Tire pressure

[ponch]

OK you Dually drivers I am about to pull for the first time in this new GMC Dually.

I have changed the tires from OEM
to Michelin LTK 235 85 R 16 M/S and
currently have all tires set at 70lbs.

Should I leave them there or raises them to 80lbs
split the front and back with different pressures or what?

This is the first time pulling with a Dually.

I am assuming that you find the ideal weight the same way you do on a single wheel.

Ponch

[billr]

Ponch,

Sorry to jump on your thread with this question....How do the 235's fit for the duals? I was concerned going from the 215 to the 235 may not leave enough spacing between the two tires when loaded? I plan to move to the same truck soon and would be interested in the same exact tire swap as you've done. I think the Michelin LTX are the best! Good choice.

Cheers,
Bill

[ponch]

Bill

Not to sound crass but I'll answer that as soon as I GET BACK. LOL

Right now I believe I have enough room, however that being said I do have a set of one (1) inch spacers on hand if needed.

Just for your info: these tires are 4.4% low on the speed reed out or 60 mph = 62.4.

By the way the difference in ride is phenomenal!

Ponch

[billr]

Thanks Ponch! Thats about what it did for my 2500 Chevy speedo when I went from 245 to 265. Understand the 1" spacers if need be. Good idea! I'll bet it also gives the truck a better look, filling in the wheel wells a bit more. Did you stick with the stock wheels?

Cheers,
Bill

[ponch]

Bill

Go to diesel place .com and check out my garage you can see the difference. Since the pictures I have put on a bug shield, window shields, Hadley horns, and polished the exhaust tube. Still have to get the mud laps and running boards that are being made as we speak.

Ponch

[rdunk]

Hi Ponch! Since my tires are 17", I can't tell you what is the right pressure for your tires. But what I can talk about I will. As you know, it is all about axle weight. My truck sticker (for 2x4) says 60 lbs, front and rear, for the max load weight on my F350. What I have found is that when I am hitched to the 5er, with about 4200 lbs pin weight, the truck front axle weight only increases by a few hundred pounds, with the balance being carried by the rear axle. What this means for me is that my rear axle ends up weighing right at twice the front axle.

With that being the case, then that would mean that each of the four tires on the rear is carrying approximately the same load as each of the two tires on the front --- thus for my set-up, the tire pressures should be basically the same, front and rear, as is stated on my sticker door plate.

FWIW, when I had the identical truck in 4x4, the tire pressure for the front tires was 5 lbs higher than for the rear tires. I am sure that was for the fact that the front axle was carrying 500 lbs more, for the added weight of the 4x4.

Another FWIW --- The max tire pressure on my tires is 80 psi.

Good luck on your first tow with the new GMC.!

[anijet]

I have an 07 Classic and am currently towing about 4000 miles a month and driving an additional 2000 miles a month. I still have the original tires and am running 70 psi in all six. Other than the backs wearing very square and the fronts are rounded ( I haven't had time to rotate them), it looks like the pressure is right.

I'm also very interested in running the 235's but I do not want to run spacers since our wheels are hubcentric. Please let us know if clearance is a problem.

[Motor31]

Ponch,

Tire pressure is best set on the basis of 2 factors, the pressure limits set by the tire / rim manufacturer and the weight you will have on the tires.

On my old Ford dually I set the duals at 50 - 60 PSI unloaded and then full up pressure (80 IIRC) when towing. I reduced the pressure for empty to ease the ride and to make sure I wasn't wearing the center of the tread prematurely.

Look at the tire and rim for max pressures. Weigh the truck axle for loaded and unloaded weight and check with the tire manufacturer for the recomended COLD pressure for each situation and fill accordingly. You already know the MS rigs are very heavy on pin weight. You should be able to find a tire inflation chart on the manufacturers web site based on model and load on the tire.

[ponch]

anijet

Yes there is a problem. The tires are touching with the M/S hooked up. Looks like it will take 1-1 1/2" spacer to open it up. That is with 70 lbs. I will raise it to 80 tomorrow and try it but I would be very surprised if 10lbs will do it.

Ponch

[sigo'suite]

Ponch,

Real trucks come from the factory with real truck tires!!

Sowwy just couldn't resist. HeHe :lol: :lol:

[anijet]

anijet

Yes there is a problem. The tires are touching with the M/S hooked up. Looks like it will take 1-1 1/2" spacer to open it up. That is with 70 lbs. I will raise it to 80 tomorrow and try it but I would be very surprised if 10lbs will do it.

Ponch

Thanks for the info. Please keep us informed how the spacers work out. I would really like a little more tire when I need to replace them.

[ponch]

Ron
I thought of that also. LOL :)

Ponch