Tyre pressure's and karting

[maddogf3]

We race in ARP F3 and I wonder if any of you could tell me in a few words what tyre pressures you run? how many laps you race for? .How you expect the tyres to behave and what is the maximum pressure you run the tyre's at? . This is only a general question for interest ,I dont expect for any one to give any secrets away . Regards Martin

[speedy king]

With Rotax Max and Vega SL7's we run about 12-14 psi, less PSi for hotter temperatures and higher for cold though this can vary at different circuits for different grip levels. For the W2 wets we ran in juniors 20Psi, we recorded fastest laps on this setting, some ran 40psi which i think is way too high.

Over the period of a 10 lap race you expect the pressures to rise. So if you go out on a higher setting you may be quick for the first 3-4 laps but then may drop speed off in the latter section and vise-versa

[maddogf3]

Thanks for that . Its exactly what I thought you would say and the same as we do with our 13inch dia stuff .( we run 14-16)
But can I ask if any of you have experimented with the theroy of " a lower pressure gets hotter quicker" and thus might lead to overheating .Where a higher pressure runs cooler .My interest is to do with qualifing . where we do not do the same ammount of laps and there for need a tyre to do its stuff quickly . I have not got the guts yet to send my driver out with low pressure and tell him to go for it . after a warm up lap . Its me that has to put the car back together .
regards Martin

[Ali Rushforth]

When I ran in ICA, I used to run about 8 - 12 depending on temp in the dry, and no more than 20psi in the wet.

I now run guys in TKM, and we break away from the norm, everyone says to run 18psi in the dry, but we run lower, never had many probs, same in the wet, people run in excess of 25psi, we run now more than 15psi, and we don't knacker the tyres!!

In my mini, with 12 inch wheels, I run in 30min qualifying and 40 min races and run 30psi front and 45+psi rear!!!

[speedy king]

We ran lower pressures with SL8's and straight away the thing just bogged out of corners and over heated, wouldnt recommend it

[TomS]

From both karts and Sports 2000 we've found:
higher pressure = get hot quickly however will go off in a 20/30min race in sports 2000 due to overheating
lower pressure = get hot much slower however wont go out throughout the race however dont run too low as they can roll of the rims etc

[jjordan]

Anything against running nitrogen in the tires? Many of us "dirt trackers " here in the states run it to stabilize pressure's from cold to hot. The pressures on the ovals are secondary to the stagger (rolling circumference). The pressures go low to just before the point where the tire tries to roll over and absorbs horspower (bad, bad.)

[Richy_Rich]

Big thread on tyre pressures here http://tentenths.com/forum/showthread.php?t=69037

Not specific to karts, but you may find something of use...

[MikeyG]

I find that at circuits where corners are more to left than the right for instance, the outside tyre runs out of tread quicker. Non rotationals are easy to rectify, you just swap tyres round, but what about rotationals. What do you do then????

[Ali Rushforth]

For rotational tyres, remove the tyre from the rim and move accross the axle.

eg, left rear tyre, removed from rim, still pointing the correct way, moved to the right rear rim. (The inside edge of the tyre becomes the outer edge and vise versa)!!!!

As for running nitrogen in tyres, I tried it but seemed to make no difference. Also, if you plan to run with nitrogen instead of air, make sure you fully deflate the air from the tyre, then inflate with nitrogen, deflate and re-inflate. This ensures that there is no air left in the tyre, it also helps remove any moisture from inside. If you don't do that then the moisture/remaining air makes adding nitrogen a pointless excersise.

[maddogf3]

Thank you gentlemen for all that info and feed back We Run nitrogen too . We found the tyres pressure are a lot more stable as regards pressure build up and drop off. I would recommend its use . They also drop to the cold pressure after about an hour sometimes very useful if you messing with pressures
Thanks again Martin

[maddogf3]

Originally Posted by Richy_Rich

Big thread on tyre pressures here http://tentenths.com/forum/showthread.php?t=69037

Not specific to karts, but you may find something of use...

Thanks richy I contributed to a lot of that anyway to see where it would go .It seems we all do it different anyway and hopefully get the same results by finishing near the front .
"Nitrogen Still Rules OK"