Deciphering CAT Scale Numbers

[dalamarjj78]

Tonight we loaded up our new trailer, packed the family in the truck and took it to the CAT scales. As this was my first time using CAT scales I was hoping a few experts could review my numbers and make sure I'm understanding things correctly.

Truck Stats:
GVWR: 7,100 lbs
Front GAWR: 3,450 lbs
Rear GAWR: 3,850 lbs
GCVWR: 13,500 lbs
Payload: 1,745 lbs

Here are the numbers from the CAT scale:

Truck & Trailer (WDH engaged):
Steer Axle: 2,860 lbs
Drive Axle: 3,740 lbs
Trailer Axle: 5,160 lbs
GCVWR: 11,760 lbs
*Truck Weight: 6,600 lbs

Truck & Trailer (WDH disengaged):
Steer Axle: 2,820 lbs
Drive Axle: 3,760 lbs
Trailer Axle: 5,160 lbs
GCVWR: 11,740 lbs
*Truck Weight: 6,580 lbs

Truck only:
Steer Axle: 3,140 lbs
Drive Axle: 2,640 lbs
*Truck Weight: 5,780 lbs

Are my calculations correct for the following:

Tongue Weight:

Truck Weight (6,600) - Truck Only Weight (5,780) = 820 lbs

Total Trailer Weight:

Trailer Axle (5,160) + Tongue Weight (820) = Total Trailer Weight (5,980)

Tongue Weight Percentage:

Tongue Weight (820) / Total Trailer Weight (5,980) = 13.7%

Assuming my numbers are right, we've got nothing to worry about, correct?

Thanks!

[tech740]

Looks like you are all set. Under GVW for the truck and under trailer GVW. My only recommendation would be to try and transfer more weight with the hitch. Is it level with your current setup?

[dalamarjj78]

Originally Posted by tech740

Looks like you are all set. Under GVW for the truck and under trailer GVW. My only recommendation would be to try and transfer more weight with the hitch. Is it level with your current setup?

Thanks, that's what I was hoping to hear.

It is pretty level with the current setup. What do you mean to transfer more weight with the hitch? Should I shift more weight towards the hitch or away from it?

The label on the truck's hitch says it can handle a max of 1,050 lbs when using a WDH.

[wiredgeorge]

I would also caution anyone with a 1/2 ton to upgrade the tires to LT if they have not already done so. I had a 2013 F150 (bought new) and it had basically car tires on it.

[dalamarjj78]

Originally Posted by wiredgeorge

I would also caution anyone with a 1/2 ton to upgrade the tires to LT if they have not already done so. I had a 2013 F150 (bought new) and it had basically car tires on it.

Shortly after buying the truck I put 4 Michelin Total Performance Defender LTX M/S 255/65 R17 tires on it.

It needed new tires anyway and I figured it would be worth spending more on good tires. Especially since we'd be towing a TT with it.

[sourdough]

Originally Posted by dalamarjj78

Shortly after buying the truck I put 4 Michelin Total Performance Defender LTX M/S 255/65 R17 tires on it.

It needed new tires anyway and I figured it would be worth spending more on good tires. Especially since we'd be towing a TT with it.

IMO you can't go wrong with the Defenders. That's what I've been putting on my trucks and I really like them with nary a problem.

[Javi]

Originally Posted by sourdough

IMO you can't go wrong with the Defenders. That's what I've been putting on my trucks and I really like them with nary a problem.

Yep... they've served me well on the dually also..

[tech740]

Not sure the type of hitch you are using but my statement meant mor torque on it. Either another chain link or a little higher on the bars. That could mean more tip in the head and more setting up the hitch. Your numbers show only 20 lbs coming off the back and going to the front. You are looking for level and getting the front wheel well close to what it started at unhooked.

[dalamarjj78]

Originally Posted by tech740

Not sure the type of hitch you are using but my statement meant mor torque on it. Either another chain link or a little higher on the bars. That could mean more tip in the head and more setting up the hitch. Your numbers show only 20 lbs coming off the back and going to the front. You are looking for level and getting the front wheel well close to what it started at unhooked.

I have a recurve r3 that the dealer threw into the deal when we got the trailer. I guess I'll need to do some research as I let them set it up and have no idea how to adjust it.

[notanlines]

Ditto^^^^ on the Defenders. It has been our go-to tire for many years. Surprisingly, Ford dealers seem to have the best price versus Michelin dealers.

[JRTJH]

It looks, from your weight tickets, that you're only transferring 20 pounds from the hitch to the front axle and 0 pounds from the hitch to the trailer axles.

Ideally, you should be shifting around 10% of the weight forward, to the front axle and about 5% of the weight aft to the trailer axles. With a tongue weight of 820 pounds, that would mean "around 80-100 pounds forward and 40-50 pounds aft"...

More important, however, is to measure the height of a "solid part of the front of the truck" (like a point on the wheelwell cutout) with the truck sitting UNHITCHED on a level surface, then hitch the trailer to the truck and remeasure that point. It should be as close as possible to the same measurement, but within an inch or so. That means that your hitch is transferring enough weight "forward" to bring the truck to "near the same level attitude" as when unhitched. That will "automatically" transfer some of the weight rearward, to the trailer axles.

While your rig is "within acceptable range from a weight perspective" it is not "within the "front/rear axle load range" (to keep the front axle/front tires on the ground in adverse driving situations)...

If you think about the geometry of how a vehicle/trailer crosses a raised railroad crossing, as the rig approaches the crossing, the front axle "goes up the incline" then as it's going down the incline, the rear axle is going up. Then as the trailer axles "are going up, both the truck axles are going down, then as the trailer "crowns the crossing" it starts down, putting excess weight on the hitch/rear axle, which lifts the front axle. That lifting can, on a wet or icy road, cause the front tires to lose traction and start to skid. More weight would help prevent a potential disaster...

Trust me when I say that a number of people have been in situations like I described and have "felt the front tires leave the ground, with no steering capability until the rig settles back to level....

While you're "OK from a weight perspective" you may not be "OK from a geometric perspective"... You want your rig as level as possible, with the front of the tow vehicle as close to the "unloaded measurement" as you can get it.

There are instructions on hitch setup procedures for your hitch brand/model on the manufacturer's website. Find them, read through them and follow the manufacturer's recommendations to set up your hitch...

Remember that when "the dealership set up my hitch for me upon delivery" that weight, both trailer total weight and tongue weight, is significantly different than it is now that you've put your equipment in the trailer. So, what they "set up" is history and "what you need to set up" is current condition... The two are likely to be several hundred pounds different on the tongue and a thousand or more pounds different in trailer weight.

[dalamarjj78]

Originally Posted by JRTJH

It looks, from your weight tickets, that you're only transferring 20 pounds from the hitch to the front axle and 0 pounds from the hitch to the trailer axles.

Ideally, you should be shifting around 10% of the weight forward, to the front axle and about 5% of the weight aft to the trailer axles. With a tongue weight of 820 pounds, that would mean "around 80-100 pounds forward and 40-50 pounds aft"...

More important, however, is to measure the height of a "solid part of the front of the truck" (like a point on the wheelwell cutout) with the truck sitting UNHITCHED on a level surface, then hitch the trailer to the truck and remeasure that point. It should be as close as possible to the same measurement, but within an inch or so. That means that your hitch is transferring enough weight "forward" to bring the truck to "near the same level attitude" as when unhitched. That will "automatically" transfer some of the weight rearward, to the trailer axles.

Thanks for the very detailed information. I'll take the necessary measurements with the vehicle unhitched and compare it to when it is hitched and see where we're at.

I have the feeling I'll end up having to buy some tools to adjust my hitch, though. Thanks again!

[sourdough]

Originally Posted by dalamarjj78

I have a recurve r3 that the dealer threw into the deal when we got the trailer. I guess I'll need to do some research as I let them set it up and have no idea how to adjust it.

Here's the manual.

https://www.rvupgradestore.com/v/vsp.../R3-Manual.pdf


Everything I saw component wise should be easy to adjust with a good socket set and 1/2" torque wrench. I suspect your biggest issue, if you have to deal with it, is the nut on the ball. Mine took something like 1 1/2"?? thin wall socket and a 3/4" long handled torque wrench so you could torque to something like 350lbs. They now happily reside on the wall in the barn..

[dalamarjj78]

Originally Posted by sourdough

Here's the manual.

https://www.rvupgradestore.com/v/vsp.../R3-Manual.pdf


Everything I saw component wise should be easy to adjust with a good socket set and 1/2" torque wrench. I suspect your biggest issue, if you have to deal with it, is the nut on the ball. Mine took something like 1 1/2"?? thin wall socket and a 3/4" long handled torque wrench so you could torque to something like 350lbs. They now happily reside on the wall in the barn..

Excellent, thank you!

[dalamarjj78]

Originally Posted by JRTJH

More important, however, is to measure the height of a "solid part of the front of the truck" (like a point on the wheelwell cutout) with the truck sitting UNHITCHED on a level surface, then hitch the trailer to the truck and remeasure that point. It should be as close as possible to the same measurement, but within an inch or so. That means that your hitch is transferring enough weight "forward" to bring the truck to "near the same level attitude" as when unhitched. That will "automatically" transfer some of the weight rearward, to the trailer axles.

I followed your suggestion and measured the front and rear wheelwell while unhitched and compared them to when the WDH is engaged. These are the numbers I got:

Unhitched:

Front Wheelwell: 34.5"
Rear Wheelwell: 36"

WDH connected:

Front Wheelwell: 35"
Rear Wheelwell: 33.5"

So the front is only raising about half an inch but the rear is sagging by about 2.5 inches.

So it sounds like I'll need to make some adjustments after all.

[travelin texans]

Originally Posted by dalamarjj78

Thanks for the very detailed information. I'll take the necessary measurements with the vehicle unhitched and compare it to when it is hitched and see where we're at.

I have the feeling I'll end up having to buy some tools to adjust my hitch, though. Thanks again!

If you own a rv & don't have tools you're in for long wait lines at dealerships service departments for even basic repairs, much longer for major issues.
Definitely buy tools & learn to do your own repairs, it'll be very satisfying & necessary, most of it is not rocket science.

[tech740]

Originally Posted by dalamarjj78

I followed your suggestion and measured the front and rear wheelwell while unhitched and compared them to when the WDH is engaged. These are the numbers I got:

Unhitched:

Front Wheelwell: 34.5"
Rear Wheelwell: 36"

WDH connected:

Front Wheelwell: 35"
Rear Wheelwell: 33.5"

So the front is only raising about half an inch but the rear is sagging by about 2.5 inches.

So it sounds like I'll need to make some adjustments after all.

I am not familiar with that hitch at all. I would look into getting more pressure on the bars. That should lift the rear and put more weight back on the trailer and the front axle.

[JRTJH]

According to step#1 on page 3 in the hitch manual that Danny linked to in his post, the first thing you need to do is place the trailer on level ground, then level it (parallel to the ground as measured at the frame rails, front and rear) and establish a "hitch coupler height" (measured at the top of the coupler dome). That is your ball height "starting point". THEN add 1/8" for each 100 pounds of tongue weight. Your tongue weight (from the CAT scale is 820 pounds, so you'd add 1" to the measured trailer tongue height. So, as an example, if the top of the dome on the trailer coupler is 18", then your "initial ball height setting would be 19" (18"+1" for 820 pound tongue weight).

My guess is that will give you an additional inch (more or less) in your rear wheelwell measurement when hitched. Then, if the hitch head is adjusted (tilted) properly, so the tension bars are "parallel to the trailer tongue when tension is applied" you should find much of that "rear end sag" is eliminated and "hopefully" the front end will still be "at the unhitched height" or "within 1" of that height"....

[dalamarjj78]

Originally Posted by JRTJH

According to step#1 on page 3 in the hitch manual that Danny linked to in his post, the first thing you need to do is place the trailer on level ground, then level it (parallel to the ground as measured at the frame rails, front and rear) and establish a "hitch coupler height" (measured at the top of the coupler dome). That is your ball height "starting point". THEN add 1/8" for each 100 pounds of tongue weight. Your tongue weight (from the CAT scale is 820 pounds, so you'd add 1" to the measured trailer tongue height. So, as an example, if the top of the dome on the trailer coupler is 18", then your "initial ball height setting would be 19" (18"+1" for 820 pound tongue weight).

My guess is that will give you an additional inch (more or less) in your rear wheelwell measurement when hitched. Then, if the hitch head is adjusted (tilted) properly, so the tension bars are "parallel to the trailer tongue when tension is applied" you should find much of that "rear end sag" is eliminated and "hopefully" the front end will still be "at the unhitched height" or "within 1" of that height"....

Yeah, i've studied those instructions and found a nice step-by-step video on youtube that walks you through the installation process. I ordered the tools I'm going to need to make the necessary adjustments so as soon as they arrive I'm going to double check these measurements.

And if I'm understanding the instructions correctly, it sounds like I may need to tilt the hitch slightly downward (it's perfectly level now) in order to distribute weight off of the rear axle and push it towards the front.

[CWtheMan]

Originally Posted by dalamarjj78

Shortly after buying the truck I put 4 Michelin Total Performance Defender LTX M/S 255/65 R17 tires on it.

It needed new tires anyway and I figured it would be worth spending more on good tires. Especially since we'd be towing a TT with it.

Just a note: To get maximum load (2124#) for towing you'll need to keep them at 44 PSI.