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. :birra:

[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. :rolleyes: 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.

[flaboy]

I just bought a basic laser pyrometer last weekend to help set my camber settings.I thought it helped out a great deal.We only checked the inside, middle,and outside temps to see if we had to much camber.When we would see more than 50-60 degress difference in temp on the inside we knew we had to much camber.

But we only got the plates in the car on Friday night at the track and din't want to spend the big money for a camber gauge at the track.But i will always take it with me to fine tune the adjustments at the track since different tracks will require some slight changes to help handling.


I may be full of sh*t on all of this...but sounds good to me.


Tim

[ddewhurst]

***We read tires and measure treadwear much more than measure temps. This is for my ITB car and Mathis' GP car.***

Chris, I understand who the G car is. Please explain when you put new tires on the car what you read of the tire surface after 4 to 6 laps to tell in the psi is correct.

Thanks ;)
David

[JimLill]

As I already had a thermocouple device in the form of a Fluke 16, which also serves as a general DVM/VOM

http://www.hmcelectronics.com/cat/3410-0109.jpg

I bought one of these for tires:

http://www.intercompracing.com/images/360013.jpg

http://www.intercompracing.com/detail.cfm?ItemID=113

[RSTPerformance]

I disagree with Dave here, and challange anyone at the track to "look at my tires" after a session and tell me what I need... More or less Camber. I will even set the car up with to much or to little on purpose and show how the temps will show me the difference even after a semi cool down lap that I try to do as fast as possible. I would be very interested to see how you would be able to look at the tire and know what change was needed.

However just to add a little more fire to this discussion, I do not think that a basic laser pyrometer gives you a good reading. It might be all in my head, but to me it makes sence. The outside edge/layer/compound of the tire cools much faster than the inner portions where a probe will read from. An example of this would be, when you have any camber the outside edge of the tire is in "in the air" and cools off. If the outside layers of the tire cool faster than the reading/tempatures will be further off with a laser vs. a probe.

Raymond

[pfcs49]

There is a tool available (circle track) that cuts a shallow/uniform depth rectangular groove across the tread of the tire (similar to that microscopic tread on a new GSCS and just as revealing as examining a gscs after it's fist session). The appearance of the tread surface also tells hugely about if the tire is "working" (car balance/driver working? etc) Non contact pyrometers are useless for tire apps. I tell anyone taking my temps to jab in the probe as if they were trying to give me a flat. phil

[JohnRW]

Tire pressure gauges that use mechanical 'Borden tube' gauges (the most common), are the most evil and treacherous devices you'll ever own. Never trust them. Compare against other gauges regularly. I've seen them read 20-30+% off. Why ? It's a mechanical gauge that uses the 'flexing' of a thin metal tube to move the gauge needle. One drop and the calibration is suspect.

Been burned once too many times. Went to a digital pressure gauge a few years ago...piezo-electric sensor that isn't prone to shocks.

That 'trusty old tire gauge' might be screwing you big-time.

You have now been warned.

[pballance]

As I already had a thermocouple device in the form of a Fluke 16, which also serves as a general DVM/VOM


I bought one of these for tires:

http://www.intercompracing.com/detail.cfm?ItemID=113
[/b]

Now why didn't I think of that before. I already have the Fluke meter, albeit a different model, but the probe is compatible. THANKS for the tip.

Paul

[tom_sprecher]

Based on my experience in the Formula group I can not see how you could have any idea what is happening with your tires with regard to optimum camber or pressure settings w/o a good pyrometer with pin probe. Laser pyrometers are good for making sure the beer is cold enough, and things like that, but not tire temps. To do it effectively you need a 2 man crew shouting out readings (first temps then pressure at each tire) utilizing the driver to record the results on a proper chart. Also, with temps don't bother to shout the hundreds place as it is already assumed and can lead to confusion.

Take them immediately after a hot lap in the first pit box you can get starting w/LF and working counter clockwise around the car. Stick the probe down into the core as there you will find more stable temps that aren't as affected by the most recent track surface. Take 3 readings per tire, moving the probe from the inside out starting no more than 1" in from the inner side wall, then one at dead center and finishing at about 1" from outer sidewall. Give the probe time to settle (2-5 sec on first reading but is gets less as you work around the car) before you shout out. The second crew member takes and calls out the pressure as the first guy is moving to the next tire. When the car comes back to the paddock make a hash mark on the sidewall to record another heat cycle, put the car up on stands and clean off any pick up (staying on line while entering the pits and paddock helps minimize this).

Without having done this for longer than you want, merely "looking" at the tires can only tell you if the driver has worked them enough for the compound being run or if it's time to pitch them due to excessive wear resulting in a bad profile (inside section of tread on LF or outside of RF surface is worn beyond serviceable limit.) If you do the above procedure consistently and keep good records you will quickly gain valuable knowledge and experience. Only at that point (if there have been no off track excursions that day) you can "look" at the tires and only to decide if you need to take more readings. These readings in turn will help decide if you need to make adjustment in either the set-up or the driver. What kind of adjustment fills books.

[lateapex911]

I can't make claim to being a wizard at setup, or engineering, but it IS interesting to see the gulf of opinion, and the strength of it.
I have talked to very respected career chassis engineers who design race suspensions, and they are not pyrometer fans. (And they run at the very front of one model classes that have considerable suspension adjustability, so they must be doing something right...)

And I've talked to engineers who would be lost without them.

Both apparently, can yeild results in competitive environments.

[shwah]

***We read tires and measure treadwear much more than measure temps. This is for my ITB car and Mathis' GP car.***

Chris, I understand who the G car is. Please explain when you put new tires on the car what you read of the tire surface after 4 to 6 laps to tell in the psi is correct.

Thanks ;)
David
[/b]

If you have to do it in 4 to 6 laps, the pyro is the best tool IF you have no historical setup data. The better way to do it IMO is to run a full session, and pull the wheels to measure treadwear indiction holes afterwards.

[tom_sprecher]

I have talked to very respected career chassis engineers who design race suspensions, and they are not pyrometer fans. (And they run at the very front of one model classes that have considerable suspension adjustability, so they must be doing something right...)
[/b]

Jake,

Out of curiosity, what do they use to fine tune their setup? Inquiring minds want to know.

[lateapex911]

Jake,

Out of curiosity, what do they use to fine tune their setup? Inquiring minds want to know.



[/b]
Well, I'm one of those "inquiring minds" too.....

For me, a pyrometer is pretty useless, as it takes humans to operate, and I have none of those, LOL.

But the "other way" is black magic to me. He said, "Well you can tell a lot by looking at the patterns, and the graining of the tire". I'm sure some can...just not me!.

Seems to work though....for him at least, LOL.

[gran racing]

For me, a pyrometer is pretty useless, as it takes humans to operate, and I have none of those, LOL. [/b]

Maybe you could speak with one of your friends who races in another class such as ITB and ask them to do it? Then, maybe you'd be willing to help them take the reading on their car? Brilliant!

[lateapex911]

yea, I had such a friend, but the guy wrecked his car and was never seen nor heard from again,...

Kidding!!!

Consider yourself "tapped"...good thing Jake Fisher doesn't need the same help, eh?

[gran racing]

He is one of the people who tunes by reading tires. Just because he and others run mid-pack, doesn't mean those same people don't know what they're doing. Last year he finally bought a pyrometer, but it was just to test for max. temp using autocross tires.

Jake, he's moved onto the dark side and bought a 240sx, dropping some silly big motor in it, and doing drifting. Besides, he does a significant amount of his tuning at his work's track. Jerk!

[backformore]

A good use of a pyrometer for someone just starting out is to measure how much of the car/tire potential is being used and determining when tires have gone over the hill.

While this requires some historical and comparitive data, it can be really useful.

By comparing your temps to someone running a similar car on the same brand or tires(during the same session), you can tell if you are pushing the car hard enough (i.e. signigicantly colder temps means you need to put your foot into it grandma).

Similarly, if you have been recording data for several events and you see a consistent reduciton in max temps, it may be time to buy new shoes.

[pfcs49]

VERY INTERESTING EXERCISE: (that I've done for a long time now): take the sums of (3) temps for each tire and express them like corner weights. If you've been scaling the car, youll be suprised at the diagonals ("cross-temps"?) (add the diagonal sums and compare them/express them as % of each other.
The results will look like good crossweights when the car setup is good/chassis working. phil

[kthomas]

Well lessee, during my "active" period as a Crew Chief, my drivers won something like 41 races in 69 starts, 2 SARRC Championships and 4 ARRC's. That doesn't mean I know anything, but IMHO (and I mean that sincerely) here's my take on pyrometers/gages.

I use a pressure gage to set the first cold pressure of the day, and each time we mount another set or rotate. I record pressures after the tires have cooled (as well as the ambient temp) for setups that we are happy with. In 15 years of ITS I may have checked pressures hot a couple times just for yuks. They mean nothing to me. The pyrometer is my primary tuning tool. In fact, the last two years I worked regularly I never unpacked my camber gage, and couldn't tell you what camber we were running. In the first few years with the Z's, however, we tracked and recorded so much data I think we should have owned stock in Weyerhauser. After enough years on the same tracks you sorta learn what you don't need.

In the bias ply Hoosier days a 1/2 lb of air made a significant and repeatable difference in the temperature distribution. Ditto my days on slicks with sports racers and prod cars. As already noted, the bias of temperature for optimum grip varies with suspension and tire type. Pre IT radials I'd shoot for even or 10 degrees max depending on which car we're talking about. On radials its more like 25 degrees hot to the inside. We seem to get a lot of benefit from camber thrust in radials, and curiously that kind of bias still results in pretty even wear (although wear in general has a LOT to do with shocks). Radials are not near as sensitive to pressure as bias ply's, although being basically a race carcass the Hoosier is pretty close. You're not losing because your tire pressure is off a pound or two.

I never make a setup change until two sessions produce the same temps, unless of course we have something way wrong (this is usually indicated by the driver running over your feet on the way to the paddock while your in pit lane waiting for him to stop for temps). If you think temps only reflect the last couple of corners then you're not sticking the probe in deep enough. Because of the huge camber most IT cars run now (eh, the ones with not enough spring and shock anyway :) ) the corners of the tires usually have a pretty big temperature gradient so to be repeatable you have to be careful and consistent about which locations along the tread you're taking temps. I always measure hottest tire first, followed by next hottest etc. The hotter the tire, the more heat loss while you're measuring.

While I can't say enough good things about Bruce Foss and Rodney Perry of Hoosier, I always do my own temps even when I also have them do them. They're usually pretty close to right. ;)

[tom_sprecher]

Oh yeah, well when I was the Crew Chief for 4 years we won I don't know how many races in CFC, 2 SARRC championships and set track records at Roebling and CMP, so there. That doens't mean I know anything but I felt like bragging. ;)

Seriously, katman, that was a great post, but you lost me when you said in 15 years you only took hot temps a couple of times yet the pyro was your primary tuning tool. What gives? The cold pressure method is the best once you have the setup you want, but hot pressure with temps can tell a lot too.

All of my experience is with Hoosier bias ply slicks (25's & 35's) so the DOT radials (Toyos, at that) will be something new (which is a good thing as I bore very easily). I appreciate your info and it looks like I might need to bone up on the differences before getting too serious.

Thanks again,

[ddewhurst]

I read this post earlier this a.m & surmised katman might have oop's a word. I don't argue with folks who WIN.

***In 15 years of ITS I may have checked temps hot a couple times just for yuks.***


Have Fun ;)
David

[kthomas]

Oops, I meant hot pressures. Good catch. Post edited.