2022 Ram 2500 Hitch Drop Needed

[jcl]

Originally Posted by Andy543

Sure. As you know, when an object is travelling in a straight line, it wants to continue travelling in a straight line. It takes a force to make it change its course. In a trailer towing arrangement, when the truck tries to make the trailer go around a turn, this presents itself as a horizontal force on the tow vehicle's hitch ball. This force acts as a lever that, if sufficient, can push the back of the truck sideways, causing it to jackknife. WD and sway control hitches make the problem worse by extending the lever arm from the truck's rear axle to the hitch point. Some hitches extend it by 1' or more. Furthermore, the horizontal force is increased by the weight of the hitch, acting as a g-force on the hitch as the trailer goes around the turn. Now, consider the force that resists the g-force of the trailer pushing on the hitch ball. That would be the friction force of the truck's rear tires grabbing on the pavement. WD hitches lower this friction force by lifting up the rear of the truck with the spring bars. So, if you try to go around a turn fast enough, such as in an accident avoidance situation, not only does the horizontal force increase, but the resisting friction force decreases, causing the rig to jackknife.

PM me and I'll send you a link to the classic engineering study that explains this all with a thorough mathematical analysis, confirmed with extensive test results.

You have focused on the reduced traction of the rear tires of the tow vehicle due to applying WD equipment. If you apply WD properly, you will still have great traction, just don't apply so much WD that you lift the rear tires off the pavement. Many tow vehicles are operating at the upper end of the rear axle weight limit when loaded for travel and hitched up, so lifting the rear tires clear of the pavement isn't a real concern.

More important is the reduced traction of the front tires of the tow vehicle due to connecting a bumper pull hitch trailer and not applying any WD. This is classic understeer, but as you say, as long as you don't try and turn your steering wheel, which you refer to as not going around corners, you should be fine, lol.

The engineering study that you have previously referenced actually showed this mathematically. Modern vehicles are set up to understeer. Applying WD helped by reducing that understeer, and the test vehicles didn't get into oversteer with WD properly set. The study is available for those who want to see for themselves. We should qualify that it is 50 years old (classic?) and thus uses vehicles from the early 1970s, with bias ply tires. Cornering traction at the limit will not be representative of modern vehicles with radial ply tires.

Prudent operators know the benefits of using WD equipment. So do truck manufacturers, who typically specific that the use of WD equipment is required to achieve their published tow ratings (your RAM 2500/3500 for example)

[jcl]

Originally Posted by Andy543

You don't have to choose one or the other. If your tow vehicle is large enough, you don't need a sway control hitch, and you will also have the maximum safety in a tight turn.

You could phrase that another way. Recognizing that most here have tow vehicles up to and including 2500/3500 series trucks, if you trailer is small enough, you don't need a weight distributing hitch. 5000 lbs trailer weight is a typical maximum per the truck manufacturers.

[AlbertF]

Originally Posted by Andy543

PM me and I'll send you a link to the classic engineering study that explains this all with a thorough mathematical analysis, confirmed with extensive test results.

Thank you for sharing the link. I recall seeing something like this in the past; I think it was a different study, but there were similarities, including 0.3 g lateral acceleration as a proxy for defining a “stable” combination.

The effective conclusion seems to be that we should all be towing with poor-handling vehicles with heavy understeer because they allow for greater cornering speed (ideally up to 0.3 g according to the researchers) before the understeer transitions to oversteer. The other conclusion – don’t put too much tension on the bars of the WDH so that you keep weight on the back tires to ensure greater traction in a turn.

The test trailer was a 31’ Airstream from the mid-1970s. The primary test car was a 1973 Chevrolet Caprice station wagon – softly suspended with a very long rear overhang. Despite the grainy photos, it was clear that the hitch ball was close to vertical.

This points to a critical deficiency in this work relative to the work done by Andy Thomson. In addition to balanced front to rear loading of the tow vehicle axles, Andy recommends a 15 degree rearward cant of the ball, and he has explained how this aids straight-line stability and how it ensures greater stability and more even side to side loading in turns. He wrote an article entitled “Setting Your Torsion Bars” on the SAE approach to hitch setup (which appears consistent with this 1977 study) and stated the following:

“The second SAE handling test is a steady state circle around the skid pad. As the G force increases, the tow vehicle will start to go outside the circle, and either the back end will break loose (oversteer) or the front tires will plow (understeer). Car companies like understeer. Now my own testing of this is takes place on a delightful exit ramp with a downhill decreasing radius turn. What I find with my combinations is that the front end will almost always start to plow first, but if you overcorrect (which is the tendency) then the back end will come around. If you just let it drift a little, it pretty smoothly continues around the ramp drifting a slight bit off line. In the SAE test they kept breaking the back end loose, which is to be expected since their hitch set up was unloading the inside rear tire and overloading the outside rear.”

He goes on to explain that he hitched an older 34’ Airstream to a half-ton pickup, and with his approach he discovered that the trailer would slide sideways on 6 tires before the truck broke loose. He didn’t measure lateral acceleration, but that must have been more than 0.3 g.

Andy also points out that an accident in a low speed turn is rare and a lot less likely to be serious than crash resulting from instability at highway speeds.

So while these old studies are interesting and reveal lots of data, they are limited. In the interest of science, they should be repeated with a range of contemporary vehicles from small sedans to large pickups, and with a range of WDH types and setups. Until that happens, I’ll stick with what Andy has taught me from his real world experience and prioritize straight-line stability at highway speeds over lateral acceleration in low speed turns.

[Andy543]

Originally Posted by AlbertF

In the interest of science, they should be repeated with a range of contemporary vehicles from small sedans to large pickups, and with a range of WDH types and setups.

I certainly agree with you on this. I'd like to see hitch manufacturers certify their performance on a test track. The 300' circle seems like an agreeable method. Try it once with the hitch, and then try it without the hitch. I would think that if their hitches could come out ahead in this test they would be bragging about it quite loudly. Alas, their silence is deafening.

[jcl]

Originally Posted by Andy543

I certainly agree with you on this. I'd like to see hitch manufacturers certify their performance on a test track. The 300' circle seems like an agreeable method. Try it once with the hitch, and then try it without the hitch. I would think that if their hitches could come out ahead in this test they would be bragging about it quite loudly. Alas, their silence is deafening.

IMO there are too many variables in each setup for hitch manufacturers to do that. Who should be able to do it is a well trained dealer of hitches and WD equipment. There is only one such dealer that I know of that routinely tests their combinations on a skid pad or test track. And they have shared their results here, at Airstream events, and in publications. Often we hear dismissive comments from those who don't believe the results. But not withstanding that, dealers are the first party to see the tow vehicle, trailer, and hitch as a combination. Any company attempting to certify performance of their towing products before that stage, or for other than the specific tow vehicle, trailer, and equipment they are testing, is shooting in the dark.

[thewarden]

Originally Posted by Andy543

You don't have to choose one or the other. If your tow vehicle is large enough, you don't need a sway control hitch, and you will also have the maximum safety in a tight turn.

This is incorrect. The size of the tow vehicle has nothing to do with preventing or adding to trailer sway. A 30ft travel trailer towed by a Kenworth can have trailer sway. Wind, road conditions, passing semi-trucks, sudden braking, and improper trailer loading cause trailer sway, not the size of the tow vehicle.

[Andy543]

Originally Posted by thewarden

This is incorrect. The size of the tow vehicle has nothing to do with preventing or adding to trailer sway. A 30ft travel trailer towed by a Kenworth can have trailer sway. Wind, road conditions, passing semi-trucks, sudden braking, and improper trailer loading cause trailer sway, not the size of the tow vehicle.

Technically, that may be true, but a larger tow vehicle can control the sway so you don't feel it and so it doesn't cause an accident. When a swaying trailer imparts a horizontal force on the hitch, it can toss a small tow vehicle around, but it can't toss a large one around. The large tow vehicle is safe, where the small one isn't.

[ROBERT CROSS]

Originally Posted by Andy543

Technically, that may be true, but a larger tow vehicle can control the sway so you don't feel it and so it doesn't cause an accident. When a swaying trailer imparts a horizontal force on the hitch, it can toss a small tow vehicle around, but it can't toss a large one around. The large tow vehicle is safe, where the small one isn't.

More...😂😂😂😂😂

So what you're saying is... The AS can be on its side in the ditch but if you didn't feel it it wasn't SWAYING.

Bob
😂

[jcl]

Originally Posted by Andy543

Technically, that may be true, but a larger tow vehicle can control the sway so you don't feel it and so it doesn't cause an accident. When a swaying trailer imparts a horizontal force on the hitch, it can toss a small tow vehicle around, but it can't toss a large one around. The large tow vehicle is safe, where the small one isn't.

The hitch ball allows free rotation, so it can't control sway. If you want to control sway, you need a pivot point projection hitch.

And what Bob said.

[wdhayes]

Originally Posted by turbosixx

Hello,
Looks like we will be purchasing a 2011 Classic Limited 30. The AS is in Dallas and I'm south of Houston. We have a 2022 Ram 2500 4x4 Cummins. I want to take some time to decide on which hitch set up I go with, so for now I want to pull it home on the ball.
Since I don't have the truck and trailer together, does someone know what amount of drop I will need for the trailer to be level.

Thanks

We own a 2024 Classic 30 foot with the Blue Ox hitch, purchased in Dallas. Just traded for a 2024 Ram 2500 4 x 4 Cummins, it required a 12-inch drop-shank.

[Rey.A]

I just happened to see this article describing drop hitches. Toward the end, there is a YouTube video showing how to determine what size drop you need. You may need to have the dealer measure the distance from the ground to the bottom of the coupler for you. Good luck!

[H.P. Inxs]

I have the same truck. Although our AS is older.
This is what I went with.

https://www.summitracing.com/parts/cht-17132?seid=srese1&ppckw=pmax-trailering-towing-winches&gclid=CjwKCAjwnv-vBhBdEiwABCYQA2ygc4Ncf5KPUYyA20c4d2Q46e_ZDHrpdsAm4 fXxNaEP8IPd2ukkhhoCQ0QQAvD_BwE

Swaped over my old Curt WDH parts.
Also cut off 2 inches off the bottom of the drop.
Love the 2.5" shank, no need for the 2-2.5 adapter.

Go through all of the hitch set up and you will be very happy.

[booma]

We have a 2015 Ram 2500 and a 2001 30’ Classic w/ S/O.
Our tongue weight is a bit higher (slide out) at 1100#
Trailer comes in at 9870#.
I just measure mine.
We have about a 2” drop from centerline of receiver to center of ball.
For a relatively quick run that should get you there OK.
Might think about an adjustable height receiver with double ball option.
I use the 2” for my utility trailer and flip it over to the 2 5/16 if I am moving the rig a short distance or around town

[tjdonahoe]

17 3/4 ram 6.7. My call is 23” high. My trailer is a 13 31’ classic with a 3” lift. Perfect setup with Reese duel cam hitch

[Boxite]

Originally Posted by Andy543

You don't have to choose one or the other. If your tow vehicle is large enough, you don't need a sway control hitch, and you will also have the maximum safety in a tight turn.

Sway is a different animal than load distribution….although they interact while manuevering.

As I’ve said previously (and with conviction) a WDH is a “band aid” for trailers too large for TVs too small. WDH’s resist horizontal change…but they also resist vertical change..and add stress to trailer axles, TV’s and hitches, in swales, crossing RR-grades, dips, etc etc.

But, If that big-trailer/small tv is the owner’s situation… a WDH, with sway-control… is a good thing to have.

I’m a happy “on the ball” kind of guy…but also enjoy a friction anti-sway bar.

[turbosixx]

Well I picked up the camper buttt with a different truck. Long story short, I'm a GM guy and wasn't feeling the Dodge. No offense to Dodge folks. Traded it in on a 2024 Sierra 2500HD. Love the truck.

I measured the top of the receiver tube and it was 24". JJTX replied that the AS is 19" and doing the math makes 5". I bought a 6" adjustable drop so I would have a little wiggle room and for other trailers. 5" was the best by eyeball since I forgot my tape measure and level.

Traveled home about 310 miles at times cruising up to 70, very little interstate. I only experienced real sway a couple of times. Worst was going through a turn on a very bumpy overpass doing 60. Each time it settled down without me doing anything. If I understand it correctly, these trucks have some sway control built in (stablitrak w/ trailer sway control).

AS was dry so I'd like to get it weighed once it's loaded, get some numbers and figure out what I need for WD and/or sway control.
I'm learning a lot reading all the replies. Thanks for all the information.