Tire Pyrometer

[Houstonnw]

Before you get a lot more responses that may or may not know what it takes to make a tire happy, learn about it yourself. Augment your pyrometer and buy the Paul Haney book on Performance Tires. There's more to adjusting tires than camber and pressure, though those are the biggies that will make the most difference.

I ordered the book, and if it tells me anything more than you want the hottest temp on the inside with about a 10 degree difference across the tire, I want a $60 discount on my AST shocks!

Houston(who owns almost every race car design book in print)NW

 

[Houstonnw]

FWIW, you should be making the tires as happy as they can be, but the ultimate tool to decide whether you have enough air pressure, camber, toe, caster, rear squat, rear steer, spring rate and damping is...

The stopwatch.

Sorry Jason, I just saw your second post, but is having the temperature gradient increasing towards the outside edge ever going to be faster?

Aren't there some absolutes, with the temperature gradient above being one of them? Just curious.

 

[kcbrown]

FWIW, you should be making the tires as happy as they can be, but the ultimate tool to decide whether you have enough air pressure, camber, toe, caster, rear squat, rear steer, spring rate and damping is...

The stopwatch.

Of what use, then, is a pyrometer in light of such things?

 

[sheizasosay]

OP- what is your toe? Just curious.

 

[csamsh]

Of what use, then, is a pyrometer in light of such things?

Just another data point.

 

[Houstonnw]

Just another data point.

Wait, do we want to try for good tire temps or do we want to only look at lap times, or could they be related, and could we use one to improve the other?

Really? Just another data point?

Edit to add: I have come back to this forum as a resource, but with some experience.

 

[kcbrown]

Just another data point.

Well, okay, but Jason's statement makes it clear that it's a highly ambiguous data point.

Put another way, it sounds like the very same tire temperature spread can indicate either too much camber, too little camber, or just the right amount, depending on track temperature, air temperature, the amount of straight line track you've driven after taking corners at speed, the specifics of the suspension setup, etc.

I suppose you can use it intelligently with respect to a specific car on a set of specific tires after you have a bunch of experience in using it with that specific car/tire combination on the track under a wide variety of conditions and know how its readings correlate with the stopwatch or with other more precise instrumentation. But it sounds like it is going to be nearly useless in the hands of someone who lacks that immense amount of required experience.


In the hands of a novice, I suppose the only thing it might tell you is whether or not your tires are vastly over/under-inflated, but not really anything else.

Is the above about right, or does it miss something crucial?

 

[Houstonnw]

Well, okay, but Jason's statement makes it clear that it's a highly ambiguous data point.

Put another way, it sounds like the very same tire temperature spread can indicate either too much camber, too little camber, or just the right amount, depending on track temperature, air temperature, the amount of straight line track you've driven after taking corners at speed, the specifics of the suspension setup, etc.

I suppose you can use it intelligently with respect to a specific car on a set of specific tires after you have a bunch of experience in using it with that specific car/tire combination on the track under a wide variety of conditions and know how its readings correlate with the stopwatch or with other more precise instrumentation. But it sounds like it is going to be nearly useless in the hands of someone who lacks that immense amount of required experience.


In the hands of a novice, I suppose the only thing it might tell you is whether or not your tires are vastly over/under-inflated, but not really anything else.

Is the above about right, or does it miss something crucial?

You asked if you missed something crucial? Based on my books, the tire temp gradient is crucial, and probably the best and most important tool you have to set up your suspension.

Now Jason and Vorshlag have much more actual experience than me. So I am just curious where the tech and the "experience" converge.

 

[csamsh]

I think it may be wise to focus less on the actual readings, and more on the relationship between your readings and lap time, tire wear, or other more obvious, measurable, important factors. Tire temp really doesn't matter, in and of itself. If you're going fast and your tires are wearing well, your tire temp is good. If you can go faster and/or wear your tires better with a different temp, those temps are better.

When I say "just data" I don't mean "not important." I mean it's just a point of reference, as long as you acquire said data in a consistent, repeatable fashion, and that the number itself doesn't really have any intrinsic value, it's just valuable relative to other results, and a good tool to compare with mfgr. data on where the tire will make the most mechanical grip.

 

[modernbeat]

Sorry Jason, I just saw your second post, but is having the temperature gradient increasing towards the outside edge ever going to be faster?

Aren't there some absolutes, with the temperature gradient above being one of them? Just curious.

There are no absolutes, but there are some good general guidelines. And yes, if your outer edge is hotter, you are most likely doing something wrong.

Of what use, then, is a pyrometer in light of such things?

A pyro is a measuring tool, just like a toe plate, a scale, or a g-sensor. It's used to gather data so you can correlate settings with results. If you can repeat the settings, you -should- be able to repeat the results.

A good example of this that most competitors have experienced is the chalk on the tire. Beginning autocrossers trying to find out the "right" air pressure will chalk the corner of the tire and make a run on a test course. They will rechalk the tire and make pressure changes until they use all the tread, but do not roll over on the sidewall. Once they find that point, they stop using the chalk, measure the pressure and that becomes the tire pressure setting they aim for. This does NOT take into account whether they were actually faster on not on that pressure. It is assumed that by using the entire tread that they will be faster. That's a good assumption, but still an assumption. If they are on a true test course that does not depend on driver skill, then they should also have s stopwatch on their runs and should be comparing pressure to time, not pressure to chalk marks. Once they find the fast time, that is the pressure to use. If they also find that the target pressure only uses a portion of the tread, or rolls over the sidewall, then that will point to other things to fix, but until fixed, the "wrong" pressure is still the fast setting.

FWIW, pressure and temp are important on DOT tires, but even MORE important on true slicks.

Another good book that may help guide everyone's thinking on what is important to tackle, and what has lower priorities is Neal Robert's book, "Think Fast". In addition to Paul's tire book, it's on my short list of recommendations.

Think Fast: The Racer's Why-To Guide For Winning

 

[csamsh]

Another good book that may help guide everyone's thinking on what is important to tackle, and what has lower priorities is Neal Robert's book, "Think Fast". In addition to Paul's tire book, it's on my short list of recommendations.

Think Fast: The Racer's Why-To Guide For Winning

Any chance you could put your short list up here?

 

[modernbeat]

The very short list is Paul's Tire book, Neil's "Think Fast" and Jan Zuijdijk's book, "Vehicle Dynamics and Damping" which is horrible to read and feels like a bad translation of a bad textbook from Dutch to English.

The tire and damping books are both about concepts. They are not recipe books. Neil's book has really good practical advice.