WDH Things I do not understand.

[Quail]

OK yes I am sure this has all been said before. This is how I set up my WDH. I measured the trucks height at the wheels wells front and rear. I hooked up the trailer. The back dropped down and the front of the truck came up. I started the adjustment process of setting the ball height and determining which chain link on the arms I needed to use. Without 10,000 small details I can now say the front and the rear of the truck drops equally when i hook up the WDH. The trailer is level. The ball is not pitched fore or aft, it is in a neutral position when the WDH is hooked up. Looks good and tows well. None of that is my question.

If my trailer weighs 3500 lbs wet it has maxed out the axle rating. Ok 10% of that weight is on the tongue because i know how to balance a load. That put s 350 lb on the tongue and 3150 on the rear axle. Now the question.

Q1: When I hook up the WDH is not 1/2 or some of the weight (350 lb) that was on the tongue moved forward on to the trucks front axle? (I believe it has because in the set up process the front end had dropped after I hooked up the chains on the WDH.)

Q2: When I hook up the WDH is not 1/2 or some of the weight (350 lb) that was on the tongue moved back to the trailers single axle? (I believe it has because in the set up process the rear end that had dropped after I hooked up the trailer rose back up to a level position when I hooked up the chains on the WDH.)

Q3: If the truck is back to a neutral ride height and the trailer is riding level do you really have any tongue weight on the hitch. The manufacturer is recomending 10 to 15% on the tongue but didn't you just move it forward and backward?

Q4: Will I not overload the trailer axle if I add 151 lb to the trailer?

I guess all I am asking is how do you have little if any tongue weight with a WDH.

[DieselDrax]

Originally Posted by Quail

OK yes I am sure this has all been said before. This is how I set up my WDH. I measured the trucks height at the wheels wells front and rear. I hooked up the trailer. The back dropped down and the front of the truck came up. I started the adjustment process of setting the ball height and determining which chain link on the arms I needed to use. Without 10,000 small details I can now say the front and the rear of the truck drops equally when i hook up the WDH.

You should read the truck's owner's manual to determine the proper amount of height to add back to the front axle. The measurement is only going to take the height of the front into account, how much the rear squats is irrelevant here.


Some manufacturers say to return 50% of the height to the front, some say 100%. For example, if the unhitched height of the front fender above the center of the axle is 35" and the height with the trailer hitched but without the WDH on is 38" then you'd return 1.5" of height to the front if the manufacturer says 50% or return all 3" back if it said 100%. Rear axle doesn't enter into this calculation.

If my trailer weighs 3500 lbs wet it has maxed out the axle rating. Ok 10% of that weight is on the tongue because i know how to balance a load. That put s 350 lb on the tongue and 3150 on the rear axle. Now the question.

Q1: When I hook up the WDH is not 1/2 or some of the weight (350 lb) that was on the tongue moved forward on to the trucks front axle? (I believe it has because in the set up process the front end had dropped after I hooked up the chains on the WDH.)

If the front has dropped lower than the unhitched height you have overadjusted the WDH and have removed too much weight off the rear axle. Also, you aren't moving the weight anywhere, the WDH is using leverage to make it seem that way.



It also won't be 1/2 the tongue weight that is transferred, at most it would be 1/3 depending on how the WDH is adjusted. Generally speaking, a WDH can transfer 1/3 back to the trailer, 1/3 to the TV front axles, and keep 1/3 on the TV rear axle but that all depends on the WDH, the truck, distances from the hitch to the TV rear axle, etc.

Q2: When I hook up the WDH is not 1/2 or some of the weight (350 lb) that was on the tongue moved back to the trailers single axle? (I believe it has because in the set up process the rear end that had dropped after I hooked up the trailer rose back up to a level position when I hooked up the chains on the WDH.)

If the rear end went back to the unhitched height you have overadjusted the WDH. You want the rear of the truck to squat, if you take too much weight off the TV rear axle and put too much on the front axle then you are setting yourself up to easily jackknife under certain conditions and in certain situations.



See above re: how much weight is transferred.

Q3: If the truck is back to a neutral ride height and the trailer is riding level do you really have any tongue weight on the hitch. The manufacturer is recomending 10 to 15% on the tongue but didn't you just move it forward and backward?

See above regarding overadjustment of the WDH which takes too much weight off the TV rear axle.

Q4: Will I not overload the trailer axle if I add 151 lb to the trailer?

I guess all I am asking is how do you have little if any tongue weight with a WDH.

If tongue weight is 350LB and you move 1/3 back (115LB) then you have 235LB of cargo capacity left before reaching the trailer's GAWR.


You always have tongue weight with a WDH, it never goes away. It is just transferred via leverage and if you have no weight increase on the rear axle with the WDH connected then you have overadjusted the WDH. The WDH isn't meant to level the truck and trailer so that it looks level/unloaded, the purpose is to ensure proper weight distribution between the TV's front and rear axles and the trailer axles for safety and control. Adjusting the WDH by look, meaning adjusting it until the trailer and truck are level or back to lookling like they're unloaded, is the absolute wrong way to adjust a WDH.


Go back to the truck owner's manual and the WDH manual, one or both should have a worksheet for you to fill in various heights at various hitch states to determine how the WDH needs to be adjusted. It all centers around getting the TV front axle weight correct since that is where you maintain or lose control depending on adjustment. Overadjust and you have oversteer and will jackknife much easier, underadjust and the front will be light, twitchy, and push in corners.


Get it just right and the truck and trailer should feel more like one unit working together.

[Quail]

Great answer, well said, easy to understand. I bought my truck used and it did not have a manual, so I had no idea that info existed. It will be easy to find out what I need for a 2010 4x4 f150. I set up my hitch watching you tube videos. Thanks for the info.

[phfkef]

This may help with understanding. https://www.ajdesigner.com/apptraile...utionhitch.php

[Quail]

Trailer towing calculator

Wow. I cannot believe all the time that I have spent online researching WDH info, that I have never seen this calculator. This is perfect and exactly what I needed.

[Bluepill]

Originally Posted by Quail

Trailer towing calculator

Wow. I cannot believe all the time that I have spent online researching WDH info, that I have never seen this calculator. This is perfect and exactly what I needed.

Any time you have some time to kill, ask an RV salesman to explain it to you.

That ought to be as funny as watching folks at a boat launch ramp.

[alb2tpa]

Just plugged in the numbers based on the vehicles placard, manufacturers weights and my measurements. The only number I am over on is the tow vehicles GVWR. I added the vehicle's unladen weight, trailer tongue weight, passenger, and cargo as per instructions. I am over by 400 pounds. All other measurements are in the green.

My trucks payload is 1950 pounds. I am not over that number, yet the truck's GVWR is. The tongue weight on my toyhauler is 1200 pounds, unloaded. People (1 Passenger), fuel and cargo in the cab and pickup box is another 600/700 pounds total. 1900 pounds max. What appears to be putting me over is the WDH transferring some weight to the truck, this is automatically calculated by the program. Truck and trailer are level and it tows well. Here is my concern with this program. My tongue weight will be reduced when I load a 900 pound bike, gear and odds and ends. Total extra weight mounted rear of trailer axels will reduce tongue weight by a certain % (?) which would bring me closer to being in the green. By the way, the trailer tows smoother with the bike loaded than without. YMMV....

[DieselDrax]

Originally Posted by alb2tpa

Just plugged in the numbers based on the vehicles placard, manufacturers weights and my measurements. The only number I am over on is the tow vehicles GVWR. I added the vehicle's unladen weight, trailer tongue weight, passenger, and cargo as per instructions. I am over by 400 pounds. All other measurements are in the green.

My trucks payload is 1950 pounds. I am not over that number, yet the truck's GVWR is. The tongue weight on my toyhauler is 1200 pounds, unloaded. People (1 Passenger), fuel and cargo in the cab and pickup box is another 600/700 pounds total. 1900 pounds max. What appears to be putting me over is the WDH transferring some weight to the truck, this is automatically calculated by the program. Truck and trailer are level and it tows well. Here is my concern with this program. My tongue weight will be reduced when I load a 900 pound bike, gear and odds and ends. Total extra weight mounted rear of trailer axels will reduce tongue weight by a certain % (?) which would bring me closer to being in the green. By the way, the trailer tows smoother with the bike loaded than without. YMMV....

You need to include your (driver) weight in the calculations as well, the payload rating doesn't include any occupants and the sticker will tell you that all occupants need to be calculated. The only factory weight where the driver is included is with the max tow rating and that is for something like a 175LB driver.

Rather than mucking around with that calculator, find a local CAT scale and get your setup properly weighed. The calculator makes a lot of assumptions that may not be true, the ONLY way to know what your REAL weights are is to actually get your setup weighed. Using sticker or dry weights for the calculator is pointless and will not provide proper results.

When I weigh my combination I do the following...

First weigh: Truck and trailer hitched, WDH bars off, truck steering axle on the steer pad, drive axle on the drive pad, trailer axle(s) on the trailer pad.
Second weigh: Truck and trailer hitched, WDH bars on, axle placement the same as above
Third weigh: Truck unhitched, steer on steer pad, drive on drive pad.

With these 3 weight results you will be able to easily figure out trailer weight, trailer tongue weight, axle weights, and how much weight the WDH is transferring to the front axle and to the trailer axle(s). You'll also be able to tell at a glance if you're over any GVWR or GAWR for any of the vehicles.

You can also then take those real weights and punch them into the WDH calculator and see how accurate it is, but nothing is going to be more accurate than hitting the scales when loaded to travel.

[alb2tpa]

Yes, that was my next plan..

[Wolf26]

As was already stated, the goal is to keep the front at about the same height, connected or unconnected.

[SailorSam20500]

Cat scale weights are good. If you can find a place to do individual wheel weights, you are even better off. Individual weights will show left/right weight variation. I know RVSEF.ORG is one group that performs this service. They have been at the Goshen rally the last 2 years.

[Tom48]

Originally Posted by Quail

Great answer, well said, easy to understand. I bought my truck used and it did not have a manual, so I had no idea that info existed. It will be easy to find out what I need for a 2010 4x4 f150. I set up my hitch watching you tube videos. Thanks for the info.

Seems like a very light trailer, still smart to stabilize it with the WDH. NOW LOAD UP AND RUN IT OVER A CAT SCALE. That is the final acid test.