Bent A Frame?

[AlbertF]

Originally Posted by ROBERT CROSS

Thank's...that 'splains it. [emoji106]

If you are comfortable with it, go camping.



I have never gone with more than unloaded FA weight, I may try and see how our rig reacts...I still am unclear on the recommendation and why works well for you. [emoji848]



Bob

[emoji631]

I think there is a fundamental difference in how pickups are set up, and how cars are set up. An SUV is like a car, with softer rear springs for a good ride, rather than load carrying capability.

Towing with a car the way I have since 2006, getting the right load on the front tires is very important, the way that is described above. I also have the idea that getting the front tires to share the load means that they also help to control yaw forces from the trailer, enhancing stability.

I would also say that pickups are designed to drive reasonably well with more load on the rear, while cars are best balanced.

The wear issue is really just break-in on a new WDH. I had to adjust after about 4,000 miles of use after a brief sway event in a 40 mph crosswind, the only sway event I’ve experienced in about 28,000 miles of towing.

I believe CanAm recommends higher capacity torsion bars with cars than with pickups. An empty 500 lb or more tongue weight warrants 1000 lb bars. I still use 1000 lb bars with a 22FB. Overkill on an empty trailer, but comfortable once it’s loaded. The tapered Eaz-Lift bars are progressive, not stiff initially.

[ROBERT CROSS]

FWIW....We have a 2500 Suburban 8.1, not a wimpy softly sprung SUV, or a performance leaning short WB Import.

Bob
🇺🇸

[uncle_bob]

Hi

The recommended weight distribution ( front restoration ) is only a starting point. There is absolutely no guarantee at all it is the best handling setup for a given rig. It's nothing more than a random guess at what to do. You have to go from there in steps to see what is best. Unless you have a setup that is to close to the limits ( = get a new TV now !!) you have room to change things a bit.

Bob

[AlbertF]

Originally Posted by ROBERT CROSS

FWIW....We have a 2500 Suburban 8.1, not a wimpy softly sprung SUV, or a performance leaning short WB Import.



Bob

[emoji631]

Interesting. Would you say the rear axle setup is just as stiff as a ¾ ton pickup? The half-ton versions, including the Tahoes, certainly seem softer to me which makes sense given that their main purpose is transporting people.

The 2,000 pound spread between GVWR and combined GAWRs is remarkable. You can carry an enormous amount of tongue weight without WDH if you want to.

[uncle_bob]

Originally Posted by AlbertF

Interesting. Would you say the rear axle setup is just as stiff as a ¾ ton pickup? The half-ton versions, including the Tahoes, certainly seem softer to me which makes sense given that their main purpose is transporting people.

The 2,000 pound spread between GVWR and combined GAWRs is remarkable. You can carry an enormous amount of tongue weight without WDH if you want to.

Hi

Be careful .... the axles each have a rating as well. 2,000 pounds "spare" on the front axle and zero on the rear still comes out to 2,000. Indeed nobody would ever design a vehicle quite that way. However You might be a bit surprised at how much actually *is* front axle.

Bob

[franklyfrank]

Originally Posted by ROBERT CROSS

Really?....got any bowed A frame pictures? Don't recall any myself.

Receivers flexed upward...on the TV?

Bob
🇺🇸

I don't believe you can bend an A frame by setting the WD which transfers trough the suspension. Only if there is a crack at the weld which would be very easy to find. It is not under the belly pan.

[ROBERT CROSS]

Originally Posted by AlbertF

Interesting. Would you say the rear axle setup is just as stiff as a ¾ ton pickup? The half-ton versions, including the Tahoes, certainly seem softer to me which makes sense given that their main purpose is transporting people.

The 2,000 pound spread between GVWR and combined GAWRs is remarkable. You can carry an enormous amount of tongue weight without WDH if you want to.

Point one...I wouldn't say... I don't tow with late model a P/U nor would I.

Point two...I could, but wouldn't. Excess weight taken from the steering axle makes for white knuckle Streaming.

POI...the 'on-the-ballers' with big 'trucks' say go for it. 😂

Bob
🇺🇸

[guskmg]

What happened to the old rule of thumb: a third of the weight transferred to the TV front axle, a third to the rear axle, and a third to the TT axles? That is a safe start then adjust according to steering and general handling feel. It is true that cars, SUVs, station wagons, and pickups all have different ratios of front to rear weight distribution. These are engineering compromises so the vehicle center of gravity stays in a safe range unloaded to loaded. Too much axle weight makes steering difficult and wears front end componts. Too little front end weight makes for too sensitive steering (loose) or none if carried to extremes. Too much TT axle weight compared to the TV causes the tail to wag the dog. This can be mitigated with a trapezoid design such as Hensley and ProPride, however, at some point the TV and TT center of gravities will be so far out of range that dynamic oscillation will develop and become unmanageable in short order. Think of the Narrowa Bridge in Washington, State. It destroyed itself in the wind due to dynamoc instability. Load wisely, go to the scales, adjust for best feel. and enjoy the trip.
guskmg

[uncle_bob]

Originally Posted by guskmg

What happened to the old rule of thumb: a third of the weight transferred to the TV front axle, a third to the rear axle, and a third to the TT axles? That is a safe start then adjust according to steering and general handling feel. It is true that cars, SUVs, station wagons, and pickups all have different ratios of front to rear weight distribution. These are engineering compromises so the vehicle center of gravity stays in a safe range unloaded to loaded. Too much axle weight makes steering difficult and wears front end componts. Too little front end weight makes for too sensitive steering (loose) or none if carried to extremes. Too much TT axle weight compared to the TV causes the tail to wag the dog. This can be mitigated with a trapezoid design such as Hensley and ProPride, however, at some point the TV and TT center of gravities will be so far out of range that dynamic oscillation will develop and become unmanageable in short order. Think of the Narrowa Bridge in Washington, State. It destroyed itself in the wind due to dynamoc instability. Load wisely, go to the scales, adjust for best feel. and enjoy the trip.
guskmg

Hi

You are getting a couple of things crossed up here.

Playing with WD only impacts what goes onto the front vs rear axle of the trailer. It does not move any mass around in doing so. It's just a spring and it flexes the connection between the trailer and the truck. Anything it does to the trailer is a side effect. You have only one setting ( one variable to play with).

Sway is related to mass and the distribution of mass in the trailer. WD by it's self does not help that. The distribution of stuff is still where it was. If things are unstable without WD, they will still be unstable with WD. That's all talking about oscillation related instability. It's one of about six very different things that gets called sway here on the forum.

Bob