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-   -   CAT Scale Results (https://www.airforums.com/forums/f238/cat-scale-results-180424.html)

afk314 04-18-2018 10:09 PM

CAT Scale Results
 
Truck - loaded for light camping with about 350 lbs of gear, 3/4 tank of gas. I was not present in the seat for any weights, wife not included either.

Trailer - close to camping weight - 70% propane, 100% fresh water, no food.

Pass #1 - TV only

FA: 3260
RA: 2820

Pass #2 - Trailer only
Tongue: 1060
Axels: 5280

Pass #3 - NO WD (bars no included in measurements)
FA: 2920
RA: 4020
Trailer: 5480

Pass #4 - WD engaged
FA: 3040
RA: 3880
Trailer: 5540

Definitely some oddities - like how did the weight on the axles go up when hitched? Airstream claims 886# for tongue as specd but I've dropped the LA batteries and would expect the tongue weight to be below original spec.

Am I right in concluding I need a little more WD - planning on adding another washer on the Equal-i-zer. Trailer attitude is good, slightly tongue down but going up again would not allow me to lower my truck bed door which would suck.

Any other thoughts? Thanks!
Adam

Countryboy59 04-19-2018 03:55 AM

Quote:

Originally Posted by afk314 (Post 2091056)
Truck - loaded for light camping with about 350 lbs of gear, 3/4 tank of gas. I was not present in the seat for any weights, wife not included either.

Trailer - close to camping weight - 70% propane, 100% fresh water, no food.

Pass #1 - TV only

FA: 3260
RA: 2820

Pass #2 - Trailer only
Tongue: 1060
Axels: 5280

Pass #3 - NO WD (bars no included in measurements)
FA: 2920
RA: 4020
Trailer: 5480

Pass #4 - WD engaged
FA: 3040
RA: 3880
Trailer: 5540

Definitely some oddities - like how did the weight on the axles go up when hitched? Airstream claims 886# for tongue as specd but I've dropped the LA batteries and would expect the tongue weight to be below original spec.

Am I right in concluding I need a little more WD - planning on adding another washer on the Equal-i-zer. Trailer attitude is good, slightly tongue down but going up again would not allow me to lower my truck bed door which would suck.

Any other thoughts? Thanks!
Adam

3000 lbs on the front axle ought to be plenty. But more importantly, how does it drive???

You’re not transferring much weight. And I’m not surprised by the tongue weight being over spec.

YippieKiYa 04-19-2018 05:30 AM

I’ll comment on the tongue weight - AS provides a general guestimate without options and without water and cargo. They’re also known to be somewhat off. As you add your supplies, the tongue weight will go up. Especially if you used a Propride or Hensley (the head adds directly to tongue weight).

I’d also suggest that good weighing technique include you and your wife in the TV so you can see how that affects the payload numbers.

Glad you’re doing this. It’s cheap, and you learn a lot about your setup. I know I find it interesting.

Sphere Guy 04-19-2018 06:46 AM

Looks like you are still 220lbs light on the front. That is is you are looking for 100% restorative force.

As well as CAT numbers, I like to measure the TV’s actual measurement of the change in heights of the TV’s “attitude”. That is how far off “normal” is the TV. Ie: does it show high or low at the front and rear axles. As well as the measurements of the AS hitch and bumper.

You are heading in the right direction.

As you noted, another washer in the head should do it. Including the extra cargo you would load. Just don’t forget the wife!

And as Countryboy noted; published hitch weights are just that, a number, nothing close to actual because every AS is loaded differently with unknown items.

Would you rather have a properly hitched setup or have the tailgate open all the way. That’s for you to determine.

ROBERT CROSS 04-19-2018 08:00 AM

3 Attachment(s)
I'm also 200# light on the front axle...I've restored to 100% with no appreciable handling improvement.

As noted it, is paramount that both TV & AS be level when WD is properly set. (tongue 1"-2" low better than high)

My tickets.... notice the weight is transferred from the TV rear axle to the steering axle and back to the AS axles.
;)When tongue is lifted the weight runs 'downhill' to the front and rear. ;)

Bob
🇱🇷

Al and Missy 04-19-2018 08:22 AM

Quote:

Originally Posted by afk314 (Post 2091056)
...

Definitely some oddities - like how did the weight on the axles go up when hitched? Airstream claims 886# for tongue as specd but I've dropped the LA batteries and would expect the tongue weight to be below original spec.

Am I right in concluding I need a little more WD - planning on adding another washer on the Equal-i-zer. Trailer attitude is good, slightly tongue down but going up again would not allow me to lower my truck bed door which would suck.

Any other thoughts? Thanks!
Adam

Axle weight will change if the trailer is not in the same attitude as when weighed with the truck. Axle weight will be higher the higher the tongue is.

Others have commented on the tongue weight. The published tongue weight means little or nothing. For good towing common practice is the tongue weight should be 10%-15% of trailer total weight. I try to run at around 12%.

You can also raise the equalizer brackets to increase weight transfer. It is an iterative process of adjusting the number of washers, the bracket height, and the shank drop to get weight distribution dialed in and the trailer level. General guidance is to restore 50% to 100% of the weight back to the front axle. Some vehicle manufacturers put their recommendation in the manual. You can get close in your driveway by measuring the distance from the center of the wheel well opening to a point on the wheel instead of weighing, then confirm your setup with a weighing.



Al

Mollysdad 04-19-2018 09:11 AM

Interesting.
Not surprising.
I'd try one more washer.

hhendrix 04-19-2018 10:11 AM

I think you're missing some very important information. I often help people setting up the WD hitches. What is also important is the individual trailer axle weights. Too much difference between the trailer axles can cause instability when towing. It's important to look how all the axle weights are distributed when adjusting your WD system.

slowmover 04-19-2018 02:48 PM

Ill assume you have the CAT Scale App

Method will help. Consistency.

Top off fuel tank at travel center arrival

First pass:
With WD engaged.

Second pass:
Simply loosen bars. Slack, not removal

Third pass
Drop trailer in designated parking spot. Cross scale solo

A fourth pass can be done for a split-axle weighing. Go to fuel desk first and be sure scalemaster knows procedure. (Manual at desk covers it)

Point here is to make no real changes between passes. All passengers aboard, etc.

ROBERT CROSS 04-19-2018 03:58 PM

Quote:

Originally Posted by hhendrix (Post 2091273)
I think you're missing some very important information. I often help people setting up the WD hitches. What is also important is the individual trailer axle weights. Too much difference between the trailer axles can cause instability when towing. It's important to look how all the axle weights are distributed when adjusting your WD system.

Trailer axle weights or individual trailer wheel weights?

Bob
🇱🇷

BoldAdventure 04-19-2018 10:23 PM

Quote:

Originally Posted by afk314 (Post 2091056)
Truck - loaded for light camping with about 350 lbs of gear, 3/4 tank of gas. I was not present in the seat for any weights, wife not included either.

Trailer - close to camping weight - 70% propane, 100% fresh water, no food.

Pass #1 - TV only

FA: 3260
RA: 2820

Pass #2 - Trailer only
Tongue: 1060
Axels: 5280

Pass #3 - NO WD (bars no included in measurements)
FA: 2920
RA: 4020
Trailer: 5480

Pass #4 - WD engaged
FA: 3040
RA: 3880
Trailer: 5540



Airstream claims 886# for tongue as specd but I've dropped the LA batteries and would expect the tongue weight to be below original spec.

My math from your numbers shows that when you hitch up and don't have WD applied, you have 858lbs of tongue actually sitting on the rear axle.

6940lbs truck - 6082lbs truck previously.

Quote:

Originally Posted by afk314 (Post 2091056)
Am I right in concluding I need a little more WD - planning on adding another washer on the Equal-i-zer. Trailer attitude is good, slightly tongue down but going up again would not allow me to lower my truck bed door which would suck.

Any other thoughts? Thanks!
Adam


I think you could adjust it. But your setup looked level to me from where I was standing but you might of been just a tad nose high.

Hi again.

https://scontent-sea1-1.xx.fbcdn.net...c1&oe=5B6DAC56

You're setup is a lot lighter than mine, I'm a bit jealous. :lol:

But from my personal experience, you def do want more weight on the front. And you could shift some weight off that rear. You have close to 1060lbs on the rear and 220lbs light in the front.

I have a much heavier setup, but look at my spread.

I started (first photo) with a FA of 5060 and end (3rd photo) with a FA of 5320 so 260lbs extra up front. And a RA starting of 4000 (first photo) and ending with 4420lbs (3rd photo).

That's balanced, compared to no WD where I had 400lbs come off the front of the truck and nearly 1340lbs on the rear axle.

Personal opinion, open to debate here among others, but you certainly could dial that in better.

Good luck.

https://scontent-sea1-1.xx.fbcdn.net...34&oe=5B70DB51

https://scontent-sea1-1.xx.fbcdn.net...93&oe=5B4EAE1D

https://scontent-sea1-1.xx.fbcdn.net...8a&oe=5B706F29

BoldAdventure 04-19-2018 10:23 PM

Quote:

Originally Posted by slowmover (Post 2091394)
Ill assume you have the CAT Scale App

Method will help. Consistency.

Top off fuel tank at travel center arrival

First pass:
With WD engaged.

Second pass:
Simply loosen bars. Slack, not removal

Third pass
Drop trailer in designated parking spot. Cross scale solo

A fourth pass can be done for a split-axle weighing. Go to fuel desk first and be sure scalemaster knows procedure. (Manual at desk covers it)

Point here is to make no real changes between passes. All passengers aboard, etc.

I basically do it the same way, but in reverse. :D

Hibby 04-20-2018 03:33 AM

Quote:

Originally Posted by BoldAdventure (Post 2091549)
I basically do it the same way, but in reverse. :D

I didn’t know we were permitted to go through the CAT scales backwards?

AirMiles 04-20-2018 04:26 AM

"I basically do it the same way, but in reverse." - WOW Bold! You must be good to back onto a CAT scale!

Also interesting that Bold chooses to travel at over 100% FALR (Front Axle Load Restoration) as do I. Here is a link to my scale tickets and picture of my rig with 11 links of weight distribution on a Blue Ox hitch. https://www.airforums.com/forums/f42/...ml#post1985301 I always travel at 11 links, 80# over FALR on these scale tickets, to improve my rig's handling. I tested even more front axle weight by trying 1500# bars which completely ruined my rig's handling to the point that I had to abort my test drive to the CAT scale. So it is possible to go too far with front axle load restoration. I've found that adjusting a weight distribution hitch is a balancing act where the "sweet spot" is found through trial and error and then confirmed with weight scale tickets.

BoldAdventure 04-20-2018 07:35 AM

Quote:

Originally Posted by AirMiles (Post 2091582)
"I basically do it the same way, but in reverse." - WOW Bold! You must be good to back onto a CAT scale!

Also interesting that Bold chooses to travel at over 100% FALR (Front Axle Load Restoration) as do I. Here is a link to my scale tickets and picture of my rig with 11 links of weight distribution on a Blue Ox hitch. https://www.airforums.com/forums/f42/...ml#post1985301 I always travel at 11 links, 80# over FALR on these scale tickets, to improve my rig's handling. I tested even more front axle weight by trying 1500# bars which completely ruined my rig's handling to the point that I had to abort my test drive to the CAT scale. So it is possible to go too far with front axle load restoration. I've found that adjusting a weight distribution hitch is a balancing act where the "sweet spot" is found through trial and error and then confirmed with weight scale tickets.

Good communication with the wife :lol:

I know some folks stick to 10% FALR. But it just feels more planted to me and overall stable when the truck is driving like it wasn't loaded or as close to it as possible.

Now, that can vary vehicle to vehicle. I have a very different setup from most. My axles aren't even stock anymore. :D

I probably adjusted the hitch about 7 times yesterday until it felt good towing to me. Finding the sweet spot for you is key.

If you're at least making the effort, you're way ahead of a lot of others out there on the road.

:punk:

slowmover 04-20-2018 10:29 AM

FALR (100%) is a starting point.

More, or less, is about degree of steering input + duration when tested.

TV tire pressure needs be nailed down first. No more than 5-7% pressure rise when REALLY close to value given by Load & Pressure Table (and always within vehicle manufacturers range). Stick with 100% and continue on down road until a couple of pressure values have been tried.

The tendency — with pickups — is to go too high on tires. To make up for TV suspension geometry deficiencies. Too high will come back to bite you. So long as pressure rise isn’t above spec, “low” values are what to learn with (keep TT tires at max until TV tire pressure sorted; take those out of equation).

One doesn’t “tune” TV steering with tire pressure. A rear anti-roll bar if not so equipped (and upsize front; must be done together); and/or a rear Panhard Rod (See Super Steer); these correct body roll and/or movement of the body against the suspension. (Cheap and cheap to install polyurethane roll bar bushings should be on everyone’s list; brand-new off the dealer lot).

Better than entry-level Koni or Bilstein shock absorbers. (Fox, King on pickups) is another aid.

Takes awhile for the trailer stern to come around. The tendency is to want that to happen “fast”. No, more a graduated thing. The sidewall flex on a pickup TV will be “best”, IMO, when the tire is at the correct pressure for the load.

What’s left in “feel” is about TV suspension. The trailer affects the TV frame, and body roll seems untoward. It’s not a TV tire pressure problem.

.

hhendrix 04-20-2018 10:33 AM

Quote:

Originally Posted by ROBERT CROSS (Post 2091431)
Trailer axle weights or individual trailer wheel weights?

Bob
🇱🇷

Axle weights not individual wheels. Adjustments in the WD can really affect the weight on either axle of the trailer. You can literally shift weight with adjustments to balance the trailer axles.

slowmover 04-20-2018 10:41 AM

Quote:

Originally Posted by hhendrix (Post 2091718)
Axle weights not individual wheels. Adjustments in the WD can really affect the weight on either axle of the trailer. You can literally shift weight with adjustments to balance the trailer axles.

Why the CAT Scale procedure exists to find this. Have to do before and after WD applied. Won’t ever be exact, but discrepancies can be addressed.

ROBERT CROSS 04-21-2018 08:06 AM

Quote:

Originally Posted by hhendrix (Post 2091718)
Axle weights not individual wheels. Adjustments in the WD can really affect the weight on either axle of the trailer. You can literally shift weight with adjustments to balance the trailer axles.

Thats the reason for level.

Good to have that differienciated ....too many folks worry too much about individual wheel weights, what to do if the street weighs more than the curb...move the fridge?.😏

Bob
🇱🇷


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