16 replies to this topic

[gabuck]

In the past I've always run with softish anti-roll bar settings 150/130 F/R on 67 F1, aimed at balanced cross-tread temps by adjusting camber and tyre pressures. But I was never been able to get cross-car temperature balance FR/FL, RR/RL until I started to run high anti-roll bar settings typically 350/330 F/R on 67 F1. This appears also to give me 'geen' operating temps (in the readings in the figures at the bottom of the screen) which I could never get with my soft anti-roll bars.

Whilst the soft anti-roll bars and cool unbalanced temperatures gave me an easy car to drive, have I been seriously compromising the potential performance by running these settings?

Questions: 1) is there noticeably better grip with tyres temperature eg 'Blue'= Low grip, 'Green' = high grip, 'Red' = low grip ?
           2) is cross-car tyre temp balance important to achieve and if so are stiff anti-roll bar settings the way to achieve this?
           3) is it correct to assume that all circuits will tend to load one side more than the other (clockwise circuits loading the left) and hence cross-car balance will always be impossible to achieve? - and does it matter?

Geoff

[tooncheesef1]

1) When they change colour is just a guideline and can be edited in the ini file. There will be more knowledgable people on here who could tell you what to set them as.
2)& 3) 24/26 Pressure is the best for single seaters (GT - 32 all round - except Porsche 28 all round). After some hotlapping, in car setup it will say on the right tyre pressure hot/cold. If you try a set it so it is front 24, rear 26psi when hot then you should have optimum grip at speed.

Do you use asymmetrical setups? Tracks such as Monza or Silverstone reward lots of time by having cambers such like -1.75, -0.75. Dark and Steve Clloyd would be great people to ask about this they're normally about.

[Bob Simpson]

tooncheesef1, on Jan 14 2012 - 04:43 PM, said:

1) When they change colour is just a guideline and can be edited in the ini file. There will be more knowledgable people on here who could tell you what to set them as.

Not in the newest Pribluda.  The colours can be edited, but they change depending on the grip level rather than temperature.

[gabuck]

Bob Simpson, on Jan 15 2012 - 02:07 PM, said:

tooncheesef1, on Jan 14 2012 - 04:43 PM, said:

1) When they change colour is just a guideline and can be edited in the ini file. There will be more knowledgable people on here who could tell you what to set them as.

Not in the newest Pribluda.  The colours can be edited, but they change depending on the grip level rather than temperature.

Does this mean that one can forget the actual temperatures just make sure one stays in the 'green'?
Geoff

[Bob Simpson]

gabuck, on Jan 15 2012 - 05:04 PM, said:

Does this mean that one can forget the actual temperatures just make sure one stays in the 'green'?
Geoff

Pretty much yes.  But if you go to extreme tire pressures, you might find that the tires will never go into the green range.  I've seen with the highest pressures that they go from blue/cold/low grip directly to red/hot/low grip.

[Frenchy]

Bob Simpson, on Jan 15 2012 - 08:32 PM, said:

gabuck, on Jan 15 2012 - 05:04 PM, said:

Does this mean that one can forget the actual temperatures just make sure one stays in the 'green'?
Geoff

Pretty much yes.  But if you go to extreme tire pressures, you might find that the tires will never go into the green range.  I've seen with the highest pressures that they go from blue/cold/low grip directly to red/hot/low grip.

I'd just like to emphasise Bob's last point about the pressures. From my experience and discussions with Lee, it is more important to get the pressures right first, then you can adjust your setup/driving style to try and bring the tyres up to optimum temp. This will probably not be possible to do for all four tyres at once but as long as you get the temp right for your most loaded tyre (outside rear) and pressures right for the rest of them, then your optimising your grip when you need it most. After each session, go in to setup and check your tyre pressures, adjust the cold pressure so that the hot pressure is at optimum, then you'll have the widest possible temp range at which grip will be optimum.

Each mod has different optimum tyre pressures and temperatures. From what Lee has told me they are:

'67--261 F, 24 psi ft, 26 rear
'65--187 F, 24, 26
'69--261 F, 24, 26
'Sports Cars--261 F, 32, 32. P910--261 F, 28, 28

The '66 mod tires all use an optimum pressure of 26 psi and 207 degrees F.

The '69 and '69 Extra tires use the same optimum pressure and temps.

I'll have to check on the new F2 mod but I seem to remember it was the same as the 66 mod.

Remember also that grip is calculated from the patch temp not the core temp. (You can display both in prib.) So if you've got you're tyres nice and green while you're going down the straight they will probably go red as soon as you start to slide in the corners and around she goes   . You want the patch temp green at the time you need the grip the most.

Note also that over-inflating the tyres gives you an increased max speed as is often done for qual at Monza, but don't forget to lower them for the race or you'll be in the sand trap at Parabolica every lap.  

Cheers
David

[gabuck]

Frenchy, on Jan 16 2012 - 05:34 AM, said:

Bob Simpson, on Jan 15 2012 - 08:32 PM, said:

gabuck, on Jan 15 2012 - 05:04 PM, said:

Does this mean that one can forget the actual temperatures just make sure one stays in the 'green'?
Geoff

Pretty much yes.  But if you go to extreme tire pressures, you might find that the tires will never go into the green range.  I've seen with the highest pressures that they go from blue/cold/low grip directly to red/hot/low grip.

I'd just like to emphasise Bob's last point about the pressures. From my experience and discussions with Lee, it is more important to get the pressures right first, then you can adjust your setup/driving style to try and bring the tyres up to optimum temp. This will probably not be possible to do for all four tyres at once but as long as you get the temp right for your most loaded tyre (outside rear) and pressures right for the rest of them, then your optimising your grip when you need it most. After each session, go in to setup and check your tyre pressures, adjust the cold pressure so that the hot pressure is at optimum, then you'll have the widest possible temp range at which grip will be optimum.

Each mod has different optimum tyre pressures and temperatures. From what Lee has told me they are:

'67--261 F, 24 psi ft, 26 rear
'65--187 F, 24, 26
'69--261 F, 24, 26
'Sports Cars--261 F, 32, 32. P910--261 F, 28, 28

The '66 mod tires all use an optimum pressure of 26 psi and 207 degrees F.

The '69 and '69 Extra tires use the same optimum pressure and temps.

I'll have to check on the new F2 mod but I seem to remember it was the same as the 66 mod.

Remember also that grip is calculated from the patch temp not the core temp. (You can display both in prib.) So if you've got you're tyres nice and green while you're going down the straight they will probably go red as soon as you start to slide in the corners and around she goes   . You want the patch temp green at the time you need the grip the most.

Note also that over-inflating the tyres gives you an increased max speed as is often done for qual at Monza, but don't forget to lower them for the race or you'll be in the sand trap at Parabolica every lap.  

Cheers
David

[gabuck]

gabuck, on Jan 16 2012 - 01:39 PM, said:

Frenchy, on Jan 16 2012 - 05:34 AM, said:

Bob Simpson, on Jan 15 2012 - 08:32 PM, said:

gabuck, on Jan 15 2012 - 05:04 PM, said:

Does this mean that one can forget the actual temperatures just make sure one stays in the 'green'?
Geoff

Pretty much yes.  But if you go to extreme tire pressures, you might find that the tires will never go into the green range.  I've seen with the highest pressures that they go from blue/cold/low grip directly to red/hot/low grip.

I'd just like to emphasise Bob's last point about the pressures. From my experience and discussions with Lee, it is more important to get the pressures right first, then you can adjust your setup/driving style to try and bring the tyres up to optimum temp. This will probably not be possible to do for all four tyres at once but as long as you get the temp right for your most loaded tyre (outside rear) and pressures right for the rest of them, then your optimising your grip when you need it most. After each session, go in to setup and check your tyre pressures, adjust the cold pressure so that the hot pressure is at optimum, then you'll have the widest possible temp range at which grip will be optimum.

Each mod has different optimum tyre pressures and temperatures. From what Lee has told me they are:

'67--261 F, 24 psi ft, 26 rear
'65--187 F, 24, 26
'69--261 F, 24, 26
'Sports Cars--261 F, 32, 32. P910--261 F, 28, 28

The '66 mod tires all use an optimum pressure of 26 psi and 207 degrees F.

The '69 and '69 Extra tires use the same optimum pressure and temps.

I'll have to check on the new F2 mod but I seem to remember it was the same as the 66 mod.

Remember also that grip is calculated from the patch temp not the core temp. (You can display both in prib.) So if you've got you're tyres nice and green while you're going down the straight they will probably go red as soon as you start to slide in the corners and around she goes   . You want the patch temp green at the time you need the grip the most.

Note also that over-inflating the tyres gives you an increased max speed as is often done for qual at Monza, but don't forget to lower them for the race or you'll be in the sand trap at Parabolica every lap.  

Cheers
David

David.

This is most informative and really does clarify the issue of tyre temperatures for me - thanks v much.

I'm still unclear however whether very stiff anti-roll bars are the only way to get cross car temp balance.

Geoff

[Frenchy]

gabuck, on Jan 16 2012 - 01:43 PM, said:

David.

This is most informative and really does clarify the issue of tyre temperatures for me - thanks v much.

I'm still unclear however whether very stiff anti-roll bars are the only way to get cross car temp balance.

Geoff

Your welcome Geoff.

The cross car temp balance is (IMHO) not so important. If you have a track that is mostly turning one way then your outside tyres are always going to be doing the majority of the work while the inside tyres are just coming along for the ride. Optimising your pressure for all tyres is all you can do. The inside tyres will not get to optimum temp but if your pressures are optimised then your getting the best grip you can. The outside tyres are the ones on the limit and so they're the ones that count. The stiffness of your ARB's and suspension in general is more of a grip (soft) vs stability/response (hard) issue.

Cheers
David

[brr]

Frenchy, on Jan 17 2012 - 01:12 AM, said:

The stiffness of your ARB's and suspension in general is more of a grip (soft) vs stability/response (hard) issue.

GPL does not seem to punish a stiff setup that much. I drive almost always with a very stiff setup and at least on faster tracks have not noticed worse laptimes.

[gabuck]

brr, on Jan 17 2012 - 01:27 AM, said:

Frenchy, on Jan 17 2012 - 01:12 AM, said:

The stiffness of your ARB's and suspension in general is more of a grip (soft) vs stability/response (hard) issue.

GPL does not seem to punish a stiff setup that much. I drive almost always with a very stiff setup and at least on faster tracks have not noticed worse laptimes.

I've only just discovered still ARB and have found a noticable improvement in control, and in fact a more enjoyable drive !

Geoff

[colepole]

I ran LeMans a couple of weeks ago and I'm sure when using high pressures that It actually changed the final drive ratio (only slightly) as the tyres warmed up.

can anyone confirm this would be the case ... just out of curiosity.

[Michkov]

colepole, on May 07 2013 - 09:57 PM, said:

I ran LeMans a couple of weeks ago and I'm sure when using high pressures that It actually changed the final drive ratio (only slightly) as the tyres warmed up.

can anyone confirm this would be the case ... just out of curiosity.

Noticed the same, always thought the higher top speed on hot tyres was down to less slip ie more grip due the hot rubber.

[colepole]

Thanks Rob for the fast reply

Not sure you totally understood what I was getting at , I , will try to make myself clearer ............... i understand the low rolling resistance makes the car faster , however, I was quite impressed that Gpl could detect the fact that the diameter of the tyres had increased thus changing the gearing slightly

e.g @10,000 rpm on cold tyres = 203 mph ..... when hot @10,000 rpm = 204 mph ( yes I had plenty of time to study it on the backstretch )

Oh and Michi ...... I'm glad I wasn't the only one ;-)

Regards Col

[MGL66]

Frenchy, on Jan 16 2012 - 05:34 AM, said:

Each mod has different optimum tyre pressures and temperatures. From what Lee has told me they are:

'67--261 F, 24 psi ft, 26 rear
'65--187 F, 24, 26
'69--261 F, 24, 26
'Sports Cars--261 F, 32, 32. P910--261 F, 28, 28

The '66 mod tires all use an optimum pressure of 26 psi and 207 degrees F.

The '69 and '69 Extra tires use the same optimum pressure and temps.

I'll have to check on the new F2 mod but I seem to remember it was the same as the 66 mod.

Does anyone have the optimum tire pressures/temps for more recent mods, like CA66, CA71, and the '55 mod?

Thanks,
Michael

[gliebzeit]

Optimum tire (tyre) pressure at normal running temperatures:

55Mod - 40psi
CA66 - 26psi
CA71 - 24psi