Bob,

We haven't been under the Gross Vehicle Weight Rating (GVWR) on our Cambridge since the day we brought it home.  For those that are new, I'll provide the details.

The original unloaded vehicle weight (UVW) rating was 14,800 with a GVWR of 16,980, a difference of about 2,100 pounds.  However, we didn't know any better at the time and didn't take into account the built-in generator that was added (279 lbs), slide-out awnings (approx. 100 lbs), and full propane tanks (80 lbs).

With those items, we should have been at about 15,200, but when we weighed the day we picked it up, it was closer to 16,000 pounds leaving us less than 1,000 pounds of cargo carrying capacity.  Too late to do anything about it at that point.  That's why we recommend making sure there is plenty of cargo carrying capacity and having the dealer weigh the rig and certify that weight prior to delivery if possible.

Most full-timers carry 2,000 - 3,000 lbs of stuff NOT including optional rig add-ons.

The day we started on the road as full-timers, we weighed the rig and it came in at 18,200.  The only number we exceeded at the time was the GVWR as far as we knew.

When weighing at a CAT scale we couldn't get a "per axle" weight on the trailer, but we were okay on the combined Gross Axle Weight Rating (GAWR) of 7,000 per axle.  We were under on pin weight, hitch capacity (24,000 lbs), towing capacity of the truck (21,500 lbs), and the Gross Combined Weight Rating (GCWR) of 30,000 lbs of the truck/trailer combination which weighed a total of 26,660.

The weight of the rig has fluctuated up and down by about 100 - 150 pounds over the years.

We removed heavy furniture and replaced it with lighter furniture and we removed the heavy basement slideout tray in the basement.  But we also added our 4 AGM batteries (90 lbs each) an inverter (75 lbs) and solar panels with wiring, etc. (approx 90 lbs) and we took out our original house battery.  We also shifted weight from the RV to the truck and Jeep, so that's why our total weight never went up more than 150 pounds - 18,350 at the max.

Once we weighed everything wheel-by-wheel, we discovered that we were slightly over on one trailer axle even though we were slightly under for both axles combined.  We also learned that the driver's side of our rig is much heavier than the passenger side.  So, we were slightly overweight on the driver's side tires and wheels.  The tire capacity on the Goodyear G614s was 3,750 lbs and we were 3,800 on one driver's side tire and 3,700 on the other driver's side tire.

We had been on the road three years and decided it was time to upgrade the tires and wheels to give us more safety cushion, so we did that in October 2008.

Then, with trailer brake failures in 2009, we decided to go ahead and upgrade to disc brakes.  With that decision, we also decided to go ahead and upgrade our axles to 8,000 lb axles.  At least we would be under weight with more safety margin on the tires, wheels, and axles and we would have better braking with the 8,000 lb disc brakes.

Of course, we knew that the actual GVWR number on our sticker would never change, but we would have peace of mind about our running gear having the appropriate capacity with some additional safety margins.

As it turned out, the total cost of the disc brakes and axle upgrade was only going to be $500 less than putting on the Mor/Ryde Independent Suspension.  So, we opted to spend the extra $500 knowing that the IS suspension would add more weight, but also, most likely, more years to the fifth wheel.

Now we have tires with a capacity of 4,805 lbs each, wheels with a capacity of 4,850 lbs each, 8,000 lb per "axle" brakes, and 8,000 lb per "axle" suspension.

We haven't officially weighed the rig after these last modifications, so I don't know an actual total rig weight, but I'm guessing it will be around 18,600 - 18,800.

People ask us all the time if we would buy the same rig again.  The only reason we wouldn't is due to the very limited cargo carrying capacity it had the day it arrived at the dealership.

So, the moral of this story is to make sure the RV has lots of cargo carrying capacity which is not eaten up by dealer add-ons or your own add-ons.  The only way to know for sure is to have the rig weighed.

Also, RVs tend to come with components that barely meet the weight standards of the rig, so when buying knew consider having the manufacturer do tire, wheel, brake, suspension, etc. upgrades.

Or, if buying used, know all your weight ratings, have the rig weighed, and be prepared to do upgrades yourself like we've done to help with safety and to extend the life of the rig.

Whew!  We hope to hit a CAT scale today, so we can at least get some official overall weights now that this last set of upgrades is complete.  I'll report back here. 

Frosty,

I'll throw in my two cents on your questions so you'll have more than one source. For nearly 12 years I towed a 15,000 pound 5th wheel with a 1986 Chevy one ton dually crew cab. The truck was rated to tow a 10,000 5th wheel. That meant I was 5000 over weight before I put my wife and dogs in the truck.

Knowing that the truck was overloaded, I am very careful to leave a large safety cushion from the other vehicles on the highway. We the traffic gets heavy, I slow down and leave lots of room and always try to maintain an out. I usually stay in the right lane so I can head for the shoulder if needed.

So here's an example of the trailer pushing the truck. I was on a 4 lane city boulevard at night headed to an RV resort. The center divider was flat and hardpack dirt. I was in the left hand lane approaching an intersection. There was a car about 4 car lenghts in front of me signalling to make a left turn. He pulled in to the left turn lane cutout and as I got within two car lengths he jumped back into my lane and then had to slam on his brakes to keep from hitting a car. I had already begun slowing down for the red light at the intersection. When he jumped back into my lane I knew I would not be able to stop without hitting him. I moved ove into the left turn cutout and hit the trailer brakes hard and then the truck brakes.

When I stopped the front of our truck was even with his front bumper. If I hadn't had that out, we would have pushed him into the car in front and done a lot of damage.

Here's another example-
I see you're from Los Angeles, so you are probably familiar with I-5 headed north to Bakersfield and the grade known as the grapevine. It's a long steep grade on a heavily travelled highway. By the time I would get to the bottom of the grade the brakes on the truck and the trailer would fade from heat friction to the point where I would not be able to stop, I would have to coast to a stop. So as I started down the grade I would shift down into first. I would try to keep my speed at 25MPH by using the engine compression and extreme braking techniques. Even with these tactics, the brakes would fade by the time I got to the bottom. So here again I always made sure to leave lots of room between the vehicles around me. I always had an out, even if I had to turn into the guardrail. Good thing was that if all else failed and I had to hit something we were only going 25 MPH.

Bottom Line- If you are careful and don't hot rod it's possible to travel safely with a heavy trailer.

I only had one failure that I can attribute to towing above the truck's capacity and that was a front brake pad shattered as I braked hard going down the grapevine. It got so hot that the brake material broke off of the metal pad. It made a spectaculiar noise. From that time on I started using the technique described above when going down any steep long grade.