Pressure
- Thread starter Oil Changer
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Some placards, such as MB E430, list more than 1 pressure, one for normal and second one for high speed. Some placards list only 1 pressure, the Honda S2000 and Lexus LS400 list only 1 pressure.
I usually run about 4-6 PSI above normal pressure for around town driving, when I go on long trips I pump up to high speed pressure.
I usually run about 4-6 PSI above normal pressure for around town driving, when I go on long trips I pump up to high speed pressure.
I run 32 psi in the V. 2 psi over the recommended pressure. We get 30 mpg.
I generally run 4-5 PSI over the placard.
If the tires are the correct size, go with what the sticker says. Everything about your car is designed to work with a certain pressure (the handling, suspension, etc) . Every car is different. My Chrysler takes 35 PSI, my Buick takes 30 PSI, my moms Civic takes 32 PSI. Just remember to check them when they're cold. If you check them when they're hot, they will be under inflated.
BTW it's normal for tires to look squishy on the bottom. Especially on the front.
Originally Posted By: Oil Changer
Goal: Best fuel economy.
Tires say 44 psi max.
Door jam sticker says 30 psi front and rear.
That's a 14 psi spread.
Tires have 32 psi in them now. Bought the car in December so they probably were set at 30 psi and the warmer temperatures were good for another 2 psi.
What should I do?
Run them up to 44 psi?
Split the difference and set them at 37 psi?
Other ideas?
BTW it's normal for tires to look squishy on the bottom. Especially on the front.
Originally Posted By: Oil Changer
Goal: Best fuel economy.
Tires say 44 psi max.
Door jam sticker says 30 psi front and rear.
That's a 14 psi spread.
Tires have 32 psi in them now. Bought the car in December so they probably were set at 30 psi and the warmer temperatures were good for another 2 psi.
What should I do?
Run them up to 44 psi?
Split the difference and set them at 37 psi?
Other ideas?
Originally Posted By: Shannow
Don't know about over there, but our placards list "regular" and "high load/speed".
That is mainly a European thing, not so much for the cars made in the U.S. and Japan and sold in the U.S. Probably ought'a be, but too complicated for many folks here...cars need two things, right?, gas & a key.
Don't know about over there, but our placards list "regular" and "high load/speed".
That is mainly a European thing, not so much for the cars made in the U.S. and Japan and sold in the U.S. Probably ought'a be, but too complicated for many folks here...cars need two things, right?, gas & a key.
Originally Posted By: Ken2
Originally Posted By: Shannow
Don't know about over there, but our placards list "regular" and "high load/speed".
That is mainly a European thing, not so much for the cars made in the U.S. and Japan and sold in the U.S. Probably ought'a be, but too complicated for many folks here...cars need two things, right?, gas & a key.
Either we are really stupid over here to understamnd this or we are being treated like we are very stupid. I haven't figured it out yet ;-)
Originally Posted By: Shannow
Don't know about over there, but our placards list "regular" and "high load/speed".
That is mainly a European thing, not so much for the cars made in the U.S. and Japan and sold in the U.S. Probably ought'a be, but too complicated for many folks here...cars need two things, right?, gas & a key.
Either we are really stupid over here to understamnd this or we are being treated like we are very stupid. I haven't figured it out yet ;-)
Originally Posted By: Scum_Frog
Originally Posted By: Ken2
Originally Posted By: Shannow
Don't know about over there, but our placards list "regular" and "high load/speed".
That is mainly a European thing, not so much for the cars made in the U.S. and Japan and sold in the U.S. Probably ought'a be, but too complicated for many folks here...cars need two things, right?, gas & a key.
Either we are really stupid over here to understamnd this or we are being treated like we are very stupid. I haven't figured it out yet ;-)
We have fairly low speed limit in North America, most states have speed limit at around 75-80 MPH. My E430 recommends 32F/33R for normal driving and 34F/42R for sustain 100+ MPH, where in North America anyone can drive 100+ MPH for hours without getting ticket ?
Originally Posted By: Ken2
Originally Posted By: Shannow
Don't know about over there, but our placards list "regular" and "high load/speed".
That is mainly a European thing, not so much for the cars made in the U.S. and Japan and sold in the U.S. Probably ought'a be, but too complicated for many folks here...cars need two things, right?, gas & a key.
Either we are really stupid over here to understamnd this or we are being treated like we are very stupid. I haven't figured it out yet ;-)
We have fairly low speed limit in North America, most states have speed limit at around 75-80 MPH. My E430 recommends 32F/33R for normal driving and 34F/42R for sustain 100+ MPH, where in North America anyone can drive 100+ MPH for hours without getting ticket ?
My subie spec's 32 psi front/rear. I run them at 34 psi front/rear, handles and rides good, my mpg over the last few tanks has been excellent as well.
Originally Posted By: Scum_Frog
Either we are really stupid over here to understamnd this or we are being treated like we are very stupid. I haven't figured it out yet ;-)
I think it is because lawyers like clear bright lines - or they like all kinds of fuzziness - depending on which side of the fence they are on.
I've had an on-going discussion (argument?) with a guy who has a VW with the dual pressure specifications. He makes the absurd conclusion that VW isn't making a specification at all - that VW is saying you can use any pressure between the 2 numbers.
Either we are really stupid over here to understamnd this or we are being treated like we are very stupid. I haven't figured it out yet ;-)
I think it is because lawyers like clear bright lines - or they like all kinds of fuzziness - depending on which side of the fence they are on.
I've had an on-going discussion (argument?) with a guy who has a VW with the dual pressure specifications. He makes the absurd conclusion that VW isn't making a specification at all - that VW is saying you can use any pressure between the 2 numbers.
Originally Posted By: HTSS_TR
We have fairly low speed limit in North America, most states have speed limit at around 75-80 MPH. My E430 recommends 32F/33R for normal driving and 34F/42R for sustain 100+ MPH, where in North America anyone can drive 100+ MPH for hours without getting ticket ?
68's the maximum legal speed down here, but even Holden has different pressures for regular and "high speed" (26 all round, and 34 all round for "more than 3 passengers or sustrained high speed")
From mucking around on Long trips in my Parent's Renault (I had to check pressures at every fuel stop on a trip as a kid), at high sustained speeds, 4 psi cold isn't 4psi hot, as the lower inflation pressure tire seems to build more pressure, which can only be due to more heat due to hysteresis.
We have fairly low speed limit in North America, most states have speed limit at around 75-80 MPH. My E430 recommends 32F/33R for normal driving and 34F/42R for sustain 100+ MPH, where in North America anyone can drive 100+ MPH for hours without getting ticket ?
68's the maximum legal speed down here, but even Holden has different pressures for regular and "high speed" (26 all round, and 34 all round for "more than 3 passengers or sustrained high speed")
From mucking around on Long trips in my Parent's Renault (I had to check pressures at every fuel stop on a trip as a kid), at high sustained speeds, 4 psi cold isn't 4psi hot, as the lower inflation pressure tire seems to build more pressure, which can only be due to more heat due to hysteresis.
How come people can only read 1/2 of the very short pressure statement on the tire?
It give a pressure AND a weight. Why omit 1/2 of the equation?
Everybody see a number, and that is all they can mentally process.
My general advice is to run the tires [cold] about 3 lbs more than the door sticker.
Higher pressures have non linear benefits for fuel economy.
When you have 15lbs in a tire, going up 5 lbs is a huge improvement, but at 35, going up 5 is minimal.
It give a pressure AND a weight. Why omit 1/2 of the equation?
Everybody see a number, and that is all they can mentally process.
My general advice is to run the tires [cold] about 3 lbs more than the door sticker.
Higher pressures have non linear benefits for fuel economy.
When you have 15lbs in a tire, going up 5 lbs is a huge improvement, but at 35, going up 5 is minimal.
Originally Posted By: Ken2
Originally Posted By: Shannow
Don't know about over there, but our placards list "regular" and "high load/speed".
That is mainly a European thing, not so much for the cars made in the U.S. and Japan and sold in the U.S. Probably ought'a be, but too complicated for many folks here...cars need two things, right?, gas & a key.
With the turtle speeds on the American roads it does not matter too much what pressure you put in your tires unless the pressure is really low. The speed factor comes in at the regular speeds over 160 km/h. Though, the dual pressure is specified not for all Europen cars, e.g., Renault.
Originally Posted By: Shannow
Don't know about over there, but our placards list "regular" and "high load/speed".
That is mainly a European thing, not so much for the cars made in the U.S. and Japan and sold in the U.S. Probably ought'a be, but too complicated for many folks here...cars need two things, right?, gas & a key.
With the turtle speeds on the American roads it does not matter too much what pressure you put in your tires unless the pressure is really low. The speed factor comes in at the regular speeds over 160 km/h. Though, the dual pressure is specified not for all Europen cars, e.g., Renault.
Originally Posted By: mechtech2
How come people can only read 1/2 of the very short pressure statement on the tire?
It give a pressure AND a weight. Why omit 1/2 of the equation?
Everybody see a number, and that is all they can mentally process.
Like the oil viscosity charts that people simply cannot comprehend.
How come people can only read 1/2 of the very short pressure statement on the tire?
It give a pressure AND a weight. Why omit 1/2 of the equation?
Everybody see a number, and that is all they can mentally process.
Like the oil viscosity charts that people simply cannot comprehend.
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