2nd Gen Non-Engine/Transmission Yet another tire inflation Q

[WBusa]

Just bought my new Coopers for the winter, and was a little surprised to find the tire shop sent me home with 45 lbs. all around. Now, I've just read many previous threads about tire inflation, and I don't want to start another debate on the subject... its clear there are about as many opinions out there as there are tires... ranging from "I run mine flat" to "never less than 500 lbs. all around" Hey, whatever works for you. But here's my question: I don't think I've read anyone say that they use the pressures printed on the door pillar plate (in my case, 65# front, 80# rear)... am I the only person in the world who pays attention to these things (i. e. , thinks that the Dodge engineers probably know better than I do)? Or is the thinking that the plate value is a compromise number that isn't really optimal for any one situation?

 

[SnoKing]

I run around 55 to 57 in the front all the time. 45 empty in the rear and 65 to 70 with the fiver. Pressure on door pillar is for a fully loaded truck. SNOKING

 

[bmoeller]

I keep mine about the same as Snow King. Since i have 215s, I put 60# up front. 40-45# rear. This empty though.

 

[WBusa]

Pressure on door pillar is for a fully loaded truck. SNOKING

Thanks, Snow King; that's an answer I can buy into... don't know why I didn't think about the fact that if they can only post one set of numbers they'd post the numbers for a fully-laden vehicle. I'm going to try 55F/50R for a while and see how I like it (with 500# of sand secured in the bed for winter). Again, thanks.

 

[WestTN]

Check on Cooper's website for a load chart for your tires. Then weigh each end of your truck and inflate accordingly. Higher than necessary inflation pressure does not damage a radial tire like it does on bias ply tires. A little higher nets a little better fuel economy and longer tire life.

 

[Beast2B]

A LITTLE higher maybe, but you want to keep the tread as flat on the ground as possible for a good balance of handling/ride/longevity. Balance and rotation are far more critical than a few pounds of inflation up or down (IMHO). Ditto Snow King when I ran stock tires.

 

[rluft]

WestTN has got it right. Get hold of a weight chart, weigh your truck and inflate accordingly. IMHO, if the door post numbers were any good then the Ford Explorer and Firestone would not have had the troubles they had a few years ago.

 

[JPope]

When I bought my Coopers a while back, the tire guy said he had inflated them to 45#, the maximum pressure for these tires. I went out and checked (read the side wall information) and he was right, but had installed load range D, instead of E. His boss checked and confirmed that I had specified load range E when ordering, and that the wrong ones had been sent and installed. So they said drive on them until the correct ones would be there the next day or so.



They got the load range E and installed them the next day.

Not saying this is your issue, but may be worthwhile to check out the sidewall, and make sure you have load range E, which is what is susposed to be one these trucks (maximum inflation pressure of 80#).



There was discussion between the boss and the installer, about checking the tires, to make sure in the future, before installing them on the rims!!!! :-laf

 

[WBusa]

Thanks, Jim. I did check their work before the truck left the shop... load range E. Your story is a good illustration that we always need to double-check the "pro's" work, because feces happen. Its just a pity that everything else isn't as easy to double-check as are tires!

 

[WestTN]

Higher inflation of a radial tire does NOT cause the tire to bulge in the middle. That is what causes the damage to a bias ply tire in the form of premature wear in the middle of the tire. Radials stay flat on the pavement unless underinflated.

 

[RJOL]

I keep my load range "E's" at about 78psi all the time. I only tow, heavy, a few times a year. I don't mind the "stiff" ride as I'm mostly on paved roads. If I did a lot of back country, off road, poor road, traveling, I would air them down. One thing I don't like about the "door post" inflation guides is that I believe the manufacturer will lower the psi in order to "soften" the ride. They are still within the saftey range of the tire, but not at the optimum for the tire. JMHO...

 

[Tardog]

When possible I chalk (make a chalk mark across the tread width) up my rear tires then drive on them for a bit and check, If the chalk is wore off the middle and still visible on th edges then air down a bit and recheck. Re adjust as nessesary. Running to much air without the appropiate load will decrease the rolling resistance but will inadvertantly lesson the contact patch. A correctly psi'd tire would have a near full contact right across the tread. But an underinflated tire can cause seroius handling problems and heat which I feel is much worse. Yes this method would work in a perfect world when the vehicle only operates at a specified weight but there has to be a happy medium or change your tire pressure according to load. You have to find what works for you. Chalking the fronts is difficult due to forces on the outer edges of the tires when cornering. my . 02

 

[SnoKing]

I keep my load range "E's" at about 78psi all the time. I only tow, heavy, a few times a year. I don't mind the "stiff" ride as I'm mostly on paved roads. If I did a lot of back country, off road, poor road, traveling, I would air them down. One thing I don't like about the "door post" inflation guides is that I believe the manufacturer will lower the psi in order to "soften" the ride. They are still within the saftey range of the tire, but not at the optimum for the tire. JMHO...

What a crock! If door jam weights on pickups are not for max weight, why would the lighter rear end state 80 and front 65 on my truck. To top that off, the sticker is for 245 tires, not the optional 265 tires that it came with. In the owners papers is a tire inflation chart, based on different loaded weights and lists the different size tires separately.



Next I will see you post that your truck does not handle well at over 70 mph. You fully inflated people need to get a life. I run my rear air up for towing and down for empty, 65 to 45. The difference in handling is VERY dramatic. These 265s are maxed at 80 for 3415 lbs each, however only require 70 in the rear to handle the GAWR of 6084 lbs (which happens to be two times the 3042lbs for the 245 standard tires). When I go for a yard and a half or two yards of gravel, I put 80 lbs in them. If I ran that much air with the 2200 lbs of pin weight for my 5er, I would be beating the trailer to death for no reason but ignorance. www.rv.net beats this to death at least once a week. For me, I will allow the tires to take there fair share of the beating, that is why they started using air in tires many years ago.



SNOKING

 

[RJOL]

... What a crock! You fully inflated people need to get a life...

Wow... maybe you should switch to "decaf" :-laf

 

[PRyker]

I agree with Snow King... I had my tires up around 80 when I was towing heavy. I parked the trailer and drove off without adjusting the tires and the ride was terrible. When I finally got around to adjusting (about 2000 miles) back to proper inflation (50 PSI) I could see more wear in the center of the tire then on the sides. The ride was harsh and plain sucked. I will never do that again. Lesson learned. It was alike a new truck again when I went back to 50 PSI.



I also have to say that I would never put load range D tires on my truck. I believe our trucks need load range E. It scares me to think how many of the trucks of members here are running load range D. I do not buy the "rated weight" argument either as they are still 8 ply tires.



Plain and simple... Load range E tires and adjust tire pressure according to loaded weight. I would like to see a chart for our trucks that show recommended pressures for weights.



Thanks



Phil

 

[Alan Reagan]

I still have my OEM Michelin's on at 118,000 miles. I run 65 front and 55 rear (unloaded). I go to 65 rear when towing. These are load range E. The wear bars have finally appeared flush with the tread so I'm going to get some new shoes on my baby. Oo.

 

[SnoKing]

Phil, look no farther than the blue folder in your grove box. It should be a two page document folded in half. If you can not find it, I will scan mine and email it to you.



Rick, maybe I had one too many diet pepsi's! Why don't you run a little test for a week. If your trcuk is basically empty and has the optional 265 tires, put around 57 lbs in the front and 45 in the rear. Drive it for a week and be sure that your mate goes for a ride and/or drives it, if that is the normal case. At the end of the week, put you tires back to 78 lbs and take it for a drive. Then you could come back to this thread and give us your comparison. It would be really cool if we got a little snow also during that week. It would be a good objective test report for everyone.



Sorry about the cafeine reaction above.



SNOKING

 

[PRyker]

Snoking,



I bought my truck used and do not have that doc you are speaking of. I would love to have a copy when you have some time. I will PM you my email.



Thanks



Phil

 

[CTA]

Just bought my new Coopers for the winter, and was a little surprised to find the tire shop sent me home with 45 lbs. all around. Now, I've just read many previous threads about tire inflation, and I don't want to start another debate on the subject... its clear there are about as many opinions out there as there are tires... ranging from "I run mine flat" to "never less than 500 lbs. all around" Hey, whatever works for you. But here's my question: I don't think I've read anyone say that they use the pressures printed on the door pillar plate (in my case, 65# front, 80# rear)... am I the only person in the world who pays attention to these things (i. e. , thinks that the Dodge engineers probably know better than I do)? Or is the thinking that the plate value is a compromise number that isn't really optimal for any one situation?

You had it right in your last statement/question ... the decal on the door is not "optimal" for "all" situations. Typically this is for a fully loaded vehicle. Other then pounding the crap out of you and wearing your tires unevenly, running the max psi without the load is pointless.



Most tire manufacturers offer tire inflation charts for their tires based on the weight they will carry. I just purchased (2) replacement trailer tires and downloaded the chart from their website (Goodyear). BF Goodrich on the other hand did not have the chart available online but when I called they made a copy of it for me and mailed it that day. I adjust my tires to the load I carry. Typically I run 45 - 50 psi in the front and anywhere from 40 - 50 in the rear when I tow a large 4x4 tractor/loader or when I tow my 30' TT.

Someone mentioned using chalk ... good idea. I ran my truck this past week in the salt and noticed after a quick road trip the outer edges (about 1. 5") were still black while the middle was white ... why, I had just returned from a trip hauling my camper at 50 psi and had not lowered the pressure since dumping trailer and unloading my hunting gear, coolers, etc from the rear.



I'll note I just had "D" rated tires installed and thought they handled the TT better then the "E" rated tires when properly inflated (more tire on the road).

Higher psi will provide a poorer ride when not loaded but will warrant better fuel economy ... but the tires WILL NOT wear evenly! :-{} Although over/under inflated tires may have affected the older (bias ply) type tires more, it is quite obvious that it is a technical impossibility that if your tires are over or under inflated and the majority of the weight is either on the outer edges (under) or in the center (over) then they will NOT wear evenly ... simple logic.

The short of it, don't run anything less then a "D" rated tire if you haul or tow and get the inflation chart from the manufacturer and know what your load weighs!

My . 02 from VT!

 

[AMink]

I run D rated tires. I questioned the guys at the shop when I got them and received the "weight rating is actually higher" answer. What are the benefits of the E rating? Is it a stiffer sidewall? Thanks.