How long of a trailer?
 

I cannot take credit for the following "guidelines".
I did not come up with them, but I did not dream them up.

The first one is based on research done by a group of folks at www.rv.org.
The second one I read about somewhere, but cannot find it again.

These are just "guidelines" and are not intended as hard and fast rules to follow.  You will find many people towing outside of these guidelines and doing fine (like me), but there are also others that have tried towing something longer than what these guidelines would suggest for their vehicle and had serious problems.

Do your own research before deciding how long of a trailer you might be able to tow without serious difficulty.  There are many online forums you can check out, some of which are on my "Favorites" page.

Okay, the first guideline:

For the first 110" of wheelbase, this allows you 20' of trailer.
For each additional 4" of wheelbase, this gets you 1' more of trailer.

Here is a chart:

(This guideline was first used by the RV Consumers Group (rv.org).)

That looks pretty simple, doesn't it?  Find out what the wheelbase of your tow vehicle is and find it in the chart above.  Is the trailer you are considering at or under the specified length? I f not, let's see if the second guideline helps any.

The second guideline:

The distance from the coupler to the rear trailer axle should be no more than twice the wheelbase of the tow vehicle.

Remember, the above length is from the coupler to the rear axle of the trailer.  It is NOT the total length of the trailer as in the first guideline.

Why this second guideline?  I think this second guideline applies more to non-RV trailers, like boat or flatbed trailers with short (less height) loads on them.   Those types of trailers usually do not have the large vertical surfaces (exterior walls) that would be susceptible to wind.  You've probably seen a small SUV or pickup pulling a very large boat, right?

So let's go back to the first guideline.  If you look at some of the physics and geometry inherent to travel trailers, you might see why length is an important factor to consider.  Ever try to carry a full sheet of plywood (or something similar in size) by yourself, on a windy day?  It can be pretty difficult to maintain control.  But how about carrying a couple of 2 by 4's on that same windy day?  Not so hard, is it?  That's because the 2 by 4's do not have the same surface area to catch the wind as the sheet of plywood does.  So, in a way, that travel trailer is just like a sheet of plywood for catching the wind.

The next thing to look at is how far the coupler is from the trailer tires?  The greater the distance, the lesser the impact it will have on the tow vehicle and the less sway it could create.  You will see travel trailers of the same overall length with the axles in different locations.  This is probably due to the floor plan or layout of the trailer in order to balance the overall trailer, as well as to provide enough, but not too much, tongue weight.

Finally, the ball, or hitch location.  How far is it from the tow vehicle's rear axle?  The farther away it is (known as rear overhang), the more leverage the trailer can apply to the tow vehicle and create the possibility for more sway.  A Jeep or a Hummer would make great tow vehicles because they have very little rear overhang compared to most pickup trucks and SUV's.  Another example of this would be in comparing a 2003 Chevy Tahoe to a 2003 Chevy Suburban.  The wheelbase of the two are different, but their wheelbase to rear overhang ratios are almost identical.  Therefore, both vehicles should be able to handle the same trailer with similar results as far as length is concerned.

If you end up breaking the length guideline by a few feet (3'-4'), you might be okay as long as you have a good sway control hitch or anti-sway bar.  Usually, the only way you can tell for sure is taking it for a tow and see how it handles.  You may be able to get the RV dealer to let you take it for a "test tow".  If you do, keep in mind that the trailer is pretty empty and does not weigh what it will once you pack your stuff in it.  If you do decide to purchase based on a successful test tow, make sure you have adequate tongue weight once you are loaded for the road.

If you end up breaking the length guideline by more than a few feet (3'-4'), but are under your weight limits, consider looking at a couple of products that may help this situation.  They are the Hensley Arrow coupler and the Pull-rite hitch.  Both of these products, as well as their owners, say they do a great job at what they are designed to do, reducing or eliminating sway.  So check them out and see what you think.  

(The references to the Hensley Arrow and Pull-rite products are not intended as an endorsement or advertisement of either product.)

In my particular case, I am towing a 2001 Prowler 27H (actually 28' long) with a 2003 Suburban 3/4 ton, and I have an Eaz-lift weight distributing hitch and friction sway control bar.  I've towed on a few windy days and really don't notice the trailer moving around much, except when the big trucks pass me by.  Then I get a little wiggle out of the trailer, but nothing serious or scary.  I'm over the first guideline by 3', which I think isn't that bad, but I would not want to be any further over it.  And I'm just under the second guideline.  I didn't know about these guidelines when I first bought the combination, but I knew I didn't want to go real long with the trailer towing it with the Suburban.

Keep in mind that these are just guidelines.  There are many factors that could make one combination of tow vehicle and trailer safer or more stable than another, such as the amount of rear overhang, hitch to trailer axle length, hitch setup, load displacement, weather and road conditions, just to name a few.

Questions?  Comments?  Need help?

Send me an email.

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