Tires for H Stock P10 G20t?

eandrade · 02-01-2005, 12:14 AM

Hi,

I am looking for R-compound tires to better compete in H Stock this year. (I went through last season on 195/60-14 Falken Azenis and did OK). Anyone have any recommendations? I am currently looking at the following options:

1) 225/50-14 Kumho ECSTA V700 - does anyone know if these will fit on the stock 14x6 wheels, and if they will rub on a G20?
2) 205/50-14 Kumho Victoracer V700
3) 195/55-14 Kumho ECSTA V700

The fastest guy in my class is in a Mini, and last year I was 2.6 seconds slower (over a 60sec course). I'm guessing I'll need all the help I can get against a car like that.

-Ernie

eandrade · 02-01-2005, 02:28 AM

So I think I answered my own question with a little googling...

http://dunlop.buffnet.net/tiretech/W...tire_width.txt

It turns out that getting a rim on the wider side of the approved rim widths will actually net you better handling due to an implicit stiffening of the sidewalls which in turn force a larger contact patch (and compromising ride). And getting a rim on the narrower side of the approved rim widths will get a better ride, but softer sidewalls and smaller contact patch. So in my case, the extra inch of width would be negated. Looks like I'll go with the 195/55-14 Kumho ECSTA V700s; I'm guessing the 10mm loss in cross section width (compared with the 205/55-14 Victoracer v700) is negligible in light of the fact that the ECSTA is a new tire.

maxQ · 02-01-2005, 11:40 AM

Quote:

Originally Posted by eandrade

So I think I answered my own question with a little googling...

http://dunlop.buffnet.net/tiretech/W...tire_width.txt

It turns out that getting a rim on the wider side of the approved rim widths will actually net you better handling due to an implicit stiffening of the sidewalls which in turn force a larger contact patch (and compromising ride). And getting a rim on the narrower side of the approved rim widths will get a better ride, but softer sidewalls and smaller contact patch. So in my case, the extra inch of width would be negated. Looks like I'll go with the 195/55-14 Kumho ECSTA V700s; I'm guessing the 10mm loss in cross section width (compared with the 205/55-14 Victoracer v700) is negligible in light of the fact that the ECSTA is a new tire.

That article is assuming a perfect world where you can vary the width of the wheel. It's comparing the SAME tire on different widths. You have the SAME width with different tires...

Go with the 205. The 225 will be too tall (I think... the stock tire is 195/55, right?) and will end hurting acceleration too much.

edit: I lied. Buy the 225... it's not THAT much taller and will net you much more traction. Your tire guy will hate you, though.

GRMPer · 02-01-2005, 11:45 AM

225/50/14 is same OD as a 205/55/14...

Honestly, the best autocross combo is to stuff the widest R compound tire you can on the stock rim. The top stock class cars that ran 14"s had 225/50/14s on 6" wide rims on the front. 205's on the rear. How do you think those Neons got so fast in the nineties?

Per

eandrade · 02-01-2005, 01:21 PM

Hm. That logic sounds right, which is why I initially opted for the 225s -- an extra inch of section width! But the Dunlop article makes sense to me from a theoretical standpoint. I think you're right though... Last year there was a guy in a Ford Focus that totally killed, and he was squeezing some *really* fat R-compounds on a narrow rim.

Quote:

Originally Posted by GRMPer

you can on the stock rim. The top stock class cars that ran 14"s had 225/50/14s on 6" wide rims on the front. 205's on the rear. How do you think those Neons got so fast in the nineties?

So I thought we had to run the same size tires all around, but after reading the rule book, it looks like I don't have to. Since this is my first set, I'll try 225s all around and mess around with air pressure to get the rotation I like. Besides, with the G20 there's an OK amount of rotation built in, and I can muck around with it a bit more with some aggressive alignment settings (man, I love the way the car handles -- too bad it's 3000 pounds!

).

GRMPer & maxQ...Thanks for your input!

-Ernie

GRMPer · 02-01-2005, 03:33 PM

The main point is that, despite what many racers think, autocrossing is not road racing at lower speeds, it is something completely different and many times the traditional racer's dogma just doesn't apply.

1) Good road racers don't necessarily make good autocrossers
2) Good road race builders and tuners don't necessarily make good autocross tuners
3) Good road racing alignments and tire pressures don't make for good autocross alignments.

On an autocross course, if you need rotation on a FWD car and you're limited in a stock class...you can run smaller rear tires, bump the rear pressures to the moon, run as much toe out as you can stand or even run positive camber in the rear. They all are valid and can work. The trick is getting a set-up that works for you and your driving.

Per
http://www.grassrootsmotorsports.com

JimR · 02-01-2005, 06:15 PM

195/55-14 is cheaper than a 205 or 225, and you can get both the Victoracer and Ecsta in 195/55-14. The Victoracer would probably last longer than the softer Ecsta, too.

Just my two cents. I'm of the "it's cheaper to go slower persuasion."

eandrade · 02-02-2005, 09:39 PM

OK...so I placed my order today...225/50-14 ECSTA V700, heat cycled and shaved. The clearance in the back is really tight (less than 1/2" between tire & lower spring perch) so I'm going to get 1/4" spacers. I'm hoping that the rubbing risk is reduced with the tires being an inch smaller diameter than what I have now (205/60-14).

Can't wait!

Thanks for all your help folks.