Tremor tire pressure

[Dgc333]

Most of your national tire chains have the difference posted right on the inflation machine. For example Discount Tires even has a sign at their drive up pressure check lane states at which ambient temps they will inflate to what pressure.

The cold pressure on the door doesn't take into account ambient temperature and is a general safe guideline but if you're trying to dial in the pressure, accounting for cold vs hot and ambient temperature is required. If I set my tires to 39 psi today while it's 95 degrees out and drive slowly around town, the rise in pressure will be less than if I get on the highway and drive for two hours. Likewise if I set it to 39 in the winter and do the same slow drive around town, it will not rise as much as today when it's 95 out.

My experience with these tires on the Tremor is that during summer temps, they will rise 10-15% in pressure in a relatively short period of time. If someone has theirs at 42 cold, it'll climb to 46-47 when at temp, which is pretty stiff riding and will begin losing some traction, especially in the wet.

Never heard of such a thing. The recommendation on the door placard is for all ambient temps.

My son manages a Tire & Service center and is a member of the Tire Industry Association and follows their recommendations. He will only set air pressure to the recommendation on the placard even if a customer requests something else. It is a liability thing.

I fully understand that the air pressure increases as you drive but the placard recommendation accounts for that as does the max recommended inflation pressure on the tire side wall. I can't think of one technical reason why you would want to set your tire air pressure differently based on ambient temperature. I certainly can understand why you would want to deviate from the factory compromise to improve ride with less pressure or improve mileage with more pressure but different pressures for different ambients doesn't make any sense.

I tend to run my tires a few psi less than the door placard to get a better ride. The Grabber ATx tires on my Tremor give me a good ride with no noticeable loss of mileage or degradation in handling. If I was loading the truck up I would increase the pressure to the 39 psi recommendation.

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[Phil_R]

I was always told "cold" tire pressure was what it should be set at at the coolest part of the day (morning) before the vehicle is driven. Everything else is guessing.

Even half the truck sitting in the shade and half in the sun will throw off the tire pressure. Don't get me started on altitude impacting your pressure reading.

So if my garage floor is higher by a 1/4 inch on the left side of my truck, because of that altitude difference, will my left side tire pressure be lower or higher than the right side

Sorry, couldn't resist.....

 

[halligan1201]

I just got off the phone with the Discount Tire shop close to me here in Tennessee. They told me that in warm / hot weather, the put the tire pressure at what the door notates. Now what surprised me John, they said they add extra pressure when the temperature is very cold. So at 25 degrees, they will set the tire pressure 2 to 4 PSI higher than recommended. I do not agree with this, and am surprised to hear them do this.
I have always figured that the "cold" tire pressure is what the measured tire pressure is at any given temperature. So if it is 30 degrees outside, I will set the tire pressure at what the door says. If it is 90 degrees outside, I will also set the tire pressure cold at what the door says.
Now I know that the tires will loose pressure when the temperature changes from hot to cold and vice versa. So I will check the pressure often enough to be sure no matter what the temperature is outside, I am very close to that recommended tire pressure.
BTW, at 39 PSI as you mentioned you said it will increase 10 to 15% more. At 15% it would increase to 44.89 PSI or 45 basically. I will check this on my tires on my Tremor the next time I go for a drive in the miserable hot weather we have now! I am sure different tires and how they are made with different compounds will increase at different rates from a cold to hot tire after driving. I find this discussion interesting and will be the first to say I am wrong if that is the case. (I hope not though..LOL!!!)

Yeah the "winter"

Never heard of such a thing. The recommendation on the door placard is for all ambient temps.

My son manages a Tire & Service center and is a member of the Tire Industry Association and follows their recommendations. He will only set air pressure to the recommendation on the placard even if a customer requests something else. It is a liability thing.

I fully understand that the air pressure increases as you drive but the placard recommendation accounts for that as does the max recommended inflation pressure on the tire side wall. I can't think of one technical reason why you would want to set your tire air pressure differently based on ambient temperature. I certainly can understand why you would want to deviate from the factory compromise to improve ride with less pressure or improve mileage with more pressure but different pressures for different ambients doesn't make any sense.

I tend to run my tires a few psi less than the door placard to get a better ride. The Grabber ATx tires on my Tremor give me a good ride with no noticeable loss of mileage or degradation in handling. If I was loading the truck up I would increase the pressure to the 39 psi recommendation.

It's a thing. I sold tires and was a commercial sales manager for many years for a national retailer that carried all major brands of tires and their own house brand. I attended many conferences, sales sessions, and tech updates classes from these suppliers, including during the infamous Firestone/Explorer lawsuit era. All of them have recommendations for pressure deviation for ambient temperature and actually if you're super nerdy about it, for changing from one elevation to another. The increase/decrease in pressure is what opened the door for the whole nitrogen upsell.

I'm not saying it's necessary or wrong not to adjust for winter/summer and from experience selling tens of thousands of tires most consumers never realize their tires are going up and down 10-15% through the year or depending on the day and their drive within a given day. My post was just simply to make those who might not be aware that their tires fluctuate that much be aware. It's 93 here. I know my tires will be at 37psi when I walk out and ten minutes into my drive they will be at 40-41, which is where I like them.

 

[AZ_Tremor]

My tires were set at 49 from the factory cold … didn’t even check them unit 3 weeks of owning the truck … now they’re set at 39…

 

[Phil_R]

Today I left for a community about a half hour away or 22 miles away from my home. Drove about 55 mph and when I left the garage with my Ranger Tremor 1 tire showed 39PSI and the other 3 showed 40PSI. It was about 80 degrees when I pulled out of the garage and when I returned it was about 87 degrees. On the way back after the tires heated up and I showed 43PSI in all tires. So, about an increase of 3 PSI increase average. About .075% increase if my math is right. Anyway, for my driving, it looks like my setting the cold tire pressure about 40PSI, will work fine. Maybe at 70 MPH, it might increase even more, however even in 70 MPH zones, I still stay in the right slow lane and run around 60 to 65 MPH. Trying to save gas and $$$! Seems like there are others too now a days starting to slow down to save gas. Pics below:

 

[StormShadow1138]

So... The number on the sticker is a lawyers number, not an engineers number. I use a pretty specific formula to figure my pressure. I can share it here but I will warn you, you will likely think I am insane, also, with my formula you MUST remain vigilant about making sure your tires are at the pressure the formula states. First, you will need access to a scale. I live just down the road from a decent truck scale so I can get measurements fairly easily whenever it is needed. Now, regardless of what tire you are using it should have 2 numbers somewhere on the sidewall, Maximum Pressure and Maximum Load. The General Grabbers on mine are maximum 50psi and 2470 Pounds. Get your truck to the scale and measure front axle weight and then rear axle weight. Divide each of those numbers by 2. For me I got 2950 front and 2250 rear with myself, my wife and 2 suitcases. That gives me 1475 front and 1125 rear. I then divide that by the maximum load (2470). That gives me a percentage. I then use that percentage as a direct proportion to psi. If I am running 60 percent of my max load I will run 60 percent of my max psi. As I write this I am running 30psi up front and 23psi in the rear. This does throw a TPMS warning but I have found, in the 30 years I have been doing it this way, that I get more tread life from my tires and very little difference in mpg. If I am pulling a trailer or hauling any type of load, these numbers all go up. AGAIN... WARNING... This works for me and may not be comfortable for anybody else. I AM NOT A FORD VEHICLE ENGINEER OR A TIRE COMPANY ENGINEER, I MAKE NO CLAIMS AS TO THE SAFETY OR LIFETIME VALUE YOU WILL GET USING THESE NUMBERS.

 

[JDowns]

Mine sit at 37. Dealer here is nice when you do a service. They actually asked me my preferred pressure before doing the tire rotation and inspection.

 

[hmott]

... On the way back after the tires heated up and I showed 43PSI in all tires. So, about an increase of 3 PSI increase average. About .075% increase if my math is right. ...

This is great info, I'm surprised at the difference. Did think it was worth pointing out that your math is indeed incorrect. That would be a median of ~7.5% or an average of ~8.2%.

 

[Phil_R]

This is great info, I'm surprised at the difference. Did think it was worth pointing out that your math is indeed incorrect. That would be a median of ~7.5% or an average of ~8.2%.

Yup, I stand corrected. My math was wrong as I see now. Sorry

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