Warm Tire Pressure

[Toves33]

I am running Michelin PR2 front and PR3 rear at Homestead with a outside temperature of 78. What setting should I set my digital tire warmer to? What should the tire pressures be when they are checked warm? Thanks again fellas!

Juan

[tstruyk]

any chance of getting rid of that PR2 for a PRC?  Is this a race or a track day?  that PR3 is gonna go off fast...

I run 135 in the PRC front, 175 in the PR5's... ran 33psi cold on the C, 22 cold on the 5, never checked hot pressures...

[r1owner]

IIRC Tommy said Michelin doesn't really have a "recommended" warm pressure, only cold.

[Super Dave]

Exactly.  Michelin's you use just cold pressures.  Someone might have put a pressure guage on it warm, but it's not of specific consequence for them at this time in their construction like other manufacturers.

I do admit that I have ran higher than 33psi cold in the PR2.  It helped it feel better.  Yes, get the PR C.  It's available through race distribution. 

[Toves33]

Thanks for the info! It's to late to get the PRC's. I just need them to last for one short practice session, 1 9-lap sprint, and 2 6-lap sprint races. I will use the temperature settings that tstruyk recommended, unless some of you have better suggestions. Going by what some of the comments are saying, do you guys only check your tire pressures at the begining of the day?

[Super Dave]

Tim's temperaturs are good. 

I check my tire pressure in the morning before I put on my warmers.

Later, I will check and adjust my cold pressure.  If it's 55 in the morning, and later it's 77, your cold tire pressure will increase.  You'll want to adjust that. 

Look for an opening in the schedule to do it.  Sometimes, I'll have a race in the middle of the day, so I can check my tires after lunch or a little later after they've completely cooled down from practice.

[Toves33]

Dave, in your opinion, will the PR 2 & 3 last for what I am using it for? Thanks!

[Super Dave]

Well, yeah, you should be good....  depending upon how fast you are.  The PR3 has a shorter life than a PR5 or a commercial Med/Soft.  The PR2 is just a completely different construction compared to the PRC that we're all talking about.  The PR1/2's are kind of mushy feeling, and they lack some feed back that previous Michelin tires had, and they restored that in the PRC.  That's one reason why I liked running more than 33 PSI in the PR2.

Now, when you do change to the PRC compared to the PR2, they are different heights when compared to each other.  So, it will change the way the chassis reacts to your inputs and how you feel things.  I might be inclinded to just say try it when you make the change.  Just take your time.

[Toves33]

Dave, this is my first amateur race. So, it's safe to safe that I will not be pushing the tires to their full potential. I will do some more research regarding the tire pressures and it all depends on what the temperature is like at Homestead that weekend. These will be the last set of PR# that I will purchase.

Have any of you heard that Michelin is coming out with a whole new race version for 08?

[Super Dave]

Oh, yeah.  I've ridden on the PRC rear's off and on since June.  I sampled a front tire that wasn't a production version DOT tire, but I liked it.  I had that in May.  I liked it. 

Melka might have some ideas on what the new stuff will be like to.  He should be there...might be lurking too...

[Sig]

is it just me or is it retarded to have cold pressure recommendations and no hot? What defines cold? 40f, 70f, 90f ?

[Super Dave]

Yes, the outside temperature would define it.  But a hot pressure could be indicated by a temperature change of 110, 75, or 40 degrees from the outside temperature, which would originally be the temperature of the air inside the tire.