I realize there are so many suspension variables involved in answering this question... I drive a very stock ITR, with Koni yellows (stock valving).

Over the last few years I've been going ever lower with my track tire pressures. I did a lapping day at NHIS yesterday, and ended the day at 40psi hot all the way around. This seemed to be the best temp for lap times and tire wear.

What do you find works best?

 

38psi cold, 225.45.15 kumho ecsta v700's, on 15x6 wheels here

 

why would you use 40 all around?

 

38 all around?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">38psi cold, 225.45.15 kumho ecsta v700's, on 15x6 wheels here</TD></TR></TABLE>

So, you're running ~48 front/44 rear psi hot?

 

i usually run 34 front 38 rear cold.
195 ecsta supra 712s.

 

Depends on situation.

I used to always run high pressures.

But, after a test and tune in autocross, I found that for 225/45/15 Kumho V700 on 15X7 wheels I like to run 35-38psi front and 33psi rear. (all cold, after run, I bleed down to cold pressures)

After witnessing some setups at ECHC, I think I will try 33psi all around (all cold) at the next HPDE and then adjust pressures as needed, depending on wear patterns on tires.

To sum it up (cold settings) on 225/45/15 Kumho V700 on 15X7 wheels on stock suspension ITR with 5mm spacers in the rear :
autocross: 35-38F/33R
HPDE: 33F&R (testing, I am not sure if these will be good settings.)

 

I've seen guys running 36-38psi hot with v700's.. any hotter and the outer thread blocks started to cup.

 

Cup? Cupping is caused by out of balanced wheels. Probably different terminology were using here.

 

This is on a lightweight EF hatch, but 225/45-15 Kumho Ecsta V700s on 15x7" wheels, with stiff suspension, and 2.5 degrees negative camber in front, and 2 degrees in rear, and for autocross I run 24 psi hot (22 cold) in front, and 28 psi hot (25 cold) in the rear, and I still have not managed to get to the little arrows on the sidewalls.

 

oops...i meant uneven wear.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pcorad &raquo;</TD></TR><TR><TD CLASS="quote">

So, you're running ~48 front/44 rear psi hot?</TD></TR></TABLE>

Honestly have no idea, but probably closer to 43/41 - i was having sidewall rollover with the lower pressures on track.

 

Interesting results people have had.

GRM did a R compound comparison on a ITB prepared Golf a while ago and found that the V700 Victoracer Khumos liked lower tire pressures than the other R compounds tested (Proxes and Hoosiers).

27F and 31R cold temps gave them the best lap times. (Hot temps were RF/34; LF/35; RR/38; LR/39).

I think on stock suspension ITRs we struggle with too little neg camber, and compensate for it by higher tire pressures to siffen the sidewalls to keep the tires from rolling over.

I'm going to keep testing some lower pressures on road courses to see if I can find the "happy" spot.

For road courses I don't see the relevance of cold tire pressures. Yes, you need a baseline for the beginning of the day. But after a lap or two, tires are hot and stay hot while you're on the track. It's the hot tire pressure that becomes relevant.

 

28f/30r cold.

I wish I knew how good the RA-1 was before I tried the V700. Food for thought...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jason Franza &raquo;</TD></TR><TR><TD CLASS="quote">
I wish I knew how good the RA-1 was before I tried the V700. Food for thought...</TD></TR></TABLE>

How good are the RA-1s? Better than the V700s?

 

RA-1's are stickier than Kumhos, but at the cost of longevity. They do provide better feedback, but once you take them over their limits they are VERY slippery. I have a set I race on as backup now, but Hoosier R3S03s are hands down they way to go.

For inexperienced drivers, I'd say go with the Victoracer V700's.

I've run Victoracers for a couple years and started at 30f/31r (around 38f/35r at temp) (I also ran about a half psi lower on the right depending on the track and the weather). And they last forever... comparatively.

In my opinion the ECSTA V700's are total crap. I have tried a couple pressure setups. They tend to heat unevenly and "chunk" the treadblocks. So i refused to run them in the front after awhile and ran them at 30 cold psi in the rear only. After sessions temps were usually about 36psi.

But I agree with earlier comments, Kumho's do like lower pressures than you think...

 

i start my cold pressures low. i have the ecsta 711's. Hot pressures are about 34 front, 35 rear or so. I'm still playing with them. They seem to go up about 4-6 psi after a session. When I've been on track the air temp has only been 60-70 degrees though. We'll see when the ambient air temp goes up.

s

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sa04 &raquo;</TD></TR><TR><TD CLASS="quote">RA-1's are stickier than Kumhos, but at the cost of longevity. They do provide better feedback, but once you take them over their limits they are VERY slippery. I have a set I race on as backup now, but Hoosier R3S03s are hands down they way to go.</TD></TR></TABLE>

LOL, I can't believe you mentioned longevity then recommended Hoosiers. That's too damn funny.

RA-1...best bang for the buck. Fast, lasts, and did I mention fast?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pcorad &raquo;</TD></TR><TR><TD CLASS="quote">How good are the RA-1s? Better than the V700s?</TD></TR></TABLE>

Trust me. I attribute AT LEAST one second per lap to those tires.

The RA-1 is by far, worth the money. You won't regret it.

However, you do have to use the slip angle/slide to go fast.

All that said, I do think the V700 is the better "entrance into the R-compound" world. If you're not used to the "silent" R-compound nature, you could get taken by surprise once the RA-1 heats up.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by George Knighton &raquo;</TD></TR><TR><TD CLASS="quote">But you're using RA-1 now, right? Are you using 205-50 or 225-50?</TD></TR></TABLE>

205, yes.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jason Franza &raquo;</TD></TR><TR><TD CLASS="quote">LOL, I can't believe you mentioned longevity then recommended Hoosiers. That's too damn funny.</TD></TR></TABLE>

I go through about 6 full sets of tires a season. For a beginner, I assume they dont want to purchase that much rubber. I don't do HPDE's or autocross my R, but I use both RA-1s and R3S03s on the racetrack. For HPDE's and lapping days, go Toyo. If you want to "race"... and win, go with Hoosiers. It's all up to you.

RA-1...best bang for the buck. Fast, lasts, and did I mention fast?[/QUOTE]

Yes, but still not as fast as R3S03's.

 

Folks, this is all great information. Even more than I bargined for.

Thanks!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sa04 &raquo;</TD></TR><TR><TD CLASS="quote">Yes, but still not as fast as R3S03's.</TD></TR></TABLE>

To me, .2 seconds per lap is not worth $200 more per set of tires.

 

What are folks paying for Toyo TA1s? I got a quote of $159 in NH.

Who does heat cycling? Toyo? Me?


Modified by pcorad at 2:58 PM 9/12/2003

 

you'd be the one that does the heat cycling.
i'm honestly not a big fan of toyos -- i think there are better tires out there for the money.