misconceptions on proper inflation!

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While reading a truck owners forum I came across a thread asking about proper tire inflation. I was amazed how many forum members recommended running at the maximum value posted on the tire and not per on the vehicle. And even when presented with evidence to the contrary some insisted they were correct. While there are valid reasons for running at higher pressures such as hauling/towing and high speed driving on the Autobahn, over inflation is not the way to go. Another reason to be careful and verify what we read on the net.
 
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Racers measure tire temperature across the tread with a pyrometer after a run looking for hot spots which would suggest an alignment, pressure or "jacking" adjustment is needed. It's probably the only way to insure the tire is inflated and aligned properly. Those who put 40 pounds of air in a passenger car tire "cause it says so on the sidewall" are beating their suspension AND occupants to distraction.
 
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Originally Posted By: Bear
While reading a truck owners forum I came across a thread asking about proper tire inflation. I was amazed how many forum members recommended running at the maximum value posted on the tire and not per on the vehicle. And even when presented with evidence to the contrary some insisted they were correct. ……………..
This reminds me of how many car enthusiasts believe it is 100% OK to use a LED or HID source in headlight optics designed for a Halogen source.
 
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40psi in a passenger car isn't that bad in terms of comfort. I generally run a split between the door and the tire and pay attention to the wear pattern on the tire. 32 on the door, 44 on the tire = 38 in the tire.
 
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I get a kick out of the LED H4 conversions with a fan on the back of the "bulb". LEDs, in an assembly with the proper optics will someday be an automotive standard, but properly designed OEM systems appear in only a few cars. rare. The aftermarket... has a LONG way to go.
 
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Misconceptions and anecdotes are quoted as scientific facts every day on this forum. I also see lots of use of the words never, always, all, and none. I carefully avoid using absolute terms unless I am really sure. My all-time favorite is, "I did such and such and never looked back." What the heck does that mean? Does it mean that you are so sure what you did is right that you will "never" consider any other options? And, I do realize I used the language "every day" in my first sentence. Of this one I am sure!
 
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All I know for certain is that I hate TPMS. I checked the pressure on all my tires with a gauge that I believe to be fairly accurate. Set each one to the recommended PSI on the door sill placard. Drove to work and the pressure on all 4 in the DIC varies wildly. Then my wife checks hers religiously, which I am thankful for, but then sweats a couple PSI difference after driving. duh
 
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Originally Posted By: racer12306
40psi in a passenger car isn't that bad in terms of comfort. I generally run a split between the door and the tire and pay attention to the wear pattern on the tire. 32 on the door, 44 on the tire = 38 in the tire.
About 10% over the vehicle manufacturer's recommendation is my limit. Or, 4psi over, at most. Barring unusually heavy loads, that is. The other thing people screw up is not having the tires fully cooled down before checking pressure. I had to go into a Subaru dealership, newish car with CEL. The dumbies "Adjusted" my tire pressure, fresh in off the 100 degree road. When I left, it didn't feel quite right......When I checked the tires (Cold), they were all 5 lbs below the recommended pressure.....Which was 8psi (Cold) below what I went in with. Irritating.
 
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Originally Posted By: racer12306
40psi in a passenger car isn't that bad in terms of comfort. I generally run a split between the door and the tire and pay attention to the wear pattern on the tire. 32 on the door, 44 on the tire = 38 in the tire.
Pothole prove New England roads and low profile tires at high PSI don't get along.
 
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Originally Posted By: HerrStig
Originally Posted By: racer12306
40psi in a passenger car isn't that bad in terms of comfort. I generally run a split between the door and the tire and pay attention to the wear pattern on the tire. 32 on the door, 44 on the tire = 38 in the tire.
Pothole prove New England roads and low profile tires at high PSI don't get along.
Wouldn't the same setup with normal PSI be more likely to damage the rims? Has the snow melted in Boston yet?
 
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Originally Posted By: HerrStig
Originally Posted By: racer12306
40psi in a passenger car isn't that bad in terms of comfort. I generally run a split between the door and the tire and pay attention to the wear pattern on the tire. 32 on the door, 44 on the tire = 38 in the tire.
Pothole prove New England roads and low profile tires at high PSI don't get along.
Meant to say "prone".
 
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When my father got his truck he was always having this issue when it would get serviced at the dealer. They would always inflate the tires to 80PSI - because that's what they need to be at if the truck is 100% loaded. However, it makes the truck very skiddish when empty. I think he would run them at 50 unloaded, then we would bump them to 80 for a load.
 
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On the rare occasions anyone other than myself touches the Jeep, I always make it clear that they are not to adjust the tire pressure. The tire pressures are set as they are based on what I've found works best for that set of tires on the vehicle, and none of my tires are stock size anyway, so the door card pressures are irrelevant.
 

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Originally Posted By: rslifkin
On the rare occasions anyone other than myself touches the Jeep, I always make it clear that they are not to adjust the tire pressure. The tire pressures are set as they are based on what I've found works best for that set of tires on the vehicle, and none of my tires are stock size anyway, so the door card pressures are irrelevant.
I took my car into Discount Tire for a rotation and they let air out of my tires mad Like dude, the tires are hot. Your 32 psi hot isn't enough.
 
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Originally Posted By: Bear
While reading a truck owners forum I came across a thread asking about proper tire inflation. I was amazed how many forum members recommended running at the maximum value posted on the tire and not per on the vehicle. And even when presented with evidence to the contrary some insisted they were correct. While there are valid reasons for running at higher pressures such as hauling/towing and high speed driving on the Autobahn, over inflation is not the way to go. Another reason to be careful and verify what we read on the net.
It was so annoying when people would bring their cars in and they would have all the tires maxxed at 51 or 44(depending on the tire) and we would have to adjust all 4 because they don't know that that is a MAX the tire CAN hold. If it was a truck with LTs on it I would ask the customer if they tow regularly and if they intended on them being so high(80psi) or not. Most don't know and it was on accident but some knew what they were doing. But 80psi in an unloaded half ton would drive like [censored] I would think and same for 50psi in a cavalier or focus. One time we pulled in a car(older small car, I don't remember what it was but it was Focus/cavalier sized) and it had 93psi in one tire. No clue how it hadn't blown out on them. It wasn't a good tire either, cheap no-name brand.
 
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I run my Honda Michelin tires at 40psi. About 20 years ago this car (the one in my sig, I'm the original owner) was the subject of a friendly bet. We used a back street at an industrial park on Sunday morning and did a breaking test with the tires hot and at 32, 36 and 40 psi from an indicated 65mph. With 3 stops at each setting the best stopping distance by 9 to 11 feet was the 40 psi. We also set up a circle and drove around it. The 40 psi setting was much better but I don't remember any more how much it was. I do remember collecting the dollar from the bet and it's still taped up on the lid of my tool box. When Social Security crashes I'll be covered. We did this testing with a couple of other cars and obtained similar results. I get excellent mileage out of the tires at 40 psi and have had not problems beating up the suspension.
 
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Originally Posted By: HerrStig
Originally Posted By: racer12306
40psi in a passenger car isn't that bad in terms of comfort. I generally run a split between the door and the tire and pay attention to the wear pattern on the tire. 32 on the door, 44 on the tire = 38 in the tire.
Pothole prove New England roads and low profile tires at high PSI don't get along.
or our miles of washboard dirt roads.my jeep will beat me up with 35 psi in its tires
 
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I run 2 psi less than the door sill placard in the cold winters, and 2 psi more in spring/summer/fall. This works because tire flexing generates heat, and winter cold keeps them from overheating, while they generate less heat in summer due to less flexing.
 
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Originally Posted By: OneEyeJack
I run my Honda Michelin tires at 40psi. About 20 years ago this car (the one in my sig, I'm the original owner) was the subject of a friendly bet. We used a back street at an industrial park on Sunday morning and did a breaking test with the tires hot and at 32, 36 and 40 psi from an indicated 65mph. With 3 stops at each setting the best stopping distance by 9 to 11 feet was the 40 psi. We also set up a circle and drove around it. The 40 psi setting was much better but I don't remember any more how much it was. I do remember collecting the dollar from the bet and it's still taped up on the lid of my tool box. When Social Security crashes I'll be covered. We did this testing with a couple of other cars and obtained similar results. I get excellent mileage out of the tires at 40 psi and have had not problems beating up the suspension.
40psi hot is not the same as 40psi cold. A good rule of thumb is the tire pressure is optimum for roadholding and braking when checking them hot, they are 4psi above what was put in them cold. Since your bet was based on hot temps, all things being equal, you should probably be running about 36psi cold. Just sayin'.
 
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