Diesel cummins & 5th wheel...what psi do U run?

[Ramblin Fever]

Have an 01 Cummins 4x4 quad cab with 265/75 R16 10-ply Bridgestone Revo tires.

Truck door placard states 80psi on rear, 65psi front (could be wrong on the front psi, speaking from memory), but I definitely remember door saying 80 on the rear.

We found a psi table booklet that came with the truck for different loads the truck is doing for them time of use.

It states, empty bed, we can run 50psi rear/55 psi front or 65 if using snow plow (we don't)

For a fully loaded bed/trailer weight, spec's 80psi, which is the max tire pressure a 10-ply tire allows.

Is this what everyone else is running? Asking, because this truck eats tires every 25k miles at the most..doesn't matter what I put on it. The wear is always even, there's no feathering, etc. I'm just trying to get our tires to last longer if possible.

I've been running 80psi rear in summer with trailer, and only 50-55psi in winter with snow....if I leave 80 in there with no load, rear of truck just hops on anything slippery and rides HORRIBLE>

 

[FordFocus]

Do you know how much load the 5th wheel in putting on the truck? You might want to try a closed shoulder (tamer treaded) tire to get better wear such as Firestone Transforce. Also make sure to rotate them regularly.

 

[Steve S]

You kind of gave yourself the answer as the tire pressure varies by the load you place on them. Have you brought your truck into a real good alignment shop? Too much pressure the ride is hard and too little pressure the tire overheats [+ the wear difference involved with the wrong pressures].

 

[The motor guy]

If you got a good amount of tongue weight on the back. Say 2000 pounds. Id run 80psi. The tire will wear in the middle if the pressure is too high and wear on the edges if it's too low.
55 on the front should be good too. Shouldn't have any problems with wear. I run 60 psi on the front of mine and 45 on the rear and they wear fine. It does seem to wear the front passenger tire a little more though. Most likely from the angle of the road and the fact that I take left turns a lot faster than right turns. I run my truck empty all the time. I don't adjust the pressures at all. I do tow a boat that weighs around 3000 pounds total trailer and all but that weight won't make a difference especially since I only tow it 5 or 6 miles.

 

[Ramblin Fever]

Thanks for all the good tips.

Running a milder tire, i.e. transforce, just won't cut it in our neck of woods....Colorado's Rocky mountains.

We need all the traction we can get; we can't get that out of a standard highway tire, truck just spins out.

Truck gets an alignment every time new tires are put on; the wear is not uneven...the tires actually wear VERY even across the board, and we rotate them every 3k miles on this truck.

Most diesel owners can seem to get at least 35-40k..we can't even come close.

 

[CapriRacer]

First, you didn't tell us the make and model of your truck. Yes, we know it has a diesel engine and the engine is made by Cummins, but folks would have to know that they only come in Dodges (I had to look that up!). But more importantly, do you have a 1500, 2500, or a 3500? DRW? Short or long wheelbase? Crew Cab? Year?

How heavy is the 5th wheel? What is the towing capacity of the truck?

Is the LT265/70R17's listed on the placard or is it another size?

I have more questions, but let's start there.

 

[Ramblin Fever]

Capri...sorry.

Truck - 01 dodge diesel cummins 2500; 5.9L H/O; Quad cab; short-bed 4x4 automatic. Truck alone weighs 8,800lbs.

Door placard states truck came with LT265/75 R16 10-ply tires; the exact tire that came on the truck was Michelin MT/S

5th wheel - 30', dual axle 7,000lb empty; roughly 8,550-9,000lbs fully loaded.

Truck's total towing capacity is in the 11,400lbs roughly trailer weight; GCWR total for the truck's capacity is 18,000

 

[bullwinkle]

I would weigh the truck with the 5th on it & see what load is on the rear axle-80 PSI is probably OK, but you'll need to find out how much weight is on the tires to drop the PSI any, 3042 lbs. X 2=6048 lbs. max. In my experience driving a fairly heavily loaded van, and a 3-5.5K trailer, more PSI usually doesn't result in uneven wear, and I've had a set of 10-ply Revos last over 60,000 miles!

 

[Ramblin Fever]

I will say the Revo's look like they're going to last longer then any other tire we've ran....we have roughly 20k miles on the Revo's...however, before winter gets here we're going to need new tires again.

We're probably just a very very slight tad above the wear bars.

Again, we're not getting uneven wear, the wear is very even in fact....it's just fast, very fast.

 

[CapriRacer]

Originally Posted By: Ramblin Fever
Capri...sorry.......


Not a problem. I always start with a reality check - and that means checking the tire size and pressure against the vehicle tire placard. Your post actually answers the next series of questions I was going to ask: Are you towing within the capacity of the truck? And you are.

But you said something I think is revealing. You mentioned that you did not want to use all season tires because of traction problems. Is this just a winter weather thing?

You also said that you rotate every 3K. Does the rotation include a front to rear swap?





It info in your post says you are towing within the capacity of the truck. I always start wit

 

[Ramblin Fever]

Not sure if you've ever been to Colorado, but here in our rocky mountains, in areas of where we go fishing, all season tires just get torn to shreds on the mild forest service roads that we drive up.

The roads aren't full of big rocks, but they can be full of pieces of fallen trees, pinecones, millions of tiny sharp rocks, etc. you get the picture.

Aside from this, all season tires have a heck of a time on a slippery boat ramp pulling our boat out; so we've just given up using them.

To give you an idea of the load and areas we travel:

This area at this time is considered mild, it's usually covered in a few inches of mud.

 

[CapriRacer]

Originally Posted By: Ramblin Fever
Not sure if you've ever been to Colorado, but here in our rocky mountains, in areas of where we go fishing, all season tires just get torn to shreds on the mild forest service roads that we drive up.......


Yes, I've been to CO, but usually I've got a specific business I have to visit.

But you've confirmed what I was wondering about. I didn't want to put words in your mouth, so I was careful not to ask if you drive a lot of windy roads - and obviously you do.

Most tire wear occurs in the cornering mode. So every time you turn the steering wheel, a little bit of rubber gets scrubbed off. Needless to say driving on roads that aren't very straight accelerates the wear issue - meaning miles driven in a straight line are practically free.

Pulling the trailer is not helpful. No matter how you slice it, trying to turn with that much load is going to require some serious steering input - and that causes tire wear.

There is also a possibility that the truck - it's an extended cab - might have the same akerman set up that the regular truck has - and that would be wrong.

So the first starting point would be the alignment. You'll want to be sure the truck is set as close to the target value for toe as possible. No "close enough is good enough". It's got to be really really close!

Afte we get passed that, it starts to get a bit complex - and I'd recommend you just live with it rather than do those things necessary to fix an akerman problem.

 

[Ken2]

Rambler

How about posting some actual weights? A truck scale at a truck stop, or a feed or landscape supply store, or a scrap metal yard, or a garbage dump can get the weights. Get the front and rear axles individually for the empty truck and the truck hitched to the trailer loaded and ready for fun. Include the trailer axle weights for your info when you next need trailer tires.

Are you getting a thrust alignment where they precisely measure the direction of thrust of the rears and align the fronts to that? Don't assume that any vehicle is assembled exactly straight.
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=4

 

[Ramblin Fever]

The truck does have a lifetime of free alignments...I'll look into that.

Ken2 - I can get the truck weighed easily enough; however, seeing as it's dead of winter here in Colorado, the 5th wheel is completely winterized.

Even if I were to hook it up to the truck, the weight wouldn't be correct, it has a 100 gallon fresh water tank; and all of the gear that goes into this trailer is amazing.

Usually when we head out, we're gone for 2.5wks or so; this includes tons of groceries, 100gallons of water in the tank, and then we also carry an extra 50 gallons of water in jugs in the bed of the truck, a ton of firewood, extra fuel, heavy generator, emergency tools, enough luggage for 3-7 people (depending who comes) and 3 dogs, etc. you get the picture.

We also carry a grill, couple 20lb bottles of propane...

This truck/trailer's loaded for bear, basically when we head out...there's no way to get a 100% weight reading without actually having all the gear we normally do.

But this is definitely something I've been wanting to do, just haven't done it...all the weigh scales we know of are in the opposite direction we normally head.