Tongue Weight Rating
Hello, We are buying a trailer for our daughter and son-in-law. They now have a Ford Expedition with 8,900# tow rating. 80% of that is 7,120#, but they should stay below 7,000# loaded (5,500 to 6...
Forum Discussion
Have been following this thread and trying to digest differing sides of the discussion.
I can only see one definition of tongue weight, which is the portion of the weight of the trailer bearing down on the tongue.
Secondly, I can only see the weight of the WDH (less snap-up backets) as being part of the tow vehicle.
I don't think the age of the V-5 reg. matters and the basic definitions are still just as valid today. I'm not sure what is used in Canada.
In regards to adding a bike rack to the rear of a TV (I think that's what was meant), that is dead load added to the rear of the TV and counts as payload. Further (with risk of being smacked), I think it's a bad idea to load a TV aft of the drive axle.
I think some are having difficulty conceptualizing what is happening. If you had a 3' 2x2 length of tubing welded to and structurally attached to the rear of the TV and protruding out as far as a spring bar would, that'd be no different compared to a spring bar. Spring bars do not move vertically at the point they are attached to the TV.
I think the harder thing to picture is what happens when the spring bars are hooked in place. In a way, it would *seem* like when you tighten up the chains, the tongue coupler gets pulled down onto the ball and therefore that the ball would get a higher vertical downward force which in turn would be transferred down to the ground.
But as you tighten up the chains, more of the weight of the rear of the truck (at the ball) is being suspended by the chains. This thus relieves some weight off the ball and rear axle of the truck. At the same time, due to leverage action, the chains pull down vertically on the A-frame transferring weight to the TT axles. Also at the same time, with the spring bars being pulled upward, there is a leverage action that tilts the front of the truck downwards thus transferring weight to the steer axle.
If I am visualizing this correctly, there is therefore no net increase in weight of the coupler acting downward upon the ball. Structurally, the TV can handle the lower rating receiver rating without WDH engaged (say 500 lbs). Then when the WDH is engaged (with 1500 lb rating), there is no net additional downward force onto the ball itself and the receiver and TV does not actually "see" the additional 1000 lbs the tongue may be. Have I got this right at all, or am I out to lunch?
When you go to a scale, the empirical data proves this to be true. It would be interesting to test this with some type of strain gauge or load cell.
Further to this discussion, I'm wondering what happens to weight transfer and weights/forces between coupler & ball when you use over or under-sized spring bars? Is there any difference in weight that the ball sees when the WDH is engaged? If you have say 1000 lbs of tongue weight, and only 800 lb bars, if you tightened the heck out of the bars to get enough weight onto the steer axle (if you even could), what happens? Same if you go the other way with over-sized bars and had say 1200 lb bars? Or does it even affect anything other than having a bouncier or harsher ride? Perhaps with too under-sized bars, there could be higher momentary up/down force between ball and coupler as you drive down the road? Could this possibly over-stress the receiver?
I can only see one definition of tongue weight, which is the portion of the weight of the trailer bearing down on the tongue.
Secondly, I can only see the weight of the WDH (less snap-up backets) as being part of the tow vehicle.
I don't think the age of the V-5 reg. matters and the basic definitions are still just as valid today. I'm not sure what is used in Canada.
In regards to adding a bike rack to the rear of a TV (I think that's what was meant), that is dead load added to the rear of the TV and counts as payload. Further (with risk of being smacked), I think it's a bad idea to load a TV aft of the drive axle.
I think some are having difficulty conceptualizing what is happening. If you had a 3' 2x2 length of tubing welded to and structurally attached to the rear of the TV and protruding out as far as a spring bar would, that'd be no different compared to a spring bar. Spring bars do not move vertically at the point they are attached to the TV.
I think the harder thing to picture is what happens when the spring bars are hooked in place. In a way, it would *seem* like when you tighten up the chains, the tongue coupler gets pulled down onto the ball and therefore that the ball would get a higher vertical downward force which in turn would be transferred down to the ground.
But as you tighten up the chains, more of the weight of the rear of the truck (at the ball) is being suspended by the chains. This thus relieves some weight off the ball and rear axle of the truck. At the same time, due to leverage action, the chains pull down vertically on the A-frame transferring weight to the TT axles. Also at the same time, with the spring bars being pulled upward, there is a leverage action that tilts the front of the truck downwards thus transferring weight to the steer axle.
If I am visualizing this correctly, there is therefore no net increase in weight of the coupler acting downward upon the ball. Structurally, the TV can handle the lower rating receiver rating without WDH engaged (say 500 lbs). Then when the WDH is engaged (with 1500 lb rating), there is no net additional downward force onto the ball itself and the receiver and TV does not actually "see" the additional 1000 lbs the tongue may be. Have I got this right at all, or am I out to lunch?
When you go to a scale, the empirical data proves this to be true. It would be interesting to test this with some type of strain gauge or load cell.
Further to this discussion, I'm wondering what happens to weight transfer and weights/forces between coupler & ball when you use over or under-sized spring bars? Is there any difference in weight that the ball sees when the WDH is engaged? If you have say 1000 lbs of tongue weight, and only 800 lb bars, if you tightened the heck out of the bars to get enough weight onto the steer axle (if you even could), what happens? Same if you go the other way with over-sized bars and had say 1200 lb bars? Or does it even affect anything other than having a bouncier or harsher ride? Perhaps with too under-sized bars, there could be higher momentary up/down force between ball and coupler as you drive down the road? Could this possibly over-stress the receiver?
