Tire Pressures

[Cummins12V98]

Thanks all. I appreciate the advice. They had 75 all the way around on my drive home from the dealer. It seemed too hard. Dropped the rears to 55 the next day trying to find a good light load pressure. Half my miles will be towing until the kids are back in school so I'll be setting everything for that until then.

Look at the inflation chart for your tires. I run 40 rears solo. PLENTY of air. Even wear as I proved with my 11Dually I ran 40K on MS2's and had even wear.

 

[Ram4Sam]

Mr. O, You don't have to buy anything......graph, plot, analyze, hypothesize all you want. I'll use my SOP meter that tells me 80lbs in an empty truck makes it ride like crap compared to running a more reasonable figure of 60lbs front and 50 lbs rear. When I picked up my 2014, the dealer had 80 lbs front and rear and it was ridiculous, rode like an old wagon behind a couple of mules.......I've run these kind of numbers in my '91 and my '01 and always got 40,000 miles or so out of a set of tires. Due to my miles driven, I never wear out the tread depth on a tire, I buy tires because the sidewalls get weathered and checked long before the tread is gone, so running extra pressure for extra miles out of the tire is pointless. I see no reason it will be any different with my '14. You should keep running the max pressure as you desire and I will enjoy a better ride and not knock my fillings loose riding around on rock hard tires @80 lbs.

Sam

 

[Cummins12V98]

Based upon my experience, and research.. I say go with the TIRE max inflation pressure. Yes, OEMs go below these pressures, but for improved ride quality (because they can..). They want the tire to absorb some of the road imperfections for an improve smooth ride, but you pay a heavy price for this. Your tires will wear faster at a lower than full inflation, your fuel economy takes a hit, a more full tire has less rolling resistance, and builds up less heat when on the highway.. Heat kills tires, and rolling resistance kills fuel. I run full tire inflation on my cars, and truck, never had problems with suspension parts, or U-joints.. the impact goes to the springs, via the wheel bearings.. U-joints should not be affected one way or another.. proper alignment and balance are also important.

The only time I've found an advantage to lower inflation pressures is off-road where it helps for traction in soft sand and such (makes for a larger ground contact area, thus lower PSI for that area, and less sinking in the mud/sand. On the paved roads.. not an issue.

I'd recommend the tire's listed pressure be your guide (ignore the sticker!).. I'd love to hear feedback on this recommendation!

I respectfully disagree!

Do you get 100-120K out of a set of Michelin's or BFG's on a 2500 RAM 4X4? I do easily.

Here is a couple pics of MS2's with 40K on them running 80psi front always and 45 rear solo and 60 loaded with 5K pin. The tires were 1/32 thinner in the middle at those pressures so I am running 40 on the rear of my 15 now.

 

[kthaxton]

I wish I would have taken pictures before my first tire rotation......
I had to experiment over many months to find the right pressures for my truck since new (October 14). I had been running between 65-70 in the rear. When it came time to rotate them, it was obvious that the center tread had worn more and the tread on the sides had little to no wear. Each lug on my tires (Toyo Open Country AT II's) has (had) a small step down of maybe 1/8 of an inch (going off memory here). The step was long gone on the center treat, but it was all there on the edges, and if I looked closely, I could see that the tread on the edges was not even contacting the ground. Nobody intends tires to be used that way, not the auto manufacturer, nor the tire manufacture.

You can Google methods of determining the correct pressure (as mentioned above, this is most helpful with other-than-stock tires) and you will find several ways to do this, and people have been doing this for decades. Only with the Ford Explorer debacle several years ago did so many become so blatantly reliant on the door seal decal.

 

[MichaelOverfield]

Kthaztion,
Good point.. it does need to be determined by the type of tires, and your specific loading and use expectations.. Personally I do not need, nor desire, a car like ride.. but I've always enjoyed the type of rough and ready, like a 1962 Land Rover with leaf springs so thick they could have just bolted the axle to the frame.. so I'm not concerned about ride quality. By all means if different tires show center wear, one needs to lower pressure to get a proper wear pattern.. no dispute from me on that, I'm simply saying I've not seen it, but I don't have those kinds of huge tires, but thanks to this discussion, if I ever do get them I'll take that advice on for action!

 

[MichaelOverfield]

Cummins12V98,

I can't say I get that kind of miles, because my tires will be replaced by age long before wear, current truck has a mere 28000 miles (2009), but I don't see center wear as you've seen.. though, perhaps I go out and put a depth mic on it to see for absolute sure on this.. good to know for sure. Besides, I could rotate the tires too! (they've not been rotated, rear is more worn than front, but plenty of tread on all).

Part of the reason for my low miles is the stupid emissions items, I know if I do too many short drives without load that stuff will give me problems.. so I'd driving a commuter car mostly, unless on a long trip mostly pulling the trailer, on the rear axle about 1000# extra, not max capacity by any stretch, but measurable more than unloaded, and I normally carry that extra 45 gallons of Diesel as well.

Also, your pressure profile is not far from mine, I'm SRW, so when I'm loaded.. I'd be @ 80 PSI all round, perhaps I could lower rear when not loaded, but I don't drive much in that configuration given the above mentioned emissions limitations...

 

[AH64ID]

Put an empty pickup tires at 80 psi and drive thru a gravel parking lot and then back onto pavement for 10' and stop. Look at where the dust is and tell me how you can even get close to even wear.

It's not possible and tire inflation charts exist for a reason.

 

[MichaelOverfield]

Apparently it varies greatly with the type of tire... I won't call those who have seen center tread wear liars, I believe they have seen what they report.. but I have just not seen it. In fact, I thought I'd go and measure.. and my tread wear, which is noticeably more on my rear tires, than on the front, is even across the treads (Depth measured, and there is no significant difference across the whole tire width), I've always inflated to 80 PSI, and these tires have just shy of 30K miles.. they will be replaced by age before I see tread wear issues.

I've been over plenty of gravel roads, followed by pavement, but next time I'll try to take a close look, but given the negligible wear difference I'm seeing I don't expect to find anything with these particular tires..

If I had to take a guess on the tires that do see the increased center wear at full pressure, I'd bet the common thread is they are all wider than the OEM tires, which may help explain it. I'd expect the wider tire to be more susceptible to "rounding" at higher pressures.. just a matter of the forces involved and greater surface area of that "psi" acting, having said that, with a Radial tire, the strands are along the radius of the tire, so the steel belt literally has to flex for the tire to begin to round, but that can happen, given the forces involved at higher load ranges and tire presssures..

Also, for another data point.. my small light car, only about 2400 lbs.. I run those tires at the 51 PSI rating, Michelin X-ice.. those tires are going to be replaced by age also, and have an estimated 50K miles on them (now close to 10 years.. no dry-rot or cracking, but getting to my threshold of age replacement real fast..) they also have no uneven wear, and they have a load capacity of nearly 4 times the weight of the car.. normally loaded with a single passenger, but they too are not wider than the OEM tires..

I kept the OEM tires on a Land Rover Discovery up to full pressure, and replaced them at 7 years when they began to show signs of aging, but they had even wear, and plenty of tread.. that is a 4600# vehicle, but the tires were rated well over that also..

I noted when doing a bit of research on trailer tires, that they always tell you to inflate to full PSI, no lesser PSI is ever recommended, even if running a lighter load. I find that to be interesting, clearly we know the full PSI and rated Load range are tied, less pressure, means less that full rated load, but more pressure, up to full rated load does not mean one must run the higher loads... and who is going to measure their vehicle loaded weights consistently and then adjust the pressure to match the load needs.. not likely it will happen, as such seems on the trailer end of the business they size to rated load, and then use full pressure.

Having said that, the one time I do recall center wear was in fact on the cheap OEM install bias ply trailer tires on my RV (nanco), they were done at about 5K (being generous), but I've come to learn, for that generation of cheap ST bias ply tire.. that was pretty typical usage before worn out, or blow out.. those were of the generation of notorious ST tires for failures..

I've just not seen the center wear issues in general, so I'm interested in what the common characteristics are with those that do see it.

 

[AH64ID]

It's not so much the type of tire as it is the width of the tire to the rim and the load, but even on a perfectly matched rim/tire combo too much pressure for the load will balloon the tire.

I have never seen a tire that rides flat at full pressure without a full load, across all kinds of tires and rigs. Even as little at 10 psi too much creates an uneven wear pattern, as shown by the dirt/pavement test.

 

[gsbrockman]

Put an empty pickup tires at 80 psi and drive thru a gravel parking lot and then back onto pavement for 10' and stop. Look at where the dust is and tell me how you can even get close to even wear.

It's not possible and tire inflation charts exist for a reason.

Can we get an "Amen" for Brother John?

In my career as a retail tire salesperson, if anyone went with a non-stock size tire, I'd draw a line across the tread with a tire grease crayon or children's sidewalk chalk, then drive the truck so as a few tire revolutions occurred. I'd then increase or decrease the tire pressure so as to maximize the contact patch. The tire grease crayon or sidewalk chalk doesn't lie...........

 

[Beast2B]

Can we get an "Amen" for Brother John?

In my career as a retail tire salesperson, if anyone went with a non-stock size tire, I'd draw a line across the tread with a tire grease crayon or children's sidewalk chalk, then drive the truck so as a few tire revolutions occurred. I'd then increase or decrease the tire pressure so as to maximize the contact patch. The tire grease crayon or sidewalk chalk doesn't lie...........

I'll see your Amen, and raise you a Hallelujah!
As a tire monkey in a previous life, that was a great way to point out to consumers how to adjust their pressure.

 

[MichaelOverfield]

Can we get an "Amen" for Brother John?

In my career as a retail tire salesperson, if anyone went with a non-stock size tire, I'd draw a line across the tread with a tire grease crayon or children's sidewalk chalk, then drive the truck so as a few tire revolutions occurred. I'd then increase or decrease the tire pressure so as to maximize the contact patch. The tire grease crayon or sidewalk chalk doesn't lie...........

This seems to be a great way to determine pressure, I like it over the arbitrary pressure on the sticker, which has been admitted has more to do with ride quality, over tire longevity or fuel economy. I think we can all agree.. blind compliance to the sticker without analysis for the particular tires, and the typical loads and driving patterns of the vehicle is not wise.

I will try this on mine, and if possible snap some pictures to see what I come up with. I'll continue to err on the side of more pressure, not less.. particularly because I'm not interested in checking and adjusting pressure all the time, and we know it does naturally drift lower over time.. so buys me less time checking and inflating tires if nothing else!

 

[Newsa]

I respectfully disagree!

Do you get 100-120K out of a set of Michelin's or BFG's on a 2500 RAM 4X4? I do easily.

Here is a couple pics of MS2's with 40K on them running 80psi front always and 45 rear solo and 60 loaded with 5K pin. The tires were 1/32 thinner in the middle at those pressures so I am running 40 on the rear of my 15 now.

View attachment 92148View attachment 92149

I don't think I will get that much mileage our of my transforce HT's. Maybe I need to let some air out. I was worried tire flex would wear out the sides. But since this is my first HD truck, I was just running them pretty full. Appreciate the info!

 

[Cummins12V98]

I don't think I will get that much mileage our of my transforce HT's. Maybe I need to let some air out. I was worried tire flex would wear out the sides. But since this is my first HD truck, I was just running them pretty full. Appreciate the info!

No problem!

Not to be arrogant but I driven WELL over 1,000,000 miles and know what works for long tire life. First thing is QUALITY tires and second is proper inflation for the load!

 

[photowrite]

It's not possible and tire inflation charts exist for a reason.

Yes! Of course! Exactly!

 

[photowrite]

First thing is QUALITY tires and second is proper inflation for the load!

Yet again, another winner!!!

 

[AH64ID]

No problem!

Not to be arrogant but I driven WELL over 1,000,000 miles and know what works for long tire life. First thing is QUALITY tires and second is proper inflation for the load!

Third is avoiding not towing on gravel/dirt roads... that's an easy way to eat quality tires in a hurry!

Of course it is nice to get back where nobody else is.