Tire Pressure Recommendations

[Texas Sooner]

We just purchased a new GMC 3500 DRW and now we can start looking for the "right" 5th wheel for us. In the meantime, we are taking our truck and current travel trailer down to the Escapee park in Livingston, Texas to take advantage of their SmartWeigh program. We did this with our previous TV and it was very informative and reassuring to know that we were within the limits (barely) for both our TV and our trailer. With this new truck, I'm not concerned about TV weights at all but I still would like to know what the weight of our truck is when it's loaded up for a trip (full fuel, passengers, cargo, etc) so that I can use that in the future when we're figuring out the weight of a new 5th wheeler.

One of the things that they require at SmartWeigh is to know the load range and tire pressures for your tires. I was able to find that out for the tires on my previous TV but can't seem to find out anything on the tires on this truck. It has Michelin Primacy XC tires - all six are 235/80R17 120/117R TPC BSW. When I go to the Michelin site I can find the tires listed there, but I can't find any reference or link to a load chart. The Tire and Loading placard (photo attached) on the door sill states cold tire pressure is 80 lbs for all six tires. The tire sidewall says that they are Load Range E, and the max load single is 3085 lbs at 80 psi and the max load dual is 2835 lbs at 80 psi (photo attached).

So, am I supposed to run the tires at 80 lbs at all times - whether the truck is empty or when it's towing? On my previous TV, the tire load chart had me running the tires at 35 lbs when empty, and then 44 lbs when towing our trailer. If someone can find a Load & Pressure chart specific to these tires I would appreciate it. It's probably there and easy to find but somehow I'm just missing it as I'm not familiar with the Michelin website - always had Goodyear in the past. If not, then some recommendations and advice would be most helpful. I want to fully understand this tire pressure situation so that we have the most comfortable ride when not towing, and the safest ride when towing - all while maximizing the life of these tires. At $300 each, I want them to last as long as possible.

Also, when I was looking for the DOT date codes on each tire I would only find them on two tires (photos with and without attached). The two that I could find them on have the same date (1022) so that tells me that they were manufactured during the 10th week (March 7th) of this year which makes sense since my truck came off the assembly line right after that.

Lastly, how often should I rotate the tires, and what is the proper rotational pattern for duallys? Thanks in advance for everyone's help!

[BeatCJ]

I would bet all 6 have the same date code. The other date codes are between the duals or in the inside sidewall.The pressure on the sidewall is the maximum inflation pressure. I commonly run my GMC DRW tires at 65 front and 50 rear when empty. There is a process to find the desirable inflation pressure, but your truck will be so close to mine that the ones I listed are good enough.

[RVnAggie]

Congrats on the new truck; the 3500 DRW gives you plenty of truck to be safe and comfortable for most any 5th wheel you might want. Happy hunting for the 5er.

I’ve found that 65 psi for all 6 tires serves me well whether towing my 15.5k 5er or running empty. As another responder indicated, lowering the rear tires 10-15 psi when empty will soften the ride some, but I have no complaints at 65psi. Just replaced the OEM Michelins on my F350 at 57,000 miles; well worn but normal and fairly even wear all around.

As for the rotation pattern, there are a variety of recommendations for different uneven wear situations, but for normal wear patterns, a common recommendation is as follows…..
Rotate front to outside rear, outside rear to inside rear and inside rear to front keeping passenger side tires on passenger side and driver side tires on driver side. This puts all tires through each position while keeping them rotating in the same direction. Since the tires have to be changed to different wheels at rotation time, I generally didn’t rotate mine until I started seeing some edge wear on the front tires.

Happy Trails,

[Texas Sooner]

Originally Posted by BeatCJ

I would bet all 6 have the same date code. The other date codes are between the duals or in the inside sidewall.The pressure on the sidewall is the maximum inflation pressure. I commonly run my GMC DRW tires at 65 front and 50 rear when empty. There is a process to find the desirable inflation pressure, but your truck will be so close to mine that the ones I listed are good enough.

Thanks for that info - sounds good. When you're pulling your trailer do you air all of them up to 80 lbs?

[Texas Sooner]

Originally Posted by RVnAggie

Congrats on the new truck; the 3500 DRW gives you plenty of truck to be safe and comfortable for most any 5th wheel you might want. Happy hunting for the 5er.

I’ve found that 65 psi for all 6 tires serves me well whether towing my 15.5k 5er or running empty. As another responder indicated, lowering the rear tires 10-15 psi when empty will soften the ride some, but I have no complaints at 65psi. Just replaced the OEM Michelins on my F350 at 57,000 miles; well worn but normal and fairly even wear all around.

As for the rotation pattern, there are a variety of recommendations for different uneven wear situations, but for normal wear patterns, a common recommendation is as follows…..
Rotate front to outside rear, outside rear to inside rear and inside rear to front keeping passenger side tires on passenger side and driver side tires on driver side. This puts all tires through each position while keeping them rotating in the same direction. Since the tires have to be changed to different wheels at rotation time, I generally didn’t rotate mine until I started seeing some edge wear on the front tires.

Happy Trails,

Hey neighbor, thanks for the feedback. We probably only live a few miles from each other - we live in between Forney and Crandall. I had not even thought about having to move the tires to different rims when rotating them. This is the first dually for me and as you can see, I don't even know what I don't know. But thanks to this forum I can get a lot of education from others.

[Tireman9]

Unless you have an irregular wear problem you can go without rotation. Do you have different wheels inner and outer on the dual rears?


Your Certification sticker indicates 80 psi so that would indicate you have LR-E tires.
Is the tire size LT235/80R17 or are they 235/80R17 There is a difference.

[00 Buckshot]

Is your truck gas or diesel? That will make a difference on the front tire pressure. With a diesel you are carrying a lot of weight empty or loaded.


My 2014 diesel dually shows 75lbs in the front and 65lbs in the rear when fully loaded.


I don't understand why yours calls for a full 80 lbs in the rear duals

[RVnAggie]

Originally Posted by Texas Sooner

Hey neighbor, thanks for the feedback. We probably only live a few miles from each other - we live in between Forney and Crandall. I had not even thought about having to move the tires to different rims when rotating them. This is the first dually for me and as you can see, I don't even know what I don't know. But thanks to this forum I can get a lot of education from others.

Well yessir, Howdy Kaufman County neighbor. I’m just down the road….south of Crandall in The big community of Warsaw.

Lots of good info and tips/tricks on here for sure.

[Texas Sooner]

Originally Posted by Tireman9

Unless you have an irregular wear problem you can go without rotation. Do you have different wheels inner and outer on the dual rears?


Your Certification sticker indicates 80 psi so that would indicate you have LR-E tires.
Is the tire size LT235/80R17 or are they 235/80R17 There is a difference.

LT235/80R17 (photo attached showing size) and the inner and outer wheels appear to be different on the rear.

[Texas Sooner]

Originally Posted by 00 Buckshot

Is your truck gas or diesel? That will make a difference on the front tire pressure. With a diesel you are carrying a lot of weight empty or loaded.


My 2014 diesel dually shows 75lbs in the front and 65lbs in the rear when fully loaded.


I don't understand why yours calls for a full 80 lbs in the rear duals

Yes, Duramax diesel.

[TB673]

Tx, if you have the aluminum rims on your GMC, the only rotation pattern is RF to LF and RR to LR. The Front aluminum rims are different than the Rear rims, so you cannot rotate the Front rims to the Rear and vice versa.


Page 359 of this link will explain.


https://www.chevrolet.com/bypass/pcf...22FEB28_3P.pdf



Tim

[Rhagfo]

Well likely the 80 psi is because GM upped the rear axle rating to over 10,000#.

[Texas Sooner]

Originally Posted by Rhagfo

Well likely the 80 psi is because GM upped the rear axle rating to over 10,000#.

Yes, it's now rated at 10,500 lbs

[jrollf]

Tire rotataion...

Are your inner dual rims steel and outer aluminum / differnt than the inner dual rims? And/or can the rear outer rims be flipped around and put on the front?

On my F350 all the rims have to stay in the respective locations. e.g. outer dual stays outer dual, inner dual stays inner dual, and front have to stay on the front. (physically, the rear outer dual rims can go on the front and vice versa, but the "back sides" of the rims are not polished, so the "pretty side" would be hidden if I swap them)

The reason I ask is if they are different, then a proper "tire rotation" involves dismounting and remounting and balancing all 6 tires as the rims can't be swapped around.

IMHO, after spending all the money doing 6 tire dismounts, mounts, and balances (and the extra chances of rims getting scratched up in the process) it isn't worth it. After a few tire rotations I could have just bought a new tire with the money I spent doing rotations.

So for me, I don't rotate, the rear tires wear very flat, pretty much square, the front wear even but faster than the rear due to scrubbing from turns. Even if I have to replace the front tires more often than the back, it is still cheaper and less of a hassle than it is to "rotate" the six tires.

Caveats...

This is based on the cost of tires for my truck which is fairly old, it runs LT235-85R 16 tires, which seem to be cheaper than tires for newer trucks with 18 to 20 inch rims. So it's possible your tires are expensive enough tire rotations will be finacially worth it.

The other piece to the puzzle is do you drive the truck enough to wear out tires, or do they age out on you first. I only use my truck for vacations and random local trips (got to get the honey-dos done!), so I usuaully age out my tires before I wear them out, another reason, for me, the expense of tire rotations isn't worth it. (I average 4k to 8k miles a year depending on vacations). I don't like to run tires more than 8 years old, this is my personal comfort level. In my environment I start to notice random small sidewall cracks around 8 years.