Tire Pressures for AutoX

danegrey · 10-20-2011, 09:23 PM

Going to run an AutoX this weekend, was wondering what tire pressures should be for Front/Rear, car is 2012 370z coupe with sports package

Thanks for any info.

wh1te370z · 10-21-2011, 09:21 AM

what type of tires are you running? Stock?

Road racing i know you want them at around F/R 32/30 HOT but thats on slicks and road racing. someone else will chime in with a better idea for ya

svmtbman · 10-21-2011, 10:39 AM

This is a good question, I'm most interested in hearing thoughts on running stock tires with a nitrogen fill at stock pressure.

wstar · 10-21-2011, 11:26 AM

You'll hear some good rough guidelines, but the bottom line is you'll get the best exact reference by looking at your own tires after a run. I'm still new at this as well, but my understanding of the very basics is (someone please correct me if I've gotten something backwards):

1) Look at the edge of the wear pattern after a run. If it looks like on corners you're wearing on part of the tire that's past the edge (there's a marker on the tire for where the true edge is), you need to increase pressure to prevent the tire from rolling over so much. Similarly, if you seem to be not using enough of the edge, you can drop pressure a bit to gain more grip.

2) Check tire temperatures across the width (e.g. near each edge, and in the center). They make proper tire pyrometers for this that use a thumbtack-type sensor you stick into the rubber, but you can also use a regular infrared thermometer to roughly do the same thing. You want reasonably even temperatures across the surface. If the edges aren't as hot as the middle, drop pressure to flatten the tire out a bit more.

Red__Zed · 10-21-2011, 11:42 AM

^yep. I like using chalk on the sidewall to check rollover as well.

Fastech · 10-21-2011, 01:09 PM

Ballpark start at 38 or so psi and look at how far the tire rolls following every run. That should be a good close start! YMMV...

Don Velocity · 10-21-2011, 08:39 PM

I'd suggest 40 ft, 34 rear. It worked for me on road courses. Stock tires, 19" sport package, stock suspension & alignment.

SeattleLion · 10-28-2011, 03:57 PM

I've been running 42 all around. Stock tires sport package. That's what my coach suggested.

danegrey · 10-28-2011, 06:45 PM

ended up running 40 front and 36 rear, we were in the middle of the group, not bad, it was more of a chance to see how the car did. My son and I both drove the car and he bested me by .146

How were your times compare to others at 42 all around.

SeattleLion · 10-29-2011, 01:32 PM

Quote:

Originally Posted by danegrey

ended up running 40 front and 36 rear, we were in the middle of the group, not bad, it was more of a chance to see how the car did. My son and I both drove the car and he bested me by .146

How were your times compare to others at 42 all around.

I'm not good enough to claim time changes. My coach did drive my car and we stuck like glue around Pacific Raceways.

axio · 11-14-2011, 06:30 PM

your temps, is that measured hot or cold? I'm going on my first track event in a month and would like to know... I'm running stock tires on sport package rims as well.

also, wstar, good tips on the infrared thermometer to check temps on the edges vs the middle, i'll have to bring mine along!

wstar · 11-14-2011, 08:00 PM

Probably the guys talking about high 30's to low 40's are talking about hot temps. Cold temps would be significantly lower, and are also less consistent to adjust by. You're better off making your adjustments right after you come off the track: check temps or chalk wear indicators, check pressure differentials, and even out the pressures while hot, dropping or adding a few PSI as necc to get the best use of the tire surface by temperature/chalk.

cossie1600 · 11-15-2011, 12:02 PM

no, you set it before you go out

SPOHN · 11-15-2011, 06:33 PM

Can someone elibrate on what your looking for such as tire temps across the tire and using chalk methods?

VQStryker · 11-15-2011, 07:41 PM

Quote:

Originally Posted by wstar

You'll hear some good rough guidelines, but the bottom line is you'll get the best exact reference by looking at your own tires after a run. I'm still new at this as well, but my understanding of the very basics is (someone please correct me if I've gotten something backwards):

1) Look at the edge of the wear pattern after a run. If it looks like on corners you're wearing on part of the tire that's past the edge (there's a marker on the tire for where the true edge is), you need to increase pressure to prevent the tire from rolling over so much. Similarly, if you seem to be not using enough of the edge, you can drop pressure a bit to gain more grip.

2) Check tire temperatures across the width (e.g. near each edge, and in the center). They make proper tire pyrometers for this that use a thumbtack-type sensor you stick into the rubber, but you can also use a regular infrared thermometer to roughly do the same thing. You want reasonably even temperatures across the surface. If the edges aren't as hot as the middle, drop pressure to flatten the tire out a bit more.

^^^What I do

usually at 40-42psi front and 36-38psi rear for me.

Also deals with the tire itself too, won't be the same for everyone.

10-20-2011, 09:23 PM	#1 (permalink)
danegrey A True Z Fanatic Join Date: Oct 2011 Location: Knoxville Age: 71 Posts: 3,190 Drives: 12 370Z BK Cherry M6 Rep Power: 649540	Tire Pressures for AutoX Going to run an AutoX this weekend, was wondering what tire pressures should be for Front/Rear, car is 2012 370z coupe with sports package Thanks for any info.

10-21-2011, 09:21 AM	#2 (permalink)
wh1te370z Track Member Join Date: Jul 2010 Location: New York, Long Island Posts: 559 Drives: PW Base Sport 6 Spd Rep Power: 16	what type of tires are you running? Stock? Road racing i know you want them at around F/R 32/30 HOT but thats on slicks and road racing. someone else will chime in with a better idea for ya __________________ 1998 BMW 328is... Track Build 2010 White 370z.... sold

10-21-2011, 10:39 AM	#3 (permalink)
svmtbman Base Member Join Date: Mar 2011 Location: Macon, GA Age: 53 Posts: 219 Drives: 2011 370Z PW M6 Rep Power: 14	This is a good question, I'm most interested in hearing thoughts on running stock tires with a nitrogen fill at stock pressure. __________________ 2011 Pearl White, Persimmon, Touring, Sport, Navigation, 6sp - PW JDM shift knob, Invidia Gemini CBE, aFe dry filters, HPS intake tubes, JDM fog light, Redline shift boot, LED interior lights, Z1 hood struts, and 30% tint.

10-21-2011, 11:26 AM	#4 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	You'll hear some good rough guidelines, but the bottom line is you'll get the best exact reference by looking at your own tires after a run. I'm still new at this as well, but my understanding of the very basics is (someone please correct me if I've gotten something backwards): 1) Look at the edge of the wear pattern after a run. If it looks like on corners you're wearing on part of the tire that's past the edge (there's a marker on the tire for where the true edge is), you need to increase pressure to prevent the tire from rolling over so much. Similarly, if you seem to be not using enough of the edge, you can drop pressure a bit to gain more grip. 2) Check tire temperatures across the width (e.g. near each edge, and in the center). They make proper tire pyrometers for this that use a thumbtack-type sensor you stick into the rubber, but you can also use a regular infrared thermometer to roughly do the same thing. You want reasonably even temperatures across the surface. If the edges aren't as hot as the middle, drop pressure to flatten the tire out a bit more. __________________ 7AT Track Car! Journal thread / Car setup details

10-21-2011, 01:09 PM	#6 (permalink)
Fastech Base Member Join Date: Aug 2011 Location: Chattanooga Posts: 27 Drives: 09 370Z Sport PG MT6 Rep Power: 14	Ballpark start at 38 or so psi and look at how far the tire rolls following every run. That should be a good close start! YMMV... __________________ Brian Flanagan 09 Base/Sport 6MT Future SCCA/NASA Weapon!

10-21-2011, 11:42 AM	#5 (permalink)
Red__Zed A True Z Fanatic Join Date: Jul 2010 Location: window seat Posts: 28,940 Drives: Mostly on two wheels Rep Power: 120	^yep. I like using chalk on the sidewall to check rollover as well.

10-21-2011, 08:39 PM	#7 (permalink)
Don Velocity Base Member Join Date: May 2010 Location: Cleveland, OH Posts: 10 Drives: 09 370Z White Sport Rep Power: 15	I'd suggest 40 ft, 34 rear. It worked for me on road courses. Stock tires, 19" sport package, stock suspension & alignment.

10-28-2011, 03:57 PM	#8 (permalink)
SeattleLion Base Member Join Date: Sep 2010 Location: Seattle WA Posts: 226 Drives: '13 Mustang GT Prem. Rep Power: 234	I've been running 42 all around. Stock tires sport package. That's what my coach suggested.

10-28-2011, 06:45 PM	#9 (permalink)
danegrey A True Z Fanatic Join Date: Oct 2011 Location: Knoxville Age: 71 Posts: 3,190 Drives: 12 370Z BK Cherry M6 Rep Power: 649540	ended up running 40 front and 36 rear, we were in the middle of the group, not bad, it was more of a chance to see how the car did. My son and I both drove the car and he bested me by .146 How were your times compare to others at 42 all around.

11-14-2011, 06:30 PM	#11 (permalink)
axio Enthusiast Member Join Date: Jan 2009 Location: SF Bay Area, CA Posts: 271 Drives: '09 370Z Rep Power: 16	your temps, is that measured hot or cold? I'm going on my first track event in a month and would like to know... I'm running stock tires on sport package rims as well. also, wstar, good tips on the infrared thermometer to check temps on the edges vs the middle, i'll have to bring mine along!

11-14-2011, 08:00 PM	#12 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Probably the guys talking about high 30's to low 40's are talking about hot temps. Cold temps would be significantly lower, and are also less consistent to adjust by. You're better off making your adjustments right after you come off the track: check temps or chalk wear indicators, check pressure differentials, and even out the pressures while hot, dropping or adding a few PSI as necc to get the best use of the tire surface by temperature/chalk. __________________ 7AT Track Car! Journal thread / Car setup details

11-15-2011, 12:02 PM	#13 (permalink)
cossie1600 A True Z Fanatic Join Date: Jun 2009 Location: californee way Posts: 5,380 Drives: 370, Leaf Rep Power: 30	no, you set it before you go out

11-15-2011, 06:33 PM	#14 (permalink)
SPOHN A True Z Fanatic Join Date: Feb 2010 Location: Covington, GA Age: 46 Posts: 14,844 Drives: Waiting on next Z Rep Power: 221	Can someone elibrate on what your looking for such as tire temps across the tire and using chalk methods? __________________

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