Tyre temperatures

[Adam43]

I was talking to someone the other day about tyre temperatures. Specifically about how the temperature should vary across the tyre (from outside to inside).

I always thought that if your suspension was set up properly then the across the tyre the temperature should be uniform (the same on the outside, the middle and the inside of the tread).

However he said that the outside should be 5 degrees higher. I can understand that it could be like this, but would have thought that it would be best to, say, change the camber to equalise the temperature across the tyre.

Does any one have any experience of this?

[Mackmot]

It depends on the tyre. In FFord the temperature should be pretty even across but in FRenault the tyres do not get enough heat so they run a lot of negative camber and work the inside of the tyre a lot more.

[shiny side up!]

I got several different answers, sometimes from the same source, when I asked this. In my experience, the answer will vary depending on what kind of car you're racing and what the track is like. Ovals are drastically different than circuits, and a sedan will be different than an open wheel car.

One interesting thing to consider is how, when, and where you are measuring the temps, as they can change drastically in a very short amount of time. Recently there have been pictures of the Ferrari F1 cars with infrared sensor mounted on the car so the data could be gathered on the track... which seems like the best route.

[Adam43]

Cheers.

Is it true, to a certain extent, that if the tyres aren't unifrom temperature then you are not utilising them correctly and should alter the set-up to?

BTW I'm mostly interested in a heavy saloon/sports car!

[THR]

ive always been told that the tires should be colder on the outside.
camber on the FR is run because the tires deflect during cornering, so to get the full footprint on the road during corners you have to run neg camber.

road cars work the same, with your jag id want the temps slightly colder on the outside, defo not hotter.
in my head i just cant see the tires working properly if the outside is hotter.
if you think about toe too, tow in makes the tires hotter on the inside if you have neg camber.
toe out would too in fact lol.

with a heavy car you have to set the temps for the corners,if its hotter on the outside then id guess the tire is rolling under the car.

[avsfan733]

it depends on the set up of your suspension as already noted but i can't think of any situation where the outside should be hotter than the inside unless you run positive camber

[shiny side up!]

I would think that for your heavy sedan you will be doing good if the inside/outside are within 10F of eachother and the wear pattern looks good...

[JR Ewing]

Originally posted by shiny side up!
Recently there have been pictures of the Ferrari F1 cars with infrared sensor mounted on the car so the data could be gathered on the track... which seems like the best route.

Seems a bit drstic for my Classic FF1600 though...

[Adam43]

Originally posted by shiny side up!
I would think that for your heavy sedan you will be doing good if the inside/outside are within 10F of eachother and the wear pattern looks good...

Surprisingly the wear is fairly even over the width.

We have good control of the camber and I was wondering if tyre temperature was a good indicator (as well as lap times!) whether we had got the camber right.

[shiny side up!]

I agree about an onboard setup being a bit drastic for most applications, JR!

Tire temps will certainly tell you if your setup is out to lunch, but when you are pretty close, they don't always help you too much. Here is a stroy that illustrates why it may be useless to worry about a discrepancy of a few degrees...

I helped out at a NASCAR team test once where they had one of the tires instrumented with infrared on the track (low budget team, couldn't do all 4 at once!!). Like normal, I measured the tires after the car came off the track, including the tire that was insrumented. The inside was about 6F cooler than the peak we had seen ~25 seconds earlier on the track, while the outside was about 16F cooler than it's max (probably due to not rolling on the outside portion of the tire as the car was eased down from speed and into the pits).

[Marsh]

Originally posted by AdamAshmore
Cheers.

Is it true, to a certain extent, that if the tyres aren't unifrom temperature then you are not utilising them correctly and should alter the set-up to?

BTW I'm mostly interested in a heavy saloon/sports car!

I've always thought that the center of the tire should be a couple of degrees hotter. Something that Carol Smith recommends in "Tune to Win". But when I meat him last year he swore up and down that the inside shoulder should be the hottest part of the tire (by about 3 - 5 deg over the outside shoulder), I think his exact words were "I know there are a lot people that disagree with me, but they are just wrong!" No if that isn't the best argument I've ever heard..

[shiny side up!]

I heard the same thing from Mr. Smith last year as well, that the inside should be the hottest. Pretty much the same explanation as to why, too. Correct or no, that guy is pretty full of himself...

[Marsh]

Originally posted by shiny side up!
I heard the same thing from Mr. Smith last year as well, that the inside should be the hottest. Pretty much the same explanation as to why, too. Correct or no, that guy is pretty full of himself...

Funny how everyone looses respect for Smith after they meet him?

[THR]

lol ya know the only people that are gunna give ya the answer about how hot ya tires should run are the manufactuers?

how many of you have had luck asking them?
woudlnt bother with michilen?!!!
but worth an ask.....

teams wont tell ya ****!

[shiny side up!]

Here in the US, Hoosier has been pretty helpful, and GoodYear as well... maybe it just depends on who you get ahold of at the manufacturer...

[imull]

I have lent my copy of Race and Rally Car Source Book to a mate but I think there is quite a good section in it about tyre temps.

[racealign]

i have worked as a tyre technician for a motorsport tyre company for 12 years at race tracks and I now own and operate my own business doing car setup and testing. The problem with pit lane tyre temperatures is that they are not "really" accurate and should be used as a guide once other factors are taken into account.
The time it takes for the car to come down the pit lane entrance road, then slow to a holt and then for your tyre man to take temperatures (often one at a time) and then recorded them means that the data has lost 'some' of its accuracy. Add to the variance what the driver did on his "in" lap (i.e. did he slow down much during the lap?, did he drive as hard as he normally would have?, did he drive well? etc etc) and also take into account what happens to the car just before the car comes into the pit road ( i.e. pit lane entrance proceeded by a long straight therefore tyres are hotter on inside shoulders (if negative camber is used) or maybe two or three left hand corners before entry therefore more heat in right front "loaded" tyre and less in the left "unloaded" tyre and may show little or no temperature on outside shoulders etc etc. After this, you have to look at the track itself, it may have one right corner on it and the rest are left handers! To make matters worse the left hander may be the first corner after you leave the pits so the four or five left corners after it and the time it takes to get back to the pits again will obviously show very little real evidence of the heat range for that solitary first corner right hand temperatures! (obviously you wouldn't do just one lap but you understand the point).
The next thing to think about is "balance". An understeering car will "load" the outside of the tyre unnaturally giving a "false" outside shoulder tyre temp.

Incorrect tyre pressure, poor tyre construction or even too small a tyre on too heavy a car (which is a fairly common problem) will allow excessive deformation of the tyre carcass and give an unnaturally hotter outside shoulder. The problem could be fixed with more camber but really it is not the correct answer. Who of you,for example, has changed their road tyres from a 60 series tyre to a 50 or even a 45 series aspect ratio tyre and discovered the difference in shoulder wear, performance and grip without any other suspension change? Believe me its not the compound that's giving the extra grip!
There is heaps more to think about with tyre temperatures and some very usefull stuff can be gained from taking them with good thinking. If you want to know more just email me at race_align@iprimus.com.au

[JohnD]

Resurrecting this thread, with an anomaly.

Recent test day, and we're trying to be more scientific. Tread temps measured in the pitlane asap after a session.
But the temps. are contrary to tyre wear, and set camber (3 degrees neg.).
Cooler on the outside, where wear is clearly greater.

Car is a small saloon.
Does the air flow across the outer side of the tyre keep that cooler than would be expected?
Is temp testing only valid on open wheelers?

To me, wear is more telling evidence.
What do others think?

John

[trikesrule]

I look at both. Then have a good think about all the variables and adjust the chassis in small increments until it's leading the race.......trikes

[GORDON STREETER]

I have tried various settings over the years and some very radical! to stop my tyres from wearing on the outside edges . The only conclusion I have come to is that running rock hard suspension, radial tyres on saloons roll onto the sidewalls and scrub the edges . The old racers trick of chalking the sidewalls and then checking after a couple of laps is a pretty good indicator of what's happening . Over inflating makes for crap handling but not so bad on nitrogen . Some cars like mine with ancient suspension weren't designed with radial tyres in mind so for a compromise I live with it.
But one thing I have found over the years is that different tyres even from the same manufacturer need a different set up to get the best. And why did Yokohama stop making the best road/race tyre the A008R ?

[ubrben]

Originally Posted by JohnD

Resurrecting this thread, with an anomaly.

Recent test day, and we're trying to be more scientific. Tread temps measured in the pitlane asap after a session.
But the temps. are contrary to tyre wear, and set camber (3 degrees neg.).
Cooler on the outside, where wear is clearly greater.

Car is a small saloon.
Does the air flow across the outer side of the tyre keep that cooler than would be expected?
Is temp testing only valid on open wheelers?

To me, wear is more telling evidence.
What do others think?

John

Could be cold tearing the outside of the tyre.

Ben

[greenamex2]

According to what I have read most of the 'control' of a tyre temperature is perfomed by it's contact with the road not air flow.

Irrespective of this, is it possible that the tyre is getting hot/wearing out on one part of the circuit and then that part is cooling down by the time you get back in the pits?

Also, how deep have you got your tyre probe set?

[meb]

As many answers as there are people...I was informed that the center temp should be the average of the outside and inside temps. I'm not suggesting this is correct, however. If the center temp is used as a guide in a sense, one can detect an inside temp that is too hot or an outside temp that is too cool.

I'm a little suspect about this generalization for all the reasons pointed out by so many above. But I have used this method to guide camber adjustments along with the fanny dyno while running around the track.

Unfortunately, a well performed cool down lap and the distance to pit make taking accurate temp measurments impossible in my case.

[AU N EGL]

Tire temps should be taken as quickly after a HOT lap as possible. Three readings across the tread.

If the the tire is HOT on the edges or cold in the middle add some air. If the the tires is hot in the middle, let some air out.

Hot one one edge might indiate you have a camber or tow problem.

Too much heat on the inside 1/3 = too much negative camber
Too much heat on the ouside 1/3 = too little negative or positive camber

[meb]

Exactly what I found. With my basic setup, I began with 3 degrees neg. Initial cornering power was quite good until the tires really warmed up afterwhcih cornering power fell off. I am happy with 2.2 deg neg as this produces a more consistent temp across the tread, and, is much more consistent thru an event.