Hitches and Weights Defined

by | Mar 23, 2022 | Parts

Hitches and Weights Defined

When you purchase a brand-new RV there are lots of things to think about and remember, sometimes the stacks of owner’s manuals can be overwhelming. Trademasters is here to help and can answer any questions you have about towing, hitches, weights, weight distributing, anti-sway, suspension enhancement, and braking. As exciting as a new RV purchase can be, it can also be confusing and sometimes a little frustrating. How much weight can my vehicle tow? Is my vehicle large enough? What kind of hitch and wiring do I need? These are just some of the questions we get every day. So, let’s dispel the myths and get the facts for towing an RV.

Let’s start with trailer hitches and wiring. If you have a pickup truck or an SUV, they will typically come with a hitch and wiring harness of some kind. Newer trucks (2008 and newer) depending on the option package, will have all the wiring needed to tow a trailer including a factory installed brake controller. These require no modifications to tow in that respect. SUVs and trucks with a basic option package will have a hitch and a 4-pin wiring harness, which is good for lights but will not operate the brakes or charge the battery. A brake controller and charge line are needed to complete the wiring package. 

Most vehicles with factory brake controllers have “smart ” controllers which can monitor the rate of change in speed. If you are braking lightly, the controller will apply the brakes on the trailer lightly, or if you spike the brakes, the controller will spike. Aftermarket brake controllers do the same thing. Gone are the days of adjusting dials and pendulums and fiddling with the controller as you’re driving. Now it’s a simple “set and forget”. 

If you get a full wiring package installed it will operate lights, brakes and charge the trailer battery. A quick note on battery charge: All trailers with brakes must have a battery to operate the brake away switch. In RV’s it’s the same battery that runs the interior lights, water pump, etc. On utility trailers or enclosed trailers, it is a small battery (about the size of a lawnmower battery) that will operate the brake away switch exclusively. It is a legal requirement that if the trailer “breaks away” from the tow vehicle the brake away switch gets pulled out, closes a circuit, and applies the trailer brakes fully. The charge line provides a trickle charge to the RV battery and is a requirement for wiring when towing a trailer. If you’re in doubt bring your vehicle to a qualified RV shop; they can determine very quickly what exists for wiring harnesses in your vehicle.

Let talk about hitches – starting with receiver hitches or bumper mount hitches first. As mentioned in previous posts, most newer pickup trucks and SUVs will have a factory receiver hitch. Some don’t have it included in the option package, but there are aftermarket receiver hitches for almost every make, model and year of vehicle on the road today. Receiver hitches are separated into three main classes: Class 2, Class 3 and Class 5. (There are some Class 4 hitches out there but not enough to be talked about here.) In most cases a 

Class 3 – in most cases will be all that is needed, and in all half ton trucks and SUVs is the only hitch available. 

Class 5 – reserved for heavy towing and are found only on 3/4- or one-ton trucks.

Class 2 – for cars and small SUVs and are designed to tow a light utility trailer, something usually under 2000 lbs. GVW. 

All Class 3 and 5 hitches have four ratings (stay with me now) and are noted on the hitch itself or in the owners’ manual. 

Some terms you need to know:

Weight carrying – defined as the maximum weight of the trailer coupled to the ball.

Weight distributing – defined as the maximum weight of the trailer coupled to the ball but with an additional weight distribution system added. This number is always more than the weight carrying number. 

Tongue weights – weight that the trailer cannot exceed, usually 10% of either of the above noted definitions. 

Making sure your trailer is level when you’re towing is so important and Weight Distribution Systems (WDS) will assist in that. Their title is also their definition. They take the tongue weight of the trailer and distribute it to the front axle of the vehicle and to the trailer axles as well. What that does is provide for a much smoother and more stable ride, especially noticeable when driving through dips and rougher roads. They also assist in better steering and braking as well. Weight distribution systems are a must have (and sometimes even a legal requirement) for RV travel trailers. 

The next discussion is anti-sway. There are two types of anti-sway systems on the market. One is the friction sway control, which is basically a “stiff arm” between the trailer reach and the weight distribution system. They are tightened manually and work well as an addition to an existing WDS and are bolted on to it. Another option is a WDS with built in sway control. While they are pricier than the base WDS, they are generally quieter and smoother when driving. The theory behind WDS and sway control comes from the “tail wagging the dog” phenomenon, where the trailer starts to swing side to side, which is uncomfortable at best and dangerous at worst. Most travel trailers tow well if hooked up correctly, levelled properly with a WDS and the weight of the trailer is balanced well. One aspect of towing that can be unnerving is when an 18-wheeler passes you on the freeway. The wind vortexes will pull you toward the semi as it approaches from behind, then push you away as it passes by. WDS and anti-sway will minimize this, but not eliminate it. It’s not dangerous, it just takes some getting used to. 

Now let’s talk about 5th wheel hitches. In many respects they are much more basic than a receiver hitch. The 5th wheel hitch is easy to couple and uncouple and is designed to fit in the truck box with vehicle specific install kits. The only decision to make is slider or fixed hitch? The fixed hitch sits approximately 2″ ahead of the rear axle and cannot move from that position. The slider hitch is designed to tow the trailer in the same position, 2″ or so ahead of the rear axle, but it can be slid back 9″ to allow for tighter turning radius in short box trucks (the idea being not to hit the bunk of the trailer into the rear window of the truck). This is a great option for short box trucks and is cheap insurance for the inconvenience of having to replace a rear window. 5th wheel hitches are typically rated from 16-24,000 lbs., which is plenty for any size 5th wheel trailer. 

We get lots of questions in the shop about axle rating, tow rating weights and suspension helpers.
Again, there are lots of opinions out there on tow rating and axle rating; here are the facts: The tow vehicle has two tow ratings that need to be considered before purchasing a trailer. The gross combined vehicle weight rating (GCWR) and the individual axle ratings. The GCWR is the max weight of the truck, trailer, fuel, cargo, people…everything. That weight combined cannot exceed the GCWR and will be found in the owners’ manual. The axle ratings can be found on the inner door post of all vehicles as a gross weight and cannot be exceeded. The only way to accurately determine the net axle weight your vehicle can carry is to weigh the truck axle by axle and subtract that weight from the gross axle rating. Then load the trailer and weigh it again. That will tell you the tongue weight of the trailer and the weight on the rear axle.  As it’s almost impossible to overload the front axle on a vehicle, we will focus on the rear axle here. 

So, let’s bring the suspension helpers into the discussion – and there are plenty of them on the market. But first, here is another fact: Suspension helpers do not increase the axle weight rating or the GCWR. Those numbers are engineered from the factory and cannot be changed – period. Suspension helpers will only help carry the load with more stability. Air bags, Timbren load boosters, Sumo springs or add a leaf all do a good job of stabilizing and carrying the load better and all do that slightly differently. Talk to a hitch-installing dealer to determine which one is best for you and fits your budget.
I’m sure there are other questions concerning hitches and towing. As always, if you have any questions about this or any other RV towing, vehicle solutions, or truck accessories, send us an email or give us a call 604.792.3132. We’re happy to help!