I have been looking at pyrometers for a little while now, and I have a few questions about them before I pick one up. First of all, I remember a few comments about IR pyrometers, and how they aren't very accurate. Most of the people who have pyrometers in my area have the IR kind, and they seem happy with them. I have borrowed a couple of the IR kind and didn't have any trouble, but that's limited experience. Should I stay away from them?

The two IR pyrometers I've found are the Longacre ($169), Longacre laser site ($249! Ouch), and the Craftsman laser site ($99...seems cheap for a Craftsman). Anyone using any of these, or have a better recommendation?

The only non-IR pyrometer I've found that looks good is the Longacre digital probe type that comes with a case and an optional brake probe ($129, $189 with brake probe). How easy are these to use vs. the IR type? Are they really that much more accurate?

Thanks for any advice from experienced pyrometer users...

 

The probe type measures the temperature just below the surface of the tire. This is probably most representative of the true operating temperature, since the surface of the tread cools very rapidly when you come into the pit. The probes are expensive and are very fragile. Don't expect them to last very long, you'll need several probes.
The IR type is much more serviceable. you really need the laser sight to show where the temperature is being taken. A memory type usually allows you to read the temperature faster and record it. Speed in taking the reading means the reading are more representative of the on track temperatures. This is more important with the IR thermometer than with the probe type.
With all that said, I use a Raytech with the laser sight, no memory. Cost was $99.00 on sale. We also have a TIF probe type but the cost of replacement probes made its use prohibitive.
Remember the absolute accuracy of the temperature readings is not as important as repeatability in your thermometer since relative temperature differences is what matters.
Good luck.

 

Surface tire temp cools way to fast too get an accurate reading of true tire temps with an Ir pyrometer. You will never see a factory tech from any tire company in a professional race series use an Ir pyrometer on tires for just this reason reason. So don't bother with infra red pyros if your looking for tire temps, as they only read the tire surface temp, and not as accurate as sticking the thermocouple probe right into the tire tread (I have both, and the infra red one is only good for spot checks of temperature, whereas my Longacres memory pyro is much more accurate for tire temps.)
As a side note, it's tuff to get accurate tire readings after an auto-x, as the heat involved is very minor due to the short runs, and relatively fast cooling time of the tires. To get the best results, you really have to get the temps as SOON as you finish your run, and as fast as possible. We use 3 positions on the tires... inside, middle and outside to determine alignment requirements - I know some teams use 4 temps per tire if they run really wide race slicks.
In auto-x, since you are not getting the tires up to normal track temps, they have a tendancy to drop just as fast as they rose, so speed is of essence.
Track racing is a little easier, as your tires get up to much higher temps, and will retain the heat inside them longer, and the rims are hot too from the braking/friction, so the tire temps retain their readings longer.

And I would seroiusly question where this info came from:

"The probes are expensive and are very fragile. Don't expect them to last very long, you'll need several probes."

The probes are not expensive and can be purchased at most electronics stores for next to nothing. I have used my probe for 10 years and never had a problem with breakage or damage.

Some of the fancier multi meters (some people call them AV-Ohm meters, sold in electronic stores) can accept a temp. probe attachment. For about the same price, you can have a pyrometer and a multi meter also (if you don't already have one).




[Modified by DB1-R81, 10:11 PM 12/20/2001]

 

I had a nice conversation with a Goodyear tire engineer once, who laughed at my short pyrometer probe. She firmly believed (this was road racing) that anything less than 3/8 of an inch or so didn't get deep enough into the tread to be very informative. I was surprised how much her measurements differed from mine but believe what she said. Seems like size does matter, after all.

Kirk

 

I dunno, but considering that the tread depth on most race tires is only 1/8 to 2/8" wouldn't she actually be measuring the carcass temperature instead of the tread? And how thick is it beyond the tread anyway? another 1/8 to 2/8"? That's almost like puncturing a tire, hehe

Anyway, I allways thought it was the tread temps that mattered...

 

Lets take this to another level..
how long are you supposed to leave the probe in the tire..
I have noticed that the temps will
1) sometimes rise.. the begin to fall
2) somes just fall

so do you wait for the temps to stop moving or do you recored the highest temp? or what?
what is the proper way?

 

http://www.longacreracing.com/articl...at.asp?CATID=3 (also has information about IR vs. Probe pyrometers)

 

sweet thanks

 

I second that. Good info...thanks!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hensley &raquo;</TD></TR><TR><TD CLASS="quote">The probe type measures the temperature just below the surface of the tire. This is probably most representative of the true operating temperature, since the surface of the tread cools very rapidly when you come into the pit.

...Remember the absolute accuracy of the temperature readings is not as important as repeatability in your thermometer since relative temperature differences is what matters.

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I've also been told the laser probes aren't as useful as a true 3/8 in. probe.

Does anyone have any recommendations for different brands of tire pyrometers, camber gauges, toe gauges, depth gauges, pressure gauges ?

what do you use and prefer now that you've tried certain types?
I guess I could just go on a shopping spree at Longacre's.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DB1-R81 &raquo;</TD></TR><TR><TD CLASS="quote">
And I would seroiusly question where this info came from:

"The probes are expensive and are very fragile. Don't expect them to last very long, you'll need several probes."

The probes are not expensive and can be purchased at most electronics stores for next to nothing. I have used my probe for 10 years and never had a problem with breakage or damage.
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I basically agree with everything Marc said about IRs, autocross and road racing, longevity, multi-meters, etc.

I've had the same probe style digital pyro sinceabout 1994 and never had to replace anything but 9 volt batteries. Mine was a simple cheapy that I bought for about $80 back then and it has been an invaluable refinement tool.

Today is pyrometer day as this thread and two seperate pyrometer conversations came up today. My wife's horse farrier (fancy name for blacksmith to justify a big bill) uses an IR pyro to find hot spots in horses feet and hooves so they can locate internal infections, etc. I'd have never guessed they were that sensative. My wife was playing with the IR and thought it was realy neat but for tire temps in the carcass itself, get a probe style unit.

 

You're all barking dogs.

Just kidding.

I've talked over the last couple of years about Real Time Infra-Red - a simple partial-brainer.

RaceCar Engineering a few months back showed Ferrari testing with just such a setup. Three sensors (inner, middle, outer) on a bracket mounted to the uprights.

DUH!

Thing about ANY tire temp measurement scheme is this:

Your best speed might not be achieved at an intuitive temp distribution.

It's conceivable, probable in fact, that overall optimal performance is achieved at camber settings that produce "incorrect" peak instantaneous temp profiles.

With manual hot pit temp taking you are so far removed from what's actually happening on the surface of the tire while it's doing it's job that all you're really doing is checking for compliance with convention and taking what you get on the track - which is of course better than nothing, but I'm not sure that learning to read a tire isn't just about as good when used in conjunction with lap timing.

AND, after you've run one session on a set of tires the correlation between the actual road camber (at the patch) and the measured camber (at the rim) has broken down. This is a huge factor that can foil an honest but insufficient effort.

Scott, who knows this is all very arguable...I'm just talking.

 

I personally use the tire wear as an indicator to let me know if I need to adjust tire pressure or chamber angles. I measure the tread depth after 3 or 4 track sessions (usually 20min sessions), and take note of the wear on the outside, middle, and inside of the tires. I then make adjustments accordingly. I have no idea if this is a good way for best track times, but I just want to get the most out of my tires

 

it's matter of how fast you can interpolate your settings to achieve that optimal contact patch for the given race track that day, is it not (whether we are dealing with solo2 vs. solo1 or road racing)?

If I can setup and worry only about my technique faster then the pyrometer pays for itself. One less thing to worry about.

[Maxwell Smart voice on] right 99?[/Maxwell Smart voice off]

 

Are they worth using on Street Tires? Say, Azenis or KD's?

 

I got the TIF 7060 probe type pyrometer from OG racing. $99.95. Seems to work pretty well.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RR98ITR &raquo;</TD></TR><TR><TD CLASS="quote">RaceCar Engineering a few months back showed Ferrari testing with just such a setup. Three sensors (inner, middle, outer) on a bracket mounted to the uprights.</TD></TR></TABLE>

Taking temps in real time will certainly give a more current measurement and obviously must be done with IR as dragging probes through a spinning tires is not healthy for tire nor probe. Of note, Ferrari or other folks using real time IR data collection are probably working on a higher budget than my $80 per decade rate for tire temp gathering or what most of us are going to have as an option. Does this infer that if you can't do real time data logging and temp collection that you shouldn't bother at all? I have a racer friend with a high nerd factor who is developing his own on-board data logging system that will have three positions per tire for temp readings who thinks he can do it at a reasonable cost. If and when that happens maybe we can get real time readings at for a sub-high pro racer budget.

My current data logging system is my stop watch, my tire pyro, my air guage, car inspection for wear and changes, and my recollections of the car and dash guages during the session (very subjective but data nonetheless). I plug that data into my computer called "the racer/junior engineer brain" and after enough times a getting confused and maybe doing it wrong a few times, I learn from my mistakes and successes and make some headway to get faster. All of those tools cost about $150 and can help make a very big difference in your performance. If we throw in the towel before we start because we can't do the ultimate systems that the extremes of the sport do, then we won't get anywhere. The fact that we are here using Hondas and other production based cars mostly on DOT tires shows that we are willing to make compromises right from the start. Doing what you can is more fun then sitting back and wishing you had an F1 Ferrari and all the tools that go with it.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RR98ITR &raquo;</TD></TR><TR><TD CLASS="quote">Your best speed might not be achieved at an intuitive temp distribution.

It's conceivable, probable in fact, that overall optimal performance is achieved at camber settings that produce "incorrect" peak instantaneous temp profiles.

With manual hot pit temp taking you are so far removed from what's actually happening on the surface of the tire while it's doing it's job that all you're really doing is checking for compliance with convention and taking what you get on the track - which is of course better than nothing, but I'm not sure that learning to read a tire isn't just about as good when used in conjunction with lap timing.
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It is certainly possible and worth looking at if you are refining your program to a level that this point could be having influence on pyour erformance. But without taking tire temps, how could you even begin to sort it out? When you do take temps, it is best to take them as soon as you possibly can to when the tire is doing it's work so if it must be at the first moment that it stops rolling (the pit) the so be it. Use the best data gathering that you can an most will agree that it is getting the temp from down nearer the carcass where it will have had less chance to cool. Once you have that data, then you can crunch it with the lap times and your other tools, etc. and figure out what works best for you.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RR98ITR &raquo;</TD></TR><TR><TD CLASS="quote">
Scott, who knows this is all very arguable...I'm just talking. </TD></TR></TABLE>
Then let's talk about it.

 

Lee,

I'm not dumping on the sort of effort you've described. And in terms of $/Decade the value of the typical approach is off the scale for sure. I just wanted to throw out some ideas that are never mentioned in this type of thread.

I've done my research into low budget multi-channel real time IR myself, and it's possible to do it for less than insane money using industrial process hardware.

I know that measuring deep in the carcass makes sense - though I've never seen a comprehensive description of the rate of heat transfer within a carcass. I've got friends who've rented tracks and put crews on track so that they could get temps as soon as possible after a specific corner. I'm sure it was quite an improvement over taking them in the hot pits, but there's another effort beyond what most of us can do on a regular basis.

In all of this the most critical element is the judgement of the "racer/engineer". And Lee, how many times have you watched a racer/engineer chase their own tail regardless of what they were working with?

Scott, who agrees that you've got to make the best use of what you've got to work with...and a smart racer with simple equipment can outperform a dumb racer with sophisticated equipment. But lookout for the smart racer with sophisticated equipment.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RR98ITR &raquo;</TD></TR><TR><TD CLASS="quote">.And Lee, how many times have you watched a racer/engineer chase their own tail regardless of what they were working with?</TD></TR></TABLE>

I think the count of tail chasers is equal to the number of racer/engineers that exist. The time frame for tail chasing is until the minute they figure it out (which can be seemingly last forever for those who never get it). On the otherhand, if you don't chase your tail for even a minute you'll never know what that damned thing following you around is. If you never saw it following you around, you are even more clueless.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX Lee &raquo;</TD></TR><TR><TD CLASS="quote">I think the count of tail chasers is equal to the number of racer/engineers that exist. The time frame for tail chasing is until the minute they figure it out (which can be seemingly last forever for those who never get it). On the otherhand, if you don't chase your tail for even a minute you'll never know what that damned thing following you around is. If you never saw it following you around, you are even more clueless.
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Sometimes it helps to have more than one engineer on a project. Other times it doesn't help at all.

Scott, who says sometimes the tail wags the dog too...I don't know exactly what I mean by that cause I'm dizzy...