30' Classic real world hitch weight

[dznf0g]

Originally Posted by earstreaming

curious to know what model sherline are you using? Thanks in advance!

lm2000

[uncle_bob]

Hi

The gotcha is that these bars are not a precision item. They interact with both the trailer and the truck suspension. The magic web worksheet does not take either set of factors into account. On the truck side the springs change rate with load, so it also interacts with the load in the truck.

To do the sort of detailed analysis one would do in other areas, you need a *lot* more data than you can get on the trailer, the truck, or the hitch. You also would need to do some vehicle dynamics modeling.

Fine tuning the "is it 936 vs 938 pounds" part seems like it's more closely defining the problem. There's still a lot missing ....

Bob

[mikeinca]

Originally Posted by uncle_bob

Hi

The gotcha is that these bars are not a precision item. They interact with both the trailer and the truck suspension. The magic web worksheet does not take either set of factors into account. On the truck side the springs change rate with load, so it also interacts with the load in the truck.

To do the sort of detailed analysis one would do in other areas, you need a *lot* more data than you can get on the trailer, the truck, or the hitch. You also would need to do some vehicle dynamics modeling.

Fine tuning the "is it 936 vs 938 pounds" part seems like it's more closely defining the problem. There's still a lot missing ....

Bob

I'm not so interested in fine tuning the difference between "936 vs 938 pounds" as I am between 886# (factory spec) and 1050# (what some people have measured).

Respectfully, you state the obvious. I realize there are parameters not covered by the web spreadsheet, but it is a starting point which reflects the hitch manufacturer's recommendations and can be followed up by talking with them directly, which I've done.

I'm not sure what you're suggesting. Since I can't get every last bit of potentially relevant data, should I just ignore the data I can get and wing it on hitch setup because it makes no difference which one I use? If that's the case, perhaps we should close down all the discussion about hitches and the effect of tension bar settings on trailer ride and structural integrity since they're apparently a colossal waste of time and bandwidth.

[james.mileur]

Luke! Luke (mikeinca), turn back; you're going toward the dark side . . . Keep at it, keep asking, lean into it, it is just the beginning of the adventure [emoji6]

[slowmover]

A spreadsheet hasn't yet delivered "best tow vehicle."

As Uncle Bob indicates (in re TW) the situation has more to it.

TW is a measurement made at rest. Static, not dynamic. It's a place-filler.

So,

might make another run at it: Assume loaded to .80 of TT GVWR and TW at .125 of that.

Or,

that a 1k TW leaves a little less than 400-lbs on each TV axle after WD tensioned.

The design of the TV means more than the less-than-useful distraction of playing with a spreadsheet. What's best spec for solo, is the question which matters (if one is serious about safety).

400/lbs per TV axle is the territory of cars, minivans and SUVs. It's a non-starter, therefore.

Hitch lash-up is where numbers come in. 90-95% get it wrong. If one wants to play with numbers, weight values acquired via CAT Scale are the starting point. Rough it in at home using Thomsons method of setting the hitch, and then tweak after the three pass scale procedure.

While this doesn't address getting ball closest to bumper, reinforcing receiver, etc, it's more than most will do.

.

[james.mileur]

[QUOTE=slowmover;2015409]

400/lbs per TV axle is the territory of cars, minivans and SUVs. It's a non-starter, therefore.

.[QUOTE]

You mean, non starter to consider them as TV since +400 lbs on each axle will be too close to safety margin for their payload capability?

[slowmover]

[QUOTE=james.mileur;2015483][QUOTE=slowmover;2015409]

400/lbs per TV axle is the territory of cars, minivans and SUVs. It's a non-starter, therefore.

.

You mean, non starter to consider them as TV since +400 lbs on each axle will be too close to safety margin for their payload capability?

More goes into TV selection by class than this.

Specifically, one isn't limited to a pickup. A basic mistake. A wide range of TV types can handle this. And have done so for over fifty years.

[james.mileur]

Got that for don't need a pick up, but, therefore non starter for what?

[mikeinca]

Originally Posted by slowmover

A spreadsheet hasn't yet delivered "best tow vehicle."

As Uncle Bob indicates (in re TW) the situation has more to it.

TW is a measurement made at rest. Static, not dynamic. It's a place-filler.

So,

might make another run at it: Assume loaded to .80 of TT GVWR and TW at .125 of that.

Do you mean 1.25, not .125?

Originally Posted by slowmover

Or,

that a 1k TW leaves a little less than 400-lbs on each TV axle after WD tensioned.

The design of the TV means more than the less-than-useful distraction of playing with a spreadsheet. What's best spec for solo, is the question which matters (if one is serious about safety).

400/lbs per TV axle is the territory of cars, minivans and SUVs. It's a non-starter, therefore.

Hitch lash-up is where numbers come in. 90-95% get it wrong. If one wants to play with numbers, weight values acquired via CAT Scale are the starting point. Rough it in at home using Thomsons method of setting the hitch, and then tweak after the three pass scale procedure.

While this doesn't address getting ball closest to bumper, reinforcing receiver, etc, it's more than most will do.

.

No doubt the design of the TV is important, but in my case the TV has already been decided (2017 F250 diesel) and I have no way of incorporating the various parameters of that truck into a decision about whether to install a 10000/1000# Equalizer hitch or a 12000/1200# Equalizer hitch.

Based on AS factory spec for tongue weight, TT GVWR, and anticipated cargo load in the truck, Equalizer says to use the 12000/1200. The dealer wants to install a 12000/1200 when the trailer arrives. Some folks on the forum use a 12000/1200. But others recommend a 10000/1000. So I'm trying to do my due diligence and work it out for myself as best I can. Getting input on actual tongue weights that people have measured is helpful since I don't have a 30' Classic I can weigh myself.

I'm not trying to do a detailed engineering analysis of the TV-TT interface, I just wanted to get a general idea of how far off factory specs on tongue weight were from real life TW's. But, I don't suppose I should be surprised that this thread has gone a bit into the weeds; discussing hitch setups on an AS forum is apparently a lot like discussing engine break-in procedures on the Porsche forum.

[mikeinca]

Originally Posted by james.mileur

Luke! Luke (mikeinca), turn back; you're going toward the dark side . . . Keep at it, keep asking, lean into it, it is just the beginning of the adventure [emoji6]

Thank you, Obi Wan (james), but my tongue was firmly in cheek. I'll never turn to the dark side!

Mike

[slowmover]

Originally Posted by james.mileur

Got that for don't need a pick up, but, therefore non starter for what?

TW is literally irrelevant in this case. .

1000-lb TW. Yes. 1.25. Middle of road number.

[mikeinca]

Originally Posted by slowmover

TW is literally irrelevant in this case. .

1000-lb TW. Yes. 1.25. Middle of road number.

Could you explain further? Literally irrelevant in *what* case?

With regard to my specific question about an Equalizer hitch, are you really saying that whether the TW is 750#, or 1000#, or 1500#, or whatever, that the spec of the hitch or the tension bars is irrelevant?

[slowmover]

Originally Posted by mikeinca

Could you explain further? Literally irrelevant in *what* case?

With regard to my specific question about an Equalizer hitch, are you really saying that whether the TW is 750#, or 1000#, or 1500#, or whatever, that the spec of the hitch or the tension bars is irrelevant?

The load on the truck is too little to matter after WD is set for FALR. Plenty of cars, vans, SUVs can tow that thing.

What bars you want to use to accomplish that is up to you. There are those who think the EQ a decent hitch. I'm not among them. Try that dedicated thread.

"Payload" is like chasing leaves in a wind. Can't collect many, the effort is not worth it.

TW isn't the same as a load in the bed. It isn't a "weight" problem, per se, it's a matter of adequate distribution via leverage of that force over the whole rig. Need to come at it from the right direction.

As before: TW is a placeholder. Static value of a lever end while at rest.

Going down the road, it changes. We used to aim at distributing TW via the One Third Rule: 1/3 to Steer Axle, 1/3 to Drive Axle, and 1/3 to TT axles. (Where a TV discrepancy existed, it was preferable to have 10% more on Drive Axle).

We also had custom hitch receivers built which spread the spring force over a longer portion of the TV. At the rear crossmember, and again at a piece of steel at the rear axle with the hitch tube running the full distance. With diagonal bracing. In many cases, the automakers supplied tech drawings.

It's easier as one applies LESS leverage with this type of receiver in order to accomplish the same end.

The hitch head wasn't bolted up, it was custom-welded for that application. Proper tilt, mainly. Control. Into and out of turns. (Don't want inside TV Drive Axle tire to lift).

Installed a Reese Dual Cam (the original and still best integrated anti-sway ordinary hitch; since superseded by the VPP class) and adjust. Greatest spring bar bend ensured greatest return-to-center force.

As to "payload" in general -- and to include TW -- need a TARE weight. Driver, max fuel and gear permanently aboard. Those segmented scale values against each axle limit spell out what one can work with.

.

[uncle_bob]

Hi

To come at this from another direction:

All of these hitches need to be adjusted once they are installed. Picking this or that component is only part of the process. They all adjust over a wide range. That adjustment process is where you need to focus your attention. Because of the range of variables, the range of adjustment on the components is much greater than the steps in the choices. I may use 5 washers or chain links. You may use 4 washers with a seemingly identical lash up. We both will be set up correctly. I checked some obscure box on my TV and you checked a different box ....

Bob