Thor Forums

[FW28z]

The topic of tow weights came up on another thread, and instead of hijacking that thread, I thought I'd start another conversation.

I came up with some interesting information about the CGWR for my 2011 model year E450.

CGWR = Combined Gross Weight Rating, which is the total weight permissible for the vehicle and anything that moves because of it; which basically means the vehicle, cargo, and trailer.

GVWR = Gross Vehicle Weight Rating, which is the total weight permissible for the vehicle, including cargo, people, and the trailer's tongue weight (but not including the trailer weight).

Normally, the trailer weight is determined by CGWR minus the GVWR.

Of course, many of you know this already, but I am providing it as background information for the topic at hand.

In around 2011 or so, Ford increased the CGWR of the E-450 chassis from 20,000 to 22,000lbs.

However, published specs from Thor show 2011 and prior years E-450 based coaches as having a 20,000lb CGWR, while the 2012 and later models having a 22,000lb rating.

I did some research and found a Ford service bulletin, Q-193, published in Aug 2010 (basically for the 2011 model year), that indicates to increase the CGWR from 20,000lbs to 22,000lbs, a heat shield must be installed on what they call a 42 pin multi-connector.

The heat shield consists of small rectangular piece of cloth basically, that cable-ties around the connector. This piece of cloth increases the CGWR from 20,000 to 22,000lbs.

Kind of stange huh?

But I had a theory about why this was so - and I contacted Ford, and they confirmed my theory was correct.

Apparently the reasoning is the extra CGWR requires the engine to work a bit harder, which increases the temperature of the engine and exhaust system. Since the 42 pin connector is located on the underside of the chassis, close to the exhaust system, the connector has to be protected from the extra heat.

That's it. Nothing more to increasing the tow capacity by 2,000lbs than a piece of cardboard.

Also, when Ford ships the chassis to the RV manufacturers, they put the heat shield in a bag attached to the vehicle for the RV manufacturer to install, should they choose to (why Ford just does not install the shield at their factory is puzzling to me).

I was able to confirm though that Thor did install the shield. So even though the Thor specs show a 20,000lb CGWR, the fact is, the CGWR is 22,000lbs.

When I asked Ford that since I had the heat shield, if I had the 22,000lb rating, and they told me to ask Thor... I suppose it's a liability response.

And I bet if I ask Thor... they will tell me to ask Ford.

At any rate, the good news in all of this is it seems the chassis is tougher than the original 20,000lb CGWR spec. And with my toad, my CGWR will not be more than 17,500bs, which is under both 20,000 and 22,000lbs. And having a 22,000lb rating just means I have more of a towing margin of safety, which being a conservative tower, I always strive to do.

Driving around the relatively flat terrain of lower Michigan is one thing, but driving to Florida over mountainous and hilly terrain is one very good reason I like some safety margin in tow ratings.