Author Topic: Tyre pressure question  (Read 2365 times)

[SJ]Pierre61

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Tyre pressure question
« on: January 12, 2007, 08:11:23 pm »
The received wisdom is that there should be an even pressure spread after a few laps, yet I read that it's a good idea to increase the pressure for qually. I thought that lower pressures gave you a larger 'footprint' for the tyre... which to my mind would be advantageous....

Confused  :jawdrop:

[SJ]Byron

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Re: Tyre pressure question
« Reply #1 on: January 12, 2007, 08:26:40 pm »
I see that THez and Steiny are viewing this topic, so I'll keep schtum and let you get some useful info!

[SJ]T Hez

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Re: Tyre pressure question
« Reply #2 on: January 12, 2007, 08:35:03 pm »
Higher tyre pressure will result in tyres warming up faster AND better steering response. Most of the times you'll be able to run faster laptimes if you do shorter stints with limited fuel. You also want the tyres to reach their ideal temperature range in those laps, so sometimes it can be usefull to raise tyre pressure. Make sure to raise the pressure only slightly as you'll risk "ballooning" the tyres (which is bad  :) ).
Don't think it has that much influence in GTL though...

sandyk

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Re: Tyre pressure question
« Reply #3 on: January 12, 2007, 08:56:55 pm »
Have to agree with Hez.. if you raise pressure for qually it will be to get heat into the tires quicker, e.g. on your outlap so the flying lap you should be good to go hard.
To add to increasing tyre pressure for qual, when on my outlap, I am usually on and off the gas pretty hard, not only to try to get heat into the rears, but bring the brakes up to temp also, so on that flying lap when you throw out the anchor at T1, you can feel confident your brakes will work. Am not sure if brake temp affects tires in rF, but I have watched the GT3 porsche guys here do it to get heat into the tires too.

I once tried to use the same theory as initially posted "I thought that lower pressures gave you a larger 'footprint' for the tyre... which to my mind would be advantageous...." so tried it in a Kart on a practise day for an enduro. I had no grip and the kart slipped off the track and rolled...wont ever do that again.

[SJ]Riven

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Re: Tyre pressure question
« Reply #4 on: January 12, 2007, 09:14:04 pm »
Just to throw another spanner into the mix, in certain mods you have tyre selections to pick from aswell.

Obviously, you'll be wanting the softest tyre available.  In the F1-1979 mod for example you have 'qualifying' tyres.. these rock, and give grip instantly on the outlap even.  However they only last for 2 laps due to their extremely soft nature.

[SJ]T Hez

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Re: Tyre pressure question
« Reply #5 on: January 12, 2007, 09:17:09 pm »
Dropping the pressure too much will cause really bad deformation of the tyres. In extreme circumstances tyres could even "slide" over/of the rims... No more grip, no more (car) control  :lag:

Also, lower tyre pressure => higher rolling resistance => slower acceleration and less top speed. You can experience this effect quite well with some of the lower powered cars.

[SJ]Pierre61

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Re: Tyre pressure question
« Reply #6 on: January 12, 2007, 11:04:03 pm »
Thanks for the knowlegable responses lady and gentlemen, I've read them twice... and, hopefully when I've read them thrice, I shall 'get it' :)

Thanks again
Pete

[SJ]Satain

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Re: Tyre pressure question
« Reply #7 on: January 13, 2007, 04:26:09 am »
Just read this post and... 0:  :jawdrop:  :jawdrop:  :argh:  :argh:  :argh:  :argh:  :argh:  o:  o:  :grrr:  :grrr:  :grrr:  :grrr:  :grrr:

All this time i have been LOWERING my tyre pressures thinking that they would last longer, and that was it. Never new this other stuff. AHhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh maybe after this my times will improve a little.
« Last Edit: January 15, 2007, 10:22:48 am by SJ_Satain »

[SJ]nissan man

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Re: Tyre pressure question
« Reply #8 on: January 13, 2007, 10:07:00 am »
you best guide to setting your tire pressure just right is the tire temps of the inner/mid/outer parts of the tire. they should never varie more than about 10 degrees C. of course many other factors affect those temps.

sandyk

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Re: Tyre pressure question
« Reply #9 on: January 13, 2007, 11:13:00 am »
thats a good point David,  I forgot about when i build my setups. I actually aim for no more than 10 degrees difference in temp from inside to outside temp, which seems to work pretty well for me.. I adjust the cambers until the outer and inner tempos have that 10 difference, then i drop the pressure or raise it until its mid way...

BTW, David, I have you to thank for getting me and my man into slotcar racing (cos we followed a link you  put up once)..we recently joined the local club here and are about set to embark on building our own wooden track :)
« Last Edit: January 13, 2007, 11:15:14 am by SJ_sandyk »

[SJ]dirtyvfr

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Re: Tyre pressure question
« Reply #10 on: January 15, 2007, 10:21:51 am »
i will ponder this and have a look about on the net, it's a complex issue and there might be a bit of confusion.

[SJ]dirtyvfr

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Re: Tyre pressure question
« Reply #11 on: January 15, 2007, 01:43:52 pm »
« Last Edit: January 15, 2007, 07:46:21 pm by SJ_dirtyvfr »

[SJ]kzcole

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Re: Tyre pressure question
« Reply #12 on: January 19, 2007, 08:59:13 am »
Interesting tyre related points. O0

Ive wondered how critical it was for all four tyres to be similar temps in relation to each other. With my hairy setups , I often have left front tyre being 30-40 degree hotter than rest of the car.I assume thats somthing to do with teh whasaname up the front thayt ye can adjust..

[SJ]Byron

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Re: Tyre pressure question
« Reply #13 on: January 19, 2007, 10:12:43 am »
Quote
teh whasaname up the front thayt ye can adjust


Now you're talking my language!

 :)

[SJ]T Hez

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Re: Tyre pressure question
« Reply #14 on: January 20, 2007, 12:44:46 pm »

[SJ]Satain

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Re: Tyre pressure question
« Reply #15 on: January 21, 2007, 12:24:42 pm »
Thanks for that T, and in words i can understand!  :excited: