The Black round things and using them properly

[THR]

hi

we have a pyrometer. which we plan to use this year on 8's and 10's slick tires.

the car being a single seater formula renault at circuits.

the question is...

what is the operating temperature of slicks?
circuit grade... dont know the actual numbers yet, or grade. ill have to find out.

we know the inside of the tyre needs to be a few degrees hotter than the outside. and that u measure the temps across the tires in the 3 places below the tread.
not on the surface.

so your thoughts on temps please!!
im sure u lot have something to say about this as its bloody important really!

[yelwoci]

THR,

The idea of measuring the Tyre temps is to indicate how the driver/chassis is using the tyres.

Ideally you want even temps (with 3C) across the tyre and you don't want any anomalies.
80/60/60 would suggest running too hard on the inside, due to camber.
60/80/60 would suggest running too high pressure
60/60/80 not running enough camber or tracking problem
80/60/80 would suggest running too low pressure

When pushing the probe under the tread go in at a tangental angle and watch for that tell tale hiss....followed by someone giving you a good kicking!

Then you must compare all corners which each other, to look where you might gain. This must be done with a view to the circuit and with the style of the driver.

What they should be depends upon tyre, so ask the manufacturuer.
My 250hp 1982 RX7 running on Dunlop D84Js (similar to TA R1) run about 55C, whereas F1 runs about 100C.
The way I drive my car, which is not hard enough(!), the tyres come in very even all round and a bit too cool.

Regards
IanC

[enzo]

With bias ply tires, look to get the temps fairly even across the tread width, with the inside slightly hotter than the outside. With radials and some newer design bias ply (that are damned near a radial), look for the inside to be 10-15C hotter than the outside, with the center the same as the inside.

To see if the camber is ok, look at how far any scuffing goes around the shoulder and onto the sidewalls. It should be nearly the same on both sides of the tire. Depending on what you see, combined with the temp spread, you will want to adjust both pressure and camber to suit.

[yelwoci]

Enzo,
Perhaps that's why I was going so slow on my 'road' radials!

I've got an excuse......

:-))
IanC

[THR]

but what is the temp for a single seater racing slick?
not F1!
F3 would be nice to know, as this is probs wot we shall be running.

[ma]

I don't know anything about what the tires are like that you will be using, but you can typically expect to want to see 175-195 F for a reletively soft racing compound to be at it's best, and upward of 200 - 240 F for a hard racing compound. I haven't got a clue about street radials!

[Tony Harman]

Hi THR
As Yelwoci says - ask the manufacturer - they will absolutley be able to tell you optimum operating temperature and pressure, make sure you also measure the tyre pressures as soon as you come off the track, it's handy to have someone who can rush round the car and shout out the pressures quickly before they start going off. (Assuming of course they're allowed into Parc Ferme)
I've got a pyrometer but don't use it that often as I KNOW I'm not getting them hot enough !!
A friend of mine has got one of the infrared pyrometers, they're great because they're so fast but also he can check out other peoples tyre temps without them knowing to see how he compares (and who says size doesn't matter eh ?)