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Old 08-02-2020, 07:19 PM   #1
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2020 25' Globetrotter
Los Gatos , California
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First Cat scale Oh boy

Second shakedown had cat scale on route. First weigh with 8 links on EazLift was too much on drive axle. Move to 7 links, WTF? Either I parked wrong or scale guy was doing something wrong?

Slow wifi do not sure pix posted so first pass was steer 2680, drive 4340, trailer 6160 and total 13180

Second pass was steer 6860, drive 3300, trailer 3000 and total 13160
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Old 08-02-2020, 07:37 PM   #2
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OK, I give up..... I can't make any sense of that!
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Old 08-02-2020, 07:41 PM   #3
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I think you entered the scale from a different direction.
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Old 08-02-2020, 07:57 PM   #4
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For whatever reason it sure looks like the numbers got reversed on the second pass. If so, you were successful in moving some weight from your drive axel to the steer axel and trailer.--Frank
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Old 08-02-2020, 08:26 PM   #5
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I mean i see the reversal, but dang moving 1040 lbs off the rear axle with just one link? That's a vertical tension increase of about 2500 lbs for 30 inch bars. I can't get my mind around that.
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Old 08-02-2020, 10:14 PM   #6
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Nope. Think both times I was on the right pads
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Old 08-02-2020, 11:00 PM   #7
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I think that on the second pass, you got both steer & drive axles on the first pad, the first trailer axle on the second pad, and the other trailer axle on the last pad. And by tightening the bars, you moved more weight to the trailer axles.
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Old 08-03-2020, 04:22 AM   #8
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My routine....

You missed at least one pass.🤔
Bob
🇺🇸

I add a max pass to to check that WD is still 100%

Notice that ticket one FAW is within 100lb of ticket 4 FAW
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Old 08-03-2020, 08:31 AM   #9
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Quote:
Originally Posted by ROBERT CROSS View Post
My routine....

You missed at least one pass.🤔
Bob
🇺🇸

I add a max pass to to check that WD is still 100%

Notice that ticket one FAW is within 100lb of ticket 4 FAW
Thanks, will try on the way home but my wife does not like waiting in 104 temp of Mojave. I think I was on wrong pads
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Old 08-03-2020, 09:49 AM   #10
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Download the CAT App. No trips inside to get a weight sheet. Do it all on your phone.
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Old 08-03-2020, 09:56 AM   #11
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Hi

There's not much hope for that data run. You need to go back and do it again. As others have mentioned, the phone app makes this a *lot* easier. You can check things and re-run *much* faster using it.

As a "first pass" at this, go back and re-run the final numbers a second time. Unless the two runs are consistent, you don't want to trust the data. Doing that every time is way to much work for me. Just check the final numbers after you get it all set up.

Bob
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Old 08-03-2020, 05:26 PM   #12
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Complete Newbie on Cat weights

I have seen other threads about the CAT weight and now have a couple of questions.

The pictures posted of the paperwork from Mr. Cross are from 2018 and NY. I'm sure the pricing is different now and possibly in CA? Any way to check the price on line?

When you want to use the services do you make an appointment or just show up and is there usually a place to unhitch and do the TV weight alone or is it scale facility dependent?

Now the technical....or point me to another thread....

What should the weight be on the TV Steer and Drive? Equal, steer higher, steer lower?????

Always wonder if my WD is set up right by looking at the slope of the AS and TV, the way I was "taught" to set it up.

Thanks!!

Rob
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Old 08-03-2020, 06:31 PM   #13
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Quote:
Originally Posted by 1970 Safari View Post
I have seen other threads about the CAT weight and now have a couple of questions.

The pictures posted of the paperwork from Mr. Cross are from 2018 and NY. I'm sure the pricing is different now and possibly in CA? Any way to check the price on line?

When you want to use the services do you make an appointment or just show up and is there usually a place to unhitch and do the TV weight alone or is it scale facility dependent?

Now the technical....or point me to another thread....

What should the weight be on the TV Steer and Drive? Equal, steer higher, steer lower?????

Always wonder if my WD is set up right by looking at the slope of the AS and TV, the way I was "taught" to set it up.

Thanks!!

Rob


First thing, when I drove professionally (truck driver) the pricing was pretty much the same no matter where I would scale. And that was between Cali and Indiana and everywhere in between. Back when I started driving (mid 90's) it only cost $7 to scale and we would get a 2nd way for free.

Second thing, On the driver's side door jamb there is a sticker (yellow) that not only shows the tire size and pressures it also shows the GVWR, FGAWR, RGAWR and the Max. Payload Capacity. Some even show GCVWR. You do not either of the two axles to be over the GAWR per axle. The front axle weight will be lighter than the rear axle, but you want to get have it closer to the FGAWR rather than too lite. Take a semi for example, the steer axle max weight is 12k lbs, the closer you can get to that weight the better the truck handles. Same will go for your TV when hooked to your TT. Example here. Say your TV has a FGAWR of 3100 lbs, and when you scale it out you find you at 1800lbs on the front axle. That will greatly reduce how well you are able to steer the TV, 2500 lbs would be better then the 1800 it scaled at. But you do NOT want to go over the 3100 lbs stated on the sticker.
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Old 08-03-2020, 10:04 PM   #14
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Follow up to axle weights

I was worried that the steer weight at 8 links was too light and also noticed when I did hard right or left turns the car would pull pretty strong in the same direction as the turn. It would lessen as I drove then be fine again Thought maybe too light steer weight causing but seemed unlikely

Move to 7 links and had the same pull to left or right happen again. Exactly the same. Mentioned to fellow AS guy, smart about these sorts of things and he immediately said it was the auto adjust in front suspension.

Happened to you? Agree?
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Renogy 400 watts and 100 suitcase, 30/100MPPT, Victron 712, 6V Duracells
Honda 2200 propane, Weboost Drive X, EEZ TMS
Traded in 2016 Sport 16, 2019 Sport 22
As they say, third AS is what to buy first
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Old 08-04-2020, 07:15 AM   #15
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Quote:
Originally Posted by 1970 Safari View Post
I have seen other threads about the CAT weight and now have a couple of questions.

The pictures posted of the paperwork from Mr. Cross are from 2018 and NY. I'm sure the pricing is different now and possibly in CA? Any way to check the price on line?

When you want to use the services do you make an appointment or just show up and is there usually a place to unhitch and do the TV weight alone or is it scale facility dependent?

Now the technical....or point me to another thread....

What should the weight be on the TV Steer and Drive? Equal, steer higher, steer lower?????

Always wonder if my WD is set up right by looking at the slope of the AS and TV, the way I was "taught" to set it up.

Thanks!!

Rob
Hi

Before you go weight anything, study up on the published weight numbers for your TV and trailer. There is an expected number empty and a max number you should not go over. You need to know them before you do much of anything.

A good start before doing anything with the trailer (even having it with you) is to drive over and weight the TV. Find out what the front and rear axles are at with no trailer involved. This will give you an idea of how your local CAT scale is set up and (maybe) if you want to find a second choice. (I have maybe 4 or 5 within a few minutes of here ...).

If your TV is fully loaded for travel when you do the weigh, that's great. Is it already past limit on either axle? If so, address that before the trailer is hooked up. Does the expected weight of the trailer put the axles above 90% of their ratings? I'd suggest that also needs to be addressed.

How do you address these issues? First step is to toss stuff out. Assuming you are still over after that process is done .... A lot of people simply trade in their TV for something bigger. A few head out and modify this or that to increase the load capacity. Both approaches have their fans. There are a few outfits that specialize in the customization approach. It's not something I'd go do myself.

Assuming you have a WD hitch, you can adjust to put more weight on the front axle vs the rear axle of the TV. Without WD, it all pretty much goes on the rear axle. That's bad from an overload standpoint. You likely take weight off of the front axle without WD which is bad from a steering standpoint.

The only thing you *must* do in setting things up is to make sure that the axle weights are safe. Once that happens, it's all about how the combo handles. For most of us, that means putting a bit of weight (a couple hundred pounds) on the front axle (when compared to no trailer).

Note that none of this involves optimizing the trailer axle weight. It gets what it gets. It needs to be safe, but that's about all people worry about.

The ideal goal would be to have all the weights far enough into the safe zone that you don't have to go weigh the rig at the start of every trip or after each grocery run. Some here seem to have one and only one way they load everything. In 50+ years of going camping ... we have never / ever loaded the same way on an two trips ... never.

If all this sounds like a PIA, there is a "simple" answer that is often used by folks: Buy a bigger truck. Add up all the numbers for absolutely everything. Toss in another 500 pounds on the truck and at least that on the trailer. Buy something that will comfortably handle those weights. Set it all up once, roll on from there.

Bob
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Old 08-04-2020, 07:32 AM   #16
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Quote:
Originally Posted by 1970 Safari View Post
When you want to use the services do you make an appointment or just show up and is there usually a place to unhitch and do the TV weight alone or is it scale facility dependent?
Go to the catscale.com website for info. Price presently is $12.00 for the initial weigh and $2.50 for each reweigh. So, $17.00 for three. Get the app and enter a payment method. Makes it super easy. You enter the location number in the app (its on a sign you right next to you when you are on the scale) and get the results in an email. No appointment, just show up and use the scale. The scales are typically at truck stops so lots of room to unhitch and do you weighs. The only tricky part, and it is actually very simple, is that you need to get out and make sure the axles are on the right pads of the scale.
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Old 08-04-2020, 04:05 PM   #17
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Quote:
Originally Posted by DCPAS View Post
Go to the catscale.com website for info. Price presently is $12.00 for the initial weigh and $2.50 for each reweigh. So, $17.00 for three. Get the app and enter a payment method. Makes it super easy. You enter the location number in the app (its on a sign you right next to you when you are on the scale) and get the results in an email. No appointment, just show up and use the scale. The scales are typically at truck stops so lots of room to unhitch and do you weighs. The only tricky part, and it is actually very simple, is that you need to get out and make sure the axles are on the right pads of the scale.
I was only half paying attention when I downloaded the app as I had never used a CAT scale before and was astounded at how easy it was. Since I have "gps tracking" turned on with my phone I didn't even have to put the number in; it knew where I was and took no time at all.
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Old 08-06-2020, 03:05 PM   #18
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Great information. I have stated the following before. The old rule of thumb to start with is to transfer the tongue weight as follows: 1/3 on the TV front axle, I/3 on the TV rear axle and 1/3 on the TT. Now having said that go to a scale and see how close you are to that distribution. It's just like airplanes, the further forward the center of gravity (CG) the more stable it is and the further aft the less stable it will be. Airplane with a forward CG will not spin as easily as one with an aft CG. Really that is what is wrong with Boing 737 Max. When they added larger heavier engine to the 737 airframe it moved the CG so far aft it take an automatic flight control system to help the pilot fly it. The same thing was true of the Boeing 720. you could not fly it at high altitude without the auto pilot. They were so unstable they would literally go belly up to the slip stream and pull the wings off. Guess where they all wound up? South America and the scrap heap. So stability is always important when operating machines that move. Even the Tacoma Narrows Bridge, "Gallopin' Gurtie" became unstable from wind loads and shook itself apart. It is better to learn about stability at the scales than whipping all over the highway with tail wagging the dog.
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Old 08-07-2020, 06:32 AM   #19
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Quote:
Originally Posted by guskmg View Post
Great information. I have stated the following before. The old rule of thumb to start with is to transfer the tongue weight as follows: 1/3 on the TV front axle, I/3 on the TV rear axle and 1/3 on the TT. Now having said that go to a scale and see how close you are to that distribution. It's just like airplanes, the further forward the center of gravity (CG) the more stable it is and the further aft the less stable it will be. Airplane with a forward CG will not spin as easily as one with an aft CG. Really that is what is wrong with Boing 737 Max. When they added larger heavier engine to the 737 airframe it moved the CG so far aft it take an automatic flight control system to help the pilot fly it. The same thing was true of the Boeing 720. you could not fly it at high altitude without the auto pilot. They were so unstable they would literally go belly up to the slip stream and pull the wings off. Guess where they all wound up? South America and the scrap heap. So stability is always important when operating machines that move. Even the Tacoma Narrows Bridge, "Gallopin' Gurtie" became unstable from wind loads and shook itself apart. It is better to learn about stability at the scales than whipping all over the highway with tail wagging the dog.
guskmg
Hi

Except that a WD hitch does not change the center of gravity. All the mass stays right where it already was. Your moments of inertia are what drive stability. Because the mass distribution does not change, they don't change....

Why?

All a WD hitch does is act as a spring. It stiffens up the coupling between the trailer and TV. You crank in spring force to "lift" weight off of the rear axle. That's all it does / all it can do.

Bob
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Old 08-07-2020, 07:25 PM   #20
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First experience at the CAT Scale for me today, using the app was extremely quick and easy.

I only did 2 passes. (1) empty truck with just me and a full tank of gas, and (2) truck with me and the trailer attached with WD hitch. We're leaving in the morning, do you think we should do another weigh on the way out or not? Difference would be wife, 2 big dogs, and a couple coolers in the truck (350 lbs est). Trailer is pretty much fully packed except a few small items.

(1)Empty truck + me + full tank gas
*Steer axle: 3320 lb
*Drive axle: 2420 lb
*Trailer axle: 00 lb
*Total axle: 5740 lb

(2)Empty truck + me + full tank gas + trailer
*Steer axle: 3260 lb
*Drive axle: 3200 lb
*Trailer axle: 5020 lb
*Total axle: 11480 lb

Truck specs:
GVWR: 7200 lb
GAWR Frt:3800 lb
GAWR RR: 3800 lb
GCWR: 15000 lb
Curb Wt: 5478 lb
Payload: 1722 lb
Conv Twr: 9300 lb
Tongue Wt: 930 lb
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