Hey guys and gals, check my math if you would please...

I've got a Load Trail 7K pound GVWR car hauler that has been showing some strange wear patters on the rear axle's tires. They're balding badly on the inside edge. I've noticed that the trailer doesn't sit level when loaded and hitched to the Dodge, it sits nose high by several inches. For reference, both axles are rated at 3500 pounds, the rear has electric brakes.

This says to me that the rear axle is taking a good bit more load than the front axle, and it's probably bent. The accelerated tire wear has become more evident recently; since we've been towing our Jeep Grand Wagoneer instead of just the Wrangler.

I bought a 8" drop ball mount today to replace my current 6" drop ball mount. This should pretty much fix the nose high condition, but now I'm starting to wonder if I won't still be overloading the trailer, even with the load evenly distributed on the axles.

Here's the math part...

According to Load Trail's website, this 5" channel car hauler weighs 2160 lbs.
- Axles are 92 lbs each
- Wheels/tires are 39 lbs each

Axles (184 lbs) + Wheels (156 lbs) = 340 lbs un-sprung weight

Shipping weight (2160 lbs) - Un-sprung weight (340 lbs) = 1820 lbs

GVWR (7000 lbs) - Un-sprung weight (1820 lbs) = 5180 lbs payload capacity

Does that math make sense?

If so, I may have bigger problems... I just weighed the Wagoneer at the dump; 4580 lbs. It has a half tank of fuel, and no cargo. We're planning to add a swing-out spare tire carrier and high lift soon. By the time we add that stuff, fill the fuel tank, load our tools, camping gear, and spare parts we'll most likely be close to that 5180 lbs... We could always carry the camping gear and tools in the truck bed until we get to our destination, but that's a pain, and I really don't like running close to the limits of the trailer.

So, is it really that bad to be running this close to the trailer limits? If we can keep the Wagoneer around 4800 lbs we'll only have a ~400 lb buffer until we're maxed out. That sounds too close to me...

 

Your figures seem to be accurate but you've left out some rather important info I think. What are the size and ratings of the tires and how old are they? With regards to your thought that you are too close to the max I heartily agree. 3500 lb axles have smaller bearings, smaller brakes and usually smaller tires, often times with less load rating as in ''c'' instead of ''d'' also. While I've towed many years several different flatbeds and two toy haulers behind four very different trucks I would never think of myself as an expert on towing but I have developed some opinions about it. One rule I have is never tow closer than 20% of a tow vehicle's or trailer's capacity. With most trailer tires now made in China and having quite a history of bad cord seperations, blowouts and desintigrations common I always recommend replacing them at three years of age regardless of wear. To get back to your setup I would strongly encourage you to upgrade to 5k axles and if you can afford it, convert to 16 inch wheels and something like a Michelin XPS tire. Also that's way too much weight for brakes on one axle only, if I've read correctly. Sorry for being so wordie but you brought up more issues than I think you thought. Hope that helps, Gerry

 

What type of axles do you have under that trailer? Spring and equalizer or torsion suspension?

Either way, you have been putting all the weight of the trailer on that back axle. Either the axle is flexing, making the tires tip inward, or it's just plain bent.

 

Your numbers appear to be accurate, but.....
Remember, when the trailer is hooked to the truck, some of that weight is transferred to the truck.....more if you are using a weight-distributing hitch. So you're really not as close as the numbers lead you to think.
As for the tire wear, it's likely just from running the wagon nose-high.....I really wouldn't expect a bent axle with the weight you haul. The drop hitch you installed should help with this......I'd rotate the tires and check for wear over the next few trips.
With all that said, if you're still concerned, you could upgrade the running gear as GerryR said, and it wouldn't be too expensive to do so.