Less of a rant than an inconvenience
Wife's Expedition picked today to light up the low pressure light.

Of course it's dark & 27° with a feels like of 17°.
Couldn't find my tire gauge & had to resort to the flimsy cheapo in my plug kit.
3rd wheel in & fine motor skill was getting tough. Hard to put the valve stem caps back on

Door sticker calls for 39psi, they were all at 30.

Luckily the Mini was fine & I didn't have to do 4 more.

That's a lot. I typically have them drop about 5psi in the cold and come back up after I'm on the road for a bit.

I run my truck tires at 50 when the door sticker says 34 or (36?).
The tires are rated for that range and the “engineers” didn’t account for driving performance and the subsequent loss of mileage at that pressure. My tires feel like squishy doughnuts at that low of a pressure.
Fuck them! I’m driving a Tundra.
Every bit of mileage I can squeeze out of this beast I will gladly take!

I tend to run a couple PSI over the door placard, I can definitely tell in the Mini, but it's a significantly stiffer bodied car.

quote:

Cold Weather Tire Pressures

Cold weather, period.

I check pressures at least monthly. They should be at the correct pressure before being driven, which means adding air in the winter to keep them at that correct pressure. If you don't they will be too soft. The pressure rise when driving will be the same summer vs winter, so no need to adjust the baseline pressure.

In snow, running at a slightly higher pressure may improve traction by making the patch narrower. But on a wet surface it could be counter productive to go higher pressure. I run a slightly narrower winter snow tire within the manufacturer's list of sizes, and run at the upper end of recommended pressure. I believe it provides some improvement in the snow.

As we all know from Seinfeld there is a certain amount of “shrinkage” when the weather turns cold.

quote:

Originally posted by KMitch200:
I run my truck tires at 50 when the door sticker says 34 or (36?).
The tires are rated for that range and the “engineers” didn’t account for driving performance and the subsequent loss of mileage at that pressure. My tires feel like squishy doughnuts at that low of a pressure.
Fuck them! I’m driving a Tundra.
Every bit of mileage I can squeeze out of this beast I will gladly take!

The engineers know better than you. Assuming you're running a stock size/weight rating, you are running way too much pressure and will wear the tire center excessively. Handling and braking will degrade and it will ride like shit. But hey, save a few pennies at the pump. Perhaps consider tire cost when you wear the center as bald as a baby's butt with tons of meat on the outer tread area still. But hey, that mpg...

^^^I run 15-20psi less than the door jamb sticker calls for because I don’t want to wear the centers excessively, I don’t want my truck to ride like shit, and I do like handling and braking. The sticker calls for 80psi in the rears which is what they need to carry the 7,200lbs the axle is rated for. Unloaded, there’s 3,300lbs on the rears, so 35psi would be sufficient, but handles and rides like it’s on marshmallows. I run 60-65psi which gives a decent ride and good handling at the expensive of 1,200-1,000lbs of load carrying ability. I just air them up to 80psi when the truck is getting close to fully loaded.

quote:

Originally posted by MikeNH:
The engineers know better than you. Assuming you're running a stock size/weight rating, you are running way too much pressure and will wear the tire center excessively. Handling and braking will degrade and it will ride like shit. But hey, save a few pennies at the pump. Perhaps consider tire cost when you wear the center as bald as a baby's butt with tons of meat on the outer tread area still. But hey, that mpg...

LMAO. I know a guy that is always talking about mpg, and yet drives a Diesel truck to work everyday on a long commute. It’s a 2500 level one, and he sold his boat prior, so he doesn’t tow anything any longer. SMH. And another one who dailies a sports car who talks about it all the time. It’s hilarious. Neither would daily my hatchback which is WAY more efficient. I’ve explained, at length, how both would benefit from racking up commuter miles on an efficient economy car with heated seats and all the mod cons, how in the long run, would save them money. The Diesel or sports car would last 15-20 years. Nope, they are both daily driving a $60,000 inefficient vehicle to work everyday and talking about MPG all the time. Some people don’t know how to pour piss from a boot.

Yeah I use the door jam, and OEM recommended pressure for the vehicle and its weight. If I go cornering in my performance car I drop PSI a few. And on my bikes I definitely drop from 36/42 PSI front/rear to 34/36 for the mountain roads and 30/30 for the track. I’ve spent a lot of time and money on training, both riding and driving. Done so many track days with professional instructors for both disciplines. Never in all that training have I had a pro suggest running higher PSI on anything. Handling and braking is the top of the food chain. You never know when you are going to have to play dodge ball on the streets, or panic brake, to a full stop, to avoid collision. If you are that concerned with MPG driving a 5000-6000 pound full size truck I think you are doing it wrong. Payload if I load my truck bed up, or towing, is another discussion, on PSI. But I don’t daily drive my truck either.

I ran near sidewall max psi when I used to autocross my Saturn, but taller sidewalls tend to flex too much when cornering.
My Mini wouldn't need to go that extreme, lower profile tires don't wallow around near as much, in comparison.

quote:

Originally posted by trapper189:
^^^I run 15-20psi less than the door jamb sticker calls for because I don’t want to wear the centers excessively, I don’t want my truck to ride like shit, and I do like handling and braking. The sticker calls for 80psi in the rears which is what they need to carry the 7,200lbs the axle is rated for. Unloaded, there’s 3,300lbs on the rears, so 35psi would be sufficient, but handles and rides like it’s on marshmallows. I run 60-65psi which gives a decent ride and good handling at the expensive of 1,200-1,000lbs of load carrying ability. I just air them up to 80psi when the truck is getting close to fully loaded.

That makes sense for an unladen HD truck but a half ton on P rated or C-load tires, running anything but the door sticker -/+ a few PSI is a bit foolish in my opinion.

quote:

Originally posted by MikeNH:

quote:

Originally posted by KMitch200:
I run my truck tires at 50 when the door sticker says 34 or (36?).
The tires are rated for that range and the “engineers” didn’t account for driving performance and the subsequent loss of mileage at that pressure. My tires feel like squishy doughnuts at that low of a pressure.
Fuck them! I’m driving a Tundra.
Every bit of mileage I can squeeze out of this beast I will gladly take!

The engineers know better than you. Assuming you're running a stock size/weight rating, you are running way too much pressure and will wear the tire center excessively. Handling and braking will degrade and it will ride like shit. But hey, save a few pennies at the pump. Perhaps consider tire cost when you wear the center as bald as a baby's butt with tons of meat on the outer tread area still. But hey, that mpg...

That has NOT been my experience.
The ride on the “squishy doughnuts” is definitely noticeable at the door sticker pressure.
I have a tonneau cover that is heavy as hell, (Lear) and some tools in the bed definitely raise the load.
The “engineers” want a ride that is 4x4 soft so as not to offend the delicate butts of those “only going to the mall or grocery store” 4x4 drivers.
The handling and braking are handled very well by my standards on my winter rated tires. My handling and braking don’t suffer a bit and the tires wear evenly across the tread.
Your so called insights and “trusting the engineers that know more than you” and “saving some mpgs”, you can stick it in your arsehole.
I’m the one that drives this truck every day.

My Jeep tires are supposed to be 40 psi, per the tire shop. I run them at 34 or it bounces and is tough to hold in a lane.
I had them rotated last week when I got my oil changed, then drove it about an hour and a half to see a hockey game. It wandered all over the road. Got there and checked my pressures, they had pumped them back up to 40 psi cold, which is about 45 hot.

quote:

My Jeep tires are supposed to be 40 psi, per the tire shop. I run them at 34 ...

I'll wager the recommended pressure on the doorjamb label is a lot closer to 34 than 40. Too many people look at the max. pressure on the tire sidewall and think this is what it's supposed to be.

Seems many of us have various ideas. I deviate a little, but heavily reference the door jam stated psi. With a heavier truck, they may list options if towing a heavy load. I seldom had 80 psi in my ‘3/4 ton’ trucks.

Yes, the ride may vary, ‘bouncy’ if to high. That depends on the vehicle. I check the tires fairly often, usually put in 5 or so above any door jam numbers.

quote:

Originally posted by egregore:

quote:

My Jeep tires are supposed to be 40 psi, per the tire shop. I run them at 34 ...

I'll wager the recommended pressure on the doorjamb label is a lot closer to 34 than 40. Too many people look at the max. pressure on the tire sidewall and think this is what it's supposed to be.

I haven't looked, but I will tomorrow. Thanks for the reminder

In the bicycle side of things tire pressure topic is even more common. This is paraphrased info that came from Michelin. Tire profile, material, and direction of weave and all things construction, all go into the recommended tire pressure. There is a rolling efficiency reason for mfg recommendation. I'll use their exaggeration to explain. If you would nail a 2x4 across a bowling alley and send the bowling ball, it may bounce straight up when it hits. If you would then use a low pressure big rubber ball it would yield enough to continue rolling. Yes, it is an exaggeration but simply shows too much air can waste energy and send it up to your suspension. I do recall long time ago adding 3 lbs for mostly hwy driving.

quote:

Originally posted by P250UA5:
Less of a rant than an inconvenience
Wife's Expedition picked today to light up the low pressure light.

Of course it's dark & 27° with a feels like of 17°.
Couldn't find my tire gauge & had to resort to the flimsy cheapo in my plug kit.
<snip>

Why didn’t you use your Airmoto?