AD08S gone blue.

[PBCup]

So obviously can't be a good thing but how much does having the blue edges matter?

 

[Tony Hunter]

Not the end of the world, but they have got too hot.

​These sort of tyres need looking after.

 

[imprezaworks]

Tony do you rate these tyres, I'm getting a set fitted tomo or fri if they turn up

 

[Chi]

Mine were perfect at llandow !!

 

[Joe#]

Mine were perfect at llandow !!

What pressures were you using?

 

[Tony Hunter]

They ain't too bad for a road tyre.

Don't let them get below -10 though.

 

[Adam G]

Mine were perfect at llandow !!

I can vouch for that mate, they felt pretty good from the passenger seat. I was impressed with them, be interesting to feel from a driving point of view and pushing them just that bit more.

 

[imprezaworks]

Only one way to find out I guess. It was a toss up between a few different makes. These seemed to tick a few more boxes

 

[PBCup]

I rate them, the grip is good and they don't roll over like normal road tyres do. On PE2s you could barely read the brand after a day at Mallory. The AD08s (apart from the blue tint on the edge) look good.
Not like it really matters but almost unusable in snow.

 

[Chi]

30 hot

 

[AdDaMan]

my P Zero Nero has gone blue on the edge too. Too much pressure you reckon?

 

[Sam@NP]

my P Zero Nero has gone blue on the edge too. Too much pressure you reckon?

​What were your hot pressures?

 

[imprezaworks]

So what's a good starting pressure?

 

[AdDaMan]

​What were your hot pressures?

Not sure didnt test them. Cold was 32psi

 

[imprezaworks]

I'm no expert but lol at 32 cold

 

[Chip-mk1]

PV=nRT

So if you were 32 psi at say 300 degrees (cold) then at 400 or so degrees you would have been WELL into the 40s.

 

[PBCup]

I ran mine at 25 cold front and 27 cold rear.

 

[Chip-mk1]

I ran mine at 25 cold front and 27 cold rear.

We started at 24 front and 26 rear at llandow, and the front pass side still went upto 34 so we let some back out.

 

[AdDaMan]

Yeah they were that high because the sidewalls are so weak. And these are 16's not 15's. (and not on track!)

 

[Tony Hunter]

Lol.

 

[Adamm.]

I thought about 30 was right for road?

 

[JamesBryan]

I thought about 30 was right for road?

Book says 30 rear, 33 front for road.

 

[Adamm.]

Book says 30 rear, 33 front for road.

Yup thought as much, lol.

 

[JamesBryan]

Yup thought as much, lol.

Obviously couldn't leave it like that and go out on track, would be well into the 40's when hot.

 

[Adamm.]

Obviously couldn't leave it like that and go out on track, would be well into the 40's when hot.

Oh yeah definitely, lad that asked never mentioned being on track

 

[JamesBryan]

Oh yeah definitely, lad that asked never mentioned being on track

Ahh you're right. Why ask about normal pressures in a track tyre thread though

 

[Tony Hunter]

If you do a bit of hooning on a hot day, they will soon get very hot.

​Has anybody checked their tyre pressures after a quick blast up the road..... No, thought not.

 

[Steven103]

​Has anybody checked their tyre pressures after a quick blast up the road.....

I have But I'm going with "was curious as to the temperature addition on a road car in comparison with a race car" as opposed to "being anal" though...

 

[Tony Hunter]

And your findings were ??

 

[Adamm.]

No I haven't but I have felt the tyre and it has felt quite hot lol.

 

[Chip-mk1]

And your findings were ??

My findings were that pressure increases with temps in line with boyles law as expected but therefore not as much as on track as temps weren't as high.

 

[Tony Hunter]

Frankie Boyles tell a good joke or two.

 

[Nick172Cup]

Frankie Boyles tell a good joke or two.

Funny live also!

 

[Steven103]

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.

 

[imprezaworks]

Fitted mine and they feel good with the minimal mileage done. So when on track from cold set them to what? Then after a couple of laps and check what they go to when hot. So my question and feel free to fill the blanks chaps

cold______psi.
hot_______psi.

 

[Tony Hunter]

I can get mine up to 80deg, with a 10 deg difference across the tyre width.

A day like today I would start at f 24 psi r 27 psi, then check after every 3 laps.

​Have started with the fronts as low as 19 psi before now.

 

[Adam G]

Have a look what Yokohama say, just to throw some brown stuff at a fan.

 

[Steven103]

Drop cold pressures maybe 7 PSI front, 3 PSI rear (from road car 33/30)
Do 3 - 5 laps (lower lap count if you're car/driver isn't working the tyres much, higher lap count if you're working the tyres properly & getting brake temp (thus the all important wheel temp!)).
Pit & drop tyre pressures to your target pressure (rule of thumb is 2.0 bar hot as a baseline to start from for a racing slick).
At end of session wait till tyres cool down to ambient temp.
Take cold pressure from each tyre.

That will give you a good starting point for cold pressures for those exact conditions. Then adjust (by trial and error) depending on tyre wear, wear patterns, track layout, car setup, driver etc (the list is endless)

Where does 7/3 PSI come from? Needing a safe cold pressure & the fact that it's far easier to bleed air than add (cold) air to a (hot) tyre.
Where does 3-5 laps come from? A good assumption for when temps & pressures stabilise for this thread.
Where does 2.0 bar come from? This is a fair "average" value given by tyre manufacturers for racing slicks. Pressure creates structure & therefore mechanical grip. Temp creates chemical grip through tearing the tyre surface (on a teeny tiny microscopic scale) and revealing fresh rubber
Why take a pressure from each tyre? Because, if the tyres are being worked, each corner will experience a different amount of load, therefore generate a different amount of heat, therefore expand the air in the tyre a different amount, therefore needing different cold pressures to ensure everything comes up to the same pressure when hot.

Have a look what Yokohama say, just to throw some brown stuff at a fan.

Have you tried to get tyre data off of a manufacturer's website before Let me know when you find anything more detailed than rolling circumferences or (at a stretch!) operating windows for pressures and temps.

 

[imprezaworks]

I can get mine up to 80deg, with a 10 deg difference across the tyre width.

A day like today I would start at f 24 psi r 27 psi, then check after every 3 laps.

​Have started with the fronts as low as 19 psi before now.

That's good enough for me, cheers tony

 

[Tony Hunter]

I know that ^

The one above.

And yes, manufacturer's are very sketchy when it comes to this information.