Tyre temperature using pyrometer

[nd55]

Hey,

anybody got any experience tuning using a tyre temperature pyrometer?

vehicle: rear wheels, fwd, zero toe.

I had (inside,middle, outside) @ 32psi: 40, 38, 34 degrees.



Thinking I'd improve the temperature gradient with reduced tyre pressure.

I got (inside, middle, outside) @ 30psi: 38, 38, 32 degrees.


Which is the better pressure setting? I'm not able to test at the track, so it's hard to work out what's going on.

Nick.

[chargeR]

I have used a tyre pyrometer on track and the temps I got are significantly higher than the ones you have and I generally get an inside temp around 5 degrees higher than the outside. I am happy with that.

To get any meaningful data you really have to be at track and get the tyres up to temperature, your numbers right now are probably not reflective of anything much.

[nd55]

> To get any meaningful data you really have to be at track

Cool. But not gonna happen, unfortunately.

Jaycar had a special on their already cheap pyrometer models and I thought I'd get one and have a play.

> 5 degrees higher than the outside.

Do you think on a street situation it's possible to get the temperature across the tyre equal?


Does anyone measure the sidewall temperature with these things? Is it meaningful?

Nick.

[Crapdaz]

dont think so cause of camber on the road is not perfect.

[e240]

The temperature is really arbitary...Unless your tyres are melted.

What you are trying to really do is measure the temperature across the surface of the tyre and understand how hard the tyres are working and then adjust the camber to suit.

To do this effectively, first you must have confirm a specific tyre pressure with which you are already consistent in timings. Then straight off a hot lap, come in and get the measurements. Always helps to have another person do this for you.

The internet is full of information on how to do this effectively.

I don't think you can reliably do this on the street because the tyres probably don't get as hot as you do on the circuit.

[EG30]

how much camber are you running?

[aaronng]

Unless you are maxing out the tyre grip and causing extreme temperatures, I doubt that the uniformity of the temperature across the width of the tyre at the levels that you found (32ºC to 40ºC) will have a detectable effect. I personally run at 36 psi cold on the street and 40 psi cold on track for street tyres.

[nd55]

> how much camber are you running?

0.7 degrees, negative.

Only testing the rear at the moment.
Don't ask about the front ... it's fooked courtesy of hairy nosed speed hump avoidance.

> I personally run at 36 psi cold

That's about where I'm at, although as mentioned at the top, I can't seem to get a good across the tread temperature reading.

It seems, I can only load up either the inside or outside half of the tyre, not both.

More camber is bound to make things worse.

Nick.

[chargeR]

What sort of driving are you doing before taking these readings? If you are just tootling around the suburbs then 0.7 camber is definitely too much. Also what are you trying to work out, the ideal pressure and alignment settings for daily driving?

[aaronng]

What sort of driving are you doing before taking these readings? If you are just tootling around the suburbs then 0.7 camber is definitely too much. Also what are you trying to work out, the ideal pressure and alignment settings for daily driving?

0.7 negative camber is fine for street. Nothing wrong with it.

[chargeR]

0.7 negative camber is fine for street. Nothing wrong with it.

I agree that there is nothing wrong but -0.7 camber is not ideal if the absolute lowest tyre wear or stopping distances are your goal. Trying to get an idea of what the thread starter is aiming to achieve by measuring tyre temps because I think if he is wanting to get good settings for good cornering grip the only way to get good data is to drive using most of the tyres capacity for cornering which is pretty dangerous on the street.

[aaronng]

I agree that there is nothing wrong but -0.7 camber is not ideal if the absolute lowest tyre wear or stopping distances are your goal. Trying to get an idea of what the thread starter is aiming to achieve by measuring tyre temps because I think if he is wanting to get good settings for good cornering grip the only way to get good data is to drive using most of the tyres capacity for cornering which is pretty dangerous on the street.
Well, the stock alignment for the Accord Euro actually comes with -1.0 camber from the factory. :) The weight of the car will ensure that the contact patch for -0.7 is very similar to if you had 0 degrees camber.

[nd55]

> Trying to get an idea of what the thread starter is aiming to achieve by measuring tyre temps


The original aim was to work out optimal tyre pressure.

However, my results seem to show that even with minimal camber (0.7) I'm not using the entire tread in any situation, neither straitline or cornering.

As posted earlier, dropping to minimal pressure (30psi) seemed to unload the outside in a straight line, and unload the inside in a curve.

I'd have thought that lower pressures would lower the mid-tread temperaure. It didn't. The difference between the outside and inside was exagerated.




I'm thinking at the moment, the the notion of a perfectly flat tread is a falacy.
Perhaps real tyres have a slightly ballooned/curved surface.

Has anyone done any testing and found there is a minimal amount of camber before there are any benefits?



> which is pretty dangerous on the street.

relax, I'm being sensible. That's why I posted here..... besides my temperature values have gotta reflect I'm not throwing it around....


> The weight of the car will ensure that the contact patch for -0.7 is very similar to if you had 0 degrees camber

I think I've shown that's not true.

Maybe the accord being heavier than a civic changes this???

Nick

[chargeR]

>
The original aim was to work out optimal tyre pressure.

However, my results seem to show that even with minimal camber (0.7) I'm not using the entire tread in any situation, neither straitline or cornering.

As posted earlier, dropping to minimal pressure (30psi) seemed to unload the outside in a straight line, and unload the inside in a curve.

I'd have thought that lower pressures would lower the mid-tread temperaure. It didn't. The difference between the outside and inside was exagerated.



I am still interested in what style of driving you were doing before you took these readings? Were you doing any cornering? Why not try and find a nice large roundabout and go around it at a speed that you feel comfortable a few times and then jump out and check the temps of the outside tyre, because if you are doing too much straight line driving it is possible that all the numbers reflect is that you have negative camber.


>

relax, I'm being sensible. That's why I posted here..... besides my temperature values have gotta reflect I'm not throwing it around....



Hehe I didn't think that you seemed the type to be racing on the streets, I doubt that those that do bother with their tyre temps :thumbsup:.

If you want I can take some temp readings from my car on the street with -5.3 camber, I am sure that will make you feel better about your numbers :p.

[aaronng]

> Trying to get an idea of what the thread starter is aiming to achieve by measuring tyre temps

The original aim was to work out optimal tyre pressure.

Yeah, try not to lose sight of your original aim. You don't want to end up choosing a tyre pressure just to satisfy the temperature gradient. Eventhough there is a temperature gradient, it could still be the optimal tyre pressure for your setup.

[nd55]

I was thinking someone might have some guidelines to follow.

At the moment I'm all over the place, the data doesn't give me a decisive way to proceed.


> Why not try and find a nice large roundabout and go around it at a speed that you feel comfortable a few times

:angel::angel::angel::angel:

That never occurred to me..... he, he.


> I didn't think that you seemed the type to be racing on the streets

I'm too old, people just laugh at me.



> You don't want to end up choosing a tyre pressure just to satisfy the temperature gradient

Is there a better way to choose pressure, short of a few laps at the track?

Nick.

[aaronng]

> You don't want to end up choosing a tyre pressure just to satisfy the temperature gradient

Is there a better way to choose pressure, short of a few laps at the track?

Nick.
On the street at street legal speeds, you'll be using less than 5/10 of the potential of your car. So I wouldn't be fussed. I'd just fill it to between 32 and 36psi, depending on the ride comfort that you need. Between the two ends, you'd see the fuel economy and ride comfort first before you start to see the handling and braking differences assuming that you are travelling at the legal limit.