Re: [Chrysler300] TIRE PRESSURE

[Keith Boonstra <kboonstra@xxxxxxxxxxxx>]

Too often we find that "recommended" pressures are not necessarily 
optimal, but they yield a value that has greater importance to the 
specifier of the recommendation than it does to you as the final user.  
E.g.- American Classic wants your whitewalls to last, or Chrysler wants 
you to feel like you're getting a softer ride.

For more decades than I'm ready to admit I've had a practice in setting 
my tire pressures that has worked extremely well.  I take very precise 
measurements of the tread depth on a brand new set of tires when I first 
get a different car, then I inflate them to a pressure I suspect will 
provide an even wear across the footprint of the tire.  After I put on 
five or ten thousand miles, I go back and take exacting new readings of 
the tread depth to see how much they are wearing - the fronts may very 
well be different from the rears.  If the outer edges are down, I'll add 
a pound or three.  And likewise, if the centers are wearing a little 
more I'll lower the pressure some.  Once I get the pressures set for a 
completely even wear, I'm good for as long as I own that car using 
similar tires.

In most of my radial tired cars with all-season tires I do find that the 
35-36 pound range gives me that even wear.  But, that being said, I live 
in Michigan and going to the Bridgestone Blizzak winter tires for ice 
and snow traction presented an interesting case in point.  I found out 
that these tires are constructed very differently.  When I first started 
running them I pumped them up to my regular 35-36 pound range and took 
off down the road without another thought.   About 15,000 miles later I 
found I had run the centers right out of them.  The centers were wearing 
at least twice as fast as the outers.

I found that I had to drop all the way down to 29-30 psi to get those 
Blizzaks to wear evenly.  I've had nine sets of them over the years, and 
dropping to that low figure has given me completely even wear on all the 
cars I've used them on.

It's amazing how much difference a little change in inflation makes, but 
then on the racetrack they'll adjust by as little as 1/2 pound on a 
single corner of the car and win (or lose) a race on it.  Bottom line is 
that every tire was designed to have a certain flat footprint.  The 
size, design, and construction of the tire, and the weight you press 
down on that particular corner, will determine what the real optimal 
pressure for that tire is.  You just have to measure and find it.

Keith Boonstra

-

On 4/7/2011 1:11 PM, Bob Jasinski wrote:
>
> Mike,
>
> I run 35 PSI in all my vehicles and have for years. I've never had a
> problem, get good mileage and handling, and tire shops I've worked 
> with all
> recommend it. All my vehicles have radial tires and include my 300G, 
> Dakota
> pickup, PT Cruiser, 2006 300, Chrysler Town & Country van as well as 
> my '88
> BMW 325i
>
> Bob J
>
> From: Chrysler300@xxxxxxxxxxxxxxx 
> <mailto:Chrysler300%40yahoogroups.com> 
> [mailto:Chrysler300@xxxxxxxxxxxxxxx 
> <mailto:Chrysler300%40yahoogroups.com>] On
> Behalf Of Michael Moore
> Sent: Thursday, April 07, 2011 10:04 AM
> To: Chrysler 300 Club International
> Subject: [Chrysler300] TIRE PRESSURE
>
>
> Here in California, a new law went into effect which requires garages to
> check tire pressure whenever a car comes in for service.
>
> I believe in factory recommended tire pressure as a baseline. The standard
> herein Ca seems to be 35 psi.
> My 2007 Subaru, my 1997 Benz, as well as my 59 TR3 have all had the 35 
> pound
> treatment and they each ride like an oxcart and steer differently at that
> tire pressure. The Benz ought to be 28 all around, the TR ought to be 
> 22 and
> the Subaru something else ? but lower.
>
> They all are much nicer to drive with FSM correct tire pressure.
>
> My 300H picked up 38 psi last week while visiting the garage.
> The FSM specifies 24 for the 300H.
> In 1968 when I bought my first set of Michelin X's for the 300H, the
> Michelin dealer said they would look low at 24 because they were 
> radial, but
> the only reason to pump them up was if people kept telling me they 
> were low!
>
> This morning I noticed American Classic, the mfgr. says to keep them at 35
> psi or the whitewalls will crack.
>
> Any experience with that? (I don't like 35!)
>
> Mike Moore
> Morgan Hill, Ca
>
> [Non-text portions of this message have been removed]
>
> 


[Non-text portions of this message have been removed]



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