Temperature Measurement

One day, you might be able to try this on your car.

 

2017

 

A very tired nurse walks into a bank,

Totally exhausted after an 18-hour shift.

Preparing to write a check,

She pulls a rectal thermometer out of her purse

And tries to write with it.

When she realizes her mistake,

She looks at the flabbergasted teller

And without missing a beat, she says:

'Well, that's great....that's just great....

Some *******'s got my pen!'

 

when you're measuring tyre temps, is the ACTUAL temperature important, or is it mainly the evenness across the thread?

 

its kinda the same in a non identical way I think

 

What a great question! Being a "tyre guy" I love this stuff. The quick answer to your question Pete is, within the correct temperature band of the tyre, the most important thing is the "spread" of temps across the tyre, but this is so very rarely the case with most applications. The bulk of this thread is dedicated to the advantages of IR thermometers over probe types..........this is unneccessary discussion. IR thermo's do not have any role in true tyre management procedures. IR Thermos do not measure temps inside the tyre and are never applied for long enought to take an accurate measurement at the heat sink in the shoulder which is well under the surface.

Rubber reverts to a semi liquid mass at around 115 to 120 deg C and as such becomes unreliable as a friction surface at these temps. These temps occur under the tread surface and not at the surface where the air cools the tyre. Tyres for the track are best at around 100 to 105 deg C and tyres for the street are best at around 70 - 90 deg C. This isnt debatable depending on compounds or tread types but rather they are determined and designed around this fact.

Heat is the second most damaging condition that tyres suffer after hard object penetration. Heat begins to store in the shoulders of the tyre and just hangs around. It wont go away other than under extreme cooling conditions and is protected by the fact that rubber and steel, the two most common components of a tyre, are great conductors or storage environments of heat. In sprint racing or super sprints, an IR thermo will show if the camber is correct on the car and if the car is being driven hard enough to use the camber angles it carries by demonstrating variances in readings across the tyre. In distance racing, it is necessary to probe the tyres to get an understanding on the retained heat in the shoulder, the bead package and the carcass. This will demonstrate to a good tech the likelihood of a delamination issue, tread shred, or fitment and balance issue from tyre growth.

In "wonder what the tyre temps are" situations, IR thermos are fine but in any situation where there is a real need to understand the temps and what the temps are doing to the tyre, probes are the only way to go.

For tyre life and to get the best from a set of specialist tyres, understanding temps and getting the correct readings of tyre temps is critical!

 

Both

 

Brettski: Bobby, how important are tyre temperatures?
Bobby: What's it to you, you have no reason to know until 2017!

 

IR sensors do have some value for on track data logging. Guess that depends on how much one can put into finding out for yourself whats going on.
In pit, probe measurements after a cool down lap don't tell you much about whats happening at specific parts of the track.

 

As 993TT says, both are important.
When tracking a car you want to know the disparity between the temps on one side of the tyre to the other (across the face).
Typically the guys measure the tread in three places, inner, outer and centre.
This way you can determine (and then adjust) if your wheel aligniment needs tweaking, or indeed tweaking just for that track.
It also lets you determine if your tyre pressures are correct.
I have been pondering getting a tyre pyrometer to better setup my car for the track.
It would seem that the only correct way to do it is by using a probe type. Apart from the reflectance as shown above the other issue is the cooling of the tyre after a race. Needless to say that the surface cools rapidly even if you come in after the last lap and try and get someone to read the temps ASAP.
But it you use a probe type and it is measuring the temp of the tyre a couple of mm's into the tyre you will have a much more accurate view of the temp of the tyre from a few minutes prior when you were out on the track. The inner part of the tyre has not had enough time to cool down.
I was @ Rocket Industries the other day and enquired about tyre pryrometers. Sadly all they had was the infra red kind and they thought they were the bees knees. When I mentioned the probe type they had no knowledge of them at all. Quite bizarre and naive really. Check out any race track or TV broadcast and you will see the tyre guys running around with probe pyrometers.

Steve

 

Pyros here

http://www.gmpracingproducts.com.au/car-setup-equipment/pyrometer-tyre-pressure-gauges.php

 

Infra red only really makes sense when used in real time like one of these gadgets.

http://www.compsystems.com.au/index.php?option=com_content&task=view&id=133&Itemid=69

And then you have to make sure that you're using a black surface calibration, as b27 demonstrated for us.

The type you use in pit lane need to be the type with a needle probe to get into the carcass. Even then, the rate of cooling can screw things up. Hence the reason why you see some pro teams coming into pit lane in practice at a million miles an hour. The quicker they can get into their pit box, the more accurate the reading.

 

so does Pap.

 

I can't believe pap didn't comment!!

 

OMG!

 

I use a K-probe on my digital multi meter. Works well and most good DMMs have a temp probe facility these days.
A dedicated instrument only makes sense to me if you're really serious and want several to take readings from all 4 tyres at once. Then it makes sense if youre buying 4 of them.
However if you're that serious mounting a brace of real time tyre heat sensors makes more sense to me as you can see whats happening over all of the lap and garner a lot more understanding of rise amd fall.

 

Yeah. it's a bit serious alright.