Track Day Tyre Temps

[jason90]

Was at the track today in my Cateraham and out of curiosity I decided to record the tyre temps after each session as follows,inside edge/centre/outside edge

I was expecting differant temps from each tyre and may be a degree or two differance on the individual tyres

But I was suprised to find temperature variations as much as 15 degrees, on the same tyre

I realise there are probably a million and one things that could cause this

Was this a waste of time or will the figures actually mean something

I am working on the assumption that if I can get the temps across the tyre almost the same it will improve times

This worked to a degree as I knocked on nearly 2 secs off my time after playing with tyre pressures

I suppose the next thing to do is play with the camber ?

Any advice greatly appreciated



Any advice greatly appreciated

[rustybin]

I would suggest that if the car is handling 'funny' then tyre temps help diagnose the problem but I wouldn't use them as a set up tool. Measurement is far too imprecise at a track day particularly if you are on your own. You should also be having a cooling down lap on the way in which renders it all a bit null and void.

You may also want to keep the timing yourself thing a bit schtum being a track rather than test day

[JeffC]

sounds like your set up is a country mile away?
I had my westy corner weight set up and full geo change couple of weeks ago, tyre temps were checked at Croft last week and I had equal temps across all of the tyres..

set up I run 2deg neg front and 1deg rear, 1mm toe in rear 1mm toe out front equal weights on front wheels , think temps were 40 degrees front and 50 degrees rear, was a cool day and I dont really have any downforce (tyres were michy slicks) edited to say tyre pressures were set at 15psi , car weighs 499kg.

Edited by JeffC on Wednesday 26th September 19:06

[Bellly]

jason90 said:

But I was suprised to find temperature variations as much as 15 degrees, on the same tyre

you stated 15 deg variation, but what were the temps: Inner, Middle, Outer
It is true that you will lose heat on your cool down lap, but there is a lot to be gained by assessing tyre temps across the tyre.

[jason90]

Bellly said:

jason90 said:

But I was suprised to find temperature variations as much as 15 degrees, on the same tyre

you stated 15 deg variation, but what were the temps: Inner, Middle, Outer
It is true that you will lose heat on your cool down lap, but there is a lot to be gained by assessing tyre temps across the tyre.

Biggest variation was from front left

Front Left
Outside edge 40
Centre 49
Inside edge 55

Front Right
Outside 52
Centre 53
Inside 55

Rear Left
Outside 50
Centre 55
Inside 54

Rear Right
Outside 57
Centre 56
Inside 57

Was running Toyo 888's at 20 psi

Edited by jason90 on Wednesday 26th September 19:52

[Bellly]

How much camber are you running on the front? May be worth reducing front camber slightly?
How was the car handling? Any understeer?
20 {cold?} psi seems very low, but then i am not clued up on these tyres/car

[jason90]

Not sure on the camber, only had the car a few months and have been just getting to grips with it on the track

No more understeer than usual, but then again I have not got anything to comapare it with. Think I'll get it booked in and set up by a garage and see if that changes anything

20psi cold seems to be about the norm, I know some people run them lower than that

Thats what its all about I suppose, seeing what works best, and hopefully learning along the way

[Bellly]

not really sure that i would change a lot on the car at the moment, all the other cross tyre temps look really good, if the tyre wear is even, i would save your money and enjoy the driving.
Or you could try slicks

[JeffC]

pressures should be checked hot, If I have 15 cold they sky to 20psi after some abuse, I always come in and re-adjust.

your 20psi cold could go up to 28psi hot which for a light car would be hopeless for grip as you wont have the weight to keep the full tyre on track.

[jason90]

Tyre wear is pretty even across all tyres, just slightly worse on the front left, but still even

Slicks would be great but they are not available here, and by the time Ive shipped them over I might as well bt a new car

[jason90]

JeffC said:

pressures should be checked hot, If I have 15 cold they sky to 20psi after some abuse, I always come in and re-adjust.

your 20psi cold could go up to 28psi hot which for a light car would be hopeless for grip as you wont have the weight to keep the full tyre on track.

Spent the last 2/3 tracks days playing around with the temps, 20 seems to work best, any lower and grip just seems to run out

Played around with the pressures tonight, went as low as 15 at one point but had to come back in

[Bellly]

Cant see anything too far out. Are you using it at the Autodrome? At least you are not having to worry about wets!
If you can get a set of slicks, then you would see a massive difference in grip levels and they would last a while.
you would probably get away with them on the road over there!

[jason90]

You know the autodrome then?,

Driving on the highway on slicks is not really a problem, really depends on the day of the week and which phase the moon is in

[Bellly]

Spent a few year in Dubai and may be doing the 24hr in January.... When i lived there in 1986 - 1989 there was not too much there!
Great place though!

[batman69]

jason90 said:

Bellly said:

jason90 said:

But I was suprised to find temperature variations as much as 15 degrees, on the same tyre

you stated 15 deg variation, but what were the temps: Inner, Middle, Outer
It is true that you will lose heat on your cool down lap, but there is a lot to be gained by assessing tyre temps across the tyre.

Biggest variation was from front left

Front Left
Outside edge 40
Centre 49
Inside edge 55

Front Right
Outside 52
Centre 53
Inside 55

Rear Left
Outside 50
Centre 55
Inside 54

Rear Right
Outside 57
Centre 56
Inside 57

Was running Toyo 888's at 20 psi

Predominantly left handed track?

Edited by jason90 on Wednesday 26th September 19:52

[rustybin]

[quote=batman69
Predominantly left handed track?

[/quote]

& right hand drive light weight car?

[jason90]

The track is Predominantly right handed

The car is LHD

[rustybin]

jason90 said:

The track is Predominantly right handed

The car is LHD

In that case I probably would have the geometry and corner weighting looked at.

[jon-]

You're hotter on both right sides which makes it look like a LH track. Are the last few corners before the pits left handers? Otherwise something is very wrong.

It's quite normal for the inside of the inside front tyre to be a fair bit hotter than the rest of the tyre the way it gets dragged around the inside of the corners.

Edited by jon- on Friday 28th September 13:24

[Bellly]

Dont know if i agree with these comments, the tyre temps are pretty uniform except for the LH Front which looking at the temps across the tyre would indicate a touch too much camber. However, that could be just down to driving style and not loading the LH Front in the corners.
If you have any doubt, get someone who has loads of experience to drive the car hard before you start changing things.
Geometry and corner weighting are fine, but unless the car is a 'mile out' drive it first and then make small adjustments rather than changing everything.