Post by: Badhabit on September 29, 2018, 05:22:16 PM
Years ago I found a tire pressure formula and want to know if it's still relavent.
Max load per tire at 80PSI and is 3415 max weight times 4 is 13660lbs. The truck weighs in at 7700 with me in it. So 7700 divided by 13660 is 56.3% so round up to 57%. 57% times 80PSI gives me 45.6PSI or round up to 46PSI on all 4.
Anyone use this formula??? or should I keep all 4 at 50 PSI?
Post by: jackelope on September 29, 2018, 05:34:57 PM
Post by: KFhunter on September 29, 2018, 06:02:07 PM
80 sounds like a crap load of air if you never haul anything.
I'd put all at four at the same air pressure, 40 in the winter 50 in the summer, easier to rotate.
Post by: hunter399 on September 29, 2018, 07:42:57 PM
Tire wears out faster that way .Should say right on tire what psi should be.
I always keep all four the same ,unless hauling then 10-15 pounds more in the rear but that's just me.
Post by: Crunchy on September 29, 2018, 08:02:19 PM
Post by: KFhunter on September 29, 2018, 08:16:22 PM
My Ram 2500 are inflated to 70 in front and 80 in the rears. Any way of getting around the sensors. I do not tow much in the winter, and like to drop them down to 55 front and 65 rears.
electrical tape over the dash light?
fake sensors in the glove box?
TPMS bypass tool? (sold on ebay, switch on and off)
Post by: jackelope on September 29, 2018, 09:26:39 PM
Post by: davef on September 29, 2018, 10:56:46 PM
Post by: GryphonHunter on September 30, 2018, 08:55:42 AM
Remember that under inflated tires build up heat which leads to catostrophic failure of the tire. @badhabit I would not trust that formula at all. 45psi seems pretty low for a 3/4 or 1 ton truck.
Post by: Badhabit on September 30, 2018, 09:14:26 AM
Post by: AWS on September 30, 2018, 09:34:55 AM
Post by: Special T on September 30, 2018, 09:41:31 AM
That 50 psi is fine for running around empty, but you have to remember to bump it up some for longer distance, summertime travel and or if there is a load. GryphonHunter is correct, heat buildup kills tires
Post by: aaronoto on September 30, 2018, 09:49:30 AM
Post by: Westside88 on September 30, 2018, 11:02:14 AM
Tpms sensors are set to a certain pressure and that setting can be adjusted and re set. So that's not a biggie. Psi is listed on the tires but that's just the hot and cold max pressures. Your supposed to go off the door like was commented. Assuming your using the correct rating tires. Otherwise I'd say just do what years of driving and common knowledge have taught you. If they were 80 max I'd run them at 60 all around and adjust from there depending on what your doing that trip.
I’ve been told the setpoint for TPMS can be adjusted, but have never actually found anyone who can or will do it. Several shops have said it’s not legal for them to change the factory settings. If that’s true there must be a lot of super duty trucks with the warning light on. Anyone know where you could get it adjusted if it is an option?
Post by: jackelope on September 30, 2018, 11:13:33 AM
:dunno:
Post by: GryphonHunter on September 30, 2018, 11:37:10 AM
Tpms sensors are set to a certain pressure and that setting can be adjusted and re set. So that's not a biggie. Psi is listed on the tires but that's just the hot and cold max pressures. Your supposed to go off the door like was commented. Assuming your using the correct rating tires. Otherwise I'd say just do what years of driving and common knowledge have taught you. If they were 80 max I'd run them at 60 all around and adjust from there depending on what your doing that trip.
I’ve been told the setpoint for TPMS can be adjusted, but have never actually found anyone who can or will do it. Several shops have said it’s not legal for them to change the factory settings. If that’s true there must be a lot of super duty trucks with the warning light on. Anyone know where you could get it adjusted if it is an option?
Good luck finding a legit shop that would monkey with TPMS pressure settings. It’s not worth it for the legal liability for the shop.
The government mandates for TPMS came about after the Firestone/Ford Explorer fiasco. The reality of that whole thing is the majority of those Explorers that had their factory installed firestone tires blowout causing the Explorer to roll over happened in the south (warm climates). From the factory Ford stated that the psi should be set at 26 pounds...WAY too low for that heavy of a vehicle. So of course the inevitable happened.
-Warm climate
-Heavy rig
-passenger rated tires
-Under inflated
-Freeeway speed
Tires becomes overheated from under inflation=catostrophic blowout.
Granted those Firestone’s were cheaply constructed tires, however, you add up all of those additional factors and you’re going to have problems.
A legit tire shop simply isn’t going to take on that liability of messing with TPMS settings. Peoples lives are at stake.
Post by: Badhabit on September 30, 2018, 12:03:00 PM
Post by: lokidog on September 30, 2018, 12:18:57 PM
Tire shops always over inflat . :twocents:
Tire wears out faster that way .Should say right on tire what psi should be.
I always keep all four the same ,unless hauling then 10-15 pounds more in the rear but that's just me.
Needed some air at Costco once, the guy put 30lb in tires rated for much higher, said that's the way it's supposed to be. I added more later to just under max specs....
Post by: Sandberm on September 30, 2018, 12:38:08 PM
Might as well just use one and pretend its the one that reads correctly. At least you will be consistently wrong...sort of like voting a straight Democrat ticket :tung:
Or just do the "kick the tire method" and call it good. :tup:
Post by: Special T on September 30, 2018, 01:01:29 PM
Spot on with one caviate. The PSI was fine for most climates, and since tire pressure is application specific if they had bumped the pressure up to 32psi they would have been fine. Only thing wrong was the pressure rating on the tire.Tpms sensors are set to a certain pressure and that setting can be adjusted and re set. So that's not a biggie. Psi is listed on the tires but that's just the hot and cold max pressures. Your supposed to go off the door like was commented. Assuming your using the correct rating tires. Otherwise I'd say just do what years of driving and common knowledge have taught you. If they were 80 max I'd run them at 60 all around and adjust from there depending on what your doing that trip.
I’ve been told the setpoint for TPMS can be adjusted, but have never actually found anyone who can or will do it. Several shops have said it’s not legal for them to change the factory settings. If that’s true there must be a lot of super duty trucks with the warning light on. Anyone know where you could get it adjusted if it is an option?
Good luck finding a legit shop that would monkey with TPMS pressure settings. It’s not worth it for the legal liability for the shop.
The government mandates for TPMS came about after the Firestone/Ford Explorer fiasco. The reality of that whole thing is the majority of those Explorers that had their factory installed firestone tires blowout causing the Explorer to roll over happened in the south (warm climates). From the factory Ford stated that the psi should be set at 26 pounds...WAY too low for that heavy of a vehicle. So of course the inevitable happened.
-Warm climate
-Heavy rig
-passenger rated tires
-Under inflated
-Freeeway speed
Tires becomes overheated from under inflation=catostrophic blowout.
Granted those Firestone’s were cheaply constructed tires, however, you add up all of those additional factors and you’re going to have problems.
A legit tire shop simply isn’t going to take on that liability of messing with TPMS settings. Peoples lives are at stake.
Sent from my SAMSUNG-SM-G930A using Tapatalk
Post by: thinkingman on October 01, 2018, 09:32:26 AM
Tire shops always over inflat . :twocents:Not sure where this idea comes from.
Tire wears out faster that way .Should say right on tire what psi should be.
I always keep all four the same ,unless hauling then 10-15 pounds more in the rear but that's just me.
My local Discount Tire always follows the door sticker and I usually ask for a few lbs more.
Higher pressure, while still within factory specs, does not cause faster wear.
Tires are engineered and manufactured to operate within certain parameters.
I just got my first-ever set of LT tires. I am running all 4 at 38lb and they are smooth and quiet.
If I was doing any heavy hauling, I would go up a few lb.
Post by: skeeter 20i on October 01, 2018, 10:01:39 AM
I've just worn out my first set of E rated KO2's, I ran them at 50psi all around when not hauling. I got great life out of them and very even wear at that pressure. Truck is a 2012 Tundra.
:yeah: I am getting great wear out of my 3 year old set at 50psi. I'll bump it up occasionally if hauling something and sometimes down a bit in the winter but 50 is where I usually run at. Love these tires..F150
Post by: KFhunter on October 01, 2018, 10:22:12 AM
Chevy Colorado, so truck don't weigh much.
I have Nitto trailgrapplers on my Dodge, I forget the size but around that 31" tall 11.5" wide 16 inch
It depends how much sidewall squish you have to the heat build up. If your sidewalls are bowed out from low pressure that constant flexion makes heat. If you had a feather weight truck, you don't need much air, but put a big cast iron diesel block engine over the front tires and your going to need a bunch of air even on the same tires as your smaller light weight truck. I could put my falkens off the colorado on the dodge and I'd have to air them up past 33psi.
Diesels are funny in that on my truck (95 12v cummins) I run 60 in the front and 40 in the rear (or less) or it beats me to death on the gravel roads. Also 60-80 psi tire spins like crazy on pavement, gravel, wherever because there's not much footprint or pavement contact on the rear of an empty truck. You just have a very narrow strip of rubber hitting the road across the bottom of a round tire with an empty truck on the rear.
With a load of hay I'll bump the rear to 80psi and fill the airbags to reduce squat but I pretty much leave the fronts at 60 all the time. I have a nice 12v air compressor.
If your going to be empty all the time or just tow a boat you don't need that much air in the rear of your Chevy Duramax
Post by: Magnum_Willys on October 01, 2018, 10:31:49 AM
Diesels are funny in that on my truck (95 12v cummins) I run 60 in the front and 40 in the rear (or less) or it beats me to death on the gravel roads.
Son has same truck but lifted, runs 45 front, 25 rear on logging roads to smooth the ride - thats with two leaves taken out in the rear with 35" ko3's
Post by: jstone on October 01, 2018, 11:23:44 AM
I have a 2015 Silverado 3500 with lifted 35” tires. 4 door regular box
Post by: Special T on October 01, 2018, 02:34:35 PM
Ok so I am a tire dummy. Don’t you get better mileage if your tire are aired up? Say max is 80 you want like 60 all around for gas mileage and ride? Less on a logging road for better ride?
I have a 2015 Silverado 3500 with lifted 35” tires. 4 door regular box
yes but only to a point, AND it reduces braking power/traction. Each vehicle has a sweet spot for mileage, traction and wear. You dont really know unless you play with it. Narrow tires have reduced rolling resistance, A tire like yours that has a larger volume than stock can do more with less air pressure. I knew a guy with a Unimog that ran severely oversized tires and ran on 5psi most of the time and with the valve core out off road.
Post by: luckyman on October 01, 2018, 04:34:01 PM
Empty and light loads I run 60# up front and 50# in the rear. With a heavy load I go 60# all around. It rides better and give even tire wear. 80# in the rear is way too much. Ive done it in the past with this truck and others and besides going through rear tires fast it ride terrible.
Post by: 6x6in6 on October 04, 2018, 07:30:50 PM
Post by: Grit dog on October 14, 2018, 08:59:33 PM
06 GMC 2500HD Crewcab 4x4 with the duramax. No sensors 10 Ply load range E.Id run 50-60psi front and 40-50 psi rear empty.
Anyone who runs their 80 psi truck tires at max pressure unless the load dictates, is not doing themselves or their tires any favors.
Post by: Lefty315 on November 07, 2018, 05:58:52 PM
Post by: CAMPMEAT on November 09, 2018, 09:10:24 PM
Post by: grimace on December 04, 2018, 02:30:34 PM
I do adjust my air pressures as I increase my payload...
I don't understand why some of you are running more psi (70-80psi) in the rear running empty, I can only guess these are stock size tires? If I ran my Toyo at II's at 60-70psi with no payload in the rain, I was spinning tires on the freeway and had a very harsh ride. This also why I've went with another tire too though...
G
Post by: luckyman on December 04, 2018, 04:24:12 PM
With almost 350k on my Ram I've figured a few things out with tires. If you go to a bigger tire than the truck came with tire shops tend to still use the specs on the door for psi. I went through several sets of Toyo mudders 20-25k each with the center wore out and plenty of tread on the outside. Then I started chalking my tires. I drive a lot of miles and I want to get my $$ worth , tires are expensive. I chalk every set of new tires I run on a straight section of road until I get a nice flat foot print, since I have been doing this I get 70-85k out of my tires. My 98 wrangler with 35"s, I run those at 18psi at each corner and got 73k out of the KM 2's, and drove great. I have a fresh set of KO'2's on it now and run those at 18psi as well. Drives excellent. My 05' Ram w/ Cummins last 2 sets of Toyo AT II's 285/75r18E I ran those 52psi in the front and 46psi in the rear and got 83k on the first set and 77k on the second set. I wanted fresh tires for hunting season or I could have made it to spring. Something changed with the Toyo tires on the second set they didnt work nearly as good in the rain and snow. I'm running Nitto Ridge Grapplers now 35x12.5x18F, 54psi front and 42psi on the rear. Ride is fairly good, not as noisy as the Toyo mudders though.
I do adjust my air pressures as I increase my payload...
I don't understand why some of you are running more psi (70-80psi) in the rear running empty, I can only guess these are stock size tires? If I ran my Toyo at II's at 60-70psi with no payload in the rain, I was spinning tires on the freeway and had a very harsh ride. This also why I've went with another tire too though...
G
Exactly What I do and get the same results. :yeah: