Hi Fellow Sunliners
To those who are new to TT towing and may be a little confused by all these ratings and terms, here is an different type of explanation where you may be able to relate to better. This also talks about many things you need to look at when you hook up and tow away into the sunset.
I’ll try this by example along with technical input verses throwing ratings all over the place. I have not put numbers to the weights/lengths but this may help explain what to look for and then fill in the numbers for that specific TV and TT.
What I am stating here comes from my own towing experiences, folks I have helped, trying the best I can to investigate TT towing accidents and research into the matter from multiple sources beyond RV forums. Consider it, “an opinion from a fellow camper” to someone new to towing who may not yet really know about all these ratings and interdependences that go beyond TV manufacture ratings.
First to clarify we are talking about TT towing using a conventional hitch with a TV that has considerable rear overhang. Conventional meaning we use a good WD hitch towing on the ball along with an adequate anti sway system for the size of TT and TV you have. Rear over hang means how far the tow ball is behind the rear axle of the TV. This can be 48 to 65 inches more or less pending brand/model TV.
I needed to clarify the towing setup being discussed here as with a conventional hitch system they have unique attributes often times that do not show up in TV manufacture ratings. The rear overhang situation is one attribute in towing on the ball that can create much havoc in a TT towing situation if not properly compensated for. Most times the rear over hang is a fixed number so we have to compensate for this issue in other ways.
So if a new to towing person asks, will my truck tow this TT? Simple enough question. From my point of view creating a stable and enjoyable towing rig depends not only being able to pull it, but more on the ability to control it. Selecting a stable towing TV & TT is not overly hard but it does take a little time to learn and understand what affects what with your combination.
Consider this a Camp fire chat so to speak on how a large part of this all works. This is how I do it. Others may have a different approach to accomplish the same end goal and we hope to hear from them too.
What I am about to go thru takes a little time to understand. It is a 10 to 15 minute read. It is not really complex once explained but it often times escapes many new comers to TT towing. Towing a TT can be very pleasurable but it needs to be understood on what affects what. You may ask some folks who have been towing a good amount of time and they have had no problems. There rig came right in easy and works well from the get go. This is good for them however their may be times when they do not totally understand why there system tows so well because it always has. What works for them with their TV and TT combination may not work well for you. You can actually learn more from a rig that does not work so well until you correct the problem and then life is good. And understanding it all does "not" occur in a 3 minute conversation ending up with you will be fine. The learning never stops.
Information about your needs should be collected, some simple math done to them and then an opinion based on it. It starts like this as one approach.
Tell us what truck model, year, engine, is it 4 x 4 or 2 x 4 drive and if a PU what cab configuration. We will also need the wheel base for your truck, distance between front and rear axle. If you know the rear axle ratio we need that too. If not we can help you find it. We are gathering info on your truck suspension and drive train. In your owners manual there is often a chart that shows what your GCWR is. We need that.
We also need to know your truck GVWR, and both front and rear axle ratings, GAWR-FRT & GAWR-RR. There are on a sticker on the driver side door or column.
Have you modified the truck from the factory? Different tires, lift kits etc? Here we are trying to see what has changed from the factory ratings.
How many people will be in the truck with you when you go camping? Are there any pets and “must have” things that need to be in the TV with you that cannot go in the TT? How many pounds of weight is that and where do they sit in the truck? Here we are coming closer to figuring out the “must have” payload in the truck.
Receiver and Tires:
Do you know what rating receiver you have on the back of your truck in WD mode? And what type/brand of tires do you have? Here we need to check if the receiver can handle the loaded tongue weight of the TT in WD mode and what tires we are dealing with. Tires are a big part of towing and so is the truck hitch equipment.
TT size and floor plan:
Now we look at the TT. What model and floor plan do you have? We need to look at the dry GVW of the TT and the GVWR as a starting place. We also need to know the dry tongue weight, length and where cargo holes are and water tanks are located.
Where do you camp:
Where do you plan to go camping and how much? Are you on the east/west coast and in what state? Do you plan to do cross county trips, local trips (20 to 50 miles) or mixture of mild to longer distance such at 500 to 2,000 miles trips once a year? Do you know if you are needing to haul fresh water with the camper? Are there many hills or mountains where you will go camping? How far above sea level will you be towing at?
TT interactions with the TV:
Here we are gaining information first about the TT and TV. Tell us your make/year and model TT so we can look it up on the web. Floor plans and dry weights tell how the camper is built and how it could load. Does it have 8% dry tongue weight per GVW, 10%, 14% etc in the dry setting? Where the storage is located helps tell where the weigth will go in relation to tongue weight. With knowing some about the camper floor plan and how you use it helps give an estimate for what tongue weight could be. It’s not exact but you can get close. If you have 8% dry tongue, we have to work at getting that up into the 13% range. If it starts in the 13 to 15% dry range and the floor plan loads towards the tongue, we need to watch out as it can be 16 to 18% when loaded and that means very high tongue weight per TT GVW. The loaded TT should be at least in the 13% range, 15% is better if the TV can handle it. 10% is the low end guideline but we caution to not go that low. Pending the TT, if your propane tanks go empty it can drop the tongue weight a few % and put you into the more unstable area if you start at 10%.
By knowing your camping family size and where they go camping it helps with the cargo weights in the truck and an estimate of how much “stuff” they will haul. A family of 5 with 3 teen age’ers can add up. And just an adult couple can add up too. The estimate of a 1,000# of camping gear is real. Many times is can be 1,200 to 1,500# with full water. My DW and I have 1,200# with no bikes and no fresh water. The bigger the TT, the more stuff you bring. By knowing the towing distances and areas you will camp at we have a better handle on if this is a heavy towing situation or a light one.
Predicting loaded tongue weight of a new camper is something that takes a fair amount of investigating on and what “stuff” weighs. The TT catalogs use dry weights. Since we have nothing for a loaded tongue weight dry is better then nothing. However dry weights do not include added options, battery weight, LP gas weight and no cargo added after the day it leaves the factory. If you see a TT on a dealers lot, look for a weight sticker in one of the cabinets. This is a better indication of the trailer actual empty weight. There is no rule of thumb for a loaded tongue weight I know of that is accurate. Using a % of the GVWR for a tongue weight may be close or it may be way off. Floor plans and where you can store gear drives the tongue weight. We can help you estimate the tongue weight by knowing your floor plan, expected cargo and dry tongue weight. The one wild card is where your fresh tank is located if you need to haul water. Often times catalogs do not list where the tanks are per floor plan. Some fresh tanks unload, load or are neutral to the tongue weight. It is however something you need to consider if you need to haul fresh water.
Now we have gathered some good information about your camping family, a brief look into intended use and we have a base to start looking at ratings and other stable towing attributes.
Now to the ratings.
So what is the definition of the TV ratings in regards to towing? I’ll take a stab at it. This is my boiled down opinion. They are not legal limits per say in the RV world but can get you into a legal situation if you are in an accident and found at fault as you are operating a vehicle beyond it's intended use.
GVWR, GAWR and GCWR are an automakers intended maximum use limit for each specific area being rated. Certain design safety factors may exist on each limit in accordance with government set regulations. Exceeding these limits can subject the driver and vehicle to combinations of conditions not tested or that goes beyond the design intent safety factors resulting in a system failure.
Now we sit down and start doing a little figuring.
Truck weight with cargo:
For an optimum setup we need to stay within the TV ratings and have some extra capacity for unexpected things within reason. The ideal way to do this and to prove to yourself we have the estimate right is to load up your truck with the all the people and pets and “must have” gear in the truck and weigh the front and rear axle. Fill up that gas tank before you go. Cost is about $7 to $9 at a truck stop.
If you want to we can help you come up with a guesstimate of loaded truck axles. There is a lot on the internet today that can get us close. The biggest hurdle is what does the truck weigh with no people inside and full of gas? Again the best way is weigh it, however if you want, we can guesstimate a loaded truck GVW and axle weights.
With some math and knowing the people you told us where in the truck and their weight we can estimate your TV axle loads. We need to say within the GAWR on both front and rear axles when we hitch up the loaded TT tongue and adjust the WD hitch correctly. If you have a family of 5, that is a fair amount of payload in the truck and it can use up a lot of your ratings in the lighter trucks. You need to have enough capacity left on the rear axle to carry your expected loaded tongue weight when all the “must have” weight is already in the TV. If you over load the rear axle it can aggravate TT sway or you can have a mechanical failure. If you went to the scale, it is then easy math to subtract the unhitched front and rear axle weight from your trucks GAWRs. The difference gives us the max weight carrying ability per axle available before you reach the limit.
Your TV manufacture also places a GVWR on the TV. Passengers, cargo and TT tongue weight need to be within this rating. When you push this limit it can aggravate the effects of TT sway and your ability to stop the truck. The truck is then considered overloaded in relation to it’s max use limit. The trucks brakes are intended to stop the weight of the truck, the TT’s brakes are made to stop the TT weight. Exceeding the weight limits can affect your stopping pending how far over you go. The manufactures give you some loading freedom on how you split the TV gross weight per axle. The axle ratings combined are higher then the GVWR on smaller trucks but the total weight of the truck is capped by the GVWR. The TV has to be a stable towing platform for the anti sway controls system to work effectively. If you are over the ratings it is that much harder to create the stable towing platform needed. Again subtract the actual loaded truck weight with no TT hitched from the GVWR and what is left can carry the TT tongue weight and maybe some more camping gear.
Tires and truck suspension play a large roll in TV handling and rig stability. Cushy riding tires are not great for towing. When the side walls flex the truck can become unstable with a TT pushing on it. The truck is actually wiggling around flexing in the side walls. There is no tow rating for tire side wall stiffness by the tire manufactures or TV manufactures that I am aware of. If your truck is over weight, odds are your tires are at or over their ratings. This aggravates left to right stability of the TV to hold the TV rigid when wind gusts or semis pass you even with a good anti sway hitch. If you have P rated tires which can be cushy, the best with what you have as a starter is to, air up the rear tires to max cold side wall pressure. The front must be at least at door sticker pressure. This concept also works for LT rated tires and in many cases the LT tire is soggy too unless at higher pressures. The front tires can take more air until you start getting a bouncing action. Take them up in 5 psi jumps until bouncing starts, then stop and back down 5psi and see if it goes away. When not towing, you can air them back down to door sticker. You can find the front end bounce point just driving around empty. Some TV’s can take full max cold pressure in the front, some bounce too much and must be less but can still be more the door sticker pressures. As with the TV so is the TT. Air up the TT tires to max cold side wall pressure. A soggy TT tire can accelerate sway.
If your truck is very soggy left to right even after you air up the tires you may need a different brand or type tire. There are times you just cannot get way from it. All tire brands are not created equal. Just a change in tires can take a stable towing rig and make it unstable and visa versa. When you go with a heavier truck the tires get stiffer by design for the extra weight. It is a side benefit of 3/4 and 1 ton trucks. But still, even LT tires differ in stiffness between brands.
Now we look at your GCW. Can you pull it and what strain are you putting on the truck? The GCWR limit is a pull rating for the most part for your TV drive train but is also plays into a stability part. If the TT gets too heavy for the total weight of the TV, the TT can negatively affect TV stability when we tow with a conventional hitch. If you stay within the GCWR you stay away from over working your TV while pulling and getting grossly out of weigth proportion. Ideally for folks starting out towing, the truck should be heavier then the loaded TT or at least equal. It is the battle of the masses here and the big guy wins when large adverse towing conditions exist. A larger % heavier TT then TV can push the truck given the right circumstances. The rear of the truck may slide or the front of the truck may flex heavy in the side walls of the tires. It is very much aggravated during wet or slippery conditions when the big TT is pushing the truck. This does not mean it is not possible to tow a heaver TT then the truck, but it aggravates conditions to create an unstable TV with small light trucks and light truck suspensions. Larger trucks have the same problem, it just takes more weight difference to get to this point.
For the pull rating if you have excess capacity, meaning your GCW is less then your GCWR, you have reserve pulling power left in the truck. The frontal area of the TT eats up pull rating when you go over 60 sq feet of area in many brands of TV’s. And the TT you are looking at, 8 feet wide 10 feet tall is above this. So we need to look at your truck GVW and about where you will land in TT GVW. When you add the 2 together if you stay at about 8 to 10% less GCW then the GCWR of the truck this gives you some reserve in case you add a pop cooler or extra food in the camper etc. Towing at capacity is not fun if you are towing in hilly areas. The further away you are the less worked your truck is. If you have a lot of mountains or a lots of hills where you tow, you may find the 8 to 10% number needs to be more in the 15% to overcome that harder towing. If you are at high elevations we even loose more power on engine with no turbo charger or super charger like diesel trucks have. If you are above the 3500 to 4,000 feet and up, let’s talk more on this reserve factor. The higher you go above sea level the less power you have on a gas engine to start with. A V8 turns into the power of a V6 at around 8,200 feet.
WD hitch and anti sway controls.
If you have a heavy trailer tongue weight, most times above the 500# range, they need a WD hitch large enough in ratings plus a little room to grow to line up with your loaded camper weights. Pending your TV, you may even need a WD hitch with less then 500# tongue weight. Also do not get confused by dry catalog weights, the loaded tongue weight with camping gear is what counts. And IMHO you need good anti away controls even if you do not require a WD hitch as TT's present wind effects not seen on sailboats, utilty trailers etc,
The are many good brands of hitches on the market, however sorting thru which one is best for your application can be a little daunting at times. Here at Sunline Club we can talk about our experinces and see if they fit your situation. Regardless of what hitch you get, the WD hitch must be set up correctly to put the front end of the truck back in the proper weight range to allow good TV steering control and to unload some of the heavy tongue weight off the TV rear axle that was gained with this long rear overhang we have.
We also need to watch the truck receiver.
While we checked the rear axle ratings, the TV receiver has to handle the WD hitch. The best approach is to have the receiver rated in WD mode equal to or greater then the WD hitch spring bars. This way you do not over torque the receiver by accident when towing in large dips or pot holes creating a hard back flex in the hitch.
The next area is TT length verses TV wheel base.
The longer the WB the more stable the truck is to start with for towing. The TV manufactures do not put a rating on this but it is an important part of having a stable towing rig. If your TV is at it’s GVWR, it’s GAWR-RR and you have light suspension, a short WB can have a larger pronounced effect in stability on the TV. The TV tires play a roll in this as well. Long TT, soft tires, light suspension, short wheel base and a TV at it max ratings all adds against itself for long term towing stability. So what is a guide to go by? Here is one that is a guide. It does not declare what rear over hang they are determined from but it is better then nothing. http://rv.org/p10382.htm
If you are outside these limits combined with at or exceeding your TV limits that points to a tow rig with out a lot of margin for things to go wrong. A good WD hitch setup properly, a good effective anti sway hitch, proper TV loading, good tongue weight and stiff TV tires can help overcome minor short falls in wheelbase length.
And lastly a very important part of towing, you the driver.
You have to be on the defensive all the time. The TV and TT will take longer to stop then normal. Your speed, keep it under control. 55 mph is a good place to start with as an upper limit. In some states it is also the legal towing limit. Check the state you are towing in. Regardless of law or not, towing fast accelerates everything that can go wrong faster. Keep an eye in the rear view mirror for approaching large vehicles. Busses, large trucks. Keep to the right as much as practical to minimize the bow wave effect of the large vehicle passing you.
As you can see there is more to TT towing then just GVWR, GAWR and GCWR. Hopefully some day the TV and TT manufacture will create a real TT towing rating system that takes into account the special things a TT presents when towing on the ball.
While this took a little bit of time I hope you now have a better understanding of where all there numbers interact with each other. Come back to us with all your numbers and we can help you sort this out.
Hope this helps
PS For some more on explaining the ratings, Towing Guides Help. Here is just one from Ford. Most all brand TV’s have these. I just picked this one as I can find it easier. The terms are fairly industry standard.
What to know before you tow
Towing Tips by Ford
Towing a Trailer –Being Equipped for Saftey by the NHSTA