Tire Pressure

[EMDDIESEL]

I cannot figure out what to set my tire pressure at. The label on my door frame gives pressures for a 245/17 size tires, i have a 265/17 tires. I have a 2001 2500 Quad Cab 4X4 with a short box. I dont tow or haul anything and i dont drive off road. All i do is highway miles. What should i set them at for the best ride quality and fuel economy. I have the fronts at 60 and the rears are 50, should i leave it like that? Any ideas?

 

[illflem]

The 10 psi difference between front and rear unloaded sounds right. I run the same as you for long hauls, but drop to 55/45 for regular going to town driving, makes for a better ride.

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95' 25004X4,AT,Driftwood,Banks Stinger,Warn fender flairs and running boards(work truck)
95 3500,5 speed 3:54,BD E-brake,Driftwood,Banks&Psycotty,34,000 GCVW apple and tractor hauler(works harder truck)

 

[DennyDay]

Wet your driveway and drive your truck across the wet area, then drive in the garage and look at the tire marks. If you are over inflated not all the tread will be in contact with the smooth concrete of the garage. If you are under inflated, the outer edges of the tire will show firm contact, with the center showing less contact.
Another way is to weigh each axle and divide by 2, this will give you the weight on each tire. Go to a tire dealer and look in his tech book and find the pressure required for the weight.
With your truck empty, I think you will find a pressure of 50# in the front and 42# in the rear will give you a good ride and also handle the weight.
Good Luck, Denny

 

[klenger]

There should be a document included with the truck paperwork (with the owner's manual) that gives the exact tire pressure for all tire / truck / load combinations. I have the same truck you do, and I'm running 50 lbs all the way around because I tow a trailer at times. Click here to see tire pressure chart for 2500.

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Ken Lenger
2001. 5 2500 QC 4X4 SWB SLT, ETC/DDX 5 Speed, 3. 54 (no LSD), camper group, trailer folding mirrors, RBR CD/Radio, LT265/75R16E AT OWL tires, trailer tow group, Patroit Blue / Agate, Westin CPS Step Bars, Jordan Utlima Brake Controller, Weather_Guard 664 tool box/
Replaces 98 Jeep Grand Cherokee V8 which is for sale.
Trailite 21' Travel Trailer, ~4000 lbs loaded.

[This message has been edited by klenger (edited 04-16-2001). ]

 

[LandShark]

It amazes me that you would want others to guess what your tire pressures should be! The only way to safely air your tires is to get the specification sheet for your exact tire from the manufacturer. The spec. sheet will list various air pressures for a given weight range. If you are not sure of your weights, get your truck (and trailer) weighed. Sometimes pressure/weight info is available at the mfg. web sites; if not call their toll free number.

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1995 2500 SLT Club 4x4, auto, 3. 54, 3300 pound Elkhorn slide in camper, AirLift air springs, Ricka dual wheel adapters (used only with the camper on), K&N, DC tow hooks, Rancho RS9000, Hellwig rear sway bar.
110,000 miles and counting.

 

[EMDDIESEL]

I am not asking anybody to "Guess" what my tire pressure should be. I am asking what the proper pressure should be for my tire size not towing anything. The sticker that shows what the proper tire pressure should be is not correct for the size tires that came with my truck.

 

[Skydiver]

A question.
On my dually that weighs 6100 lbs. The 65/35 % split comes to 533. 75 lbs on each of the 4 rear tires. What is the minimal safe psi to run in the rear,215/85/16. Have been told the front is 70% of the 6100lbs. 30% of 6100=1830. 1830 divided by 4=457. 5 lbs per rear tire.
Yes the center of the tread is wearing out at 60 psi. Only tow about every 6 to 8 weeks.
I'll get it weighed next week.
Thanks Tim

 

[LandShark]

EMDDIESEL: With the tire information you provide we can only 'guess' at what your minimum safe inflation pressure should be. Once again: The ONLY way to figure safe minimum inflation pressure is to know the exact tire (Manufacturer, model, size, and Load letter (usually D or E for our trucks) then match the load (weight) on the tire to the manufacturers spec sheet. Then you sometimes have to factor the speed you are running at.

There are TDR members that use a 'formula' to determine safe inflation levels. This may work for one particular tire but would not cover all tires. Tires that look the same can have different allowable loads and could, for example, have a maximum inflation pressure of 35psi or 80psi. or even higher.

Skydiver: You're on the right track. Unfortunately there is no one inflation pressure that is right for those of us that tow or carry heavy loads. To get the best ride, traction, wear, and load carrying ability we must adjust our tire psi for each condition. When empty, I run my rears at 45psi. With my 3300 pound camper on the truck I pump the rears up to 80psi. I have the OEM spec. sheet that came with my 1995 which shows that a lightly loaded 3500 should use 40psi in the rears. Another part of the sheet shows 35psi as a minimum psi for a 1360 pound tire load. (this is for a LT215/85R16 Load Range E OEM tire). The spec. sheet also indicates increasing psi by 10 for continuous speeds over 65mph and that continuous of over 75mph is not recommended for vehicles loaded beyond what they consider a 'light load'. You really need to get the spec. sheet for your tires to make the correct decision.

 

[BHORNER]

Try this. Works for me.

Find a truck scales and get your truck weighed, The scales should tell you your front, rear & combined weights. then look at the rating on your tires. (Should be something like 3042 @ 80 psi for singles and different # for duals)
Take your axle weight and divide it by the # of tires you have; then divide the per tire weight by the rating and multiply that by the max tire pressure (80 psi).
For example, my 2500's rear axle weighs 3,300 lbs and my tires are each rated at 3042 lbs @ 80 psi. To calc the tire pressure; (1650/3042) x 80 psi = 43. 4 psi. The front axle weighs 4,300 lbs, so the tire press is (2150/3042) x 80 psi = 56. 5 psi.

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Barry Horner
Lake Forest
Orange County, Ca

2001, SLT+, ETH, 6 speed, White quad cab, short bed, Sport, 2wd , 3:54 anti spin, Camper Special with trailer tow, 16x8 Forged Aluminum with 265x75 tires, Fog lights, Audio controls steering wheel mounted, AM/FM cassette with CD, Travel Convenience group, Keyless entry with remote, Leather agate heated seats. Line-X bed liner. ARE LS 2 tonneau cover. Pillar mount boost and EGT. EDGE EZ and McLeod clutch.

 

[Missouri Mule]

The load range rating on your tire is what mostly determines tire pressure.
Usually in your 16 inch diameter tires load range D tires max pressure is 65, load range E is 80.
It is the diameter of your wheel that determines how efficiently your tire will cool. Load Range E tires have more rubber than D's that's why the max air pressure is higher. The more air the cooler the tire stays and less chance of leaving a section of tread on the highway.
Changing from stock wheels to steel or aluminum wheels(especially aluminum) will also help cool the tire.
Because I don't when I'm going put a load on or run at highway speeds I keep my fronts at 70 and rears at 80. But Florida has good roads.
When I had a ford van the manual stated I could deflate to around 50 lbs if no load or highway driving.

 

[John Berger]

Follow the instructions on the tire chart that came with your truck. I run my fronts at
65 psi, my rears at 60 psi when I tow my trailer. Lately, I've been running with those inflation pressures all of the time.

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1999 Dodge Ram 3500 Quad Cab 2wd; 5 spd; 4:10 LSD rear; Mag-Hytec differential cover; US Gear EGT and Boost gauges. Stewart Warner Fuel Pressure Guage with dual senders. Amsoil foam air filter and synthetics from nose to tail.
Cummins Power, don't leave home without it

 

[Okie-Go]

I think the tires are 265-75R16 not 17. I run 60 in mine. Doing good so far. I do bump up the rear to 75 when I get loaded. I think the 5 I am away from maximum will allow for expansion.

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2001 quadcab slt 2500 HO 6spd. LWB,2wd,dk garnett red, trailer tow package,camper special, anti spin 3. 54 axle, speed liner,oversized stainless steel chicken slide,66 gallon in bed aux. tank,K&N air filter,Reese 20k hitch, Terry 2000 EX 30ft. double slide 5er, 2000 20ft gooseneck for haulin jeep, firewood and huntin stuff. 5X12 tagalong for haulin the 4 wheeler. Okie Newton

 

[SlyBones]

I use the formula posted above. It does take into account the fact that tires have different weight limits and different max tire pressures. So I think it should work fine for all tires. Or get the spec sheets like mentioned. The tire charts that come with the truck dont cover enough range for all the different tires and ratings.

More than likely the tire spec sheets put out by the Manufacturers used some formula like this. I am sure they tested tires for max load and pressure, typical load, and maybe a few others. I seriously doubt the test every tire at every weight and pressure. Would cost way to much money. I bet they used a formula too.

 

[Un-Hemi]

You know, on all my cars I have generally run the PSI right up to the number on the sidewall, with the rears 4 to 8 lbs less. When I bought my used truck (40,000 miles) a couple of months ago, I'd read about the dreaded steering wander on this website and attributed its lousy steering to 'the steering box/alignment'. I took it into a reputable alignment shop here in town and had the alignment checked; it was well within spec. I drove the truck across the street to the dealer fully expecting to go to war with the service manager. He put his front-end guy (Rick) right on it and Rick took the truck for a burn down the highway. Brought it back and said that, yes, it did handle a bit strange. Had I checked the tire pressure? Well, no, it looked OK to me (not flat). Turns out that all four were at 80 psi. The doorpost sticker says that the tire pressure should be 50psi on the fronts and 80psi on the rears (2500). Lowered the fronts to 50psi and it's better, if not good. Makes me wonder how many of the steering box/alignment woes on these Dodges are really the fault of incorrect tire pressures in oversized tires on wide wheels with wierd offsets? Hmmmmm...
I like the idea of calculating the tire pressure based on the actual load as a percentage of the max. tire capacity. I'm going to adjust the pressures and try it as soon as I weigh the truck this weekend. Max capacity @ 80psi on these Michelins is 3042lbs (single), by the way.

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Tom Glover - VE7DQ, C-GWTG
99 QC SLT, LWB 4x2, ETC/DGP, Wht/Agate, etc.

 

[TowPro]

This is a good way to check it, only I would take my kids driveway chalk, make the tire real well all the way across the tread, move the truck far enough to see how the chalk is wearing off the tire. I did this and found 32-35 in my rear empty works best. Now my tires are wearing great.

Or you could use chalk line chalk, drive through a pile and see the mark it leaves the next couple times the tire goes around.

NOTE: don't buy red chalk for chalk lines, its made to be non removable on some surfaces.

Originally posted by C. D. Day:
Wet your driveway and drive your truck across the wet area, then drive in the garage and look at the tire marks. If you are over inflated not all the tread will be in contact with the smooth concrete of the garage. If you are under inflated, the outer edges of the tire will show firm contact, with the center showing less contact.
Another way is to weigh each axle and divide by 2, this will give you the weight on each tire. Go to a tire dealer and look in his tech book and find the pressure required for the weight.
With your truck empty, I think you will find a pressure of 50# in the front and 42# in the rear will give you a good ride and also handle the weight.
Good Luck, Denny

 

[MikeJ]

all those formula's and all that airing up and down is fine if you don't change your weight or load very often, but I run over 140,000 miles a year, sometimes making 3 or 4 runs a day. I'm liable to haul 100 lbs one load and the very next one 6500 lbs. I keep my Michelin's at 70 lbs, front & rear. I got 88,000 miles out of my factory Goodyear's, 156,000 miles out of my 1st set of Michelin's, and so far about 90,000 out of the set I have on now. I haven't worried about the ride quality. All I need in my case, is the ability to haul a load and to last, so I keep them aired up and rotated every 6,000 to 8,000 miles.

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1997 3500 club cab, 10' flatbed, 3:54, auto, 4 Firestone air bags, 332,000+ miles