Tire Gauge and Pyrometer

[Sandro]

I need to get a better Tire Pressure Gauge and a Pyrometer. What do you guys recommend, will a $30 0-60psi Longacre or Intercomp gauge do a good enough job or while Im spending the money should I upgrade to a little better and go with a 2.5 or 3 inch? Am I corect in sayng the bigger the gauge face the more accurate it usually is?
What about liquid filled? or are the built in dampeners good enough?
Also any preference over brands


Then for pyrometers the only reasonably priced one I have seen is the Longacre for about $100.

Will that do the job or have I missed one somewhere? The ones that record all 12 temps are great but for an extra $200 I can buy tons of pens and paper.

Thanks in advance.

[924Guy]

I was happy with my basic $30 Longacre pressure gauge, till I dropped it too many times and it lost its accuracy. Get a case and look after it! I've replaced mine with the more expensive Longacre digital one, about $140.

Pyrometer - you are talking about the contact/probe-type, right? I've been quite happy with mine, no memory capability. Of course, I'm never the one taking measurements, but my crew chief hasn't bitched me out about buying it! LOL One tip I'll share - get an inexpensive digital voice recorder! My crew chief clips one to his collar and uses it to record temps - one-man operation. Just always take them in the same order, of course. Been quite happy with it.

[Greg Amy]

These are probably the two most important tools for at-track chassis setup. Thus, don't skimp. Spend the money for the good, repeatable stuff and you won't regret it.

And, instead of a cheap pyro and a voice recorder, spend the money on the LCD-screen recording pyrometer. That way you can take the temps faster (very important) and won't have to write them down, say them into a recorder (like you have a fourth or fifth hand in addition to the ones juggling the tire gauge, tire pyrometer, pen and pad) and you won't have to worry about typos, smudged handwriting translation, or "did I mean left-rear wheel outer, of left-outer wheel rear, or...?"

Buy the good stuff. It's worth it.

[charrbq]

Do what Greg said. If not going for the voice recording, get one that at least records in LED fashion each of the temps on all four tires. It's fine to use a "scribe" to record all your readings, and two guys taking temps and pressures, but when the scribe has to deal with two people giving him numbers, plus extra curricular input from track events, you can end up with a mess of missed numbers.

I've tried liquid tire guages before. They have the advantage of shock proofing, and are supposed to be more accurate, but the one I used was SLOW to respond. Get a good one, put it in a seperate case from the rest of your tools, take care of it, and it will last a long time. Even still, it's not a bad idea to replace it every few years. They do loose calibration eventually. It's also a good idea to get a larger face to see on the fly, and to get one that's precise. Two pound increments don't cut it if you're serious. It can also be a good idea to get one with a swivel chuck and/or a luminous dial. I never thought about either until I tried twisting the hose to fit the valve and my eyes. Also, on a cloudy day, the luminous dial can really help old tired eyes full of wind.

[924Guy]

I think you misunderstood, Greg. The voice recorder takes the place of writing the numbers down. The readings are called out as they're taken, but no second crewmember is needed for scribing. It's a one-man show, he's only holding the pyrometer. We do our tire pressures back at our paddock spot (only 50-100' from the pit lane), so that isn't a concern, but tire pressures could easily be done the same way if desired in the pit lane. He then has time to go back after the fact, in the paddock when everything's cooled down, to write everything down - even replay the temps if needed. Takes no longer in the pit lane than a memory pyrometer.

[charrbq]

No, I understood Greg. I was only offering alternatives. Not all tracks have immediate access to the paddock where pressures and temps can be immediately recorded. Both start dropping rapidly as soon as the car hits the pit lane. The tire guys will tell you that.

[RSTPerformance]

You learn something new everyday.... I love that idea of recording the temps!!!

Let me tell you, we love our crew to death, but it is unbeleiveably fustrating to have someone write down the temps and after getting back to the paddock 10 minutes later question if they wrote them down in the correct order.

If they wrote them down correctly then the outside temp should be about 10-20 degrees less than the inside temp (typical for us dependind on the track). If the crew writes them backwards then the temps will show the inside as being cooler. That is not what we want so we would want to increase camber, but might not as we are not confident that the numbers are in the correct order.

End result, no changes to the car can be made, we have wasted "a" session we have no way to "re-test" the car to make any adjustments, and we are not confident that we are giving it our 100% effort.

It generally doesn't happen, but it has. Thanks for the great idea!!!

Raymond

[gran racing]

These are probably the two most important tools for at-track chassis setup. [/b]

Is this really the case? I'm not sure. I'll go along with tire pressures, but still am not sold on the pyrometer (for sprint races with the types of cars we're running). Since I wasn't racing much this past year, I spent it doing some research. I've spoken with some very exprienced people (Hoosier tire, a couple GrandAm / ex-IT guys, and a few others) and they've steered me away from relying on a pyrometer. I'm not saying there isn't value to it, but I wonder if too much emphasis is place on it? I then quickly turn to Carroll Smith's book "Drive to Win" (page 2-16) where he states that he doesn't use a pyrometer much and how he reads the tires.

[Greg Amy]

Oooookay, whatever...

Let's just say I wouldn't bother to do a test day, practice session, or qualifying session (well, certainly not a test day) without both... - GA

[RSTPerformance]

Tire Tempatures are not valuable if you don't know what they mean, or how to use them. But if you do know how to use them to learn something about the cars handling then they are very valuable... For example, how else would you determine the correct camber settings?

Camber is probably one of the most important parts of our cars setup. And sure I will say that the tempatures you get on one car could be completely different from one to another, and that they could be different on the same car with different drivers. It takes a team and a good driver whom can analyze the data and figure out what adjustments to make.

Also thinking a bit here, dave, those people who say that it is not valuable may say this because they get the "correct" or optimal settings from someone else who has done the testing (easy to do for a spec class or similar cars). Then they just set it and forget it for each track. The problem is that if you want to win you need to get every inch of perfectness, and every day something is different.

I may be wrong, and I will admit to anyone who can give me some better advice... please educate me I need to get faster!!!

Raymond

[Andy Bettencourt]

I agree 100% with Greg. How the heck are you going to set your tire pressures without a pyrometer? How do you know what camber allows the most contact patch without a pyrometer? Too much spring can be detected in tire temps front-to-rear. It's a multi-functional tool.

I have tweaked as little as .5 pound of tire pressure on one tire to get to an 'optimal' track-specific set up. I see NO WAY you can set up a car properly without a pyrometer. NO WAY.

[charrbq]

The more quality, reliable tools you have that can provide you valuable information, the more you know and learn by the elimination of unknown variables. Tire pressures and pyrometer readings provide a wealth of information about such things as alignment, compounds, track surface, driving style, spring rates, and a myriad of other things.

[gran racing]

Drive to Win
The Essential Guide to Race Driving
by Carroll Smith

(A very interesting read by the way!)

Page 2-16

"Reading The Tires"
There are two methods of 'reading' the tires in order to optimize their performance. The first (and most common) is by use of a pyrometer to measure the temperature profile across the thread surface. I have already pointed out the folly of trying to achieve even temperature distribution - but there is another reason why I don't use a pyrometer much.

The speed of change of a racing tire's tread temperature with load has to be seen (either real time or data logging) to be believed. For an indication watch the color change on the in-car cameras from acceleration to braking to cornering to acceleration. What we read in the pits is a not very acurate evidence of what the temperature was during the last load cycle before the car stopped.

I don't use a pyrometer very much except as a warning that I may be geting near the compound limit or that I have an oversteer/understeer imbalance....

I spend a lot of time looking at the surface of my tires."

He then goes on to explain how this is done in his book.

When speaking with Hoosier, we talked about the tires, length of races / sessions, compound, and a bunch of other stuff. I have to say that much of the conversation was waaaaaay over my head but got the general rationale for our application / tires / events. I will also admit that using a pyrometer to many people (including myself at first) is easier to digest and grasp.

Open your mind a bit, take some time and give it some thought. Maybe afterwards, you continue think that anyone else who doesn't use a pyrometer to tune the car is just plain foolish. Since I'm so new to the whole tuning side of racing (this has been a big weak spot for me before), I'm willing to look at things differently than you and using a pyrometer isn't the gospel. A few things things that pop into my head: When a car is coming into the pit, what is impacting the tire pressures? Is it giving a good reading of the entire track or just a section? What is happening in that section? Using the theory Carroll Smith and some others use, how does that contrast with using a pyrometer? If you're using brake ducting, how does that impact the tire temps. and the adjustments being made? What happens if that ducting were taken off or put in another location?

I'll also say that using a pyrometer is much better than what I've been doing in the past - nothing.

[924Guy]

Yes, we do take our tire temps in the pits using the aforementioned procedure, just like everyone else. The only way to get more accurate tire temp data is to wire some IR temp sensors into my data system, not going there yet!

IMO it takes a lot of practice and data to begin to understand and really tune with tire temps - just like Raymond said, they can vary so much due to other conditions, you really need to have a handle on all those other factors and know when you just have to throw away the data, whether you want to or not.

So IMO you should take all the data, and study it, because eventually you will start to make sense of it, and then you'll be able to dial in that last tenth or two.

[Andy Bettencourt]

The key to good tire temps is to come in on a hot lap and pit RIGHT AWAY. You take the temps of the tires that are most imprtant to you first, then go from there. Tire temps after a cool down lap are virtually useless IMHO.

What he describes is being wrong about achieving EVEN temps - you don't want exactly even. What you need is slighly different for each suspension type.

You have to understand your temps - and why they could lead you in the wrong direction. The only way to MEASURE temps s with a pyrometer. They tell you so much. SO MUCH.

I am a firm believer that anyone who doesn't use a pyromter to tune their car IS foolish. There is just no way - at our level - to do otherwise. I don't care what Carroll says. MAYBE, if you are already 9/10ths of the way there, you can 'tune' with other factors - but only if you know what you are looking for. And if you are that advanced, you know how to use a pyrometer to get you those 9/10th's.

You would have to have a HUGE tire budget to just use the 'look' of the tires to tune...and DAYS at the track. Go to the track, see who has the track records, and see what tools they use to test - and what event to event records they keep. You will be surprised.

[gran racing]

Andy, You're missing Carroll Smith's point, and I only included a portion of his book. No where did he / I state reading the tire temps wasn't done as part of the hot lap. I'm not looking for a response to this, but more of an internal question to you - did you or have you taken some time to give this type of tuning method any thought? Or did you simply react with what you "know" to be the answer?

Go to the track, see who has the track records, and see what tools they use to test - and what event to event records they keep. You will be surprised. [/b]

Exactly what I did and was very surprised!!! After speaking with him and looking at his accomplishments, it got me looking into this (WITH AN OPEN MIND) further. He stated that for years he did his tuning based on a pyrometer. When he stopped relying on the pyrometer, things changed for the better.

While people's success in club racing means something, it certainly doesn't mean that those individuals are experts in automotive racing.

Listen, I'm not here trying to convince you that using a pyrometer isn't the way to go. The pyrometer method sounds much easier, I can write it down on paper and try to make sense of it. It is very easy to put quickly put aside any other methods. For the time being I'll probably start using a pyrometer, but will also continue to tap into other peoples knowledge.

(Btw, I have also been told by many of the same people who spoke with me about reading a tire, that for other types of tires and compounds, using a pyrometer is the way to go.)

[Andy Bettencourt]

Correct - for every book that tells you there are better options, there is one telling you it is the best.

My point is that at the level we are at as 'tuners', a pyrometer is a key tool. Graduate to other methods if you will but I see no way to do so without the basics, a mentor looking over your shoulder, and a HUGE trial and error (tire) budget.

YYMV. I am out.

Yes I have read the book. Liked most of it...and I always listen to others and the way they tune. There is always a better way...but sometimes the tried and true ways are like that for a reason.

[ddewhurst]

IMHJ, if the tire manufacture or a sucessful racer at the same track don't give you tire pressures for a specific type of tire how will you determin optimal tire pressure without a tire pyrometer? A cooler/warmer temp at the center of the tire & you are not using the tire to it's max capability. Pressure wouldn't tell you the center of the tire is cooler.

This is the 2007 David & I am always egar to learn

[tom91ita]

for tire pressures, i am sold on the digital ones and don't worry about absolute accuracy as much as repeatable. that is, i can have any newbie crew person helping and be confident that they are accurate to the limit of the device (0.2 psig).

for the 0-60 dial gauges, i don't think that is as likely.

also, since i have had the same gauge for several years, i am comparing what 34.2 psig felt like last time i was there and not if the gauge is actually 34.0 or 34.6 psig, etc.

[shwah]

We read tires and measure treadwear much more than measure temps. This is for my ITB car and Mathis' GP car. I agree that you cannot get an accurate picture of what the tire is doing over the entire lap, only the most recent turn or two with temps. I do think a pyrometer is a good idea, but don't consider it the end-all suspension tuning tool.