THSCC Forums

while i am sure i was not the only one with issues regarding traction i was curious if others had as severe issue as i feel i did.

my car was both tail happy and pushed like a dumptruck in the same run. the suspension set-up is way better than stock so i am ruling that out.

the tires are michelin pilot sports and i am running 225/50/16 's at around 30psi cold. i am running low pressure because i have found higher pressure is not good on track for traction. but this is autoX.

i am campaigning in TIR this season so RRR's are not an option. the rears are new & the fronts are worn to 3/32" approx.

i have a set of 451's i use for rain on track. 245/45/16's. anybody want to buy some michelins?

I was quite surprised at the grip levels on Sunday. The Miata never pushed with Aaron or I. It would get loose only if you "hacked" it up.

You sure you werent asking too much from the equipment? 30psi on street tires is insane

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02 Focus SVT
STF 9

i autox like i used to play golf. "hack away" thus the reason for my post.

Insane high or low? I ran 42/37 nearly all last year in the Falken 451s. I had rear grip issues yesterday at the same pressures. Generally I feel Sanford is pretty grippy. I was suprised that I had more grip on the coated sections and one section of the regular asphalt (slalom right after the turn around) seemed particulary slick to me (part that was not coated).

Overall, I put on a show. It looked like I had just got back from the Randy Melton driving school. Right before my first run, I discovered that I had a torn outer CV boot and all of my grease had dumped out all of the wheel well, etc. The CVs were not clicking, so I figured I could do the morning runs and then go home to work on the CVs. Anyhow, I spun/was sideways at least once on each morning run. Not pretty to watch.

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Richard Casto
1972 Porsche 914
2013 Honda Fit Sport
2015 Honda Fit EX
http://motorsport.zyyz.com
Money can't buy happiness, but somehow it's more comfortable to cry in a Porsche than a Kia.

LOW!

That's R compound territory.

I'd wager that 30 psi is lower than most people at the event with R comps were running.

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02 Focus SVT
STF 9

I never got the car to work as well as last time I drove there on the same tires.... Not sure exactly why. Probably a combination of things -- V710s have about 70 runs on them now, and they were just flipped. I also experimented with pressure from about 32-38 front and rear and never found a sweet spot. Oh and I was also driving like a hack, but that's the only way to make the car go stupid fast.

Sorry, I'm not much help except to say that in my experience Sanford grip has always seemed to be black magic to me. Good one event for me and bad the next with no "real" changes in the car. I guess that's something I need to work on!

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Mike Whitney
whit32@gmail.com, 919-454-5445
V10, V8, V8t, I6, I6, V6, F4t, I4, I4, I4, I4, I2, 1, 1

That is some low pressures on street tires. I run 32/30 on the V710's. I can go maybe 2 pounds lower at most.

The grip yesterday was not that bad. Yes, you had to get everything started a lot earlier on the sealer, the braking and the turning. A little too late and you paid for it dearly.

I had a lot of issues with the last chicago box. I thought it was the grip. Come to think about it, it was probably the lack of front brakes

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Jim Pastorius
2008 Silverado VortecMax
1992 Camaro CMC#92
2002 BMW R1150R

2009 3rd Place CMC Mid-Atlantic Championship
2009 CMC Hyperfest Winner

What do you normally run in the miata on the street Ryan? I am on my fourth set of azenis and I have always run them at 28 all round.

When I ran street tire class with the S2000, I started the season running 35/32 (F/R), but by the end of the season I had moved down to 32/28.

i was running 35psi all around on rt615 azenis and was happy. the car stayed put really well through out the day. of course the black stuff was slick and i really had to slow down for it, but all in all i was happy w/ my tires. some novices commented on how 'uneventful' my runs looks. thats good news to me

the only time i got squirrely really all day was being stupid in the bracket race w/ hot tires (i had 4 runs almost all in a row and im sure the pressures were super high).

in short, id try a little more air. youre probably in the Q5 region of the traction/pressure bell curve

On my Sumitomo's I run about 35 all around

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02 Focus SVT
STF 9

That's too high on a Miata for any street tire. Back 'em down to about 28psi.

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Vincent Keene
'06 Ford Mustang GT (track rat)
'15 Dodge Charger R/T (yeah, it's got a HEMI!)
'07 Ford Fusion SE (205,000 miles and counting)
'98 Chevy Z-24 (retired)
'93 Acura Integra (Team SWB 24HOL Car)

As a fellow STS driver, I was quite happy with your performance Richard . Thanks for making my day easier, and BTW, I was watching your nice 270 spin right after the P and entering the slalom. Nice move on backing over the cone to take the cone penalty and not a DNF.

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Rodney

'08 Bullitt mustang, CAM 7
Autox VP '09-'10, President '11-'12, interim President 2nd half of ‘14
proud recipient of the Bowie Grey service award '12
Now just a guy driving a mustang....

I run low pressures -- on any tire I run really. But on the z06 w/ 710s I run 31/29

On street tires I also run low pressures, especially on low grip/cold days. I wouldn't say 30psi on well worn street tires is too low. It really depends on what the car is telling you though. I am a huge advocate of making drastic changes to see what works. Try one run at 40/40psi... then drop the rears 5psi for the next run. Then drop the fronts. etc. Keep playing until the car tells you that you are close by being fairly well balanced. Remember, if the times are faster, it doesn't matter what it feels like (nor what others tell you). Find whats fast, not what feels good.

of course, at Sanford it is pretty easy to get push in one spot then loose in the other, with the variety of surface treatments in one run.

BTW, I found the grip to be better than expected yesterday. I had heard horror stories of a slippery surface where RRRs aren't that much of an advantage. But, yesterday the RRRs were a definate advantage and worked rather well.

adamb

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Adam Breakey
Founder - www.autocrossforum.com
SS 75 Red(isfasterthanyellow) Z06

Yeah, I sucked on all of my runs. On that spin I think I was getting it into reverse just as I came to a stop to avoid the DNF. On one spin (may have been that same one) I was trying to power out of it, but I think that without a LSD I was only spinning one of the front wheels and couldn’t get it to pull the car forward.

I actually really enjoy courses like that. I love driving offset style elements, but it actually brings out a bad habit of mine (braking late and turning at same time) and that aggravates a bad handling trait of my car (snap oversteer when the rear is unloaded).

Overall, it was fun, but not what I had intended to do from a driving point of view. I really wish I could have stayed and gotten at least a single clean run to see what my time would have been. Other than spinning so often, I felt that each run felt pretty quick. After all of the mistakes in the morning, I felt I might have been able to know exactly where to back it down a notch or two.

Who ended up winning STS?

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Richard Casto
1972 Porsche 914
2013 Honda Fit Sport
2015 Honda Fit EX
http://motorsport.zyyz.com
Money can't buy happiness, but somehow it's more comfortable to cry in a Porsche than a Kia.