Rik Sandberg wrote:
Norm,
There we have it then. A newbie's big chance to learn something.
I don't disagree with your 10% tongue weight rule of thumb. It is generally about right. What I disagree with is, saying that more than 10% tongue weight will cause trailer sway. This is incorrect. It may cause a handling problem for the tow vehicle, but it will not cause the trailer itself to be unstable. Towed with a proper vehicle more (within reason) tongue weight is better.
In other words, a trailer with too little tongue weight will not be stable behind ANY vehicle. A trailer with extra tongue weight will be extra stable behind a strong enough tow vehicle, but prone to handling problems behind a tow vehicle that is not strong enough. The tow vehicle capability is the determining factor in this case, not the trailer.
Rik
Norm wrote:
Hi Rik,
I don't say it, the research from U-haul, Purdue University etc say it. Their research is about cars that are not set up to handle 18 wheeler trailers. Their suspensions are a bit different than a car are designed to handle very heavy loads. A car be put together with heavier suspension, weight distributing hitches in order to carry heavier tongue weight. The research is for stock cars and people who don't know what they are doing and don't have your expense. The whole question was started by a newbie to towing. I would not question your statements about 18 wheelers.
I also teach Coast Guard Auxiliary classes on safe boating and trailering. We recommend the 10% rule for cars pulling trailers not 18 wheelers.
----- Original Message ----- From: "Rik Sandberg" <sanderico@earthlink.net> To: "Norm Bundek" <nbundek@earthlink.net>; "For and about Montgomery Sailboats" <montgomery_boats@mailman.xmission.com> Sent: Tuesday, August 28, 2007 10:01 AM Subject: Re: M_Boats: Tongue weight
Norm,
As I said *"Now whether the tow vehicle can handle the weight or not is another issue."*
If what you say is true then 18 wheelers should be spinning out all over the country as we speak.
Obviously, to start with, one needs to know and not exceed the capacities of their hitching equipment.
Uhaul doesn't differentiate between sway caused by an over/poorly loaded tow vehicle and a poorly loaded trailer. There is a big difference, even though the end result may be the same (car/boat in ditch). The cause of the problem came from opposite ends of the rig.
Yes, too much tongue weight on the tow vehicle can make them unruly. That's why finding just the right tongue weight for some combinations (little car/big boat) can be tricky. If your tow vehicle can handle the weight though, or, if you do something (like a torsion hitch) to equalize the weight on the tow vehicle's axles, more tongue weight will make your trailer more stable every time. Especially if the tongue weight is increased by taking weight (such as an outboard motor) off the transom (ie behind the trailer axle) and placing it up near the tongue (in front of the trailer axle).
Something else to consider is; the distance of any heavy object behind the trailers axle(s). this is especially a problem for us with our sailboats and their long overhang behind our trailer's axle(s) One can improve trailer stability by removing something heavy (like an outboard, or a rudder) from the transom of their boat and placing it inside the cabin, or perhaps on a shelf on the trailer frame, under the boat, *just ahead* of the trailer's axle(s). This will take away the pendulum effect of the transom weight (ie long lever arm) and place the weight just ahead of the trailer axle where it will affect the actual tongue weight felt by the tow vehicle very minimally and yet have very little leverage against the trailer axle(s).