Hi: I'm looking for a TT to pull with my '09 Highlander (110" wheelbase). Has anybody ever seen any firm guidelines/formula for maximum trailer length given a tow vehicle's wheelbase? Assuming a proper setup with weight distribution hitch and sway bars, should I really be that concerned with length? I'm looking in the 20-25 ft range.
JD and Beastlet
11-19-2009, 07:16 AM
While it's generally agreed that a longer wheelbase helps with towing stability, I've never seen any specs on the issue.
We're towing a 30-footer with our Sequoia, the wheelbase of which is relatively short compared to the pickups that are the most common tow vehicles with this length of trailer. Now, any properly adjusted sway control device should minimize the effects of the tail wagging the dog. In the end we opted for the ProPride 3P hitch which by design eliminates sway.
11-19-2009, 12:58 PM
I tow a 24 Ft Enclosed Car Hauler behind my Tundra DC regularly. Estimated loading weight 9000 Lbs.
Draw Tight WDH with Reese Friction Sway Control.
11-20-2009, 02:24 AM
RV Reporter Articles (http://rv.org/p10382.htm)
This is the generally accepted guideline. Adding a good WDH with integrated sway control allows you to go over some on this.
The length vs. wheelbase issue never becomes an issue in straight line, everyday towing. It may become an issue with emergency maneuvering.
As always, these are guidelines. Some will follow them, some will not. Those that do will look down their noses at those that don't. Those that don't will call those that do the stupid police.
11-20-2009, 06:46 PM
Thanks everybody for the info! Thanks much tomhole for the interesting article!
11-23-2009, 05:31 AM
For the table referenced above, I'd add that it very much depends on the trailer and tow vehicle designs, and how they're connected. I'm currently pulling a 32 ft camper (bumper to tongue... ~28 ft box) with the same truck that I previously pulled a 23 ft camper, and the 32 ft handles as good or better in all situations. Part of this is the dual-cam sway control, but mostly it's the better weight distribution, and the distance from the trailer wheels to the tongue seems better proportioned for stability. Look at semi trucks to see how much different recommendations may depend on exact configuration and truck design. That said, you most certainly can have too much length if the TV components aren't setup to handle it.
12-02-2009, 09:08 PM
Ok, I might have some valuable information for this topic. As one who has built several trailers for my own use behind my light duty's (up to and including 1 tons) and who spent three years driving semi OTR (basically the lower 48)... I should have some credibility. This question involves many dynamics and there is not a one answer fits all category.
One of the biggest mistakes I've noticed with many 1/2 ton or SUV type tow vehicles is tires. If you going to tow anything that exceeds 3/4 of the CGVW this can make a big difference in handling. Soft side wall load range Cs tend to have too much lateral flex and can lead to lateral instability. Front and rear... think about it. Any lateral movement by the tow vehicle's suspension/tires is exasserbated by the trailer. If you going to be above this on the CGVW then I would seriously recomend load range D at a min... load range E is even better. Most do not do this since they tend to ride harder, but in my opinion it is critical. My personal choice is BF Goodrich All Terrain KOs in the stock size... these have heavy side walls and in my size are an 80 psi tire. You do not have to run 80psi if the tire is not loaded heavy, but even at 55 psi they are much more laterally stable. I know of one accidient with a high end SUV at max CGVW that got "set up" on sway... that ended up in a wreck... killed a $50 SUV and a $50k Sailboat. A set of slightly oversized 32 psi ballony tires started it. Heck we have a 96 Bronco that had those fat round ballony in its stock size... it was a real PIA just by itself, yet alone pulling, until we put so 10.5 x 31 or so BFGs with 55psi... different truck then. Oh BTW we got 105,000 miles on that set of BFGs.
The next critical item is weight and balance. This is the biggest single mistake that many many people make and is extemely dangerous when out of whack. I think the rule of thumb here is 10% of the trailers weight is to be on the tongue. Basically if you can even think of lifting the tongue by yourself... its way way way too light. And NEVER do you want negative tongue weight. Yes this does and often happen to folks when loading a hitched trailer or repositioning weight inside a trailer.... this is a MUST. Learn to know your hitches ride height when proper... if its outside a very limited range around that your weight/balance is off.
Also... dont over load your tougue... the hitch, tougue, and the tow vehicle's rear framing is designed around a certain max towing class... which translates to a max tougue weight. Go beyond it by too much and bad things can happen with broken hitches, bent or broken frames and tougues. This happens way to often too. It also lightens the front end on pull behind hitches and also leads to handling issues.
Next: long longer and longest!
Ok, many people have a relatively short wheelbased SUV for normal running around and want to tow their [enter name of you favorite toy here] and go on their vacation. Yes, it is done every day... but the longer the wheelbases the better the rig will handle. The trade off is in backing... short wheelbase with a long trailer backs much easier than the opposite. But you don't back all that much and it can be done with any wheelbase... if your good at it.
When I was designing and building my show trailer... I read that the ideal bridge length for pull behind hitches (not applicable to fifth wheel bed hitches, "bridge" is the length from the pivot point of the tougue to the center of the trailer's axle group) is 1.25 times the tow vehicles wheelbase. This is a good rule of thumb for general all around handling and backing, but it is affected by other dynamics. As you likely noticed this basically eliminates most SUVs and long trailers. Now this bridge can be increase a little when using a triple axle group... as they add a little more lateral and antisway stability by design... even more with quad axle. But most are tandlem groups.
Basically, if your going long on the trailer.. go long on the tow vehicle. Many of the extended cabs with the 8ft bed work quite well for long trailers without antisway. If your thinking of two trailers, one behind the other... its really critical.
Take notice of your long haul semi's .... nice LONG wheel bases... two finger steering. Mine handled better than any of the light duty 1/2, 3/4, or 1 tons I've owned. (yes, my semi and other heavy equipment experience is showing... these ARE light duty)
But as you likely noticed there are several factors that add to the dynamics of any rig... large or small... but the above are the primary items.
Long, steep, or long AND steep down grades and brakes... and how to run them is another topic. For this class ... (or any class for that matter) 100% maintainence on your brakes is a MUST.... and never tow a trailer that weighs over your tow vehicle's weight without trailer brakes... and even thats pushing it (75% of the tow vehicles weight is likely a better rule of thumb). ALWAYS have your trailer brakes set proper (Yes you typically must set most of them manually)... as well as your controller setting on electric brakes. On long grades slow down at least 40% or the posted speed if the grade has one (or even less if your at CGVW), and use your transmission to hold you back.... DO NOT depend on the brake system alone... they will heat and fade... not more than 10 or 15% of your hold back should be with the brakes... use the transmission and engine resistance for most of it. Drive line components are for another day... but for towing in general I favor a manual transmission... they can handle long pulls and down grades better.
Dont underrate this advice... its 40 years worth of experience and 2.6 million miles talking... 600,000 of them in a semi, including 6+% downgrades as long as 17 miles at just shy of 80,000 lbs.
12-03-2009, 03:05 PM
Dem that there was a terrific post! Thanks for the insight, and welcome to TS. You should also check out OT (off topic) for laughs or distraction. (points sent)