Jump to content
TEAM SHELBY FORUM

Track Day Question


mark.barton

Recommended Posts

For those of you who take your car out for exercise on track days, I have a couple of questions.

 

First, most people recommend raising your tire pressure to 40 psi when you run around the track. If you drive your car to the track like I'm going to, how do you get an accurate pressure when the tires are warm?

 

Second, my car is equipped with the "temporary mobility kit" which includes an air compressor. Does that have enough umph to raise the pressure to 40 psi or do most tracks have air available?

 

I really want to run this car on a track, but I don't want to have a support vehicle to drag a bunch of tools and stuff. What does everyone else do for track days?

 

Mark

Link to comment
Share on other sites

I wouldn't use the mobility kit. I believe it uses the Tire Goo type stuff at the same time and won't give out air alone.

 

 

 

At the track yesterday, a buddy of mine was using one of these that worked really well: http://community.craftsman.com/Craftsman-C3-19-2-volt-Cordless-Inflator-reviews

 

I just set my tires at 34. They could have been higher, as the edges were scrubbing a bit. But meh, I don't like to mess with too much out there in the pits.

Link to comment
Share on other sites

One good solution is to pick up an air tank and fill it on your way to the track. One tankful should get you through the day and then some.

 

Also handy to keep around the garage if you don't have a compressor at home (which I HIGHLY recommend, BTW).

 

Here's a selection from China....er.....Harbor Freight

 

http://www.harborfreight.com/catalogsearch/result?keyword=air+tank

Link to comment
Share on other sites

1. The mobility kit is selectable between tire slime + air or just air. However ...

 

2. +1 on the portable air tank. I always bring mine to the track for track use as well as the drive home.

 

3. The track preparation section in the Boss 302 owner's manual supplement recommends 41 psi hot. Starting out at about at about 35 psi cold gets my tires to 41.

 

4. Taking pressure readings as soon as you can after getting off the track will help you determine the proper starting pressures for the track conditions that day. Pyrometer readings across the tread will help in fine tuning the proper tire pressure also.

Link to comment
Share on other sites

1. The mobility kit is selectable between tire slime + air or just air. However ...

 

2. +1 on the portable air tank. I always bring mine to the track for track use as well as the drive home.

 

3. The track preparation section in the Boss 302 owner's manual supplement recommends 41 psi hot. Starting out at about at about 35 psi cold gets my tires to 41.

 

4. Taking pressure readings as soon as you can after getting off the track will help you determine the proper starting pressures for the track conditions that day. Pyrometer readings across the tread will help in fine tuning the proper tire pressure also.

 

 

The portable air tank sound like it is the way to go. It's a lot easier to lift the air tank out of the trunk than unpacking the mobility kit. I also plan on purchasing a quality air pressure gauge for checking tire pressures at the track and maybe a pyrometer.

 

Thanks for the pressure info from the Boss 302 owners supplement. The GT500 owners manual and supplement doesn't list anything other than the cold pressures.

Link to comment
Share on other sites

Late to the party as usual- but this is the pump I purchased and used this past year- it's very quiet and effecient

They also carry a high quality tire gauge

 

http://www.griotsgarage.com/product/12+volt+air+compressor.do?sortby=ourPicks

 

http://www.griotsgarage.com/product/racing+tire+gauge+with+bleeder+valve.do?sortby=ourPicks

 

 

----------

Link to comment
Share on other sites

40 psi is the upper limit that I run my tires at the track. That's a hot tire pressure. If I start out at 35, I'm at 40 after several laps. I use several methods to determine the correct pressure, in addition to how the car feels. One is the pyrometer that dig mentioned. Those readings can be somewhat misleading at times depending on alignment settings. The other method I use is to chalk the tire sidewall. If you apply some chalk to the edge of the tire beyond the tread, you can tell how far the tire is rolling over. That can help you determine alignment settings also. There can be considerable differences with pressure and alignment settings between different brands and types of tires. Nitto vs Goodyear for example.

Link to comment
Share on other sites

All of this information is very valuable.

 

The easiest thing to do is the most important on the track. Your tire pressure, the tire is your contact point between your suspension (and the seat of your pants) and traction.

 

I can usually tell very quickly if the tire pressure is incorrect, Your car will talk to you around the track, listen to the clues, screeching tires does not always say that you are going as fast as the car can go through a corner, too little tire pressure will wipe out a set of tires very quickly. Newer style tires with low profile need higher pressure. At least 40 to 42 pounds should do it HOT after you leave the track.

 

You spend the money for the track, took the time to go to the track, so take the time to set your tire pressure for maximum enjoyment. (Good question BTW).

Link to comment
Share on other sites

All of this information is very valuable.

 

The easiest thing to do is the most important on the track. Your tire pressure, the tire is your contact point between your suspension (and the seat of your pants) and traction.

 

I can usually tell very quickly if the tire pressure is incorrect, Your car will talk to you around the track, listen to the clues, screeching tires does not always say that you are going as fast as the car can go through a corner, too little tire pressure will wipe out a set of tires very quickly. Newer style tires with low profile need higher pressure. At least 40 to 42 pounds should do it HOT after you leave the track.

 

You spend the money for the track, took the time to go to the track, so take the time to set your tire pressure for maximum enjoyment. (Good question BTW).

 

 

I absolutely agree, low tire pressure means trashed tires and maybe a trashed car. I have seen recommendations for say autocross where you need to start your tire pressure at 40 psi cold because of the nature of the course (no tire warm up, low speed, etc.), but I have not really read what people do on a "real" road course.

.

So, 35 psi cold, 40 to 42 psi Hot, check pressures as soon as practical after leaving the track. Adjust pressures based on the butt test :shift:

Link to comment
Share on other sites

Let me float this idea here (courtesy of my TTOD autocrosser and very, very technically minded son-in-law):

 

Just about every performance tire I have seen has some marks cast into the rubber of the sidewall somewhere near the edge of the deepest cuts in the tread pattern where it fades into the sidewall. My SIL always runs out and inspects my tires to see how close the tread scrubs approach those markings. He says the marks are there for a reason: if the scrubbing is far, far away from the marks, the pressure is too high, and the tire is not coming close to its potential. If the scrubs are up to the marks, the pressure is likely right and/or the tire is operating close to its potential. If the marks are scrubbed off, the tire is too soft and the tire is well below its potential and could be dangerously under-inflated. All this is in the area of "rough use", that is to say, going as fast as can be done while maintaining control.

 

I know from checking my own tires after autocrosses and a track day, that what SIL says seems to be generally true. Can anyone contribute to the data pool? Could this be a myth? Any tire engineers out there?

Link to comment
Share on other sites

Frank S. Those marks are one of the things I was referring to about chalking the tire sidewall. If you chalk the sidewall, you can easily see how far the tire is rolling over and if it's hitting the marks. I usually run less pressure in my rear tires than my front.

Link to comment
Share on other sites

Let me float this idea here (courtesy of my TTOD autocrosser and very, very technically minded son-in-law):

 

Just about every performance tire I have seen has some marks cast into the rubber of the sidewall somewhere near the edge of the deepest cuts in the tread pattern where it fades into the sidewall. My SIL always runs out and inspects my tires to see how close the tread scrubs approach those markings. He says the marks are there for a reason: if the scrubbing is far, far away from the marks, the pressure is too high, and the tire is not coming close to its potential. If the scrubs are up to the marks, the pressure is likely right and/or the tire is operating close to its potential. If the marks are scrubbed off, the tire is too soft and the tire is well below its potential and could be dangerously under-inflated. All this is in the area of "rough use", that is to say, going as fast as can be done while maintaining control.

 

I know from checking my own tires after autocrosses and a track day, that what SIL says seems to be generally true. Can anyone contribute to the data pool? Could this be a myth? Any tire engineers out there?

 

Those marks are the sidewall markings for the treadwear indicator locations in the tread. At SEMA this year my friend and I spoke to a number of performance tire reps and each one repeated the same thing about the marks.

My friend had been using those marks on his Nitto NT01’s for years. The Nitto guy said it was just a coincidence on that model tire that the arrows could also be used for tire rollover. He said on most passenger tires the little arrows are too far away from the tread to be of use as a rollover indicator.

 

As for air:

Nearly every track has air available on site, so purchasing a tank or compressor for a first timer is superfluous. Besides, you get to meet new folks at the track when asking around for a place to get air.

Another method is to slightly over inflate the tires before leaving home, then bleed off what isn’t required after the first session.

A good tire gauge with a bleed valve is a must, a portable air source not so much.

Link to comment
Share on other sites

Those marks are the sidewall markings for the treadwear indicator locations in the tread. At SEMA this year my friend and I spoke to a number of performance tire reps and each one repeated the same thing about the marks.

My friend had been using those marks on his Nitto NT01’s for years. The Nitto guy said it was just a coincidence on that model tire that the arrows could also be used for tire rollover. He said on most passenger tires the little arrows are too far away from the tread to be of use as a rollover indicator.

 

As for air:

Nearly every track has air available on site, so purchasing a tank or compressor for a first timer is superfluous. Besides, you get to meet new folks at the track when asking around for a place to get air.

Another method is to slightly over inflate the tires before leaving home, then bleed off what isn’t required after the first session.

A good tire gauge with a bleed valve is a must, a portable air source not so much.

 

 

Having never been to a track day, I wasn't sure if tracks had air available for the regular folk. Heck, I can't even get free air at a gas station anymore, so I assumed it probably would not be available at a track. (I can just see it now, walking over to someone and saying: Hi, my name is Mark. I'm new to this track day thing. Would mind loaning me a couple of pounds of air for a few hours? I promise I'll return when I'm done with it.)

Link to comment
Share on other sites

Here is what I started with when I first took my 2007 SGT out to the Track...

 

http://www.tirerack....e.jsp?techid=58

 

Good Luck!

 

EDIT = I have printed this out and keep a copy of it with me in my tool box...

 

 

Thanks Gregg. That is really good information to have. I see that the chart is for D.O.T competition tires, but it should be fairly accurate for high performance street tires as a place to start, right?

 

PS. You've been to Heartland Park, do they have air available?

Link to comment
Share on other sites

Thanks Gregg. That is really good information to have. I see that the chart is for D.O.T competition tires, but it should be fairly accurate for high performance street tires as a place to start, right?

 

PS. You've been to Heartland Park, do they have air available?

 

 

It is a good place to start... And, YES, it is a chart for DOT Comp Tires... But once you "track" your car a couple of times, you will figure out what works best for you, your car and the brand of tires you are using...

 

Pretty sure HPT has Air available at the Tech Station... Also has weigh scales available and 100 Octane Unleaded Race Fuel if you want :shift:

 

Really good group of drivers who turn out monthly for the $100 / session Touring Club Events on Wednesday Nights (May thru Oct)...

 

http://www.hpt.com/index.php?option=com_content&view=article&id=201&Itemid=234

 

I usually try to make it during the Spring and Fall, as the Summer months are just to hot and windy for me to have any "fun" at the track...

 

The picture in my Signature Block was taken just exiting the Chicane on the Back Straight... Wooohooo!!!

Link to comment
Share on other sites

It is a good place to start... And, YES, it is a chart for DOT Comp Tires... But once you "track" your car a couple of times, you will figure out what works best for you, your car and the brand of tires you are using...

 

Pretty sure HPT has Air available at the Tech Station... Also has weigh scales available and 100 Octane Unleaded Race Fuel if you want :shift:

 

Really good group of drivers who turn out monthly for the $100 / session Touring Club Events on Wednesday Nights (May thru Oct)...

 

http://www.hpt.com/i...=201&Itemid=234

 

I usually try to make it during the Spring and Fall, as the Summer months are just to hot and windy for me to have any "fun" at the track...

 

The picture in my Signature Block was taken just exiting the Chicane on the Back Straight... Wooohooo!!!

 

May. I have to wait until May? AAaaaaaaaaaaaaagh..............

 

Very, very cool picture by the way

 

I should add that it's Kansas, it's always something and windy.

Link to comment
Share on other sites

May. I have to wait until May? AAaaaaaaaaaaaaagh..............

 

Very, very cool picture by the way

 

I should add that it's Kansas, it's always something and windy.

 

 

Depending on when they post the actual schedule, there is a chance that the 1st event could be at the end of April... A lot depends on the weather and the ambient temps... But for the $100, it is definitely $$$ worth spending... Just be prepared to go thru a set of tires and brakes a lot "faster" than normal...

Link to comment
Share on other sites

Depending on when they post the actual schedule, there is a chance that the 1st event could be at the end of April... A lot depends on the weather and the ambient temps... But for the $100, it is definitely $$$ worth spending... Just be prepared to go thru a set of tires and brakes a lot "faster" than normal...

 

 

Well, if that's the price I have to pay (tires and brakes that is) I believe it's worth it. As someone on these forums had in their signature: smiles per mile.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...
...