Tire Pressure and Temperature Gauges recommended for track use

[Toyarzee]

What temperature and pressure gauges are you guys using at the tracks?

The temperature compensating pressure meters for $500 to $1k is far too much for me. A simple and accurate pressure gauge, analog or digital, should be just fine as I'm not competitively racing where the difference of 0.2 psi at 160° is going to break my session. I also don't trust the non-contact laser/infrared temperature meters for an accurate tire temperature reading.

[strat61caster]

I've always had good luck with Longacre products, they were kind of the go-to for the kart world when I was doing it as a kid and you really only needed a pressure gauge accurate from 5-20 psi or scales with small pads accurate in the 30-200lb range. Might be a little pricey to some but the reliability for many years of hard use is typically well worth the price if you care about such things. I have no experience with their temperature probes but have seen others I don't think are dumb using them.

I think this is the latest model of my current gauge which is about 5 years old now:
http://www.longacreracing.com/produc...+by++%C2%BD+lb

[CSG Mike]

[ame="http://www.amazon.com/Longacre-Accutech-Economy-Pyrometer/dp/B000F1P4SW"]Amazon.com: Longacre Accutech Economy Pyrometer F&C: Automotive[/ame]

That will get the job done, as well as any cheapo tire pressure gauge.

Personally, I don't use a pressure gauge at all; adjustment is done by pyrometer and alignment only.

[renfield90]

So Longacre products are great. I'm using one right now. But their lower end pressure gauges aren't the best.

At Nationals someone ran over my old Longacre gauge in the practice course grid. A couple of friends had a newer but lower end model and I borrowed both to check - they both read the same, but also read ~3psi below what my gauge had been reading.

After Nationals I bought their higher end liquid filled gauge ([ame="http://www.amazon.com/gp/product/B0055EFU8I?psc=1&redirect=true&ref_=oh_aui_detailp age_o04_s00"]Amazon.com: Longacre Liquid Filled 2½" GID Tire Gauge 0-60 by ½ lb - 52002: Automotive[/ame]) and promptly compared it to my friend's same gauge and it was ~3psi higher. It bugs me a bit that Longacre would produce gauges that read differently, but I felt comforted that my older higher end model agreed with my newer higher end model. In the end it doesn't matter too much as long as you know what the correct pressure for your tire is on your gauge, but it does make comparing notes with other people's setup a little tricky.

I don't advise that people eschew the use of tire pressure gauges. Tire pressure is the most important setup item with a tire. Formula 1, Indycar, NASCAR, IMSA, etc. teams all closely monitor and adjust tire pressures with a very high degree of precision (half a psi or less).

[Toyarzee]

Thanks guys.

Follow up question: how do you guys best combat the possible inaccurate readings from the drop in temps after a cool down lap and slow drive back to the pits?

I assume most tires will behave differently, but I'm trying to get a ballpark understanding of proper monitoring now that I've switched from basic summer tires to competition tires... just threw on some NT01's and I'm not logging live data from any tech

[renfield90]

Originally Posted by Toyarzee

Thanks guys.

Follow up question: how do you guys best combat the possible inaccurate readings from the drop in temps after a cool down lap and slow drive back to the pits?

I assume most tires will behave differently, but I'm trying to get a ballpark understanding of proper monitoring now that I've switched from basic summer tires to competition tires... just threw on some NT01's and I'm not logging live data from any tech

You will get very little if any pressure drop driving to the pits after a lapping session. If it bothers you, you could always fill tires with nitrogen or dried air which will reduce temperature-related pressure changes.

[CSG Mike]

Originally Posted by Toyarzee

Thanks guys.

Follow up question: how do you guys best combat the possible inaccurate readings from the drop in temps after a cool down lap and slow drive back to the pits?

I assume most tires will behave differently, but I'm trying to get a ballpark understanding of proper monitoring now that I've switched from basic summer tires to competition tires... just threw on some NT01's and I'm not logging live data from any tech

Temps drop quickly, but pressures do not. If you're using strictly pressure as a guide, a few minutes won't make a significant difference.

[Toyarzee]

Originally Posted by CSG Mike

Temps drop quickly, but pressures do not. If you're using strictly pressure as a guide, a few minutes won't make a significant difference.

Then will tracking my tire temps (inside, middle, outside) after pulling back up to the garage before downgrade meetings actually prove useful for my purposes of monitoring tire wear, alignment, etc.?

[CSG Mike]

Originally Posted by Toyarzee

Then will tracking my tire temps (inside, middle, outside) after pulling back up to the garage before downgrade meetings actually prove useful for my purposes of monitoring tire wear, alignment, etc.?

Absolutely

[strat61caster]

The key is consistency, you don't want to compare measurements between the run you came off and rolled around for 15 minutes to cool the brakes to the run you went directly to your pit and took measurements to the day it was raining.

If you do the same thing every time you can adjust and find the optimum setting for you and the equipment available to you, like the 3 psi difference in the longacre gauges above, if I say I always set at 27 and you set at 30 and we've both verified that changing isn't a benefit then it doesn't matter if the true pressure of our tires is 25 or 35.

Until of course your tools break and you have re-baseline your setup.


As to the importance of pressures vs temps, in the HPDE/amateur sphere, 1-2 psi isn't a game changer vs. tire temps directing alignment, suspension, and driving changes which can have a bigger impact (both positive and negative). NASCAR and F1 already have the other settings dialed in to a high level of refinement, the driving is so skilled that those 1/4 and 1/2 pound air pressure changes can be valuable consistent hundredths or even tenths of a second per lap.

[renfield90]

Originally Posted by strat61caster

As to the importance of pressures vs temps, in the HPDE/amateur sphere, 1-2 psi isn't a game changer vs. tire temps directing alignment, suspension, and driving changes which can have a bigger impact (both positive and negative). NASCAR and F1 already have the other settings dialed in to a high level of refinement, the driving is so skilled that those 1/4 and 1/2 pound air pressure changes can be valuable consistent hundredths or even tenths of a second per lap.

It's a less a question of skill - I'm not a pro, but on certain tires I can detect a change in the balance of the car caused by 1-2psi - and more one of magnitude. Your average street tire is going to want pressures in the 30-45psi range, vs. true slicks which want their pressures around 20psi or sometimes even lower. Longacre will sell you 0-60, 0-30, and even 0-15psi gauges as a result.

When pressure is lower, 0.5psi is suddenly a much larger adjustment in terms of percentage. If you had some hypothetical tire that was inflated to 1psi and you adjusted by 0.5 psi, that's a massive 50% change.

[Toyarzee]

Originally Posted by strat61caster

The key is consistency.

That's my concern. Even if I'm militant about finding a routine where I can get as close as consistent as possible, I'm worried that this elusive issue will cause data collected to be less accurate and useful. Plus at Buttonwillow and some other tracks, a cool down lap and 5 mph lap around the garages will drastically alter my temp readings and I'll find myself only getting good pressure readings.

[Toyarzee]

Also, what source do you guys reference when citing optimal pressure and temperature ranges for different tires? Or is it mostly guess and check, and other drivers input?

[strat61caster]

Originally Posted by renfield90

It's a less a question of skill - I'm not a pro, but on certain tires I can detect a change in the balance of the car caused by 1-2psi - and more one of magnitude. Your average street tire is going to want pressures in the 30-45psi range, vs. true slicks which want their pressures around 20psi or sometimes even lower. Longacre will sell you 0-60, 0-30, and even 0-15psi gauges as a result.

When pressure is lower, 0.5psi is suddenly a much larger adjustment in terms of percentage. If you had some hypothetical tire that was inflated to 1psi and you adjusted by 0.5 psi, that's a massive 50% change.

I never implied that the difference couldn't be felt by an amateur (I know I've felt happy about 1/4 psi adjustments before) but rather that it's of minimal value in the amateur HPDE world vs. other settings that can be manipulated such as camber, toe, spring rate, sway bar, damping, etc. Being "in the ballpark" is usually as good as you need to be.

Originally Posted by Toyarzee

That's my concern. Even if I'm militant about finding a routine where I can get as close as consistent as possible, I'm worried that this elusive issue will cause data collected to be less accurate and useful. Plus at Buttonwillow and some other tracks, a cool down lap and 5 mph lap around the garages will drastically alter my temp readings and I'll find myself only getting good pressure readings.

And that's why people who are good at setting up cars make the big bucks. I always look at it like a divining rod "My current data shows I'm here, I want to go there" i.e. if my fronts are hotter than the rears by 10 degrees I can interpret that as understeer and make adjustments, maybe the next data set the tires are 20 degrees hotter overall and the delta increased to 15 degrees, whatever I did didn't work (or maybe the driver is doing poorly i.e. overworking the fronts under braking, or maybe it did work but other factors contributed to the increase) and you use your divining rod to adjust from there.

Yup some snapshots are dark, some are light, some are hot some are cold, some are 20 feet from the track exit some are 200 feet, the car is the same and so is the driver, if the metaphorical camera is in the same position you can make steps to bring the image into focus.

Originally Posted by Toyarzee

Also, what spurce do you guys reference when citing optimal pressure and temperature ranges for different tires? Or is it mostly guess and check, and other drivers input?

I never found anything other than random forum posts, for instance, contrary to renfields post above from what I've seen the current crop of street tires on an 86 or similar lightweight vehicle like to be sub 30 psi ambient, low 30's when hot, some people have claimed as high as 34 but I find those setups seem to have a big split between tire pressures indicating to me that they're band-aiding a handling problem elsewhere. By the end of last year I was setting my tires at 27 psi in the morning and leaving it alone the rest of the day as the other variables (namely camber and driving) were more valuable to track and tweak for me.

Experimentation (read: guess and check) will always win out in motorsports, build intuition, write down adjustments and results, and use that to guide future guesses. It was a valuable piece of advice as a kid that if you always follow the guidance of someone you will always be a few steps behind them, something unacceptable if you're competing with the guy.