Yeah, the more is better isn't always correct. My Mercedes just recommends 31 psi in the front and 35 in the rear. If you're going to be driving over 100, then it's 35 in the front and 35 in the rear. When you go outside of car manufacturer's spec, you can end up with uneven tire wear. usually when you have too much air, the middle of the tire ends up wearing away faster.
Max Tire Inflation
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Originally Posted By: AZjeff
.............. Sometimes we're given very good advice if we're smart enough to consider it. (With a "below the line" comment of "Why know when you can guess?"
Originally Posted By: circuitsmith
So you know more than the car maker, eh?
Have you ever actually tried using the "proper" air pressure?
JEEZ!!!
You boys still cranky over the Tuesday results? I asked what I thought was a simple question. I guess I was expecting an engineering response as in: " the tire technology has improved to a degree that allows for a stiffer sidewall and hence increased max inflation pressures." Or something like that.
Instead, AZ insinuates I'm not smart enough to follow the advice given (by Nissan), (30 psi, please, and forget the cold weather changes) but suggests we guess instead of "know."
Then, bad Circuit jumps in claiming I said I knew more than the car maker. Where in my OP did I say that?
I simply said 30/30 is not acceptable to me. When the weather gets cold (27 overnight tonight), the tire pressure has a tendency to head south after a few of those nights. If you want to cruise at 75 mph+ on 28/28, have at it. That is not my choice.
I was simply seeking feedback as to why allowable max inflation pressures had increased.
I guess you flew right by that OP part about "constructive comments."
D-amn, this board has certainly changed over the past thirteen years.
Capri- thanks for the input. That is what I was looking for!!
.............. Sometimes we're given very good advice if we're smart enough to consider it. (With a "below the line" comment of "Why know when you can guess?"
Originally Posted By: circuitsmith
So you know more than the car maker, eh?
Have you ever actually tried using the "proper" air pressure?
JEEZ!!!
You boys still cranky over the Tuesday results? I asked what I thought was a simple question. I guess I was expecting an engineering response as in: " the tire technology has improved to a degree that allows for a stiffer sidewall and hence increased max inflation pressures." Or something like that.
Instead, AZ insinuates I'm not smart enough to follow the advice given (by Nissan), (30 psi, please, and forget the cold weather changes) but suggests we guess instead of "know."
Then, bad Circuit jumps in claiming I said I knew more than the car maker. Where in my OP did I say that?
I simply said 30/30 is not acceptable to me. When the weather gets cold (27 overnight tonight), the tire pressure has a tendency to head south after a few of those nights. If you want to cruise at 75 mph+ on 28/28, have at it. That is not my choice.
I was simply seeking feedback as to why allowable max inflation pressures had increased.
I guess you flew right by that OP part about "constructive comments."
D-amn, this board has certainly changed over the past thirteen years.
Capri- thanks for the input. That is what I was looking for!!
AZjeff
$50 Site Donor 2023
Wow, honored to be quoted. Sorry, but I was happy to see Barry check in and offer informed, experienced advice based on his area of expertise. But you were looking for justification to run it up to 39 simply because the max is 51 and it seems there's no valid connection.
Nobody blinks running a couple PSI over or under placard, that's probably within the design margin of error. Running 39 when the placard is 30 is something else. You're running on around 23% less contact patch area at that pressure. That's a good thing?
And I'm less unhappy about the election than had it gone the other way. Conservative values, 2A, you know, evil white guy stuff.
Nobody blinks running a couple PSI over or under placard, that's probably within the design margin of error. Running 39 when the placard is 30 is something else. You're running on around 23% less contact patch area at that pressure. That's a good thing?
And I'm less unhappy about the election than had it gone the other way. Conservative values, 2A, you know, evil white guy stuff.
Tire pressure is to be set cold, so if you set the tire pressure...say at 30 psi when your air temp is at/near it's lowest, you should be good...shouldn't drop at all..How much if any increase in tire pressure occurs with highway driving at 28 degrees?
Every owners manual I've ever read has emphasized in the strongest possible language (for an owners manual) to not let anybody tell you that over or under inflation of your tires is okay. It's not. Just read it for yourself.
I have gotten into very slippery snow where I severely under inflated to get traction. But drove very slowly and this was a temporary thing. I'm wondering why you would want to over inflate your tires? That is, inflate them above what the door jam says. The manufacturers say this is dangerous.
I have gotten into very slippery snow where I severely under inflated to get traction. But drove very slowly and this was a temporary thing. I'm wondering why you would want to over inflate your tires? That is, inflate them above what the door jam says. The manufacturers say this is dangerous.
Depending on application, the vehicle OEM recommendation can be not the best solution. Like with E rated tires on pickups. My 2500, they recommend 60 front and 70 rear. Yes, but that is also at max GCWR. I run them at 55 psi when empty or lightly loaded. Tire wear is improved and also mpg a little better. I attribute that to less wheel hop on rough roads at the higher pressures when empt. Also, braking and overall handling are improved at the lower pressures when empty. This methodology is not different than commercial heavy truck tires. In that situation, at least the tire OEM has specific load/pressure charts to give you the optimum pressure based on the tire loading. The pickup OEM's aren't intelligent enough to provide that, along with they have strong armed the tire OEM's into punting on the issue, so some of us have to improvise.
As said before there is no reason to increase your pressure just because the new tires have a higher max rating. However, the pressures on the door are a oversimplification of what pressures will give the best performance. If you have a good reason and know (actually know not just think you know) what you are doing you can get much better results when deviating from the prescribed tire pressures.
LOL! Yeah, the OP obviously does NOT know how to read a door placard. I would never go that high on tire pressures. Guess common sense isn't so common anymore
The other side of this is that unless you really enjoy looking at the TPMS light on colder mornings, inflating the tires a little over the door jamb recommendations is probably wise.
You can actually go well beyond what's recommended and you won't see any increase in center tread wear nor any loss of traction. If anything, steering response is noticeably sharper with no decline in wet or snow grip. You will have noticed that if you typically corner with any vigor at all the sides of the tread see more wear than does the center, which also points up the value of rotations.
Many of us have played with tire pressures for years.
The main downside I see with higher inflation pressures is an unacceptable increase in ride harshness if one gets too carried away.
Incidentally, the OP is a licensed pilot and is employed in a position of unquestioned competence, so to imply that he lacks either reading skills or common sense, as some have, is way off base.
You can actually go well beyond what's recommended and you won't see any increase in center tread wear nor any loss of traction. If anything, steering response is noticeably sharper with no decline in wet or snow grip. You will have noticed that if you typically corner with any vigor at all the sides of the tread see more wear than does the center, which also points up the value of rotations.
Many of us have played with tire pressures for years.
The main downside I see with higher inflation pressures is an unacceptable increase in ride harshness if one gets too carried away.
Incidentally, the OP is a licensed pilot and is employed in a position of unquestioned competence, so to imply that he lacks either reading skills or common sense, as some have, is way off base.
I don't run the prescribed door placard pressures in the tires on my 2500 when empty. Way too high for an empty pickup. The TPMS light is situated in the dash perfectly for me to ignore it. Just like the seatbelt light is placed in the right place for the same ability to ignore it. The information display does show tires being lower than recommended at start up, but easy one button dismiss and I never see that again.
And sidewall max pressures are hardly in line with what should be run. My commercial tires, max sidewall is 120 PSI. Michelin recommended pressure on those tires, with 17,000 lb per drive axle, 34,000 lb total, is about 98 psi. Even lower if lighter loads, clear down to 75 psi for the minimum load weight on the chart, which is still heavier than the load on my tires when empty. 447,000 miles out of the last set of these tires. Still had 8-9/32nd tread, no uneven wear, and I got $150 from the dealer for each of the take off tires. I used similar methodology on my pickup tires, since the OEM and Tire folks are not forthcoming with similar information, and run my pickup tires at 55 psi when empty or light loaded, and the recommended 60 front / 70 rear when I will be really loading the pickup down.
And sidewall max pressures are hardly in line with what should be run. My commercial tires, max sidewall is 120 PSI. Michelin recommended pressure on those tires, with 17,000 lb per drive axle, 34,000 lb total, is about 98 psi. Even lower if lighter loads, clear down to 75 psi for the minimum load weight on the chart, which is still heavier than the load on my tires when empty. 447,000 miles out of the last set of these tires. Still had 8-9/32nd tread, no uneven wear, and I got $150 from the dealer for each of the take off tires. I used similar methodology on my pickup tires, since the OEM and Tire folks are not forthcoming with similar information, and run my pickup tires at 55 psi when empty or light loaded, and the recommended 60 front / 70 rear when I will be really loading the pickup down.
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