Husky Centerline TS adjustment 32218

[Planenut]

I have the 800-1200lb bars.

Hitch installed by dealer back in November 2019 when we purchased the 2004 Classic. Seems to pull well behind my 2006 Chevy 2500HD Duramax.

Weighing included:
Full tank of Diesel plus 5 gal tank of diesel, Me, tools, solo stove, charcoal grill, charcoal, generator, gas, tent, chairs etc. (wife and dog were not with me 140 total).
Camper stocked plus 54 gals water in fresh tank.

Picture is of scale. The front axle gets 140lbs lighter when connected to the trailer. The rear axle increases by 840lbs.

I have not tried the measure fender well method as described in the manual for the hitch.

Should the front decrease any at all? Is this acceptable or do I need more tension on the bars?

Thanks

[Night owls]

I also have the same hitch set up. To be honest the last time I didn't even use it and dropped the airstream right on the ball and it towed flawless. I don't think I'll even bother anymore with it. I have a Ram 2500 diesel. Towed over 1000 miles on our last trip in all types of conditions out west, next to semis and never had sway or stability issues. Have you ever tried towing without the setup? Just curious since I noticed you also have a 3/4 ton pickup truck.

[Planenut]

I’m sure my truck would tow it fine but the dealer provided it and I’m sure it enhances the stability so I may as well use it unless I’m only towing a few miles.

[BayouBiker]

The physics and engineering demonstrate improved stability, handling and steering response for trucks and all other vehicles designed and marketed for towing medium to heavy loads. In these situations can you get by without weight return to the front axle? Sure if can live with the knowledge that your stability speeds for sway and under steer have dropped by 5-15 mph, safe cornering has dropped by 0.1-0.2 g and hard braking stopping distance from 60 mph has increased by 10-40 feet so you have a much lower margin of safety for any emergency you might encounter.

I don't know anyone who after barely avoiding a catastrophic situation would say they wish their vehicle performed more poorly. Why set yourself up for that?

Planenut, you are in the ballpark of where peak stability would be for your set-up, so many variables it is hard to know exactly where ideal is so without any other information there is little point in changing it. If steering "feels" a bit sloppy or unresponsive, you can move up to the 140 back to the front with more tension, You can also shift payload in the truck forward a bit to help further. If the set-up porpoises on highway bumps you can also add tension and shift that weight forward and increase rear tire pressure by 5 psi over recommended (this is a good idea anyway for additional stability in cornering).

Again you are in the ballpark, but experiment if you wish. Less tension won't help you with stability or handling though, and it would be very unusual to go above the 140 back to the front and see net improvements because steering and suspension design is not set-up to perform well in that scenario. If it is an improvement a much better approach would be to shift payload forward.

[Profxd]

Brian, I see you’re still spreading the manure.

[BayouBiker]

Circle where I'm wrong and bring your calculator and equations to prove it. I'll wait....

[Profxd]

Originally Posted by BayouBiker

Circle where I'm wrong and bring your calculator and equations to prove it. I'll wait....

You’ve seen the links and studies posted that prove a WDH degrades handling. Limiting WDH use by vehicle manufacturers is your proof and they all are doing it. You will find no manufacturer recommending 100% FALR on any current vehicle. because it makes things worse. Your so called “model” you quote all the time is what? What simulation software do you use? You refuse to post a screen shot of it so I’m calling you a fake. Much of the information you put out about WDH use is wrong and goes against the laws of physics.

[BayouBiker]

The links and studies show conclusively a WD hitch with sway control dramatically reduces sway tendency. They all universally show WD improves steering response and reduces under steer bringing vehicles designed for towing heavy loads much closer to ideal neutral steering and thus improving cornering speed and radius.

These are all improvements.

Sure one can get a 1970's sedan with loose sloppy suspension, and spongy tires then overload it with a trailer 4000 lb to large, and show that applying any WD while partially relieving the overloaded rear axle and tires so the vehicle will even go down the road without frying the differential or blowing out the rear tires will degrade handling. But that situation is so far from anything we see here it is beyond foolish for you to continue to harp on it.

There are some vehicles, particularly performance SUVs that don't benefit from significant WD but that is also the exception.

Manufacturers are in the business of selling vehicles, and are incentivized to report maximum trailer weight. They can't know what size trailer each customer is going to use so their guidance must fit all situations.

Tell me Profxd, for a particular competent vehicle, for optimized stability what is the relationship between ideal FALR and trailer weight? What would that imply about the guidance from a manufacturer? Hint for most real world combinations, 100% FALR and more is optimum for stability.

[Profxd]

You can increase sway damping by increasing WDH tension but in contrast handling degrades at the same time . That’s the part you don’t understand and is fact. Adding WDH tension will not improve both sway damping and handling simultaneously. That is fact and is the basis for reducing FALR. 100% FALR is proven to be less then ideal by every vehicle manufacturer that follows SAE j2807, which is all of them. Educate yourself before you give out advice to people.

[Profxd]

Let me explain in a way even you can understand.
Scenario 1
The mass of the tongue is added to the tow vehicle. Since tire grip(cornering stiffness) is not proportional to the amount of mass added to them, the result is the degradation of tow vehicle handling.
Scenario 2
With tongue mass added to the tow vehicle you now add the WDH. When tension is added you reduce the amount of grip(cornering stiffness) at the tire without changing the amount of mass. Unfortunately the WDH doesn’t move and/or relocate mass so the gap between the mass and tire grip (cornering stiffness)further widens. This does not improve handling. It in fact further reduces the combinations ability to handle even more.

Brian do you understand the principles of a mass at a velocity? I don’t think you do.

[BayouBiker]

If a vehicle under steers at speed for a properly designed highway or off ramp curve and the owner makes an adjustment that reduces under steer gradient, maximum cornering speed and handling stability increases. Rational people would describe this as an improvement, not degradation.

Additional WD tension will continue to improve handling stability and max cornering speed until the vehicle crosses optimal neutral steering and experiences over steer.

You predictably failed to answer the questions posed so I will. Ideal front axle load return is inversely proportional to trailer weight. Therefore as one approaches max towing capacity the optimal amount of FALR is reduced. My setup has an advertised max towing capacity of over 17,000 lbs but a practical limit of 15,000 lb. At that weight optimal FALR is about 65%. But I don't tow 15,000 lbs, I am towing 7,100 and at that weight, optimal FALR is 100% with forward biased payload distribution.

At 17,000 lbs, optimal FALR drops further and had the manufacture provided FALR guidance it would have been about 50% max. However that only applies to max tow weight. See how this works?

As to your scenarios they are confusing since tongue weight is a torque generated load with very little mass associated with that load. I will presume you meant load and not mass. Scenario one applies to a vehicle who's suspension and steering is optimized for the initial configuration. A pickup will initially experience improved handing (higher turning velocity) with modest additional payload. If the load is due to a trailer, the situation gets more complex and will depend on trailer inertial moments.

Your description of Scenario Two is convoluted and incorrect. I described the results much more accurately in my initial comments. Here is an accurate technical description:

Tension restores load to the front axle increasing corning stiffness of the front axle decreasing the slip angle for any particular corner and speed. It partially unloads the rear axle, increasing rear tire slip angle. If rear slip angle is less than front the vehicle under steers, if it is greater the vehicle over steers. Optimal handling occurs when slip angles are the same (4 wheel slide). Thus the net effect of WD tension will depend on the particulars of the configuration. Further complicating this is the effect WD tension has on inside rear tire loading while cornering. A properly set up hitch will maintain load on the inner rear tire increasing rear axle cornering stiffness.

Profxd, my grades in physics, statics, and chemistry were top of my class of several thousand students at U of W. I require a refresher every once in a while but I can still keep up.

[Profxd]

Originally Posted by BayouBiker

If a vehicle under steers at speed for a properly designed highway or off ramp curve and the owner makes an adjustment that reduces under steer gradient, maximum cornering speed and handling stability increases. Rational people would describe this as an improvement, not degradation.

Additional WD tension will continue to improve handling stability and max cornering speed until the vehicle crosses optimal neutral steering and experiences over steer.

You predictably failed to answer the questions posed so I will. Ideal front axle load return is inversely proportional to trailer weight. Therefore as one approaches max towing capacity the optimal amount of FALR is reduced. My setup has an advertised max towing capacity of over 17,000 lbs but a practical limit of 15,000 lb. At that weight optimal FALR is about 65%. But I don't tow 15,000 lbs, I am towing 7,100 and at that weight, optimal FALR is 100% with forward biased payload distribution.

At 17,000 lbs, optimal FALR drops further and had the manufacture provided FALR guidance it would have been about 50% max. However that only applies to max tow weight. See how this works?

As to your scenarios they are confusing since tongue weight is a torque generated load with very little mass associated with that load. I will presume you meant load and not mass. Scenario one applies to a vehicle who's suspension and steering is optimized for the initial configuration. A pickup will initially experience improved handing (higher turning velocity) with modest additional payload. If the load is due to a trailer, the situation gets more complex and will depend on trailer inertial moments.

Your description of Scenario Two is convoluted and incorrect. I described the results much more accurately in my initial comments. Here is an accurate technical description:

Tension restores load to the front axle increasing corning stiffness of the front axle decreasing the slip angle for any particular corner and speed. It partially unloads the rear axle, increasing rear tire slip angle. If rear slip angle is less than front the vehicle under steers, if it is greater the vehicle over steers. Optimal handling occurs when slip angles are the same (4 wheel slide). Thus the net effect of WD tension will depend on the particulars of the configuration. Further complicating this is the effect WD tension has on inside rear tire loading while cornering. A properly set up hitch will maintain load on the inner rear tire increasing rear axle cornering stiffness.

Profxd, my grades in physics, statics, and chemistry were top of my class of several thousand students at U of W. I require a refresher every once in a while but I can still keep up.

Again your off into the weeds. Reducing Understeer until you hit neutral is not improving handling while towing. Neutral is right at the edge of instability, handling degrades as you reduce Understeer. If you can’t grasp the facts and physics all I can recommend is that forums members should be cautious taking advice on WDH setup from you. You talk a good game but based on the paragraph above it’s obvious you don’t really understand.

[BayouBiker]

A simple web search on optimal cornering and neutral steering will clear this up. I urge anyone who is curious to do so. Also over steer is not so much unstable as it is undesirable because most novice drivers don't respond to it particularly well. This is not a question of physics, as physics provides the means to know the under steer gradient, but physics places no judgment on that number. The concept in debate is at what point is handling optimized, and if one moves closer to that point does that imply improvement or degradation. The general consensus in the industry is optimization is the point where time around a particular curve is minimized. So tell me profxd, where does optimization occur if not at neutral steering? Then tell me why does the SAE include neutral as a pass in their handling test?

[Profxd]

Originally Posted by BayouBiker

A simple web search on optimal cornering and neutral steering will clear this up. I urge anyone who is curious to do so. Also over steer is not so much unstable as it is undesirable because most novice drivers don't respond to it particularly well. This is not a question of physics, as physics provides the means to know the under steer gradient, but physics places no judgment on that number. The concept in debate is at what point is handling optimized, and if one moves closer to that point does that imply improvement or degradation. The general consensus in the industry is optimization is the point where time around a particular curve is minimized. So tell me profxd, where does optimization occur if not at neutral steering? Then tell me why does the SAE include neutral as a pass in their handling test?

Unlike a single vehicle, a vehicle trailer combination that has a Understeer Gradient value that is negative (oversteer) is unstable. You must consider how much lateral acceleration the vehicle is subject to as well. A VTC could have a positive value (Understeer) at 0.1g lateral acceleration and a negative value (oversteer) at 0.3g lateral acceleration. The established standard for UG when towing is to maintain at least a neutral 0 value at 0.3g lateral acceleration. Increasing tension on the WDH causes the VTC to reach negative (oversteer) at a lower lateral acceleration value. This why the vehicle manufacturers must limit FALR, otherwise they will not be able to meet the minimum 0 neutral steer requirement at 0.3g lateral acceleration. As with a single vehicle, the VTC also has a forward straight ahead critical speed associated with it in a oversteer state.

[BayouBiker]

More accurately it is undesirable. It's "unstable" in the sense that with no active corrective steering response, over steer tends to increase yaw angle, increasing lateral force which induces more tire slip and more over steer. It feeds on itself leading to a jackknife. Experienced drivers will compensate and prevent jackknife.

You are correct that under steer gradient is a function of lateral acceleration and therefore it is quite sensitive to towing weight as was previously addressed. But the manufacturer provides guidance for the worst case (max towing capacity) where optimal FALR is least. Most of us tow well below max combined weight limits where optimal FALR is much much greater than manufacturer guidance. The complex variable nature of optimal FLAR vs. trailer weight is one reason FLAR guidance tends to be vague.

[Lafitte]

Are y'all competing for post counts ?

[BayouBiker]

IDK, y'all trying to get a smart *ss award?

[Profxd]

Originally Posted by Lafitte

Are y'all competing for post counts ?

Though he’s the self appointed expert on towing dynamics on this forum he still can’t quite grasp the principles of Understeer Gradient. Someone needs to call out the misinformation he provides to unknowing forum members.

[BayouBiker]

Google for a technical description of under steer gradient and steering dynamics. You'll find no inconsistencies or misinformation in any of my posts. If you find something that looks questionable, post it here, and ask me about it. I'll wait....

[Profxd]

Right from the post above and goes against what the automotive industry, the SAE, and others that understand towing dynamics have proven as fact.

“Additional WD tension will continue to improve handling stability and max cornering speed until the vehicle crosses optimal neutral steering and experiences over steer. “