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AD08S gone blue.



  172
Oh yeah of course, I hope I didn't come across as rude - no intent. Promise! :p

But if CS was only full of things that you & the likes of chip didn't know, then there'd be nothing in between for us mortals!
 
  WRX
Have you tried to get tyre data off of a manufacturer's website before :p Let me know when you find anything more detailed than rolling circumferences or (at a stretch!) operating windows for pressures and temps.
I prefer what feels right to me, I can use other people's figures as a rough guide but until I've put their theory into practice, I have an open mind. I will say that I was a little surprised when I saw their numbers lol.
 
  Lotus Elise
Interesting thread, but it just reinforces my opinion that by far the best way to go about tyre pressures is to just forget theory & set them when hot. So many variables to account for, that theory takes too long compared to a few installation laps.

Only when you have a lot of constants (a driver that works the tires sufficiently, a setup that doesn't change massively) and some past data is it viable to start making improvements to any predictions based on PV=nRT. When you really think about it, you realise that not a single letter in that equation is a simple one.

The average hard compound racing slick (sports & production, no idea about formula cars) has an operating window of what, 80 - 100 degrees Celsius. How many club racers let alone track day drivers achieve that surface temp with the sort of ambient temp we get in the UK.

I 100% agree with you when it comes to track days, racing is very different though and then there's racing on slick! 100 degrees for a slick is too high 95 degrees and you're falling off the performance plateau.

Regarding tyre data speak to your supplier every motorsport tyre supplier I've dealt with has been hugely helpful sending all sorts of data, graphs etc. Yokohama and Pirelli have it hidden away in downloadable PDF on their motorsport website.

I love how much tyres affect vehicle dynamics.
 
  182cup & 172 racecar
Oh yeah of course, I hope I didn't come across as rude - no intent. Promise! :p

But if CS was only full of things that you & the likes of chip didn't know, then there'd be nothing in between for us mortals!

​Lol, I don't know a lot really, just old.
 
  172
Well that's why I was surprised, the Avons used in British GT (I think you did the GT4 class a few years back, or am I making that up) seemed to hate anything north of 90 & Dunlops in the smaller sizes look like they'd absolutely destroy the shoulder if they got anywhere near that, whereas Pirelli quoted 80 - 110 degrees for the equivalent tyre :eek:

You had much useful advice from emailing? I know the trackside advice can be fantastic, but most people aren't fortunate enough to be buying several new sets at each circuit. I know as an Engineering student you've got far more interest than most, but would you say you put more thought (vs track time) into tyre pressures than most higher-level club racers? It would seem you need a season or two worth of data before you can use PV=nRT more accurately than simply dropping hot pressures throughout FP sessions.

Indeed! It's a cliché but they are the only contact patch... My favourite bit is going backwards. You can determine so much about how the car is working from wear patterns, graining size direction etc really quickly. Probably less interesting for you, since you can tell what the car's doing because you're the one fighting it :p


​Lol, I don't know a lot really, just old.

Experience is hardly worthless is it!
 
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  Ph2 172 Track Toy
Isn't a bit of trial and error or even common sense the way to go for your average trackday goer?

I just picked my pressures cos it sounded good in my head. The car felt good to me so I'll go with that again. It's a shame I turned them blue but I dare say that was down to the 30 min session at the end of the day where I was really pushing. But in my defence I was having lots of fun.
 
  Lotus Elise
Well that's why I was surprised, the Avons used in British GT (I think you did the GT4 class a few years back, or am I making that up) seemed to hate anything north of 90 & Dunlops in the smaller sizes look like they'd absolutely destroy the shoulder if they got anywhere near that, whereas Pirelli quoted 80 - 110 degrees for the equivalent tyre :eek:

You had much useful advice from emailing? I know the trackside advice can be fantastic, but most people aren't fortunate enough to be buying several new sets at each circuit. I know as an Engineering student you've got far more interest than most, but would you say you put more thought (vs track time) into tyre pressures than most higher-level club racers? It would seem you need a season or two worth of data before you can use PV=nRT more accurately than simply dropping hot pressures throughout FP sessions.

Indeed! It's a cliché but they are the only contact patch... My favourite bit is going backwards. You can determine so much about how the car is working from wear patterns, graining size direction etc really quickly. Probably less interesting for you, since you can tell what the car's doing because you're the one fighting it :p

Yeah we did GT4 on Avons by far the worst slicks I've experienced. The lap time barely drop off after 4/5 heat cycles which tells you more about their performance when new rather than their durability.

We race on Pirelli and they are hugely helpful, they gave us a bollocking at Oulton as our rear tyres were 101 and told us to keep them below 95. We are test with Pirelli next month actually :)

I wouldn't say I've put more thought into pressures then most club level racers but I'd say some out their certainly don't put enough effort in but more so with temperatures. I'd say I've certainly put more effort into reading and researching though.

Tyres tell you everything and can be wonderful things when its all going well but can be absolute b******s when when they want. I'm such a tyre geek.
 
  182/RS2/ Turbo/Mk1
Isn't a bit of trial and error or even common sense the way to go for your average trackday goer?

I just picked my pressures cos it sounded good in my head. The car felt good to me so I'll go with that again. It's a shame I turned them blue but I dare say that was down to the 30 min session at the end of the day where I was really pushing. But in my defence I was having lots of fun.

Theory is useless without having some experimentation as well, equations can be useful to get you in a reasonable ballpark but you will always rely on trial and error to fine tune.

Also trackdays are about what feels good, not always what is quickest, where as a racer will sacrafice feel for speed, so the same numbers dont always apply to both.
 


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