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I have just recently ordered new Michelins Primacy MXM4 for my 2002 E430. My wife drives this car and the last two sets of tires worn out on the edges. The centers were fine. These are 235/45/17. They are what I consider low profile. I know the tire pressure is on gas lid, but what about what the tire recommends? Don't want to ruin my new Michelins; they don't give them away!
 

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I have just recently ordered new Michelins Primacy MXM4 for my 2002 E430. My wife drives this car and the last two sets of tires worn out on the edges. The centers were fine. These are 235/45/17. They are what I consider low profile. I know the tire pressure is on gas lid, but what about what the tire recommends? Don't want to ruin my new Michelins; they don't give them away!
You're getting closer, Wade. One forum ABOVE is the W210 forum, which is what you have. ;)

If you were seeing even wear on the edges, they were underinflated for the load on the car. I'd bump them up a couple or three pounds depending on how worn the old tires were, and then be sure to monitor for a while (1,000 miles at a time, you can buy an inexpensive tire tread depth gauge and compare the edge blocks to the center blocks) and rotate them every 5,000 miles.

NOTE: Be sure never to check or adjust tire pressures when tires are warm (this is one way tires end up underinflated, people check them when they are warm and bleed off air), and never exceed the pressure rating stamped on the tire sidewall.

Good luck and we'll see you in the W210 forum.
 

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Duh! thank you for forum advice I'm a newcomer and getting use to forum posting. thanks for advice on tires though.
 

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One of the odd things about our beasts in that the recommended tire pressures on the fuel filler door differ from those inside the driver's door. I prefer to run mine using the 27 psi all around as advised inside the fuel door.
 

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Duh! thank you for forum advice I'm a newcomer and getting use to forum posting. thanks for advice on tires though.
Actually there was more tire advice in the post you had in the general section: I think Eric gave you the link to the 210 forum.

Good luck with the new tires.
 

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I just purchased the exact same size and brand Michelin's last month and have been running 30 PSI in the front and 34 PSI in the rears. I think it calls for 28 and 34 in the gas door.
 

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One Sage Tire-Guru once enlightened me to this Rule-of-Thumb:

"The Correct tire pressure is that level in which the Pressure DIfferential between a HOT tire, and a Cold tire is 4 PSI"
 

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One Sage Tire-Guru once enlightened me to this Rule-of-Thumb:

"The Correct tire pressure is that level in which the Pressure DIfferential between a HOT tire, and a Cold tire is 4 PSI"
That strikes me as really odd...having lived in cold climates (Colorado) and hot (Phoenix) I can tell you there is a world of difference between a hot tire on a cold day and a hot tire on a hot day (and the various vice versas), as well as a much greater difference in pressure between a hot and cold tire in each locale.

Which of course leaves me wondering how you'd ever get to the 4 psi differential...much, much, much trial and error at the least....and then repeat when the seasons change? ;)

IIRC that is alleged to be one of the benefits of running nitrogen, that it doesn't expand and contract as much as atmospheric air (which is 78% nitrogen anyway...right?)
 

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compared to 80-100F in the summer my tires lost a good 4-5psi now that is in the 20-30F.
i just went outside and measured my cold tires and they are 30,29psi front and 34,36psi rear. i will be driving for a good 30 miles later and check the pressure again to see how much it changed.
 

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That strikes me as really odd...having lived in cold climates (Colorado) and hot (Phoenix) I can tell you there is a world of difference between a hot tire on a cold day and a hot tire on a hot day (and the various vice versas), as well as a much greater difference in pressure between a hot and cold tire in each locale.

Which of course leaves me wondering how you'd ever get to the 4 psi differential...much, much, much trial and error at the least....and then repeat when the seasons change? ;)

IIRC that is alleged to be one of the benefits of running nitrogen, that it doesn't expand and contract as much as atmospheric air (which is 78% nitrogen anyway...right?)
And yet there may be some truth in it. The AMG C63 states (on the fuel flap) that when inflating a hot tyre, put in 3 psi more.
 

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compared to 80-100F in the summer my tires lost a good 4-5psi now that is in the 20-30F.
i just went outside and measured my cold tires and they are 30,29psi front and 34,36psi rear. i will be driving for a good 30 miles later and check the pressure again to see how much it changed.
renault12ts said:
And yet there may be some truth in it. The AMG C63 states (on the fuel flap) that when inflating a hot tyre, put in 3 psi more.
I'm not saying there is zero truth in it, but given all of the variables holding 4 lb (or 3 lb) out as a yardstick isn't really much more useful than simply monitoring tire wear and adjusting your cold pressures accordingly.

After driving on I-10 in an Arizona summer the tires radiate enough heat when stopped that you can't even hold your hand close to them for very long, much less touch them. And after driving in 20 degree temps in Colorado at freeway speeds the tires are still pretty cool to the touch. There is absolutely a correlation between temp and pressure (see below) but there is enough variation in the tire and ambient temp conditions (as well as other variables) that I'm not sure how broadly useful a flat "x" lb. ROT is.

This chart shows ambient air volume changes based on temps from -50F to 120F with a mean of 70, for tires something in the -30 to 150F is probably more useful. I only post it to show the differential linked to temperature.

And then you add pressure to the equation (simply compressing air makes it warmer), expansion of rubber, heat retention...I just think there are too many variables to be able to flatly conclude that if you play with your tire pressures to achieve the 3 or 4 lb differential, it's not going to work out when the seasons change or if you drive into a different climate (or altitude).

Of course where I live there isn't a whole lot of difference anyway. :D :D
 

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i just went outside and measured my cold tires and they are 30,29psi front and 34,36psi rear. i will be driving for a good 30 miles later and check the pressure again to see how much it changed.
checked tire pressure after a good half hour drive. front 31,32psi and rear 35, 36psi. temperature is about 10 degrees colder now then when i checked earlier today and my tire pressure gauge is an old cheapo type, so there is high error in this testing.
 
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