Tire Pressures

Hello,

Live in New England.

Had a new set of 4 all weather tires put on recently;
Nokian's WR G2. Car is a 2009 Buick LaCrosse

Asked the tire shop to set the pressures at 30 psi, as that is what the
car sticker by the door says.

He set it at 33 psi, and I notice after driving a while that it goes up
to 35 psi per the TPMS readout.

The folks at the tire store said emphatically that they always set the
pressures "a bit" higher as it prolongs tire life, etc.

I think that I read somewhere many years ago, also, that this was a good
idea.

Question: even though car's sticker says 30 psi, is having
it set to 33 psi when cold, going to 35 when warmed up "safe" ?

Good idea ?

Thanks,
Bob

On 10/08/2011 10:00 AM, Bob wrote:
> Hello,
>
> Live in New England.
>
> Had a new set of 4 all weather tires put on recently;
> Nokian's WR G2. Car is a 2009 Buick LaCrosse
>
> Asked the tire shop to set the pressures at 30 psi, as that is what the
> car sticker by the door says.
>
> He set it at 33 psi, and I notice after driving a while that it goes up
> to 35 psi per the TPMS readout.
>
> The folks at the tire store said emphatically that they always set the
> pressures "a bit" higher as it prolongs tire life, etc.
>
> I think that I read somewhere many years ago, also, that this was a good
> idea.
>
> Question: even though car's sticker says 30 psi, is having
> it set to 33 psi when cold, going to 35 when warmed up "safe" ?
>
> Good idea ?
>
> Thanks,
> Bob

Depends on the car, really. But so long as the cold pressure is not
higher than the max pressure on the sidewall it's not going to cause
catastrophic tire failure. Hot pressure is more or less irrelevant.
What is important is how the car rides and handles. I've found that on
my company car (Chevy Impala) running the tires at the recommended
pressure results in a floaty ride and imprecise handling, and also fast
wear on the outside edges of the front tires, so in that car I do run
the pressure a little higher than spec. But really that just requires
some experimentation to determine whether that's the case for your car
or not. (I suspect that the Lacrosse is basically the same chassis, yes?)

nate


--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

Bob > wrote in :

> Hello,
>
> Live in New England.
>
> Had a new set of 4 all weather tires put on recently;
> Nokian's WR G2. Car is a 2009 Buick LaCrosse
>
> Asked the tire shop to set the pressures at 30 psi, as that is what the
> car sticker by the door says.
>
> He set it at 33 psi, and I notice after driving a while that it goes up
> to 35 psi per the TPMS readout.
>
> The folks at the tire store said emphatically that they always set the
> pressures "a bit" higher as it prolongs tire life, etc.
>
> I think that I read somewhere many years ago, also, that this was a good
> idea.
>
> Question: even though car's sticker says 30 psi, is having
> it set to 33 psi when cold, going to 35 when warmed up "safe" ?
>
> Good idea ?
>


It's perfectly /safe/. But is it something that will be liked by your
government-mandated tire-pressure-monitoring system? That's another story.

If your TPMS eventually complains, take the pressures back down to 30. If
the TPMS light stays off, leave the pressures where they are.

I'm suspecting Buick has specified the slightly-lower pressure simply to
help improve the ride.

--
Tegger

Bob wrote:
> Hello,
>
> Live in New England.
>
> Had a new set of 4 all weather tires put on recently;
> Nokian's WR G2. Car is a 2009 Buick LaCrosse
>
> Asked the tire shop to set the pressures at 30 psi, as that is what the
> car sticker by the door says.
>
> He set it at 33 psi, and I notice after driving a while that it goes up
> to 35 psi per the TPMS readout.
>
> The folks at the tire store said emphatically that they always set the
> pressures "a bit" higher as it prolongs tire life, etc.
>
> I think that I read somewhere many years ago, also, that this was a good
> idea.
>
> Question: even though car's sticker says 30 psi, is having
> it set to 33 psi when cold, going to 35 when warmed up "safe" ?
>
> Good idea ?
>
> Thanks,
> Bob

I usually cold set the fronts at 32-33 and rears at 31-32.
Auto manufacturers like the mushy soft ride of 26-30.
Unfortunately that makes for minimum control and is prone
to roll overs, as Ford found out the hard way a few years ago.

>> Question: even though car's sticker says 30 psi, is having
>> it set to 33 psi when cold, going to 35 when warmed up "safe" ?
>>
>> Good idea ?


Drive through some mud, or put some chalk on the tires and drive around the
block making sure to do some tight turns.

Find out what the actual contact area of the tire is.

If the tires are not the same profile as the ones that came with the car,
the optimal pressure may not be the same as the recommendation.

If you overinflate the tires, you will have reduced contact area on the
edges, and so your tires will wear out faster in the center. This will
also affect your handling adversely. But then again, underinflation is
just as bad.

Unless you actually look at the footprint you won't know.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 10 Oct 2011 10:24:59 -0400, (Scott Dorsey) wrote:

>>> Question: even though car's sticker says 30 psi, is having
>>> it set to 33 psi when cold, going to 35 when warmed up "safe" ?
>>>
>>> Good idea ?
>
>
>Drive through some mud, or put some chalk on the tires and drive around the
>block making sure to do some tight turns.
>
>Find out what the actual contact area of the tire is.
>
>If the tires are not the same profile as the ones that came with the car,
>the optimal pressure may not be the same as the recommendation.
>
>If you overinflate the tires, you will have reduced contact area on the
>edges, and so your tires will wear out faster in the center. This will
>also affect your handling adversely. But then again, underinflation is
>just as bad.

Yes. If you underinflate, you'll somehow wear the tires out faster at
the edges. I've certainly done that.

The goal is to have the tires flat on the bottom, so the whole width
of the tire is evenly pressing against the road.

AIUI, if you take the area of the tire that touches the road, multiply
it by the tire pressure, add that value for all 4 tires together, and
the sum will be the weight of the car and its contents.

There is also the fact that high tire pressure increases mileage, but
I have no idea how much. I don't know if low pressure really makes a
softer ride or not, but smaller wheels with the same diameter tire,
thus a wider side wall., will make a softer ride. 16" or 17" wheels
with a narrow side wall will make a harder ride.

>Unless you actually look at the footprint you won't know.
>--scott

On Tue, 11 Oct 2011 00:44:39 -0400, micky >
wrote:

>
>Yes. If you underinflate, you'll somehow wear the tires out faster at
>the edges. I've certainly done that.

And as someoen said, it's the cold pressure that all the numbers are
given for. It's assumed that the tire will warm up and the pressure
will increase. But they don't want people on the hood measuring
tire pressure while the car is moving.

On Oct 8, 10:00*am, Bob > wrote:
> Hello,
>
> Live in New England.
>
> Had a new set of 4 all weather tires put on recently;
> Nokian's WR G2. *Car is a 2009 Buick LaCrosse
>
> Asked the tire shop to set the pressures at 30 psi, as that is what the
> car sticker by the door says.
>
> He set it at 33 psi, and I notice after driving a while that it goes up
> to 35 psi per the TPMS readout.
>
> The folks at the tire store said emphatically that they always set the
> pressures "a bit" higher as it prolongs tire life, etc.
>
> I think that I read somewhere many years ago, also, that this was a good
> idea.
>
> Question: even though car's sticker says 30 psi, is having
> it set to 33 psi when cold, going to 35 when warmed up "safe" ?
>
> Good idea ?
>
> Thanks,
> Bob
____________________________
Well, except for the fact that THEY DIDN'T LISTEN TO YOU, THE
CUSTOMER'S INSTRUCTIONS!!! (Read my tire pressure drama at:
http://groups.google.com/group/rec.a...a2e9e247d449c#
) Technically nothing wrong with that, except that it more frequently
triggers your TPMS indicator. As a general rule I ride 2psi higher
than the door/hood/trunk/wherever decal, unless that puts me over the
max. inflation pressure shown on the tire itself. I.E.: My last 3
cars have all specified 30psi cold, hence I inflate 32psi cold.

Irrelevant to this discussion, but there is out there in WWW Land a
site that suggests you inflate your tires to 36-37psi cold IN WINTER
if you live north of 45 degrees north, and closer to the door sticker
come spring & summer, implying that 36psi in winter = IE 30psi in
summer. Whaddever my brain hurts!!

-CC

On Oct 8, 12:18*pm, Nate Nagel > wrote:
> On 10/08/2011 10:00 AM, Bob wrote:
>
> > Question: even though car's sticker says 30 psi, is having
> > it set to 33 psi when cold, going to 35 when warmed up "safe" ?
>
> Depends on the car, really.

Reely? How's that work? For which cars is it safe/not safe?

>*But so long as the cold pressure is not
> higher than the max pressure on the sidewall it's not going to cause
> catastrophic tire failure.

What if you drive on it, say, at a "perfectly safe" 80 mph, and hit a
wicked pothole?

> What is important is how the car rides and handles.

Good to know tread wear isn't important...

>*I've found that on
> my company car (Chevy Impala) running the tires at the recommended
> pressure results in a floaty ride and imprecise handling, and also fast
> wear on the outside edges of the front tires,

That doesn't make any sense. Far more likely you brake while
cornering, too hard.

> But really that just requires
> some experimentation to determine whether that's the case for your car
> or not.

You should shut the **** up about **** you know nothing about.
-----

- gpsman