Front Axle Load Restoration question

[Bobbo]

Using a WDH to transfer weight back to the front wheels DOES NOT create an opportunity to add more weight to the rear.

[joeysmith]

Originally Posted by BayouBiker

Don't mind Bob he is not a fan of the Andersen hitches. He does have a valid point, the Andersen is a bit finicky, many people want their hitches to be less of a fuss. But every hitch has its quirks. His points about vehicle geometry are correct also so your setup does make the Andersen have to work that much harder. Me? I like the hitch for its performance once you have it set-up well.

Anyway do move the frame mounts back, the 29" is another guideline that is not a rigid rule. When my springs are compressed 1/4 inch I have about 3 threads showing behind the nut. The further back the mounts are the more leverage the hitch has to move weight. Another 2 inches back will give you 7% more leverage for the same tension. As long as you're moving them consider adding another chain link or two. Also look into shifting cargo forward inside the vehicle if possible. Can you put heavy stuff in the rear seat area? That is the best way to get weight on the front axle.

Thanks for flagging that I should be able to move the mounts further back. Any idea how far back would be too much? That may enable me to get more leverage to shift more weight back to the front?

Also good point about trying to place some heavy items in the rear seat area. My kids and dog are back there but I might be able to squeeze a few items there (possibly)...

Thx again for the tips.

[joeysmith]

Originally Posted by Bobbo

Using a WDH to transfer weight back to the front wheels DOES NOT create an opportunity to add more weight to the rear.

My TV has a payload limit of 1767lbs.
I am currently consuming about 1300lbs of that budget. Even though I have 467lbs of available payload, I am running into the Rear Axle Weight Rating limit of my TV (reached 4240lbs and limit is 4380lbs). This means I only have 140lbs of actual available weight I can add to my TV’s trunk area...

I was trying to shift some of the rear loading to the front so that I have more margin on my rear axle (add more items to TV trunk area).

Am I thinking about this incorrectly?

Thx.

[Profxd]

You are trying to shift load off the rear axle just so you can put more in the TV. This is misuse of a WDH. Follow the vehicle manufacturers for returning load to the front axle, they know the vehicle better than any one on this forum. For the payload you want to carry and the trailer you want to tow, your vehicle I is inadequate.

[BayouBiker]

Longer Chains don't have any downside, as long as there are no clearance issues. Also since the trailer is relatively light, consider moving some of the smaller heavy items to the trailer, as close to the axles as practical.

[joeysmith]

Originally Posted by Profxd

You are trying to shift load off the rear axle just so you can put more in the TV. This is misuse of a WDH. Follow the vehicle manufacturers for returning load to the front axle, they know the vehicle better than any one on this forum. For the payload you want to carry and the trailer you want to tow, your vehicle I is inadequate.

Thanks for the feedback.
Settling into needing to be careful of how much we can bring along on trips.

[Bill M.]

"Using a WDH to transfer weight back to the front wheels DOES NOT create an opportunity to add more weight to the rear."

Why is that?

Can you put some of the heavy items in the trailer over the wheels?

[DCPAS]

Originally Posted by Profxd

You are trying to shift load off the rear axle just so you can put more in the TV. This is misuse of a WDH. Follow the vehicle manufacturers for returning load to the front axle, they know the vehicle better than any one on this forum. For the payload you want to carry and the trailer you want to tow, your vehicle I is inadequate.

Following this logic, anyone whose rear axle rating is exceeded without weight distribution should not use weight distribution to get within rear axle limits. Is that what you are saying?

[Bobbo]

Originally Posted by Bill M.

Can you put some of the heavy items in the trailer over the wheels?

Putting weight into the trailer is an eminently acceptable solution as long as you keep in mind that the trailer also has a GVWR and axle weight and tire weight limits of its own, and affects tongue weight.

[Profxd]

Originally Posted by DCPAS

Following this logic, anyone whose rear axle rating is exceeded without weight distribution should not use weight distribution to get within rear axle limits. Is that what you are saying?

No that’s not what I’m saying. In fact the main purpose of the WDH is to keep the the rear axle within its rating but due to the addition of trailer tongue load only. If you can stay below RAWR using the TV manufacturers recommended FALR % you are good to go. If you have to go to a higher FALR % to remain below RAWR then you need to shed payload from the rear of the TV. Once you start trying to compensate for TV payload with the WDH, you put a high amount of unnecessary stress on the WDH, the TV hitch, and most importantly the trailer A-frame. The WDH is rated for a trailer tongue load and should only be used to compensate for the effect that tongue load has on the TV not it’s payload. Since so many obsess with the TV being level, they crank up the WDH tension to correct for TV payload as well as trailer tongue load. This is primary reason you so many creases and popped rivets on these trailers.

[BayouBiker]

Profxd, It is well established that addition of a weight distribution hitch and return to front axle weight transferred due to torque generated by tongue weight improves steering feel, handling performance and ride comfort, particularly when loads are well below RAWR without WD. How can you support the idea that having poorer performance is "good to go"?

Also in this thread Joey is following your advice. He is attempting to compensate for the effect the tongue load has on the TV, he is not attempting to shift payload weight to the front axle. If he were to exceed 100% FALR, then he would be shifting payload weight to the front.

Ford only provides WD tension guidance at maximum tow limits, in the same way they offer tire inflation at max payload. They do not provide tire inflation guidelines for 500 lbs under max. So the vehicle owner has to apply sound judgement in interpreting the physical principles that go into setting tire pressure limits and WD limits. With tires you reduce the pressure with load reduction to obtain optimal ride quality, wear and cornering performance. With WD you increase FALR with trailer load reduction to obtain optimal performance.

[Profxd]

Originally Posted by BayouBiker

Profxd, It is well established that addition of a weight distribution hitch and return to front axle weight transferred due to torque generated by tongue weight improves steering feel, handling performance and ride comfort, particularly when loads are well below RAWR without WD. How can you support the idea that having poorer performance is "good to go"?

Also in this thread Joey is following your advice. He is attempting to compensate for the effect the tongue load has on the TV, he is not attempting to shift payload weight to the front axle. If he were to exceed 100% FALR, then he would be shifting payload weight to the front.

Ford only provides WD tension guidance at maximum tow limits, in the same way they offer tire inflation at max payload. They do not provide tire inflation guidelines for 500 lbs under max. So the vehicle owner has to apply sound judgement in interpreting the physical principles that go into setting tire pressure limits and WD limits. With tires you reduce the pressure with load reduction to obtain optimal ride quality, wear and cornering performance. With WD you increase FALR with trailer load reduction to obtain optimal performance.

We have argued this endlessly in the past so I wont hijack this thread explaining how you are wrong about FALR. Lower tongue weights reduce the need for WDH tension and it’s far better to minimize its use when ever possible. Yes Joey is doing the right thing and not using the WDH solely as a means to increase payload.

[joeysmith]

Originally Posted by Profxd

We have argued this endlessly in the past so I wont hijack this thread explaining how you are wrong about FALR. Lower tongue weights reduce the need for WDH tension and it’s far better to minimize its use when ever possible. Yes Joey is doing the right thing and not using the WDH solely as a means to increase payload.

Thanks to u and Brian on all of the input.

My goal for this thread was to better understand how to think about the FALR specifications in the Ford docs so that I can dial in the right setup to stay safe.

At this point I am going to take it at face value (FALR of 50%) as what to target when tuning the system for safety. Given that constraint, I will keep an eye on how much weight I add to the TV and TT (with some focus on being creative in adding to the TT whenever possible).

It sounds like there may be opportunities to assume a higher FALR than 50% when not maxing out on the trailer weight but I am not yet fully understanding why I can safely ignore that constraint. This is due to my own limitations on understanding this topic.

Generally I think it is very unfortunate that there is so much complexity in this topic. Everyone here is just trying to keep safe and figure out what guidelines to adhere to. Unfortunate that the industry is unable to state the guidance more clearly and in an easily digestible form.

I am assuming that strictly adhering to the FALR guidance is the safe thing to do and that I do not need to ignore the guidance (and target a higher FALR) if my goal is to stay safe. Correct?

[BayouBiker]

The physics of towing is very complex and you will not go wrong following Ford guidance and Profxd's advice. Your ride may not be quite as comfortable, but it will be less likely to oversteer.

Trailers must have the weight biased forward of the axles to prevent sway, similar to the way caster steadies wheel tracking. But that forward biased weight must be managed by the tow vehicle rear axle. If the tow vehicle is large and heavy, no problem but if it is close to its capacity to handle lateral forces, the extra rear axle lateral demand will cause rear tire slip to be greater than front axle tire slip and the vehicle will oversteer when cornering hard. Using WD to shift load off the rear axle will just make this issue worse. This is why Ford provides guidance at max trailer capacity. As one moves below these limits, rear axle tire slip is reduced so more WD can be applied without risk of oversteer. Another way to reduce rear tire slip relative to front is to increase rear tire pressure and reduce front tire pressure.

Hope this makes sense.

[SilverBamby]

Originally Posted by BayouBiker

The Andersen hitch is easy on the trailer and gives really nice sway performance, I'd work a bit more with it before giving up.

We are looking at using the Andersen WDH for a similar weight transfer.
Looking at Spring Bars Vs Chains, as shown in picture:
To create a reaction moment of 2,500 ft-lb; the spring bars, with a lever of 20.5" will require a tension of 731 lb in each chain.
The Andersen, with a lever of 7.5" will require a tension of 1,997 lb in each chain. How much compression of the red urethane 'springs' does that translate into ?

[BayouBiker]

Hi Silverbamby, happy to help you. The illustration is interesting because it does depict in general terms how the two designs work for their primary force moments, but unfortunately the author left out the counteracting forces and in so doing created an incorrect and very deceptive comparison.

For typical applications, the required moment around the rear axle is between 1,500 and 7,000 ft lb. (The illustration shows the primary moment around the ball).

Probably too much here to describe accurately how the two designs work, but when accurate, the vertical chain model will require between 2 and 3 times the tension the horizontal model requires.

For your 16' Caravel depending on the geometry of the tow vehicle the required tension could be between 200 and 370 lb per chain. The springs will provide 500 lb of tension each without any difficulty so you will have about 1/8-3/16 compression for your setup.

[Profxd]

Originally Posted by BayouBiker

Hi Silverbamby, happy to help you. The illustration is interesting because it does depict in general terms how the two designs work for their primary force moments, but unfortunately the author left out the counteracting forces and in so doing created an incorrect and very deceptive comparison.

For typical applications, the required moment around the rear axle is between 1,500 and 7,000 ft lb. (The illustration shows the primary moment around the ball).

Probably too much here to describe accurately how the two designs work, but when accurate, the vertical chain model will require between 2 and 3 times the tension the horizontal model requires.

For your 16' Caravel depending on the geometry of the tow vehicle the required tension could be between 200 and 370 lb per chain. The springs will provide 500 lb of tension each without any difficulty so you will have about 1/8-3/16 compression for your setup.

The blind leading the blind!

[ROBERT CROSS]

Originally Posted by Profxd

The blind leading the blind!

Oh poor me, only to be smart as thee.....não!
Your taking the interwebspace all to serious...diga adeus por favor.

Bob
🇺🇸

[Profxd]

Originally Posted by ROBERT CROSS

Oh poor me, only to be smart as thee.....não!
Your taking the interwebspace all to serious...diga adeus por favor.

Bob
🇺🇸

You forgot to post the pictures of your weigh tickets in that response Bob.

[BayouBiker]

Profxd, the vertical chains cause a mostly canceling clockwise moment on the ball as well. The illustration neglected it. Talk about the other forces, why they should be ignored and lead the blind out of the corner.