Apologies if you are fed up with answering this question time and again, but your feedback would be much appreciated. graemlins/thumbup.gif

Just wondering what pressures you guys are running on track days.....(I ride a 98 750)

Cheers in advance! images/icons/grin.gif

I run 30/30, but that's just me. Sometimes...when it's 110 degrees or hotter...I'll drop the front to 29. Again...my 2 pennies.

You drop the pressures on hot days?? That doesn't seem a bit backwards?

It depends on the tires you're running, in any case. On good tires, 30/30, maybe 31/29 depending on how the bike is feeling on the track.

But, on more street-oriented tires (D207, BT010, etc), I run a lot higher at the track (32/32 or more). The main reason is that street tires start overheating at the track if the pressures are too low (and end up even more slippery).

On the street, I run at least a couple more PSI to keep wear at bay.

I've heard of guys checking tire pressure when they come off the track, hotter tires mean higher pressure. I don't do it that way but have seen guys do it. The Nascar guys do that, they also have the bleed off valves. I run 30/30 for D208's

Originally posted by nudiepix:
You drop the pressures on hot days?? That doesn't seem a bit backwards<font size="2" face="Verdana, Arial">Hotter air expands more than cooler air. When I drop the pressure by a pound or so in the front on really hot days I seem to experience less tendency to slide the front. Again...just my meager 2 pennies.

[ 07-17-2002, 07:42 AM: Message edited by: poacher ]

31 frt. and 28 rear...with either pirelli, or metzler SC's, or RS's images/icons/grin.gif

Most of the time people are check the air comming off the track to see if they are running the correct amount of air when cold... They need to see how much change there is...

A good rule of thumb is to have a 10% change from cold to hot.. images/icons/smile.gif

John

Originally posted by poacher:
</font><blockquote><font size="1" face="Verdana, Arial">quote:</font><hr /><font size="2" face="Verdana, Arial">Originally posted by nudiepix:
You drop the pressures on hot days?? That doesn't seem a bit backwards<font size="2" face="Verdana, Arial">Hotter air expands more than cooler air. When I drop the pressure by a pound or so in the front on really hot days I seem to experience less tendency to slide the front. Again...just my meager 2 pennies.</font><hr /></blockquote><font size="2" face="Verdana, Arial">I would agree if tires didn't heat themselves up. The only thing I've seen by dropping pressure is more overheating, especially on hotter days. Yes hotter air will heat the tires more and cause pressure to go up more, but if you check pressures when the tires are already at air-temp, then the pressure change is already accounted for. The tires may not cool off as much, but you really don't want your tires too hot.

The only difference then becomes tire flex, and the tires heat up more as a result. Granted, my track time is only limited, but they've all been on fairly hot days (90+) and I always had to keep the pressures up to keep the tires from melting.

Originally posted by GSXR-Freak:
Most of the time people are check the air comming off the track to see if they are running the correct amount of air when cold... They need to see how much change there is...

A good rule of thumb is to have a 10% change from cold to hot.. images/icons/smile.gif

John<font size="2" face="Verdana, Arial">Yah, that's what most of the racer dudes recommend for rough estimates...though I've heard more like 10% front, 15% (or more) at the rear. Depends on how hard you push the rear tire and how many tires you can afford.

Originally posted by nudiepix:
</font><blockquote><font size="1" face="Verdana, Arial">quote:</font><hr /><font size="2" face="Verdana, Arial">Originally posted by poacher:
</font><blockquote><font size="1" face="Verdana, Arial">quote:</font><hr /><font size="2" face="Verdana, Arial">Originally posted by nudiepix:
You drop the pressures on hot days?? That doesn't seem a bit backwards<font size="2" face="Verdana, Arial">Hotter air expands more than cooler air. When I drop the pressure by a pound or so in the front on really hot days I seem to experience less tendency to slide the front. Again...just my meager 2 pennies.</font><hr /></blockquote><font size="2" face="Verdana, Arial">I would agree if tires didn't heat themselves up. The only thing I've seen by dropping pressure is more overheating, especially on hotter days. Yes hotter air will heat the tires more and cause pressure to go up more, but if you check pressures when the tires are already at air-temp, then the pressure change is already accounted for. The tires may not cool off as much, but you really don't want your tires too hot.

The only difference then becomes tire flex, and the tires heat up more as a result. Granted, my track time is only limited, but they've all been on fairly hot days (90+) and I always had to keep the pressures up to keep the tires from melting.</font><hr /></blockquote><font size="2" face="Verdana, Arial">Sounds like we're getting into personal preference territory. Whatever helps you keep from taking a soil sample @ the track is A-O-K by me bro. graemlins/bounce.gif

Originally posted by poacher:
Sounds like we're getting into personal preference territory. Whatever helps you keep from taking a soil sample @ the track is A-O-K by me bro. graemlins/bounce.gif <font size="2" face="Verdana, Arial">Indeed.
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