My first experience with Load E tires, and I didn't find a specific answer in the manual or archives, so...


The tire sidewall states a minimum of 55psi, and a max of 80psi. What pressures should be used for around-town non-towing, and for towing (6000lb tag)? 80psi seems awfully high, but I don't want to damage the tires by underinflating either...


Thanks in advance!


Mark

For around town I use 65 front and 55 back. You need the extra in the front because of the diesel.


Chilly

GM takes the "You're not going to sue me because the average person does not know how to maintain their vehicle" stance.


It's unfortunate but we live in a society that " When I am stupid, I blame (sue) someone."


So GM gives the Maximum load ratings so you do not sue them when you have a blow out because you overloaded the weight for the air pressure rating of the tire.


From looking at the tire manufacturers loading sheet and my driving and loading habits I finally settled on:


Around town:
Front = 55 lbs
Rear = 50 lbs


When I am towing:
Front = 55 lbs
Rear = 65 lbs



Hauling:
Depends what I am hauling.
Example:
80 lbs all around with the back loaded with stone.


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http://www.dieselplace.com/forum/smileys/Clown.gif</LI>Edited by: JohnnyO

Well stated JohnnyO

May be all wet here, but I thought the info was on the drivers door jamb? Too wet to go out and look for you right now...LOL


I run 55 all around whem empty and air up to 75 front 80 back when planning a tow.


80 empty = rough ride





Good Luck

Im with chvysrus i run 55 all around and 75-80 when hauling or towing

My alignment tech put 60 all the way around after aligning my front end. He also told me to rotate every 6k or so. I jack up the rears to 80 when pulling.

The 04 door stickers says 60 front and 80 rear.


Since the front end is only rated to 4500#, I wouldn't go much over 60 in front since that is above the load capacity of the tire.


The rears need pumped up to get the load capacity or go to 265 and get a better ride w/ less air pressure.


We usually throw 100+ bags of bean seed (50# ea) and 110 gal. of fuel in the back of our trucks and I now the F-I-L doesn't add air just drives it.Edited by: Dmax Tim

The 04 door stickers says 60 front and 80 rear.


That '04 diesel motor must be heavierhttp://www.dieselplace.com/forum/smileys/Confused.gif. The '03 door jam says 55 #'s in the front, 80 #'s in the rear.

Thanks for the info guys, I know what to do now. http://www.dieselplace.com/forum/smileys/Thumbs Up.gif


Mark

Hey Johnny it's the extra ponies the 04 are going to have to carry http://www.dieselplace.com/forum/smileys/Clown.gif

The load sticker does state 55 front 80 rear. Most load E tires state 80 PSI max to achieve max load capacity. My truck came with Fierstone steeltex load E 245/65 R16. At 17000 miles they were completly shot. Tread bars showing and tread blocks pulling away from the carcass. I atrribute alot of this to improper air pressure. I ran the stated 55F and 80R. I replaced the firestones with Bridgestone Duler Revos. 265/75 R16. They guys at the tire shop insisted I ran the stated air pressure. They did tell me to bring it back at 4000 miles and we would re-adjust. Taking measuements across the tread in 4 spots showed that the front tires needeed to be raised and the rears needed to be lowered. I am now running 65F and 55R. This is with a camper shell and 200 lbs. of gear. I also tow a single axle trailer that weighs 2500 LBS. fully loaded over 75% of the time. I will remeasure the tread depth and let you know in another 4000 miles. I can tell you that after raising the front end 3/4" via torsion bar adjustment and changing the air pressure the truck has never driven better. If you do raise your truck be prepared to have it aligned and have the headlights realigned. You will also throw off your gas gauge. The warning use to come on at 3 gallons and now it comes on at 1.5 gallons.

I run 65 psi all around empty and raise the rears as necessary when loaded or towing. 55 psi in the fronts is too low and there only to reduce "ride harshness" complaints at the expense of the tires. Running the fronts at that pressure will literally destroy your tires in about 1/3 of their normal wear-life because of the engine weight on our vehicles.http://www.dieselplace.com/forum/smileys/Angry.gif

My truck came with Fierstone steeltex load E 245/65 R16. At 17000 miles they were completly shot. Tread bars showing and tread blocks pulling away from the carcass. I atrribute alot of this to improper air pressure. I ran the stated 55F and 80R.


I had the same tires and pressure new from the dealer. after a few thousand miles I could see the thread wearing down rapidly.


I lowered the pressure of the rear based on the manufacturer load charts and some of the posts here.


@ 7K I rotated the tires. The front tires, now on the rear have 14 K miles (7K miles on the rear) and there is no noticable wear. And the original rears that are now on the front are showing no additional wear.


I think I have the pressures right now for the type of loads I am carrying.Edited by: JohnnyO

In case anybody was looking for them, afer a good hour of searching I finally found the load/inflation tables:


http://www.trucktires.com/zip/Light_Truck_Tables.ZIP


Bottom of page 81 for the stock E-range tires.


Mark

http://www.dieselplace.com/forum/smileys/HiHi.gif Great Post - here is some additional info.


My 2004 2500HD has a GVW of 9200# with a front axle rating of 4670# and a rear axle rating of 6084#. When I found the Michelin and Goodyear load ratings for the LT245/75/R16/E I discovered that the GM RECOMMENDED tire pressures of 55# front and 80# rear equaled the MAXIMUM axle rating. 55# of tire pressure equaled 2335# load X 2 (two tires on the front) equals 4670# the front axle rating (Same for the rear). So as stated before the recommended tire pressures of 55# front and 80# rear are for a truck that is MAXED out.


Last Saturday I weighed my truck at a public scales. 2004 2500HD, Ext Cab, Short Bed, LT, 8.1/Alli, 4X4, with a Century High C Cap, Rhino linning, 3/4 tank of gas, one person and no crap in the back.


Total 6760#, Front 3880#, Rear 2860#


When you compare those actual weights to the tire/load tables for the 245s it appears you could safely run 45# in the front and less than 35# in the rear.


Can't bring myself to run 35# in the rear so I settled on 50# all the way around for now. Truck rides and handles very well. May try 45# all the way around but I don't think I will feel any difference. Tire wear won't be an issure until the snow melts. Anyone running 45# all the way around?? How do you like it??http://www.dieselplace.com/forum/smileys/Thumbs Up.gif

Well, correct me if my thinking is wrong here - but you are saying that 55 psi matches the maximum load rating for the tire on the front. I disagree. At 55 psi you should not load the tire more than the maximum rating because of it's LOW INFLATION. The tire is E rated. The tire by design can carry MORE than the 55 psi recommended weight load when fully inflated to 80 psi. When you inflate the front to more than 55 psi you are NOT exceeding the load rating but actually creating load carrying margin beyond the recommended vehical loading. AND you are reducing excessive wear on a tire with low inflation for purposes of ride softness at the sacrifice of tire wear.http://www.dieselplace.com/forum/smileys/Geek.gif Sorry, just a bit of a sore spot with me when the factory recommended inflation caused my fronts to be scalloped, cupped, out-of-round and eaten-up for no reason other than trying to make a 7,000 pound 3/4 ton truck feel like a mini-van to appease whiners. I also suspect that a lot of the steering wear issues in our trucks might originate with the UNDERINFLATED tires causing imbalance and excessive wear on components. Funny that my 2001 with 76,000 miles on properly inflated fronts not only gets over 50,000 miles in tire wear but has had NO steering slop or rattle!http://www.dieselplace.com/forum/smileys/Ermm.gif

http://www.dieselplace.com/forum/smileys/Confused.gifIdle_Chatter: Don't disagree with a thing you said. True - IF you inflate the tires to a pressure that is above the AXLE rating but within the max pressure of the tire you build in a loading margin. However, I have seen lots of tires worn in the middle from what appears to be over-inflation with respect to the weight on the tire. I am certainly no tire expert but I have had good luck with REDUCING tire pressures (within reasonable limits) to be more in line with the actual weight on the tire using the load /inflation tables.


If you are not going to use the load/inflation tables for a specific tire to determine the recommended tire pressure based on actual weight on the tire, then what good are they? You would just inflate the tire to the maximum pressure listed on the sidewall and call it good.


Most of the tires dealers I have talked to don't seem to know s**t about propoer inflation. We need a "REAL TIRE EXPERT" to helps us out. I think we are all looking for safe load carrying capacity, good handling, good ride and long tire life. The issue is how do we get all of these things???http://www.dieselplace.com/forum/smileys/Question.gif

Well, correct me if my thinking is wrong here - but you are saying that 55 psi matches the maximum load rating for the tire on the front. I disagree. At 55 psi you should not load the tire more than the maximum rating because of it's LOW INFLATION. The tire is E rated. The tire by design can carry MORE than the 55 psi recommended weight load when fully inflated to 80 psi. When you inflate the front to more than 55 psi you are NOT exceeding the load rating but actually creating load carrying margin beyond the recommended vehical loading. AND you are reducing excessive wear on a tire with low inflation for purposes of ride softness at the sacrifice of tire wear.http://www.dieselplace.com/forum/smileys/Geek.gif Sorry, just a bit of a sore spot with me when the factory recommended inflation caused my fronts to be scalloped, cupped, out-of-round and eaten-up for no reason other than trying to make a 7,000 pound 3/4 ton truck feel like a mini-van to appease whiners. I also suspect that a lot of the steering wear issues in our trucks might originate with the UNDERINFLATED tires causing imbalance and excessive wear on components. Funny that my 2001 with 76,000 miles on properly inflated fronts not only gets over 50,000 miles in tire wear but has had NO steering slop or rattle!http://www.dieselplace.com/forum/smileys/Ermm.gif


I totally agree with everything above. My 2500 Ext/SB corners and breaks MUCH better with more that 55psi in the front tires. Due to the weight of the Duramax/Allison combination, even at very high tire pressures (80 psi or less) the ride is still very nice. Its too much air in the back of an unloaded bed that causes the harsh ride.

If you are not going to use the load/inflation tables for a specific tire to determine the recommended tire pressure based on actual weight on the tire, then what good are they? You would just inflate the tire to the maximum pressure listed on the sidewall and call it good.





The best tire pressure is that which causes the most even pressure across the entire contact patch while at the same time allowing for the largest contact patch. This is usually measured with a tire pyrometer, or chalk or other marking compound for those who do not have a tire pyrometer.


Overinflation might allow for better gas milage, but will quickly show itself with a much higher temperature on the center tread versus the inner and outer edge tread. Lower tire pressure might allow for a larger contact patch on uneven surfaces due to the tire being more able to envelop the uneven surface, but this will also cause for quicker tire wear, and less support to the tire sidewall showing up as vague and delayed stearing. The pyrometer will show this as BOTH outer edges of the tread being hotter than the center tread. Low pressure will also casue the tire to overheat, and if left long enough at high enough speeds, the tire will fail (blowout).


A tire pyrometer will also show too much negative camber as all the tires heat on inside edge of the tread. Of course not enough negative camber will show as excessive heat in the outer edge tread.


Taking this topic further to where none of you will probably have any problems, you can also use a pyrometer to determine if the rubber compound it too hard or too soft for the given application. After the temperature is even across the entire contact patch, too cold or too hot of an average temperature will show that the rubber compound is out of range for the given driving style.


I could go into how tires show caster, toe, and shock issues, but I think that would get a little off topic.Edited by: Amric

This I know. All tires need a certain amount of air pressure vs. load to keep the side walls from flexing to much. Every time a sidewall flexes it creates heat. If the tires are underinflated they will get hot and break down. Not just treadware but a true failure. This is what caused all of the rollovers.( along with high center of gravity and improper driving techniques). Acording to actual tread depth measuments taken at 4k on a brand new set of 265/75 R16 Revos, my front tires were under inflated at 55psi. The tread depth measurments do not tell you how much to raise the pressure , just that it needed raising. I took a educated guess and put them at 65psi. According to tread depth measurments on the rear tires they were over inflated at 80psi. Another educated guess led me to lower the rears to 55psi. I will remeasure tread depth in 2 to 3k and let you know how it is going.

I have 35K on my original Firepops and they are still going strong. I bought another set (firepops) to replace the originals with, but so far seems a shame to pull them off early. I would guess they have about 10K + left. Only rotated them once at about 15K.

Well, we are all on the same page now - I was a little inspired by the "55 psi is the maximum for our load rating" reverse logic. Overinflation will definitely cause crowning (or excessive center wear) and extra ride harshness. BUT I refer you to my original post on this issue where I stated that I run 65 psi all the way around and add to the rears when required for loading conditions. I think that GM finally got its head out of the rear if they have raised the recommendation to 60 psi in the front - but they were sacrificing our tires and possibly damaging our front ends by "recommending" a minimum safe pressure only for "political" reasons to reduce ride harshness complaints. I've seen so many posts about "how do I soften my ride?" and the same person will be back in a week complaining about how their DMAX doesn't pull their 15,000# fifth wheel as well as their gasser did. It's a TRUCK - if it hauls and pulls like a truck, it's gonna ride like a truck.http://www.dieselplace.com/forum/smileys/Confused.gif

http://www.dieselplace.com/forum/smileys/Approve.gif Idle_Chatter: I agree we are all on the same sheet of music. I still am trying to see if there is a better way to determine the proper tire pressure for a given application then by "guessing" or using a pyrometer like AMRIC (a very valid method, but most of us don't have a pyrometer lying around). Somewhere between the pressure on the sidewall (80# in this case) and the wheel weight VS load/inflation tables (rear at 35#) is the answer. Load capacity, sidwall flex, contact pattern, ride quality, etc all come into play.


Have you ever weighed your rig? Can't remember reading any members post of total, front and rear weights for a Duramax (especiall an ex cab, short bed). Would like to know how much more weight the DMax adds to the front end over an 8.1http://www.dieselplace.com/forum/smileys/Thumbs Up.gif

Well, I've never had the opportunity to weigh my truck, but after some scrabbling around I was able to locate the following two weight reports:


(1) GAWR (Front) = 4670 lb
(2) GAWR (Rear) = 6084 lb
(3) GVWR = 9200 lb


2500HD Crew Cab Short Box 4x4:


Actual Weights of Truck (CAT Scale at 10 acre. 2003/07/27
(4) Front axle = 4320 lb
(5) Rear axle = 3120 lb
(6) Gross weight = 7440 lb


2500HD Extended Cab Short Box 4x4:


(1) Front 3920
(2) Rear 2840
(3) Total 6760


Basically it shows what has been "ballparked" many times that our shortbox 4x4 2500s fall into the 6800 to 7000 total weight range and that the front axle is about 1200 pounds heavier than the rear!Edited by: Idle_Chatter

My final thought on tire pressure. My Firestones did wear out quick at 17K. My new Bridgestones were showing the same wear patterns at 4k. So I did readjust pressure to 65F55R. HOWEVER, I just replaced my shocks today. I have seen alot of new and used shocks and the factory ones were bad. The fronts were worse than the rears. Kind of alarming at only 21K. Good news is the Edelbrocks fill great. I will post an update on my tread wear in about another 4k.

No one has addressed trailer sway. Blow every tire on your rig up to the max while towing and skip all the fancy sway control devices. Most sway is caused by sidewall flex from low tire pressure. Edited by: MOTO HEAD

what about psi in a 285/70r17 in a load range D. The tire manufactor's says 55 in the front 50 in the rear. I find this hard to beleave.

You are really going to need to watch your tread wear. Buy a 6" metal slide ruler with 1/32" increments. Measure tread depth across the tire at 3-5 spots in a straight line. Low centers = over inflation,low shoulders =under inflation, any thing else could be balance,rotation alignment or shock asorbers. There are to many factors to just look for a standard pressure. Driving style,load,rim width vs tire width so on and so forth.

door pressure recommendations on our 3500's Goodyears are 70psi front and 65psi rear ... I run those pressures at all times (empty or loaded) and do a 7 tire rotation every 5,000 miles .... have 52,000+ miles on these tires and they appear to be good for at least another 20,000 .... plan to replace them in late May (prior to a 7,000+ mile cross country tow) with the exact same tires, by then they should have around 65,000 on them


Jim

...I still am trying to see if there is a better way to determine the proper tire pressure for a given application then by "guessing" or using a pyrometer like AMRIC (a very valid method, but most of us don't have a pyrometer lying around).


Sure there is. It's pretty easy, but does take a bit of time. Simply draw a straight chalk line across the face of all of the tires then drive forward for 2 or 3 revolutions - must be done on flat, dry, pavement. If the line is worn away in the center you are over inflated for the load. If it's worn on the edges the tire is under inflated. If it is worn on only one edge you have some type of alignment problem. I used to be a manager in a couple of different tire shops. I have used this method with great success for many many years. Obviously, you must redo this for different loads, empty vs camper in the back vs towing etc.

You are really going to need to watch your tread wear. Buy a 6" metal slide ruler with 1/32" increments.


Much cheaper to go to an auto parts store or tire shop and buy a tread depth gauge. They are only a couple of bucks and will measure in both 32s and MMs.

Oldman,


Had the slide ruler in my electronics toolbox. Good to know you can get a real tire depth gauge at the auto store.

Have to agree with shark bait. I have owned 3 different motor homes over the years and there is only one way to determine the right air pressure needed and that is to weigh the front and rear of the truck and then go to the tire pressure charts. Antthing else is guessing. As far as tire wear there are many factores beside air pressure. as an example a 90 degree turn scrubes off as much rubber as a 250 mile straight run poor shocks can kill a tire fast also etc.etc.

http://www.dieselplace.com/forum/smileys/Approve.gif More info on the subject since I got a few folks fired up about using wheel weight and load inflation tables to determine the propper tire pressure for a given application.


After this thread got started I E-Mailed BF Goodrich (the winter tires on my truck) and essentially asked the same question we have been debaiting about using the load/inflation tables. I really did not expect a response.


Much to my surprise on Tuesday I got a CALL from one of the customer service representatives at BF Goodrich. This was a very knowledgeale person - not the average minimum-wage worker reading FAQ from a computer screen. We discussed the tire pressure, weight on the tires, load/inflation table subject for about 15 min.


Bottom line from BF Goodrich (it would be good to see what other manufactures would say) is that the BEST way to determine the proper tire pressure for a given application is to WEIGH each wheel (or at least the axle) and then refer to the load/inflation tables for the SPECIFIC tire in use rounding UP to the next 5 PSI increment and then MEASURE the tread wear every 3,000 miles to make sure the tires are wearing evenly. IF uneven tire wear is found adjust the pressure accordinly. The rep also stated what we all know that UNDERINFLATION is much worse on a tire than overinflaltion, so if you are going to deviate from the load/inflation tables go for more pressure. The rep also said that using the wheel weight and load/inflation tables method will give good performance, even tread wear and maximum tread life. I am going to try about 5 psi above the load/inflation tables and see what happens.


This has been a very interesting thread. I am not posting this information for any reason other than to give us all another data point from an "expert" to consider. http://www.dieselplace.com/forum/smileys/Thumbs Up.gif

I used to pit on a superstock race car team they have 4 scales. I will visit them and use there scales. Ohyea I had better check the max. load rating on the scales before my Silverado blows the stuffing right out of them.

Bronco,


Your going to blow the stuffing right out of those race scales. BTW, how are the Edelbrocks doing for you?


Steve

COOL! I was wondering when this thread would be pulled back up. There are several folks due to give an update, myself included. I have been running 65 PSI in the rear and 60 in the front for over 6k. The tires are wearing better than ever. Nice and flat across the rear the fronts are a little qustionable yet. This is with a 3K trailer and 500 LBS in the bed.


As far as the Edelbrock shocks go? They are a trully great shock. I just came back from driving on 100 miles of dirt road with some serious washboards. Before I could never find a good speed, now the washboards were mostly tame. Pavement driving is a treat as well.

Bronco,


What size tires are you running?

I am running Bridgestone Dueler Revos on the factory forged aluminum rim. The tire size is 265/75 R16 Load Range E.

Just noticed the thread. A word on tire ratings. Load ratings for the 245's vary considerably with just 10lbs less air than recommended max. For example, at the recommended 80psi load rating is 3042lbs. But just lower the psi to 70, only 10lbs, and the load rating is reduced to 2765lbs, a considerable difference, since the max load rating of a D rated 245 is 2623 lbs, your approaching D ratings by just trying to get by with a little less air. When manufacturers specify certain air pressures for a given load rating, they're not lightly suggesting it. 80psi seems like a lot, and it is, but the 10 ply E tires are designed for it, and need it to get the max load ratings. Similar variances occur with all tire sizes, and most folks I believe are unaware of how important proper tire inflation is when loading a tire. My .02


Mike


Source: Tire and Rim Association Inc.

My sticker says 55 front and 80 rear, I feel 80 is too much in rear and 55 is marginal in front, so I go 65 all around.