went to scales, need help understanding

[ChrisSusan]

So we finally took the rig to the scales, knowing we were pushing the limits. If someone could help me understand all the numbers I would greatly appreciate it!

Followed directions of the Cat scale guy on the intercom. Ended up with following readings:
steer axle 2800
drive axle 4080
trailer axle 6640
gross wt 13520

then weighed truck
gross weight 5760 (with driver and 3/4 tank gas. )

First question: should I have put truck on 2 scales instead of one?
Can I determine tongue weight with above info? Maybe 1120 lbs? (I added steer and drive axle weights together from full rig weigh, then subtracted the total truck only weight)

in truck: When I add second person , top off the gas tank, and add tongue weight of 1120 (if that is correct) I am at GVWR of the truck.

To get weight of trailer I took total weight minus truck weight and get 7760.

So if I add 7760 trailer to 7100 truck I get 14860.
But cat scale said total is 13520. Oh wait, I added another person and more gas, which were not weighed. So let's do that.
13520 plus 230 is 13750.
Seems like I am adding tongue weight twice. Confused? Yes.
Hope you aren't and can help. Thanks!



additional info:
2012Ford F150 FX2 ecoboost 3.55
GVWR 7100#
tow weight 9800
GCWR 15300

Rockwood 8310ss
GVWR 8450

[ChooChooMan74]

Not sure how you did it, but this is how you should have done it.



It takes 3 passes to get all the information on a travel trailer equipped with a WDH.

1 Pass, Truck only, pad 1 and 2

1 Pass, Truck and Trailer, W/O WDH, pad 1,2,3

1 Pass, Truck and Trailer, W/WDH, pad 1,2,3

To get tongue weight, Take Pad 1 and 2 (truck weight)truck only and subtract it from pad 1 and 2 (truck w/o wdh) and that is the tongue weight.

[dwaynerz]

If using a cat scale, you put 1 axle, or set of axles, on each scale platform ( there are 3). As far as weighing just the truck, I would split the axles onto 2 scale platforms and see what was what.

I think where your problem is coming from is that you didn't wiegh it in "ready to travel" condition. You can deterine tongue wieght if you split the scales when weighing the truck by itself, and then reweighing with trailer attached. That will give a more accurate weight and a better dea of where you stand concering your true weghts.

[MtnGuy]

Originally Posted by ChrisSusan

So we finally took the rig to the scales, knowing we were pushing the limits. If someone could help me understand all the numbers I would greatly appreciate it!

Followed directions of the Cat scale guy on the intercom. Ended up with following readings:
steer axle 2800
drive axle 4080
trailer axle 6640
gross wt 13520

then weighed truck
gross weight 5760 (with driver and 3/4 tank gas. )

First question: should I have put truck on 2 scales instead of one?

Yes, the truck axles need to be on separate sections each weigh-in.

Originally Posted by ChrisSusan

Can I determine tongue weight with above info? Maybe 1120 lbs? (I added steer and drive axle weights together from full rig weigh, then subtracted the total truck only weight)

If the WDH spring bars were not in place, the 1120 lbs. is your tongue weight.

Either the WDH was not hooked up, or it needs some serious adjusting. I don't know the stats on your truck, but if you don't have the maximum tow package (indicated that you don't have by the listed 7100 lb. GVWR), your rear axle probably has too much weight on it. Many F150s comes with a 3850 maximum rear axle weight rating. Check the sticker on the driver's side door for the axle ratings.

Also, the front axles tend to run about 3300 lbs......2800 lbs. means you are missing about 500 lbs there. The WDH spring bars need to adjusted big time.

Originally Posted by ChrisSusan

When I add second person , top off the gas tank, and add tongue weight of 1120 (if that is correct) I am at GVWR of the truck.

At, or over.

Originally Posted by ChrisSusan

To get weight of trailer I took total weight minus truck weight and get 7760.

So if I add 7760 trailer to 7100 truck I get 14860.
But cat scale said total is 13520. Oh wait, I added another person and more gas, which were not weighed. So let's do that.
13520 plus 230 is 13750.
Seems like I am adding tongue weight twice. Confused? Yes.
Hope you aren't and can help. Thanks!

OK, that is a bit confusing. All passengers, cargo, and fluid levels should be exactly the same every weigh-in, or the results will be messed up. Don't add or subtract passengers.

ChooChoMan74 posted on how to weigh at CAT scales.

1 other thing......the tongue weight may be over the rated receiver weight.....there should be a sticker on the reciever with the listed weights.

[ChooChooMan74]

Here is a good site for some good education.

Learn To RV

The weighing section
Learn To RV: What Can I Tow?

Some more helpful info. All 3 passes, all cargo in the truck should be the same. With the exception of the WDH bars. They should be off on truck only, and on the bumper, bed for no WDH.

What you want to achieve with the WDH is to get the front axle weight as close as you can to the figure that you got with the truck alone.

[davel1971]

you cant accurately measure what your tongue weight is until you get a truck measurement with axles in separate scales Doesn't sound like you did