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Discussion Starter · #1 ·
All to often we have people coming onto the forum, (rightly so) looking for info etc on tyre inflation.

Keep in mind I have not adjusted my tyre pressures since Summer time and that is the first big giveaway as Summer tyre pressures remain higher due to the effect of the ambient surrounding temeperature or direct sunlight upon them.

Here we are in the UK starting to get our annual drop in temperatures and more importantly a drop in normal tyre pressure.

The first instance is the solid orange, low tyre pressure warning light and immediately the dash board changes to show you what tyre is under inflated. In my case the front left hand one (UK, passenger front).

It was merely a case of pull out the portable compressor from the boot, connect and inflate. The warning light was now off by the time I got back in the car.

How easy is that? If only the newcomers will now search the forum and find their answer. (ps I will inflate the rear left again) :p


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All to often we have people coming onto the forum, (rightly so) looking for info etc on tyre inflation.

Keep in mind I have not adjusted my tyre pressures since Summer time and that is the first big giveaway as Summer tyre pressures remain higher due to the effect of the ambient surrounding temeperature or direct sunlight upon them.

Here we are in the UK starting to get our annual drop in temperatures and more importantly a drop in normal tyre pressure.

The first instance is the solid orange, low tyre pressure warning light and immediately the dash board changes to show you what tyre is under inflated. In my case the front left hand one (UK, passenger front).

It was merely a case of pull out the portable compressor from the boot, connect and inflate. The warning light was now off by the time I got back in the car.

How easy is that? If only the newcomers will now search the forum and find their answer. (ps I will inflate the rear left again) :p


View attachment 2396352577 View attachment 2396352578
that appears to be a large drop in pressure to kick on the warning light. you must drive on the low end of normal tire pressure. i get cold winters and maybe see a two pound drop, but i run at thirty eight pounds summer
 

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I'm running OEM sized tires so I run my pressures at what the sticker in the door jamb says.

I'm anal about checking pressures; at least once every 2 weeks, more frequent if I have time. I don't rely on the dash display for anything. And yes, if my tires are 3 pounds low, I add 3 pounds. While checking pressure I also inspect the tires for stones, nails, cuts, alignment, etc..

My TPMS will kick on when the temperature drops, but here on the Gulf Coast, that drop is temporary, like half a day, so I never adjust. If they predict the cold to stick around a while, I will add air. Which is a royal PITA because I have to bleed off air when the temperature rises. But new shoes for these vehicles ain't cheap. I am.
 

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2017 Jeep Renegade Limited AWD 2.4L (Former Vehicle)
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All to often we have people coming onto the forum, (rightly so) looking for info etc on tyre inflation.

Keep in mind I have not adjusted my tyre pressures since Summer time and that is the first big giveaway as Summer tyre pressures remain higher due to the effect of the ambient surrounding temeperature or direct sunlight upon them.

Here we are in the UK starting to get our annual drop in temperatures and more importantly a drop in normal tyre pressure.

The first instance is the solid orange, low tyre pressure warning light and immediately the dash board changes to show you what tyre is under inflated. In my case the front left hand one (UK, passenger front).

It was merely a case of pull out the portable compressor from the boot, connect and inflate. The warning light was now off by the time I got back in the car.

How easy is that? If only the newcomers will now search the forum and find their answer. (ps I will inflate the rear left again) :p


View attachment 2396352577 View attachment 2396352578
I remember the first time I ever saw that light (coming from a non TPMS vehicle) I was so confused and brought it to a local shop and told them the Check Engine light is on. They hooked it up and after awhile told me it’s just the low air pressure warning. 🤣🤦🏼 Embarrassing.
 

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Here we are in the UK starting to get our annual drop in temperatures and more importantly a drop in normal tyre pressure.
Yup. Not just you guys in the UK; this is the time of year to be systematically checking tire pressure anywhere that has seasons. In the Northern Hemisphere, of course...

My experience is that during the summer and winter, when temperatures are more-or-less stabilized, I can get away with check pressures (with a tire gauge) every couple months.

But as temperatures fall during the, well, fall, I need to check every couple weeks or so. That's because -- in addition to the normal slight leakage -- as Puddlesplasher points out, the average falling temperatures also reduce the air pressure.

Generally not knowing what the ambient temperatures are going to be for the next couple of weeks, I always inflate to the pressure on my door-frame sticker. Threre's enough tolerance for that.

And I always when the tires are cold.

We've got an insulated but unheated garage, that's significantly less cold than outside temperatures. But I don't compensate for that.

Then in the spring, it's a bit less-critical to check pressures often. Any normal leakage is more-or-less compensated for by rising average temperatures. So I check about every month in spring.
 

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puddlesplasher I found it funny how when you guys spell tire "tyre" on your little Jeeps.
 

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puddlesplasher I found it funny how when you guys spell tire "tyre" on your little Jeeps.
Kinda makes sense to me. Can't confuse it with the other meaning of "tire"; in need of sleep or rest.

"Looking for a new tire is tiresome." makes less sense than, "Looking for a new tyre is tireseome."
 

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Discussion Starter · #8 ·
that appears to be a large drop in pressure to kick on the warning light. you must drive on the low end of normal tire pressure. i get cold winters and maybe see a two pound drop, but i run at thirty eight pounds summer
My tyres are generally at 33psi or 34.5Lbs. that 1/2 pound psi is the difference between running over inflated and against the guidelines or having the light come on.

I deliberately over inflated by 1psi to see what happens with 34psi. Nothing but happiness I suspect:D
 

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My tyres are generally at 33psi or 34.5Lbs.
First, I'm confused... psi = pounds per square inch (obviously). So 33 psi is not equal to 34.5 lb.

Do you mean the recommended pressure on the sticker is 33 psi, but you keep yours at 34.5 psi?

33 psi sounds a bit low for the recommendation. I realize that different tire sizes have different recommendations. My Trailhawk has 215/65R17 tires, and the recommendation is 36 psi. Our two VWs have recommendations of 34 psi and 35 psi, respectively. Like I said, 33 psi sounds low for a Jeep tire...
 

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Discussion Starter · #10 · (Edited)
Marek.

15 Pounds per Square Inch in the UK equals 1 bar. (15psi = 1 bar)

Therefore when a tyre is meant to be at 1.3 bar with no light, illuminating. What pressure do you reckon ot shopuld be and why? How good is your arithmetic.:cry: (

I raised this topic because it occurs every single, change of Season and the posts start piling in. I agree with the beginners to the forum that they may have a similar scenario. The whole point of my topic was to alleviate any anxiety that the people have.

Back on track, My tyres should be 34psi. (15 + 15 + ( 15/10 = 1.5 x 3 psi). Let us not overly exagerate that 0.5 as a

That is 2 bar (2x 15psi) = 30 (or 1.5 per bar)

and that means that

2.2 bar (33psi UK tyre inflation) is normal.

However as I suggested in Winter blah blah balah... when driving with a cold tyre in a cold environment, one needs to allow the internal tyre pressure to increase, thus increasing the heat inside the tyre.

Guys. I thought that you all knew about reasons in the Autumn/Winter why tyre pressures may slightly decrease.

Here was me fed up with new people asking the same question time after time after time. :eek::ROFLMAO::whistle:
 

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Man, I don't want to poke the puddlesplasher prickly bear... ;) But if we're splitting hairs, 1 Bar (average sea-level atmospheric pressure) is 14.5 psi plus change. Actually 14.5038...

But you're right -- 15 psi is good enough for rough estimation.

And yes, 2.2 bar is about 33 psi.

How is your recommended tire pressure marked on your door-frame sticker, you being in the UK? Bar, or psi? (Oh, wait... Do you have the OEM tires?)

when driving with a cold tyre in a cold environment, one needs to allow the internal tyre pressure to increase, thus increasing the heat inside the tyre.
I'm confused by what you wrote here. Yes, in winter your cold tire pressure will be lower than in summer, assuming the amount of air in the tires is the same. In other words, if someone adjusts their tire pressure in late summer while the weather is still warm, and doesn't check it again into winter, the pressure will be significantly less when it turns cold -- and that doesn't even account for normal air leakage.

Tire pressure should always be adjusted to what is recommended, and while the tires are cold (or at ambient temperature -- that is, not after being driven any significant distance, which would warm them up and increase the pressure). That means you should be checking pressure more-often in the autumn, and you'd be gradually adding air to the tires as the average temperatures fall.

I think that's what you mean too... :unsure:
 

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To add a little extra to this thread…I’ve seen people deflate their tires (tyres) totally with the change of seasons. The sense behind this is that “summer air” is more dense and weighs a tad more than the “winter air” and can improve the mileage a tad. I personally have never done it, but heres a better explanation if anyone is curious…

 

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To add a little extra to this thread…I’ve seen people deflate their tires (tyres) totally with the change of seasons. The sense behind this is that “summer air” is more dense and weighs a tad more than the “winter air” and can improve the mileage a tad.
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And if that is not enough, you can factor in the Temperature rating the tire/tyre. Off Road, All Season and Touring tires/tyers fluctuate at a different rate as their temperatures change.
🤔
 

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And if that is not enough, you can factor in the Temperature rating the tire/tyre. Off Road, All Season and Touring tires/tyers fluctuate at a different rate as their temperatures change.
🤔
Well, yeah... But that basically means that tires with higher temperature ratings won't heat up as fast at super-high speeds (or heavy loads) as lower ratings. I don't think that would be much of a factor compared to seasonal ambient temperature changes...
 

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Yep, only something to consider. Most manufacturers recommend setting tire pressure cold. If we haven't already, we will certainly at some point replace our tires/tyers. Based on our selection at purchase, those recommendations become guidelines. The FCAG recommendation for our Rene is 35 psi cold. I prefer to set our pressure @ 37 psi when hot. In my case it's simply more convenient to air up all the vehicles at once, that means in the garage when cold.
No biggie, just means I need to consider the temperature rating on the tires/tyers. 😎
 

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Yep, only something to consider. Most manufacturers recommend setting tire pressure cold. If we haven't already, we will certainly at some point replace our tires/tyers. Based on our selection at purchase, those recommendations become guidelines. The FCAG recommendation for our Rene is 35 psi cold. I prefer to set our pressure @ 37 psi when hot. In my case it's simply more convenient to air up all the vehicles at once, that means in the garage when cold.
No biggie, just means I need to consider the temperature rating on the tires/tyers. 😎
Yes... "checking cold" means the same as "checking at ambient temperature." That can be on the freezing street, or in the garage -- the pressure difference won't be enough to matter.

What matters is, not to check pressure after driving. Because that can change the tire pressure five or six degrees, or more.

What's recommended on the sticker is important. My Trailhawk has 36 psi recommended, but it has different-sized tires than your Renegade.

What I'm not sure about is, what tire pressure do you set on aftermarket tires that are a different size than OEM? The sticker wouldn't apply any more, and the tire manufacturer won't give operating recommendation because different vehicles are, well, different. The maximum pressure marked on the tire certainly shouldn't be used for operational pressure...
 

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I chalk the tire tread when the tires/tyers are at operating temperature, that's when wear occurs. Following that I check for a wear pattern, and adjust pressure till I'm satisfied. Certainly not a process I would recommend to everyone, just a car guy thing I've done for years.. 😎
 

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Most manufacturers recommend setting tire pressure cold.
That's interesting. Yes, they do; everybody, in fact, as far as I know. I assume they take into account warming up during operation; that's a real variable, depending on the time of year and how fast and far you drive (though I assume tire temperature stabilizes after a while...?).

Checking pressure when cold/ambient takes out that variable.

Yet you say:

I chalk the tire tread when the tires/tyers are at operating temperature, that's when wear occurs. Following that I check for a wear pattern, and adjust pressure till I'm satisfied. Certainly not a process I would recommend to everyone, just a car guy thing I've done for years.. 😎
I can see where you're coming from. But that seems like an awful lot of work for the payoff. Like I said, operating temperature can mean pressure six or more psi higher than ambient. So you'd be starting off more than 15% higher psi than recommended.

So what pressure do you end up at after your process?
 

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Based on my driving in Southern California on Pirelli 225-75-17's, 33psi cold gets me to 37psi at freeway speeds. Curiously our TPMS corresponds with my digital pressure gauge. As for the payoff, our vehicles are my hobby....oh yeah I'm retired. 😎
 
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