I guess the only way I see that happening is that the slightly softer sidewall is soft enough to ruin the gains you get by stuffing more tire than you should. Mr. Hale's test should be very enlightening.

Why not? Z2's will apparently heat cycle out over time with street miles. I've not noticed a drop off in performance whatsoever in full depth rivals,.to chorded rivals. Those that think you're going to die if you drive rivals in the rain, are either fueled on estrogen, or just bad drivers in general. Daily driving rivals is fine, I don't get it.

I've had two events on the RS3 v2 and so far it seems to be true about the lower operating temperature. I still don't know about Hankook's better wet traction claim. It's been very dry in the California Bay Area.

I think I read somewhere that different rim diameters are going to be allowed in stock class (next season)?
Has anyone considered to run on 16" instead of 17" rims?
A taller 245 tire on a 7" wide 16" rim would be less pinched and therefore possibly deliver more grip (as opposed to a 17" rim).
(I understand that the sidewall would flex more, but this could be overcome by turning sooner).

This is also true of the Hankook RS3, whether old or new version. Even at temperatures down into the high to mid 30's, and dry pavement, the old RS3s still provided significantly more traction than a set of Blizzaks, which is what I run the "other" six months out of the year. Rain does not become a problem until you've got them worn to a pretty shallow tread depth, but that holds true for any tire.

At least they don't have to be shaved to not self-destruct during autocross or track time, that is what makes for a bad daily driver tire, IMO.

Agreed. Some people don't seem to understand that there is a difference between optimal grip on an autocross course and adequate grip for driving on the street.

Rims in Street can be +/- 1" in diameter of OEM. 16x7 is legal right now.

Since 16x7 is legal, has anybody considered to run on 245/45 16?

The only ones available are Bridgestone RE11A of the consummate autocross tires... Is stick with 17s where you have more and better options


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Ok. I was thinking of Hoosier A6 or A7 but I meanwhile understand that these tires are not allowed anymore in stock class. (I think some S2000 were running 245/45 16 tires even on 6.5" wide rims).
What Autox classes are still running R-comp tires?

There is a seperate Street Class for R Comps.

Which will end after 2014 season AND that ruleset does not allow the +/-1" diameter, so it's a moot point.

You have to run CSP, SM, or Prepared class to run R-comps any more.

I don't know about the rules for next year, but currently "Street" does allow for +/- 1" in diameter for wheels. The width must stay OEM and the offset must be within 6.25mm (I think?).

Stock rules were frozen from 2013 as the street r for 2014 so the diameter rule addition didn't apply


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So Street R has no diameter changes allowed, but Street does?

Correct.

Roger that.

This thread needs to be renamed to street r, I always get confused which thread I'm in :)


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@qoncept

Care to fix it to help stop confusion :)

Lol, I thought I was in the other thread, lol.

so after a double header at an airport, with pyrometer testing and logging, the R1R's in 235/40 seemed to like to be around 38 hot...


does this match the experience of others?

I have the Toyo R888 in 235/40 17 on 8" wide rims and run them at 31 psi (hot) and 35 psi when it's wet. Oftentimes the rear tires don't get as hot as the front tires, so I usually run them at a higher pressure.

What rims and tires (size and type) do the CSP guys run?

I thought people were running high 20's / low 30's on R1R's...

Did you get your set shaved or running at full depth?

I'm not aware of any attempts at a CSP build to-date. I don't expect anyone to make any real effort at this for 3 reasons:
1) CSP is spec-miata class, general consensus is the twins don't have a prayer.
2) A legit build really makes the car pretty much un-streetable and means you have to modify body work to fit appropriate tires.
3) All signs point to SP being the next rule set and classing structure to get completely re-vamped very soon... maybe even displaced in favor of "prepared light" intermingling in prepared classes and/or increased SM classing structure.

-1.3/-1.2 camber, 0 toe front, -1.1/-1.1 camber, 1/16th toe in rear, using an IR Pyrometer i was getting colder readings in the center of the tire compared to the outer and inner parts... basically telling me that i need more air


38psi is where they seemed to have balanced out


measurements were taken less than 15 seconds after the completion of a run and with no cone stop box no hard braking was performed at the end.


also 20psi hot? what? lol

Anything you do towards CSP would translate upward into SM...

Where you can then get slaughtered by cheating-bastard-AWD cars like the Evo and GTR.

No matter what psi I run on race tires/street tires I always have a near cold inside shoulder. How are you using that part of the tire at all?

How much camber do you have?

It's also worth noting that depending on the brand, an IR pyrometer measures a fairly large circle for heat. Not knocking 7th gear's methods at all here, he's shared a ton of valuable data for us all, but a probe pyrometer is usually better. (I just acquired one, if I get anything useful out of it I will share.)

See point number 1 here: http://www.thermoworks.com/blog/2012...d-thermometry/

Points 2 and 3 are irrelevant if you're always measuring the same tire compound and are only trying to ensure that temperatures are even across the tire.

I am maxed on stock crash bolts...like the rest of us. I think I got -1.2 on both sides. Seriously, my tires are ready to be flipped on the rim, the inside shoulder is brand new.

please note that I was getting down on my knees to do the dirty work :)


so I was measuring about an inch away from the tire.





most def, but only if your goal is to get accurate readings in terms of absolute temperatures




otherwise, the IR Pyrometer is a great tool to quickly asses the relative distribution of the temperatures. ie, I'm not overly concerned as to what the core tire temperature is, the short stints combined with a lack of any real ability to tune the car means that I've only pressures to play with,


for this, an IR tool is great to quickly figure out whether you've got too little or too much





if you are under inflated the center will be colder or same temp as the inside. I was going off 30 cold, which is what I read online, and it wasn't until I got to 38-39 hot (which translated into around 34 cold) that I was getting the center to start working more.

food for though: you could be overdriving your car.


Too much steering input and hard braking during the wrong time could lead to premature tire wear.


but I don't know you as a driver so hard to judge, :)

http://scca.cdn.racersites.com/prod/...s%20FINAL1.pdf

SM, the ruleset that let's you do anything, cheating? Also, slaughter? Oh you meant you'd get slaughtered because you haven't developed to the limit of the class like Panda did, and the twins should just be given classes that they don't need to spend time developing within?

Ya got me, I must have been thinking of Pro Solo, where AWD has such a huge advantage.

As for the cheating bastard AWD comment, that goes way back to the Audi in Trans Am days, where AWD was banned because it worked too well and was deemed an unfair advantage. I rib my friends for their cheating bastard AWD and their cheating bastard turbos all the time (the latter because of the history of turbo boost level not being policeable in pretty much any form of motorsport).

Anyone considering CSR for nationals?

maybe. i have some old Hoosiers that will just last long enough to get thru Nationals.
plus i have one sticker 245 A6 that i need to use or sell to somebody. any takers?

I considered it. But, the car won't be fully prepped this year, so I decided against it.

I'm thinking that, aside from some activist-types, Street-R classes (except for SSR) will be very thin this year. Hard to make the case for buying a fresh set of hoosiers in a size that isn't very easy to unload to others that will be allowed to stay on r-comps.

If I had a set of A6s available, or cheap, I'd consider it. I have a brand new set of Z2s waiting to go on so CS makes more sense.

Well, that wasn't the worst weekend I've had. :D

http://www.scca.com/events/news.cfm?eid=7001&cid=51916

Congratulations!
(I once worked in the US and also went autocrossing at Devens and iceracing at Newfound Lake in NH, which was lots of fun).

I noticed that many people have a Tire Rack sticker on their windshield, is this primarily because it looks good or because this is somehow sponsored also?