Recommended Boxster S Tire Pressures for DE

[George3]

OK, guys... I'm lovin' this.  I can't wait to start futzin' with the car to get it right.  Let me add another "complicating" factor...

All that being said about the pressures  --  I get all my tires to around 40 lbs hot -- then before the next run, it starts to drizzle or a short rain shower (with no standing water on the track)  --  What adjustments need to be made to the tires, etc ??

(Reason I ask, is this Monday & Tuesday I'm going to a Summit Point DE and there is a chance of showers in the mid-80's forecast).    Thanks  

[Hammerin Hank]

In addition to dialing in the pressures by taking tire temps acrossed the tire, you may want to try filling with nitrogen. It will decrease the variance between hot and cold pressures.

Keep in mind, street tires generally need more pressure than a race/dot track tire due to their softer sidewalls. You may also want to chalk the sidewall and around the thread shoulder to see how far the tire is rolling under. The idea is to keep them off the sidewalls with pressure, but not so much as to loose grip. The roll under issue typically doesn't come into play until you start pushing the limits, however. If you're just starting out, concentrate on getting the car balanced from a handling standpoint. Just be careful not to go too low with the pressures. An under-inflated tire will run hotter. With street compounds, they tend to "grease" when they get too hot. It will feel like the track got oiled down all of a sudden. Not good, if you're honkin' on it. Best advice, baby steps. 

[Hammerin Hank]

George3 wrote:

...

All that being said about the pressures -- I get all my tires to around 40 lbs hot -- then before the next run, it starts to drizzle or a short rain shower (with no standing water on the track) -- What adjustments need to be made to the tires, etc ??

(Reason I ask, is this Monday & Tuesday I'm going to a Summit Point DE and there is a chance of showers in the mid-80's forecast). Thanks

Decrease pressure in the wet. How much? It depends on the tire, the car and the driver. When I was running my FWD cars, I'd pull anywhere from 5-7 psi out. It's also better to make the car slightly understeer in such conditions. You can do that by messing with the pressures, front vs. rear or with any suspension adjustability you may have (ie. swaybars).

[catchacab]

george
it was nice meeting you at summit

It is nice to see you enthusiasm for drivers ed your question shows intellect and maturity for the sport check out www.rennlist.com discussion forums

For street tires i would follow porsche recommended pressures for hot tires after you finish your first run session take your pressures and adjust where needed

Remember for every change of ten degrees in climate your tire pressure will change one degree also the sun shine directed at your tires will change your initial pressures


With steet tires and this being a new endevour you will probably not be able to notice one or two pounds difference in pressure

Keep up the great work

[George3]

Thanks.... it was very nice to meet you as well.

Everyone is very friendly and helpful....  Makes for a nice club!

I will check out the forum.  Lots to read.  Lots to learn.  Lots to do.

[APXD 30]

>zero.    I backed my car out of the garage on Saturday to find my RR was flat

At least I was at home considering Porsche doesn't give you a spare these days.

[George3]

Yeah, I got a flat on my RL.... JUST BEFORE I HAD TO LEAVE FOR THE SUMMIT POINT D.E. !!!!!    (had to get a new tire)  

Let me tell you, that was a bummer.  Anyway,  I ran my tires at 38 lbs cold on my 987S.  By the end of the first run they were at 45 lbs hot.  By the end of the day on Monday, they were smokin' in the turns at 43 lbs... P e r f e c t !!  They really shined in turn 5 and through the esses.

[Brian Minkin]

George,

I am glad that you had success with the tire pressure.  What you experienced is right in line with Michelin's suggestion.  Good to hear that you had a good event.

[APXD 30]

I'm glad the pressures worked well for you.   I am the proud new owner of two 265/35R19s.    Can't repair P-car tires, only 30% life left in them and they should be equal.....$$$

[George3]

Sorry to hear that... it's too bad.  I got away with only buying one Michelin PS 265/35/ZR19.  Mine was way less than 30% tire wear.

Can you run a plugged tire?  (at a DE)