Thor Forums

[FW28z]

Originally Posted by JamieGeek

They only installed a 8,000lb hitch (since 10/1/2014). They did not increase the towing specification. The amount any coach can tow is obtained by taking the GCWR value and subtracting the coaches weight.
In my case that math comes out to: 18,500 - 11,500 (I had it weighed) = 7,000lbs. (Except that my unit only has the 5,000lb hitch on it.)
In addition, you also have to make sure that the tongue weight of whatever you are towing does not make you exceed the GVWR value.

The amount you can tow being the lessor of all the variables (GCWR, Hitch ability, GVWR).

I see your point. I kind of had my blinders on, and I was thinking of primarily the E450 which is what I have, and the CGWR is 22,500, and the GVWR is 14,500, so it does have a 8,000lb theoretical towing capacity.

However, if you base it on using CGWR - GVWR, the E350 is only 6,000lbs, and the Chevy 4500 is 3,700lbs.

In your calculation, you might be able to subtract the CGWR from your actual weight rather than the GVWR, but the conventional formula I think is subtracting GVWR from the CGWR. I'll admit that I don't know if you can "borrow" from the excess capacity under the GVWR or not.

The published formulas I have seen from the vehicle manufacturers use CGWR - GVWR rather than actual weight. Whether this is a liability issue or some other reason I have no idea. I don't know if there is a difference between towed weight and hauled weight. Perhaps it depends on the particular vehicle.

On the other hand, my Dodge RAM 1500 had a published 8,000lb tow rating but it was factory supplied with a 10,000lb hitch; so I guess the manufacturers rely on the owner to be educated to the point that they do not overload their rig.

Kind of strange though that I could not find where Thor actually publishes towing capacities, they just publish the vehicle's GVWR and CGWR and state the coaches are equipped with a 8,000lb hitch. That is a bit deceptive in my view.

What is even stranger is that Curtis Mfg. (trailer hitch mfg) states that their Class III hitches range from 3,500lb to 8,000lb capacity. That is weird.