Dialing in the WD with ProPride Hitch

[LvngTheStrm]

Hello all,

I'm a long time reader but first time poster. As a newbie, you all have been super helpful in getting my Airstream living off on the right foot over the past year. Thank you very much.

We are about to embark on our first several-month-long trip and would like your help in dialing in the correct amount of weight distribution on our ProPride hitch. Since I didn't have any towing experience before last year, I am not sure exactly what "feel" I am shooting for. After reading the forums, I have been playing between 6" and 7" of height on the bars. I can't really tell the difference while towing. I never have sway and the porposing quickly stops after going over bumps in the road.

I took Etta to the scales and came up with the attached numbers. I am under all of my weight limits. But I am wondering if they help tell the story on how much WD to put on the bars.

Thanks again!

[Profxd]

6 inches looks perfect.

[SteveSueMac]

Congrats on the new rig and great job with tickets and measurements.

What does your Ford 250 manual say it wants for “FALR” (front axle load restoration)? Sometimes they’ll want 100%, sometimes 50% - all depends.

You took 480# off the front axle when you connected the trailer. Since CAT scales can be off 20#, your 6” and 6.5” measures effectively get you to 50% FALR (adding back 240# of the 480# you lost from the steer axle). That may be sufficient - again refer to your truck’s user manual for specifics. They’ll tell you what FALR is recommended to ensure you’re not going to experience over or under steering. Notice with your fender measurements (not just scale weights), you lifted your front end (on a heavy 250 no less) by 1.125” - that might have some effect on steering. Whether Ford wants all, some, or none of that back will be found in your manual.

Note that at 7”, you’re pretty close to even on front and rear axles of the truck and some suggest that’s a good place to be for balance. I did that accidentally and like it [emoji3]

Another thing to notice is your truck alone (8760 on its axles) subtracted from the truck with trailer attached and no WD (9800 on both axles) approximates your tongue weight at 1040#. At 6” of WD on the jacks, you distributed 220# of the tongue weight to the steer axle of your truck, and 100# to your trailer axles - all 320# came off your drive axle on your truck. I believe (but could be wrong) that bought you 320# of cargo capacity in your truck as the full 1040# of tongue isn’t riding in your hitch...

At 7” you’ve taken 440# off your drive axle putting 320 of that to your steer axle and 120# of that to your trailer axle.

You can always keep experimenting. You definitely don’t want porpoising and you say you’re not getting much - that’s good. Others will chime in with better insights but sounds like you’re in good shape so far!

[LvngTheStrm]

Originally Posted by Profxd

6 inches looks perfect.

Profxd, thank you for the input. For my education, why do you think 6" looks perfect?

[nryn]

I am currently on a several-month-long-trip and have a 27’ Globetrotter, F-250, and ProPride. We’re about 2400 miles into the trip now and I’ve been experimenting with the hitch a lot. I wouldn’t say I was getting a lot of porpoising, but some. I called ProPride for some advice and spoke with Sean and Brent.

I ended up flipping the orientation of the plates on the hitch and coming up a good 4-5” before the trailer was level. This was not the configuration others suggested but I think they forgot to factor in the fact that my trailer has the Dexter lift kit, which raises it 3”. Raising the trailer resulted in an absolutely perfect ride. No pushing, no porpoising, and absolutely stable tracking. I’m at about 6” on the tower height, though I think I’ll come down .25”.

With the F-250 I found that dialing up the WD did not help the ride at all. More modest settings, between 5 and 6” and about 50% FALR were perfect. Other vehicles require close to 100% FALR apparently.

The scales will give you a quantitative safety reference but they won’t tell you what ride feels best. I’d say play with the WD settings, see what feels best, then go to the scales and make sure you’re within desired margins (I think that even with a 30’ you’ll be totally fine).

[Profxd]

Originally Posted by LvngTheStrm

Profxd, thank you for the input. For my education, why do you think 6" looks perfect?

As mentioned above, you’re returning 50% or less of the weight you lost to the front which is what most vehicle manufacturers set as the limit.

[Profxd]

As a FYI the root cause of porpoising is the trailer it’s self, pitching fore and aft is due to its loading/ weight distribution. The TV suspension and the WDH can aid as resistance to reduce it by ideally it should be resolved at its root cause. Another reason that centralizing trailer loading around its axles/center of gravity is so important.

[ROBERT CROSS]

Originally Posted by Profxd

As a FYI the root cause of porpoising is the trailer it’s self, pitching fore and aft is due to its loading/ weight distribution. The TV suspension and the WDH can aid as resistance to reduce it by ideally it should be resolved at its root cause. Another reason that centralizing trailer loading around its axles/center of gravity is so important.

As opposed to harmonic oscillation caused by the road surface, mostly on seamed roads, also described as 'porpoising'.

...snip
"As mentioned above, you’re returning 50% or less of the weight you lost to the front which is what most vehicle manufacturers set as the limit."

A limit or a recommendation?🤓

Many folks choose the percentage that gets the best results for their applications, are we rong? 😂


Bob
🇺🇸

[Profxd]

Since they don’t say 50-100% and understeer gradient is solely dependent on the TV and hitch weight it sure looks like a limit. Ford states “Always use” when referring to the amount of FALR for the F150. You can twist it around however you like.

[LvngTheStrm]

Originally Posted by SteveSueMac

What does your Ford 250 manual say it wants for “FALR” (front axle load restoration)? Sometimes they’ll want 100%, sometimes 50% - all depends.

Sorry for the delay in my response. Where do you find the FALR information? I have scoured my owner's manual and Ford website.

Thank you.

[nryn]

Originally Posted by LvngTheStrm

Sorry for the delay in my response. Where do you find the FALR information? I have scoured my owner's manual and Ford website.



Thank you.

Download the towing guide for your model year Ford truck. It’s a useful reference for a bunch of things.

[LvngTheStrm]

Originally Posted by nryn

Download the towing guide for your model year Ford truck. It’s a useful reference for a bunch of things.

I finally found the information toward the bottom of the 2018 Ford towing guide. They actually call it the "weight distribution correction factor" and they use it to adjust the weight distribution until you hit your targeted correction factor in reducing the amount the front fender raised after hitching to the trailer. But I suppose it can be applied to weight as well. They list the F250 correction factor to be 50% which is right between 6" and 6.5" on my ProPride towers. So, I guess my sweetspot according to the numbers is 6.25".

I am about to tow extensively so I will be able to adjust my heights and see if I can tell a difference on similar highway conditions.

Thanks again all!

[jcl]

Originally Posted by LvngTheStrm

Sorry for the delay in my response. Where do you find the FALR information? I have scoured my owner's manual and Ford website.

Thank you.

I found it in the 2019 F250 Owner's Manual, under towing.

They don't use the term FALR (front axle load restoration).

The section reads as follows:

Originally Posted by 2019 Ford F250 Owner's Manual

Weight-distributing Hitches

WARNING

Do not adjust the spring bars so that your vehicle's rear bumper is higher than before attaching the trailer. Doing so will defeat the function of the weight-distributing hitch, which may cause unpredictable handling, and could result in serious personal injury.

When hooking-up a trailer using a weight-distributing hitch, always use the following procedure:
Park the loaded vehicle, without the trailer, on a level surface.
Measure the height to the top of your vehicle's front wheel opening on the fender. This is H1.
Attach the loaded trailer to your vehicle without the weight-distributing bars connected.
Measure the height to the top of your vehicle's front wheel opening on the fender a second time. This is H2.
Install and adjust the tension in the weight-distributing bars so that the height of your vehicle's front wheel opening on the fender is approximately halfway between H1 and H2.
Check that the trailer is level or slightly nose down toward your vehicle. If not, adjust the ball height accordingly and repeat Steps 2-6.

They specify it by measuring the front fender height, and call for it to be returned to halfway, so that equates to 50% FALR if you use the more accurate scale method. The manual doesn't prescribe an upper limit for FALR, as their caution is that you shouldn't use WD to lift the rear axle higher than before you hitched up the trailer, and that correlates to a lot more than 100% FALR.

[nryn]

Originally Posted by LvngTheStrm

I am about to tow extensively so I will be able to adjust my heights and see if I can tell a difference on similar highway conditions.

We are about 2500 miles into our journey and I usually start a day of driving at 5.5” or 6” and at the first stop, move up or down by a .5” increment if necessary and “feel” dictates. I can usually tell by too much porpoising or too much “pushing” though both of those things have decreased dramatically since adjusting the nose height on the hitch receiver.

Your rig’s weight distribution may change based on tank levels, who sits where in your TV, etc. but your “sweet spot” should prove a good starting (and often ending) point for most days.

[ROBERT CROSS]

Originally Posted by Profxd

Since they don’t say 50-100% and understeer gradient is solely dependent on the TV and hitch weight it sure looks like a limit. Ford states “Always use” when referring to the amount of FALR for the F150. You can twist it around however you like.

How about this 'twist'...

Maybe the vehicle is not designed to accept anything more than 50%. If steering is unstable at 50 what are the options?

My recommendation ...CAT scales.

Bob
🇺🇸