Must READ- facts & figures on axles & towing

[CUMMINZ]

I used a set of portable truck axle scales yesterday and did some interesting weighing that may prove or discount your ideas on what axle weights do to your tires and wheels. You may find out how easy it is to overload your factory wheels. This is mainly for your truck wheels. KEEP IN MIND I HAVE NO PASSENGERS & BED IS EMPTY OF FIREWOOD, ECT. MY REAR AXLE WHILE TRAVELING NORMALLY WEIGHTS 7080#S. I will also show how raising and lowering your hitch will or will not effect your RV axle weights. Facts will be at bottom. Scales are in 100# increments.



WITH 5TH. WHEEL PIN HOOKED UP

2400#S FRONT AXLE WEIGHT 2650#S REAR AXLE WEIGHT

TOTAL FRONT AXLE 4800#S TOTAL REAR AXLE 5300#S

BOTH RV AXLES ON SCALES

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REAR AXLE ON MY 06'DUALLY

NO LOAD ..... 1900#S ON OUTSIDE WHEEL

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REAR AXLE ON MY DUALLY

WITH RV LOADED ..... 3100#S ON OUTSIDE WHEEL

KEEP IN MIND THAT 06" DUALLY WHEELS ARE RATED AT 2600#S.

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RV unhooked and sitting on front jacks

Front jacks lowered 8"s from normal

Front axle= 2400#s

Rear axle= 2600#s



RV unhooked and raised 8"s from normal

Front right wheel= 2100#s

Rear right wheel= 2700#s





HOW MANY OF YOU HAVE TRIED RAISING AND LOWERING YOUR PIN OR HITCH TO TRANSFER LOAD ON RV AXLES. DOES THIS PROVE IT IS NOT WORTH THE EFFORT??.



The next issue is wondering how the crown of highways, parking on curbs with one rear wheel, blocking just the rear outside wheels while parked and everyday traffic of rough roads may effect your wheels. :-{}

 

[Bertram65]

I don't think you have anything to worry about unless you take off one of you rear wheels or have a flat.

 

[BGlidewell]

Scales



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[GAmes]

What is the point?

 

[CUMMINZ]

Ga

Whick part do you take exception too! There are two issues.

 

[GFritsch]

Am I missing something? With regards to the load on your rear wheel, the weight on the outside wheel will be roughly half when both tires are in contact with the ground. Cornering or running over uneven road surfaces will change the independant load on each tire, but for the most part the two tires share the load?

 

[GAmes]

Whick part do you take exception too! There are two issues.

I must be really dense. What are the issues? I've never heard of raising or lowering the hitch to change tlr axle loads. That is a no brainer. And parking on one tire for a short while is not like driving on one tire.

 

[BGlidewell]

He's making a point that lots of SRW owners make about uneven road surfaces that can cause one tire to carry the load. Lots of people say that a trailer that is not level will have more weight on one axle than the other.

 

[boatpuller]

He's making a point that lots of SRW owners make about uneven road surfaces that can cause one tire to carry the load. Lots of people say that a trailer that is not level will have more weight on one axle than the other.

On his trailer raising and lowering the tongue doesn't make a large % difference between the axles, but on some trailers it does, especially the trailers with torsion axles. Also he wasn't changing pin height he was changing height with his jacks which are not at the pin, would make a very large difference on how much weight was on the axles, all the weight forward of the jacks that is behind the pin will be pushing down on the front of the trailer which will take weight off of the axles, I believe that if he took his weights on the RV axles when jacking on the pin he will change the results quite a bit, I know with a boat trailer by moving the tongue just a few inches up or down you can change axle loads by much more than 100 pounds, I had a trailer that you could overload the rear axle if you raised the tongue 2 inches from level, the load on the rear axle increased by 500 pounds.



Caleb

 

[CUMMINZ]

Wheel loading

I am including 3 more pictures. When I pulled my RV with my SRW 04. 5 and drove close to the shoulder of the road the truck and RV tires would react extreme because of having only one tire on the ground. The roll of the road would make the rig want to go to the ditch. Now that I pull with a dually that is much different but does cause a more acute problem with loads. If I am not loaded and on a narrow road I can drive (not that I want to) with the front tire and inside rear tire right at the extreme right side of the road with the outside rear wheel off the pavement and not feel a thing. This is not done because I want to but other drivers force me there. BUT when I am loaded and I am forced to the outside shoulder and the inside tire carrys all the load I can tell it. The rear wants to walk off the road. At this point is where I am concerned because I am loading the inside rear wheel way past the designed weight and super loading and twisting that same tire. At this point is where I think we are damaging our rear tires. The next time when I don't expect it and I am driving at 70mph or faster with a tire over 100 degrees I have a blowout and I wonder why??? This happens to all our trucks.



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[steved]

A couple things we are sort of forgetting... the weight rating of wheels and tires is continuous. Running with one wheel supporting all the weight is an instantaneous load, and isn't happening for any significant distance. What I have read is that wheels and tires are designed with a safety factor built in, just like a chain.

I for one have ran LR E tires (on an F-Superduty) with almost 15k sitting PERMANENTLY mounted over those four tires (my GVW was just shy of 17k on all 6 tires). I have ran that way at 85mph for hours on end. We only coughed a tire once in a while, and mostly were already damaged. This was a "small" truck-mounted drilling rig. The setup was built overloaded. The only reason I am stating this is because I know those wheels and tires were well over there weight rating...

As for jacking the pin up and down... theoretically, you could have ALL the weight of both axles on just the rear (pulling up into a sloped driveway) or on the front (dropping down into a sloped driveway) if you are lifting either axle off the ground (I do this occaissionally with my tandem). And again, instantaneous load.

And you could always move the pin forward in the bed to distribute a slight amount more weight onto the front axle...

Just some thoughts...

steved

 

[Andersonville]

You got too much time on your hands Dude!

 

[Hoefler]

Another thought, if you noticed, there is two different load ratings on all tires of this size, a single and a dual rating. The dual rating is always significantly lower than the single rating. Which is taking the above situation into consideration. When you are driving down the road, you go through dips, swells, pot holes, etc. . The sudden increase in load is unimaginable, at times in excess of 10 times the load or more. Point being, the tires and wheels are engineered with this in mind.



The notion of raising or lowering the pin height to adjust for level is the only reason to adjust it. Like said above, you can over load one axle, especially with torsion and/or triple axle rigs. There was a post awhile back were a a triple axle was 1" out of level and he was destroying the rear axle tires from being over loaded. The weight was well with in the load range of all six tires together, but being out of level caused the rear axle to be overloaded.

 

[Ragain]

My Airstream travel trailer is equipped w/ torsion axles, and yes, it is VERY sensitive to coupler height! Doesn't take much variance @ the tongue to cause one axle to carry more than the other. (air ride conversion in the works... someday) Also, I take it that you are worried about deep wagon ruts causing inner/outer dual to carry excess weight? I would think that sidewall flex would compensate for that... to a degree. I imagine that on a "test track" setting if duals were subjected to a continuous wagon rut straddle, there would be a measurable differentiation in tire wear between inner/outer tires. Too many variables in actual highway surfaces would prevent that from being a problem.