barbara is 61st with 92.068.
at 0.975, Ken is 20th with 96.732, Barbara is 40th with 94.429.

That probably does seem reasonable. 0.975 is equivalent to 1.5 seconds on a 60 sec course?

But both cars in this example are heavy cars: our heavier cars tend to have much increased suckage when driving on street tires vs hoosiers. I probably need a pax factor of like 0.5 to compensate for the street tires on my Z06

[newportroyal]

There was discussion earlier this year of using different multipliers of front, rear, or all wheel drive, or maybe even a different multiplier for each class.  It's my understanding that NER has created its own multiplier for the Karts, so it seems with enough data, the same could be done for SS to HS.

The only issue I see is that this really doesn't seem to be the norm for most clubs and regions.  It seems most of them just use a blanket multiplier.

It's going to be a slippery slope with people crying foul no matter which way it goes, whether it be no multiplier, blanket multiplier, or additional individual class multipliers.

[NERDY]

From what I've read about street tire PAX scalars over the years, 0.975 is pretty aggressive. The right cars on the right tires can totally make that up and win PAX easily. I've heard of 0.985 being a good conservative yet workable number. As PZ mentioned different cars respond differently to street tires vs R-comps.

Being a nerd, I have a spreadsheet for tracking the combined pax results for the whole season, and it already is set up to do a street tire scalar. After 3 events, Barbara and Bryan are the top two road-tire competitors. Using no street tire modifier, they are 29th and 30th. Using 0.985, they move up to 22nd and 25th. Plugging in 0.975 brings both drivers up to 19th and 20th.

I vote for a 0.900 multiplier... Who's with me?

-Bryan