Spring rate help?

BGTV8

You want not more than 10-15 degrees C total spread between inner, middle and outer tyre measurements and the spread needs to be even. If the temps inner to middle are close, you can drop some camber.

The other thing to remember is that unless your pit is closest to pit entry, you will drop temps in the time take to transit the pitlane .. can be as much as 10 degC or more.

An R-Spec tyre that measures under 65-70 DegC is probably not working hard enough to generate maximum grip.

An infra-red temp gauge is an approximation only - you want a pyrometer with a probe to get into the tread proper for accurate readings, UNLESS the IR technology you are using is top-shelf (professional motorsport quality)

wstar

Eh, I doubt there's a ton of difference in various IR temp gauges. They're just a simple scientific instrument, and they have a certain accuracy and work a certain way. My Fluke (that I originally bought for electronics stuff) claims 1%, and coming off a DE cooldown lap and all the way back into the paddock I'm sure contributes way more error than that. I get that the the pyro in the carcass in the hot pit is more-accurate, but at this level I generally don't need to be more accurate. I just want to know the general shape of the temps: which band of the tire is running hotter or colder.

This is kind of what I was talking about at one point earlier, about trying to find out what it really matters to obsess over at an amateur/learning level. There's a pretty wide gap between "what you need to measure/adjust/fix just to make the car reasonably-drivable and not destroy tires", and "what you want to do to squeeze every thousandth in tight competition". In some areas I still have no idea where to draw the line yet. But I'm pretty sure at this point that tire temps/pressures, as critical as they are to the car, can be done for DE-level stuff with just an IR temp gauge and a simple pressure gauge after getting back to your parking spot in the paddock and still get you in the ballpark well enough. Most of the time you can even see gross pressure/alignment errors visually if you just look at how the rubber melts/wears.

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Journal thread / Car setup details

BGTV8

It is not so much about differences, but the fact that an IR temp reader reads the surface temp but what you really want to know is the temp in the underbelt

Anyway, for amateur purposes, you are mostly correct - it is the relative difference between inner, md and outer temps that is key ... you want an even graduation of temps - say 5 DegC apart - across the face of the tread as a lead indicator to camber sweet spot. What I am trying to communicate is that you want to measure these differences as close to hot-track exit as you can - i.e. by the time to trundle down the put lane and turn to the paddock out-back, your graduations will have morphed significantly enough to distort the knowledge you are after. Tyre pressure will be affected as well, but nowhere near the same extent.

For example, real-time monitoring of my RHF tread surface temps at T12 at Philip Island GP circuit (290mm wide Dunlop SS12 compound slick) now shows (inner to outer) going from 88/85/82 to 108/100/94 in the space of 150 metres as the car is turned in and accelerated thru the mid-corner. Once I take steering angle out of it, the temps drop 15 DegC in the next 300 metres. I borrowed the setup from a semi-Pro team because I was blistering the inside of the RH front at PI after a track resurface a few years ago because the settings I was using from prior seasons was too agressive and we had to take a bit of camber and some toe out of the car to get the tyre to last (blistering set in with temps over 115 DegC on the SS12).

One of our 370Z owners over here (Keith Flanagan - KF365 here) had a couple of delamination/tyre failures with Dunlop DZ03G in T12 as well, because it is a very hi-speed corner and the car stays loaded for an eternity (maybe 8-10 seconds from turn-in until you pull all the steering out of the car). It is the temps in the carcass that lead to failure, not the outer tread surface ....

On a cold day where track temps are ~15DegC, by the time I exit the track and get to the top of pitlane (where crew can use a probe on the tyre), the IR surface temps can be back to 60 DegC or less but the temp under the surface layer can be up to 15 Deg higher - so it can be very easy to get confused. That is my real message !!

Toe (and caster) can also influence heat build-up on turn-in and in the case of toe-out, inner temps in straight running.

This thread had an earlier post on the inter-connected-ness of springs, suspension settings and even driver habit and if I have learned one thing in the past 40-odd years, it is that there is always something new to learn, that simple things usually work best - because us amateurs don;t have the funds to invest in full-time engineers to can run the calcs all the time. There were a couple of book titles recommended as well which are a great source of information and the basis for personal experimentation.

Keep experimenting and you acquire knowledge .... and tread your own path !!