Numbers Matter

Many motorhome brochures contain a specs page. A table with numbers and abbreviations can usually be found there. Here’s an example:

example table of specifications

Many of these numbers are easily understood like height and width but others are less obvious. GAWR, GVWR, GCWR, UVW, and NCCC may seem obscure but in truth, they are some of the most important in determining if the coach will have enough capacity to service your needs. These numbers can also explain why one model costs more than another even though they appear similar.

GAWR: Gross Axle Weight Rating is the maximum permissible weight for the axle.

GVWR: Gross Vehicle Weight Rating is the maximum permissible weight for a fully loaded motor coach.

GCWR: Gross Combination Weight Rating is the value specified by the manufacturer of the vehicle as the maximum allowable loaded weight of this motor coach and any towed trailer or towed vehicle.

UVW: Unloaded Vehicle Weight is the weight of this motor coach as built at the factory with full fuel, engine oil and coolants. Does not include cargo, fresh water, propane gas or dealer installed accessories.

NCC: Net Carrying Capacity is the maximum weight of all occupants including the driver, personal belongings, food, fresh water, waste water, propane gas, tools, tongue weight of towed vehicle, dealer-installed accessories, etc., that can be carried by the motor coach.

The table above is of particular interest because it was for a coach I was considering buying. The numbers appear pretty good but the devil as always is in the details.

First, these numbers apply to a coach with only the base options. Any additional options will add weight and reduce payload.

Let’s looks the first line of the second table (model 3412).

If we look at the NCC column we see we can put 5300 lbs of stuff in our RV. That’s a very good number. Many RV’s have much lower NCC’s (2000 lbs or less).

But remember that’s for a base coach. I wanted additional features like a larger refrigerator and bigger generator. That reduced the NCC to about 4000 lbs. Seems like plenty but consider we have not loaded up our RV yet. So let’s run some numbers:

13 gallons of DEF fluid = 90 lbs
Family of 4 = 600 lbs
Propane = 32 lbs
Food, dishes, chairs, books, junk, etc = 2,000 lbs

So our total is approximately 2,700 lbs

Recall the NCC for this model is about 4,000 lbs with options so we can load her up and still have about 1,300 lbs to spare.

But I also want to tow a car to avoid having to move my Class A in and out of camp to go sight seeing.

To tow a car I’ll need:

Tow dolly = 500 lbs
Car = 3,500 lbs
Tongue weight: 100 lbs

or about 4100 lbs.

We add the 100 lbs of the tongue weight to the cargo load giving us a total cargo load of 2,800 lbs. We’re still within the limits of this coach.

But there’s another number we need to worry about. It’s GCWR. Recall this is combined weight of the motor coach and towed vehicle.

So let’s run the numbers.

UVW = 25,700 lbs
Additional options = 1,300 lbs
Cargo, people, etc = 2,700 lbs
Tongue weight = 100 lbs
Towed weight = 4,000 lbs

The total combined weight is 33,800 lbs.

The GCWR for this coach is 33,000 lbs.

Oops! We’re too heavy. Now one could argue my numbers are too high for cargo but I’m being conservative for my own peace of mind.

And keep in mind the numbers for this coach are much better than average for the price point I’m thinking about. Considering how much money we are spending, the cost of moving up outweighed the stress I was feeling about weight limits.

In the end, I opted for the next level up. Same floor plan, same length but with a larger tow capacity, GCWR and GVWR. Doing the math saved me from a nasty surprise of overloading my motor coach and possibly damaging it.

do the math image

I know crunching the numbers isn’t for everyone but considering the amount of money involved it’s worth the effort. If you are uncomfortable doing this, ask your dealer to help you do these calculations. If the dealer resists, maybe you should consider looking elsewhere.

The real cost differences of higher priced models aren’t in the trim but in bigger engines, beefier transmissions and more robust axles. Take the time to understand the numbers and you will have fewer regrets later.

Written on October 20, 2016