Sanity Check on Weight/Distribution

[BayouBiker]

I should have mentioned that Airstream designers understand the trade offs and try to put the fresh tank between the axles to minimizes cornering instability so if your tank is between the axles, my statement is not accurate, it may well be a slight advantage to carry some water. good catch you guys.

[Profxd]

Originally Posted by ROBERT CROSS

TW at the axles...interesting concept.

We always travel with full FW. The tank is between the axles on 'Cloudsplitter' with little effect on towing stability.
YMMV with a front of or behind tank mounting.

Bob
🇺🇸

I agree adding 400lbs just barely above the axles is a net positive for stability. My TW increases by 20lbs. I’d much prefer to and do run full of water especially if it’s going to be windy. I’ve filled my water tank just for the trip home.

[A W Warn]

I almost always carry a full tank of water. That way sloshing (weight transfer) is not an issue.
If anyone cares to look back over the last 15 years of posts, there are many old timers like me that recommend and practice this method of keeping the center of gravity low, to improve trailer stability.
Inland Andy, I miss his comments since he left the forum, was one who commented about it often. He even did a write up that was posted on Inland RV's website. Since the new owners, all of his years of shared wisdom is now gone from that website.

[GOUSC]

I was just curious if your tongue weight was 720 vs the 880 you mention. Should it be the difference in what the TV weighs with W/D and what it weighs without the trailer attached (8,080 - 7,360)? Once you add the WD, isn’t the 720 the amount of weight added to the tongue? If you are towing on the ball then I would think that 880 would be the tongue weight. I’m not saying I’m right- I’m just asking the question as I may be wrong in my thinking.

I have the same Globetrotter you and Jeff have. My tongue weight is in the 1,000 lb range as well based on the scales. Like you said, the scales don’t lie so there must be something in the shank length adding addt’l tongue weight for Jeff and me.

Your #’s otherwise look good to me.

[BayouBiker]

The tongue weight, a load which is torque based, is the downward force generated by the forward bias of the trailer center of gravity and that force is mostly constant, unchanged by the balancing forces of WD. So tongue weight is the non WD addition to the TV. You are however correct that when WD is added the net load on the ball/receiver drops due to a net lift from the bars. In this case to 720 but the trailer is still exerting the same 880 tongue load on the ball.

Hope that makes sense.

[Silvr_Bullet]

Originally Posted by BayouBiker

The tongue weight, a load which is torque based, is the downward force generated by the forward bias of the trailer center of gravity and that force is mostly constant, unchanged by the balancing forces of WD. So tongue weight is the non WD addition to the TV. You are however correct that when WD is added the net load on the ball/receiver drops due to a net lift from the bars. In this case to 720 but the trailer is still exerting the same 880 tongue load on the ball.

Hope that makes sense.

makes for nonsense

[ROBERT CROSS]

Originally Posted by BayouBiker

The tongue weight, a load which is torque based, is the downward force generated by the forward bias of the trailer center of gravity and that force is mostly constant, unchanged by the balancing forces of WD. So tongue weight is the non WD addition to the TV. You are however correct that when WD is added the net load on the ball/receiver drops due to a net lift from the bars. In this case to 720 but the trailer is still exerting the same 880 tongue load on the ball.

Hope that makes sense.

It makes more sense when mentioned that TW is measured UN-HITCHED.
Once hitched that weight is distributed, even without WD.

Bob
🇺🇸

[GOUSC]

Originally Posted by BayouBiker

The tongue weight, a load which is torque based, is the downward force generated by the forward bias of the trailer center of gravity and that force is mostly constant, unchanged by the balancing forces of WD. So tongue weight is the non WD addition to the TV. You are however correct that when WD is added the net load on the ball/receiver drops due to a net lift from the bars. In this case to 720 but the trailer is still exerting the same 880 tongue load on the ball.

Hope that makes sense.

Yes, it does. Thanks. As applied to the OP's situation his tongue weight is 880 as tongue weight is determined w/o weight distribution. This is the weight that has to be in the 10-15% parameters. His hitch may have certain limits with, and without WD. I know my 3/4 ton GMC has a strong enough tongue weight without WD so I'm not concerned in my situation and it is within the 10-15% parameters.

However, my previous Suburban had 600 lb tongue weight w/o WD and 1,000 lbs with WD. So, the OP's hitch may have a higher rating with WD since part of that weight is distributed forward and back but that has no effect on determining tongue weight as the tongue weight is 880, determined w/o weight distribution.

Is this correct for the OP?

[BayouBiker]

Yes you have it exactly correct.

[ROBERT CROSS]

Oh so TW is now considered to be receiver weight hitched WO WD engaged?....Anyone want to buy a TW Scale?🥴

Bob
🇺🇸

[BayouBiker]

Unless my statics instructor was wrong, they better match up......

In all seriousness, the final Cat scale weights will give you the most accurate indication of true effective tongue weight because the scales are calibrated, they are exactly level and the geometry is exactly aligned so the weight is distributed in equilibrium to the three axles and the effective hitch point will also settle out, so the possibility for measurement error is minimized.

[ROBERT CROSS]

Brian,

Does this add up...Is it all about the squat?

Our 1200lb (Sherline scale)TW when hitched adds 1920lb to the TV rear axle on the CAT.
I don't believe using the CAT to estimate TW is all that accurate.

Plus on the CAT's the lighter the load the less accurate the results, Plus/minus 50-100lbs would not be out of line.


Bob
🇺🇸

[grumblin]

Originally Posted by Bill M.

I would strongly prefer 13% tongue weight to 10% tongue weight.

This. All day long - I'd prefer 13%-15%. 10% is down in the nether regions as far as I'm concerned.

[Silvr_Bullet]

Originally Posted by ROBERT CROSS

Brian,



Does this add up...Is it all about the squat?



Our 1200lb (Sherline scale)TW when hitched adds 1920lb to the TV rear axle on the CAT.

I don't believe using the CAT to estimate TW is all that accurate.



Plus on the CAT's the lighter the load the less accurate the results, Plus/minus 50-100lbs would not be out of line.





Bob

[emoji631]

I believe your absolutely right, tongue weight is not isolated when hooked up to TV. When TV is the individual axle weight is what’s important and that reflects the effect of weigh distribution. Weigh your Trailer with weight on the jack and that’s weight before weight distribution. BTW, hitch weights limits by class hitch and manufacturer limits are separate issue. And of course weight limits of the trailer and TV.

[DCPAS]

Originally Posted by ROBERT CROSS

Our 1200lb (Sherline scale)TW when hitched adds 1920lb to the TV rear axle on the CAT.

1,200 lbs tongue weight increases rear axle load 1,920 lbs?

[sheriff1]

When weighing with the Sherline scale make sure you bounce your body weight on the tongue a few times before you read the scale. I found that by just lowering the tongue onto the scale gives an inaccurate reading. Not as much as you are seeing but easily a couple hundred pounds.

[Bill M.]

"Our 1200lb (Sherline scale)TW when hitched adds 1920lb to the TV rear axle on the CAT.
I don't believe using the CAT to estimate TW is all that accurate."

Your weight sure does not sound accurate. I got 800 lbs added to the truck for my 25' when hitched (with the wd engaged). Nobody else has reported the kind of discrepancy you have. Makes me wonder just what you did? wrong?

[Silvr_Bullet]

Originally Posted by Bill M.

"Our 1200lb (Sherline scale)TW when hitched adds 1920lb to the TV rear axle on the CAT.
I don't believe using the CAT to estimate TW is all that accurate."

Your weight sure does not sound accurate. I got 800 lbs added to the truck for my 25' when hitched (with the wd engaged). Nobody else has reported the kind of discrepancy you have. Makes me wonder just what you did? wrong?

Isn’t that why one makes a pass with just the trailer the wheel trailer on one scale and the trailer jack stand on the second scale. Curious why that wouldn’t be accurate? How about the section that trailer axles are on is that weight accurate?

[ROBERT CROSS]

Originally Posted by DCPAS

1,200 lbs tongue weight increases rear axle load 1,920 lbs?

Yep... it does, it squats the rear of the TV, removing weight from the front axle, and that weight moves to the rear TV axle.
It can't disappear, it has to go somewhere.🤔

\SNIP QUOTE
"Isn’t that why one makes a pass with just the trailer the wheel trailer on one scale and the trailer jack stand on the second scale. Curious why that wouldn’t be accurate? How about the section that trailer axles are on is that weight accurate?"

I don't use the CAT for TW...the scales aren't really calibrated for light loads.
FWIW my CAT TW was 780lb, Sherline 1200.


I make 4 passes....

1st, just the TV loaded for the trip, now you have the target FAW
2nd TV & AS no WD
3rd TV & AS max WD
4th TV & AS with WD set to the proper returned weight to the FA.

Bob
🇺🇸

[DCPAS]

Originally Posted by ROBERT CROSS

Yep... it does, it squats the rear of the TV, removing weight from the front axle, and that weight moves to the rear TV axle.

I see what you are saying. That is without WD engaged.