tire pressure

What is the best tire inflation pressure for 2007 RX350 with Michelin 18
inch tires?

Although the door stickers say 30PSI, dealer says to put in at least 35PSI.
Only have 800 miles on car.

"oklaman" <ok (AT) dum (DOT) org> wrote

What is the best tire inflation pressure for 2007 RX350 with Michelin 18
inch tires?

Although the door stickers say 30PSI, dealer says to put in at least
35PSI.
Only have 800 miles on car.

When I worked for an automaker, I had the privilege of driving well over 100
new cars, keeping around 60 of them for at least 6,000 miles.

I've found that tread life will be extended by inflating tires about 5 PSI
over the automaker's recommended tire pressure, with the tradeoff being a
slightly harsher ride.
--

Ray O
(correct punctuation to reply)

Ray O wrote:

"oklaman" <ok (AT) dum (DOT) org> wrote

What is the best tire inflation pressure for 2007 RX350 with Michelin 18
inch tires?

Although the door stickers say 30PSI, dealer says to put in at least
35PSI.
Only have 800 miles on car.


When I worked for an automaker, I had the privilege of driving well over 100
new cars, keeping around 60 of them for at least 6,000 miles.

I've found that tread life will be extended by inflating tires about 5 PSI
over the automaker's recommended tire pressure, with the tradeoff being a
slightly harsher ride.
--

Ray O
(correct punctuation to reply)
You also get much better mileage. My 2005 RX330 give me 28 mpg (US)

with about 3 pounds over recommendation

Lets face it guys an gals - time to think! Lexus dealers say to use
dino oil because it has improved so much! So in the hundred or so years
that we have been pumping it out of the earth, it has improved a lot.
Right. And it is better than that dratted new stuff that was invented
to do a better job of lubing and cleaning engines at high temps. Lexus
says their engines run at higher than normal temps so there is less
emission of bad stuff to the atmosphere. So we now have the question of
tire pressure - expect to find that they have improved the quality of
air so much recently that it is now ok to run tires at a lower pressure
- say 30 psi. And that higher pressure that some people use is just not
required anymore, esp with these higher milage thin little bling bling
18 or 19" tires!

Ah so - improved oil and improved air!

mcbrue airily under the bridge in the trailer down by the river

06 LS430

LOL its the tires that are improving. The new compounds in the rubber,
as claimed by the manufacturer of the tire, will not wear as easily on
lower pressures compared to the older tires. Hence, they can say that
its OK to run them at 30psi. Understand that the tire pressure listed
in your door jamb or owners manual or fuel door is the MINIMUM COLD AIR
PRESSURE that the tire should be at 32 DEGREES FAHRENHEIT. When you
drive, the air expands with temperature and you get a higher pressure
when it counts, on the road. For every 10 degrees fahrenheit that the
temperature is above freezing, you should add 1psi to the vehicle
specification. If its 70 degrees out, you should add between 4-5 psi
over the specs when your tires are cold, this means driving within 1
mile to get to the air pump or pumping it yourself at home if you have
a compressor.


--
NYLexSC

You are just plain wrong. Oil HAS improved greatly. No, not in crude form,
bubbling out of Jed Clampett's "shootin' at some food" backwoods....but as
refined and as sold for today's engines. The science of lubrication has
moved forward. They now have additives that work better than years ago. I do
agree that synthetic is probably better, but regular dino oil changes works
fine for many many miles. Consumer Reports studied this a few years ago and
concluded that following the manufacturer's recommedations (meaning NOT more
frequent as most dealers and Jiffy Lube claims), in most cases, would have
you squishin' bugs for many many trouble free miles.

As to tire air...I have found that the manufacturer's recommedations seem to
work best for ride, economy and tire wear. Why reinvent the wheel? (So to
speak!)


"mcbrue" <mcbrue (AT) aol (DOT) com> wrote

Lets face it guys an gals - time to think! Lexus dealers say to use
dino oil because it has improved so much! So in the hundred or so years
that we have been pumping it out of the earth, it has improved a lot.
Right. And it is better than that dratted new stuff that was invented
to do a better job of lubing and cleaning engines at high temps. Lexus
says their engines run at higher than normal temps so there is less
emission of bad stuff to the atmosphere. So we now have the question of
tire pressure - expect to find that they have improved the quality of
air so much recently that it is now ok to run tires at a lower pressure
- say 30 psi. And that higher pressure that some people use is just not
required anymore, esp with these higher milage thin little bling bling
18 or 19" tires!

Ah so - improved oil and improved air!

mcbrue airily under the bridge in the trailer down by the river

06 LS430

NYLexSC wrote:

LOL its the tires that are improving. The new compounds in the rubber,
as claimed by the manufacturer of the tire, will not wear as easily on
lower pressures compared to the older tires. Hence, they can say that
its OK to run them at 30psi. Understand that the tire pressure listed
in your door jamb or owners manual or fuel door is the MINIMUM COLD AIR
PRESSURE that the tire should be at 32 DEGREES FAHRENHEIT. When you
drive, the air expands with temperature and you get a higher pressure
when it counts, on the road. For every 10 degrees fahrenheit that the
temperature is above freezing, you should add 1psi to the vehicle
specification. If its 70 degrees out, you should add between 4-5 psi
over the specs when your tires are cold, this means driving within 1
mile to get to the air pump or pumping it yourself at home if you have
a compressor.
--
NYLexSC
------------------------------------------------------------------------

Actually, you are incorrect when you say that the minimum cold air
pressure applies (only) to 32 degrees F. It is the (minimum) pressure
that your tires should be set to when they are at the temperature of
the surrounding air. This is also known as the "ambiemt temperature".

Tires will heat up approximately the same amount above a wide range of
ambient temperatures when driving -- and raise the pressure by the same
amount -- irrespective of the starting temperature.

If your owners manual or tire pressure sticker says 33 lb/sq in, then
set it to that (or slightly higher if you wish to improve tire and gas
mileage) but set it the same for all outside temperatures.

Correct, it is the AMBIENT temperature (also known as 'cold pressure').

When I sold tires 22-23 yrs ago, we had a 'rule of thumb' with regard to
tire pressure: if you drive more than 5 miles at any speed, the tire
pressure will increase approx. 5 psi. On my 05 ES330, I always keep the
tires at 35 psi 'cold.' If I've driven more than 5 miles when I stop in to
check my tire pressure, then when I put the air pressure gauge (ALWAYS buy
one and keep it in your car, service station gauges (usually built-in to the
air nozzle housing are notoriously inaccurate) on the tire, the air pressure
'hot' should be about 40 psi (less the '5 psi rule' = 35 psi 'cold)
therefore, I don't need air. Of course, if the gauge reads less than 40,
then I add air 'til it equals 40.

Been using that 'rule of thumb' for 20+ yrs and all the tires on all my cars
have always worn evenly (less of course shock/strut/alignment wear).


<jss1941 (AT) gmail (DOT) com> wrote

NYLexSC wrote:
LOL its the tires that are improving. The new compounds in the rubber,
as claimed by the manufacturer of the tire, will not wear as easily on
lower pressures compared to the older tires. Hence, they can say that
its OK to run them at 30psi. Understand that the tire pressure listed
in your door jamb or owners manual or fuel door is the MINIMUM COLD AIR
PRESSURE that the tire should be at 32 DEGREES FAHRENHEIT. When you
drive, the air expands with temperature and you get a higher pressure
when it counts, on the road. For every 10 degrees fahrenheit that the
temperature is above freezing, you should add 1psi to the vehicle
specification. If its 70 degrees out, you should add between 4-5 psi
over the specs when your tires are cold, this means driving within 1
mile to get to the air pump or pumping it yourself at home if you have
a compressor.
--
NYLexSC
------------------------------------------------------------------------

Actually, you are incorrect when you say that the minimum cold air
pressure applies (only) to 32 degrees F. It is the (minimum) pressure
that your tires should be set to when they are at the temperature of
the surrounding air. This is also known as the "ambiemt temperature".

Tires will heat up approximately the same amount above a wide range of
ambient temperatures when driving -- and raise the pressure by the same
amount -- irrespective of the starting temperature.

If your owners manual or tire pressure sticker says 33 lb/sq in, then
set it to that (or slightly higher if you wish to improve tire and gas
mileage) but set it the same for all outside temperatures.

I've just bought a 2004 RX330 and the tyres seem fairly worn at 38000 K's.
Took it to a tyre dealer today, he checked them and said the previous owner
probably ran them at 30 psi as the sticker says, which gives soft ride but
terrible wear.
Told me to run at 36-38 and will be much better - haven't noticed much
change in ride yet...

"Mike Piacente" <mpiacente (AT) adelphia (DOT) net> wrote

Correct, it is the AMBIENT temperature (also known as 'cold pressure').

When I sold tires 22-23 yrs ago, we had a 'rule of thumb' with regard to
tire pressure: if you drive more than 5 miles at any speed, the tire
pressure will increase approx. 5 psi. On my 05 ES330, I always keep the
tires at 35 psi 'cold.' If I've driven more than 5 miles when I stop in
to check my tire pressure, then when I put the air pressure gauge (ALWAYS
buy one and keep it in your car, service station gauges (usually built-in
to the air nozzle housing are notoriously inaccurate) on the tire, the air
pressure 'hot' should be about 40 psi (less the '5 psi rule' = 35 psi
'cold) therefore, I don't need air. Of course, if the gauge reads less
than 40, then I add air 'til it equals 40.

Been using that 'rule of thumb' for 20+ yrs and all the tires on all my
cars have always worn evenly (less of course shock/strut/alignment wear).


jss1941 (AT) gmail (DOT) com> wrote in message
news:1159022562.606829.87760 (AT) i42g2000cwa (DOT) googlegroups.com...
NYLexSC wrote:
LOL its the tires that are improving. The new compounds in the rubber,
as claimed by the manufacturer of the tire, will not wear as easily on
lower pressures compared to the older tires. Hence, they can say that
its OK to run them at 30psi. Understand that the tire pressure listed
in your door jamb or owners manual or fuel door is the MINIMUM COLD AIR
PRESSURE that the tire should be at 32 DEGREES FAHRENHEIT. When you
drive, the air expands with temperature and you get a higher pressure
when it counts, on the road. For every 10 degrees fahrenheit that the
temperature is above freezing, you should add 1psi to the vehicle
specification. If its 70 degrees out, you should add between 4-5 psi
over the specs when your tires are cold, this means driving within 1
mile to get to the air pump or pumping it yourself at home if you have
a compressor.
--
NYLexSC
------------------------------------------------------------------------

Actually, you are incorrect when you say that the minimum cold air
pressure applies (only) to 32 degrees F. It is the (minimum) pressure
that your tires should be set to when they are at the temperature of
the surrounding air. This is also known as the "ambiemt temperature".

Tires will heat up approximately the same amount above a wide range of
ambient temperatures when driving -- and raise the pressure by the same
amount -- irrespective of the starting temperature.

If your owners manual or tire pressure sticker says 33 lb/sq in, then
set it to that (or slightly higher if you wish to improve tire and gas
mileage) but set it the same for all outside temperatures.

I wouldn't run them higher than 36 psi.

The ruled USED TO BE: if the tire was a 'P metric' tire (size on sidewall
started with letter 'P,' e.g., P20550R15) then maximum 'cold' psi should be
35.

IF it was a 'metric' tire (no 'P' at beginning of tire size, e.g.,
20550R15), then max 'cold' psi should be 36.

Yes, 30 psi will give you a much softer ride and you will feel the bumps and
road roughness much less, BUT 1) the tires will wear ALOT faster, you'll
probably get 20,000 to 30,000 miles out of them (this depends of course on
whether they're 'high performance' or 'regular passenger/truck' tires --
performance tires are made out of a softer rubber compound so they're
'stickier' and grip corners better even if they're inflated to 35 or 36 psi
and they wear out much faster than normal equally inflated passenger car
tires). Passenger tires inflated to 30 psi will only get about 30,000
miles; 2) the braking is longer -- you'll notice you'll have to apply the
brakes earlier than you would if the tires were at 35/36 psi; 3) a tire
inflated at 30 psi has much more 'rolling resistance' than a tire at 35/36
psi. 'Rolling resistance' is essentially another term for 'friction' or
'drag:' the higher the rolling resistance, the harder the powertrain has
to work to move the car forward or backward; therefore, you use more
gasoline. If you want to conduct an experiment (this worked great at the
tire store to show customers why they should keep their tires properly
(35/36 psi -- by the way, tires made specifically for trucks usually have
psis of 40-60+), take two tires which are mounted on rims (some call them
'wheels'), inflate one to 30 psi and inflate the other to 35/36 psi. Now,
try and roll them using just one finger. You will see that the 30 psi tire
requires more effort than the 36 psi); 4) cornering is 'mushier' in a 30 psi
tire -- you will have to turn the steering wheel harder, it feels kinda like
you're 'fighting' the wheel, not to mention the rolling resistance in taking
a corner is much higher than a 35/36 psi tire. A tire at 30 psi has much
more sidewall flex especially in cornering and that's why it feels
'mushier'.

A tire at 35/36 psi does 'ride harder' -- you'll feel the bumps and road
roughness alot more BUT:
1) you should get at least 40,000 - 60,000+ miles out of them (again, it
will depend on whether they're high performance or passenger car/truck
tires). Routinely, I've always gotten AT LEAST 50,000-65,000 miles out of
my tires because I kept them at 35-36 psi); 2) braking is ALOT
better/faster; 3) lower rolling resistance and therefore better gas mileage;
and 4) much quicker cornering (you can take corners faster and almost with
just one finger on the wheel) because the sidewalls are much more stiffer at
36 psi than 30 psi and therefore less flex.

Sorry if this is rather 'long winded.'


"Bear" <who (AT) where (DOT) com> wrote

I've just bought a 2004 RX330 and the tyres seem fairly worn at 38000 K's.
Took it to a tyre dealer today, he checked them and said the previous
owner probably ran them at 30 psi as the sticker says, which gives soft
ride but terrible wear.
Told me to run at 36-38 and will be much better - haven't noticed much
change in ride yet...

"Mike Piacente" <mpiacente (AT) adelphia (DOT) net> wrote in message
news_2dnRNkwNCKCIjYnZ2dnUVZ_sCdnZ2d (AT) adelphia (DOT) com...
Correct, it is the AMBIENT temperature (also known as 'cold pressure').

When I sold tires 22-23 yrs ago, we had a 'rule of thumb' with regard to
tire pressure: if you drive more than 5 miles at any speed, the tire
pressure will increase approx. 5 psi. On my 05 ES330, I always keep the
tires at 35 psi 'cold.' If I've driven more than 5 miles when I stop in
to check my tire pressure, then when I put the air pressure gauge (ALWAYS
buy one and keep it in your car, service station gauges (usually built-in
to the air nozzle housing are notoriously inaccurate) on the tire, the
air pressure 'hot' should be about 40 psi (less the '5 psi rule' = 35 psi
'cold) therefore, I don't need air. Of course, if the gauge reads less
than 40, then I add air 'til it equals 40.

Been using that 'rule of thumb' for 20+ yrs and all the tires on all my
cars have always worn evenly (less of course shock/strut/alignment wear).


jss1941 (AT) gmail (DOT) com> wrote in message
news:1159022562.606829.87760 (AT) i42g2000cwa (DOT) googlegroups.com...
NYLexSC wrote:
LOL its the tires that are improving. The new compounds in the rubber,
as claimed by the manufacturer of the tire, will not wear as easily on
lower pressures compared to the older tires. Hence, they can say that
its OK to run them at 30psi. Understand that the tire pressure listed
in your door jamb or owners manual or fuel door is the MINIMUM COLD AIR
PRESSURE that the tire should be at 32 DEGREES FAHRENHEIT. When you
drive, the air expands with temperature and you get a higher pressure
when it counts, on the road. For every 10 degrees fahrenheit that the
temperature is above freezing, you should add 1psi to the vehicle
specification. If its 70 degrees out, you should add between 4-5 psi
over the specs when your tires are cold, this means driving within 1
mile to get to the air pump or pumping it yourself at home if you have
a compressor.
--
NYLexSC
------------------------------------------------------------------------

Actually, you are incorrect when you say that the minimum cold air
pressure applies (only) to 32 degrees F. It is the (minimum) pressure
that your tires should be set to when they are at the temperature of
the surrounding air. This is also known as the "ambiemt temperature".

Tires will heat up approximately the same amount above a wide range of
ambient temperatures when driving -- and raise the pressure by the same
amount -- irrespective of the starting temperature.

If your owners manual or tire pressure sticker says 33 lb/sq in, then
set it to that (or slightly higher if you wish to improve tire and gas
mileage) but set it the same for all outside temperatures.