Looking for the weight police...interpreting my weights

[remoandiris]

Finally got my loaded truck/5er weighed.  Still have to get the unloaded 5er weights.  That will happen in a week or two.  

Truck only (hitch installed)

Front axle - 4740

Rear axle - 3880

Total truck weight 8620

 

Truck with loaded 5er attached 

Front axle - 4820

Rear axle - 7120

Truck and 5er front axle only - 18420

Total combo - 25600

5er (both axles) attached to truck - 14500

5er (rear axle) attached to truck - 6860

 

If I am reading the numbers correctly;

Pin weight is 3240 (loaded rear axle - unloaded rear axle = pin weight)

5er weight is 16980 (total combo weight - truck only weight = loaded 5er weight)

 

Some of the other numbers don't add up though.  Am I overthinking it?

 

At least I am within parameters.

Truck GVWR - 13000

GAWR F - 5600

GAWR R - 9375

Truck GCWR - 29200

5er GVWR - 18465

GAWR - 8000 (x2)

Listed CCC- 2822

[Chad Heiser]

5 hours ago, remoandiris said:

Finally got my loaded truck/5er weighed.  Still have to get the unloaded 5er weights.  That will happen in a week or two.  

Truck only (hitch installed)

Front axle - 4740

Rear axle - 3880

Total truck weight 8620

The above weights are self explanatory.

Truck with loaded 5er attached 

Front axle - 4820 - front axle weight increased by 80 pounds.  This is part of your pin weight.

Rear axle - 7120 - rear axle weight increased by 3240 pounds.  This is also pin weight.

Your total pin weight by adding these two numbers together is 3320,.

Truck and 5er front axle only - 18420 - I'm not sure exactly what you mean by this.  If you mean only the front axle of the trailer was on the scale and the rear axle was not and you assume your total combined weight is correct at 25600 then your rear trailer axle weighs 7180 lbs (25600 - 18420 = 7180).  This does not match the calculations below.

Total combo - 25600 - Did this come straight off the weight ticket or did you calculate it somehow?  I get 26440 for your total weight.  See below.

5er (both axles) attached to truck - 14500 - This is self explanatory and should be easy to calculate on a typical truck scale.

5er (rear axle) attached to truck - 6860 - I'm not sure exactly what you mean by this and it doesn't match above numbers.  Was this a calculated number you came up with or did you just place the rear axle of the trailer on a scale by itself?  If this number is assumed to be correct, then the front axle of the 5er is 7640.  I came up with this by subtracting your listed rear axle weight from the total 5er axle weight (14500 - 6860 = 7640).  This does not match the calculations above and is way to much spread in weight between an axle pair on a trailer.  Assuming these numbers are correct (which I am not sure of), this would tell me your trailer is sitting very nose low adding weight to the front trailer axle and removing it from the rear trailer axle.

Also, if the combined weight of the two vehicles (truck and 5er) was 25600, that does not add up when you add the loaded truck front axle (4820) + the loaded truck rear axle (7120) + both 5er axles (14500).  These numbers give 4820 + 7120 + 14500 = 26440.  I'm not sure how this came about or why it doesn't match the number you list.

If I am reading the numbers correctly;

Pin weight is 3240 (loaded rear axle - unloaded rear axle = pin weight)  - Your pin weight also includes the load added to the trucks front axle.  The pin weight will equal the total combination weight (you say 25600, but I'm not sure if that is correct) - total trailer axle weight (14500) - unloaded truck weight (8620).  With your numbers that is 25600 - 14500 - 8620 = 2480.  This seems very light and doesn't match above.

5er weight is 16980 (total combo weight - truck only weight = loaded 5er weight) - this is correct, assuming your numbers are correct (which I am not sure about).

 

Some of the other numbers don't add up though.  Am I overthinking it?

 

At least I am within parameters.

Truck GVWR - 13000

GAWR F - 5600

GAWR R - 9375

Truck GCWR - 29200

5er GVWR - 18465

GAWR - 8000 (x2)

Listed CCC- 2822

See my embedded responses.

[remoandiris]

35 minutes ago, Chad Heiser said:

See my embedded responses.

Yeah, that's what I was saying.  All the numbers weren't adding up.  The total combo weight is off the scale's digital readout.

The weigh station was a single slab at my local moving company.  First I pulled onto it with the truck's front axle and got a weight.  Then the whole truck and got a weight, then the truck and the trailer's front axle, then the truck and both trailer axles, then I pulled the truck off and got both trailer axles and finally only the trailer's rear axle.  

I did a lot of walking from my truck to the scale's digital readout and back.

 

[Yarome]

There seems to be some issues with some of these numbers... or at least how they are defined. My math is working out closer to Chads. You're getting fairly close on some of your ratings. I don't know how "loaded" your 5er is or how you had your TV configured while weighing, but as it sits (and using some of the adjusted figures from the OP) you're pushing 90% on your 5ers axles and 96.5% of your 5er's GVWR. Your TV's GVWR and GCVW are pushing 91% and 90% respectively.

[By your numbers, your 5er's total weight is 17,820 vs. 16,980. (14.5k on your axles + 3320 pin weight).]

I don't know your TV's engine, gear ratio specifications, tire ratings all the way 'round or other add-ons you might have, but something to bear in mind. If you are a full-timer that puts on miles and/or makes mountain range crossings on a somewhat regular basis your load out, as it sits, would be considered by many to be maxed. 80% being a fairly widely accepted safety margin for continuous towing. The likelyhood of driving under adverse road/weather conditions increasing exponentially.

Food for thought.

[Yarome]

19 minutes ago, remoandiris said:

First I pulled onto it with the truck's front axle and got a weight. 

I would also agree with Chad that your 5er individual axle weights are widely disproportionate and "will" likely cause you issues if not corrected.

You might also consider getting weights on each individual tire. That will help to get your loads balanced and ensure you're getting enough pin weight while still getting your 5er axles balanced out. 

[remoandiris]

7 minutes ago, Yarome said:

I would also agree with Chad that your 5er individual axle weights are widely disproportionate and "will" likely cause you issues if not corrected.

Maybe.  Or there is simply simply something wrong with the manner it was weighed.  That isn't rocket science, so I am not sure how it could have been dorked up.

The only saving grace I can think of is I have been rolling like this for 3 years with no issues. 

I think I'll swing back by the moving company on the way home and do it again.  

[Alie&Jim's Carrilite]

Were you setting your parking brake while the rear wheels were on the scale?  That will give false readings.

[Chalkie]

4 minutes ago, Alie&Jim's Carrilite said:

Were you setting your parking brake while the rear wheels were on the scale?  That will give false readings.

That is an interesting observation, one I am not willing to dispute, but in the interest of learning could you explain this more?

[Yarome]

2 hours ago, Chalkie said:

That is an interesting observation, one I am not willing to dispute, but in the interest of learning could you explain this more?

Chalkie - It depends. Most TV + 5er's can set their brakes. Class A's and the like... not so much. The issue being rigs that apply brakes on all axles (ie., air brakes). .. and you're on "plate" cat scales. Engaging all brakes can "tweak" the scale pads so they won't move as freely as they should and bunk up your weight readings. Rigs that only apply brakes on one axle are typically fine.

Not to mention that those that apply brakes to multiple axles don't generally apply braking pressure equally. The best practice? Don't. I've yet to meet anyone that's died by rolling off a scale when the little arrow points to the big P.

[I'mdonewiththis forum]

Remo, was the scale by chance elevated and there was a ramp built on both ends of it?

[Star Dreamer]

Did you unhook the trailer and drive just the truck on the scale, then hooked back up and drove the truck and the trailer on the scale? If not then your weights are not correct. If you did then your weights are off because you are getting a transfer of weight from an axle that is not on the scale to the axle on the ground or the opposite due to the approach not being perfectly level. With the platform scale you can get an accurate total truck weight without the trailer and a total combination weight which will allow you to calculate the trailer weight but will be hard to do individual axle weights.

You either need to go to a truck scale that can weigh individual axles or get individual wheel weights done like at a rally.

[remoandiris]

16 hours ago, Alie&Jim's Carrilite said:

Were you setting your parking brake while the rear wheels were on the scale?  That will give false readings.

No.  I put the truck in park, then walked in to the building and looked at the digital readout.

[remoandiris]

14 hours ago, Mntom said:

Remo, was the scale by chance elevated and there was a ramp built on both ends of it?

No.  It was level with the rest of the driveway.

[remoandiris]

11 hours ago, Star Dreamer said:

Did you unhook the trailer and drive just the truck on the scale, then hooked back up and drove the truck and the trailer on the scale? If not then your weights are not correct. If you did then your weights are off because you are getting a transfer of weight from an axle that is not on the scale to the axle on the ground or the opposite due to the approach not being perfectly level. With the platform scale you can get an accurate total truck weight without the trailer and a total combination weight which will allow you to calculate the trailer weight but will be hard to do individual axle weights.

You either need to go to a truck scale that can weigh individual axles or get individual wheel weights done like at a rally.

I weighed my truck by itself over a week ago.  Full tank of gas, hitch installed.  The day I weighed the whole rig, the truck burned about 2 gallons on the way to the scale.

I think your third sentence, about transfer weight, is most probable.  

[Big5er]

Remo, how many pads (scales) did your scale have? Three, like a CAT scale? Or is it one big scale? 

If it is 3 scales, how did you center your vehicle on it?
Like this?

This is the advantage of a CAT scale. It's real easy to "split" the tow vehicle, but not to easy to split the trailer, even if you pull the truck off the scale on what "looks" to be a fairly level surface due to weight shift. On a big scale you need to weigh the combination all at once.

The only other way to do it and get accurate individual axle weights is (as previously mentioned) take it to a rally where there is someone weighing RV's. They will use individual scales and give you individual tire position weights. There are several companies that can do that for you at a reasonable cost such as

http://rvsafety.com/weighing-teams and https://escapees.com/knowledge/smartweigh

[remoandiris]

13 hours ago, Big5er said:

Remo, how many pads (scales) did your scale have? Three, like a CAT scale? Or is it one big scale? 

 

It was one big scale.

[noteven]

reo  - I think you were facing the wrong way on the scale 

[I'mdonewiththis forum]

It sounds to me like there is a problem with the calibration of the scale.

[remoandiris]

There is a CAT scale a few miles from the park I am at.  It is directly en route to the next park I will go to.  So, I think I'll stop there and get a weight, if it has the three scales as Big 5er diagrahmed.  Will have the dogs, cat, and wife in the truck, so that will be about as close as it can be to our actual weight traveling down the road.

[Chad Heiser]

1 hour ago, remoandiris said:

There is a CAT scale a few miles from the park I am at.  It is directly en route to the next park I will go to.  So, I think I'll stop there and get a weight, if it has the three scales as Big 5er diagrahmed.  Will have the dogs, cat, and wife in the truck, so that will be about as close as it can be to our actual weight traveling down the road.

If you do that, run across the scales fully loaded then go in and get your weight ticket, drop the trailer and run across the scales again for a re-weigh (typically $2 more for the re-weigh) with just the truck.  With these two weigh tickets, you can calculate all your weights (except individual axle on the trailer). 

I'll be doing this again over Thanksgiving to see what changes came about with my new straight down pin box.

[remoandiris]

Got it done today at a CAT -certified scale.

Truck only;

Front axle - 5080

Rear - 4060

Gross - 9140

 

Truck and trailer

Front - 5060

Rear - 7220

Trailer - 14360

Combined gross - 26640

 

Lost 20 lb off the front with the 5er attached. 

[Chad Heiser]

1 minute ago, remoandiris said:

Got it done today at a CAT -certified scale.

Truck only;

Front axle - 5080

Rear - 4060

Gross - 9140

 

Truck and trailer

Front - 5060

Rear - 7220

Trailer - 14360

Combined gross - 26640

 

Lost 20 lb off the front with the 5er attached. 

So with those numbers:

Trailer weight = 17500 (Combined Gross - Truck Gross)

Pin weight = 3140 (Trailer weight - trailer axle weight) or (Truck rear axle w/trailer - truck rear axle empty - weight transferred from truck front axle to truck rear axle with trailer connected)

This means you are carrying approximately 18% (3140/17500=0.179) of your total trailer weight on the pin.  This isn't horrible, but is a little low.

You are running at about 91% of your trucks gross combined weight rating (GCWR) (26640/29200=0.912). 

Your trucks front axle is at 90% (5060/5600=0.903)

Your trucks rear axle is at 77% (7220/9375=0.770)

Your trailer axles are at 90% (14360/16000=0.8975)

Again not horrible, but creeping up on some of the limits.  I like to be in the 80% to 85% of my ratings to have a little cushion and not beat things up.

Overall, everything looks pretty good.  The only thing I might do is try to shift some of the trailer weight forward to add a little pin weight.  Your truck axle can handle a little more weight and it may help your overall towing experience.  You do have to be careful you don't overload the truck GVWR though.  It is 13000 lbs and you are at 12280 lbs as loaded during this weight session (truck only gross + pin weight).

[remoandiris]

I appreciate your interpretation and advice.  I am a little disappointed I can't use a SRW with this 5er, but it is what it is.

[Dave]

G'day All:

 

Weighing on a single pad scale is rarely good for anything other than gross combination weights.  The reason is you rarely can get the full combination level with only one axle on the scale.  One or the other, truck or trailer is usually on the ramp.  This renders the series of weighs inaccurate.

 

You need a multi-pad scale found at most truck stops.  But even there, you need to make sure you can "split trailer axles".  Many truck stops have CAT scales with four pads that allows you to weigh steering axle, drive axle, and split trailer axles on pads 3 and 4.  However, there are some CAT scales at leading brand truck stops that have four pads, but adds pads 3 and 4 together in the computer and will just give you the sum of all trailer axles.  So ask at the fuel desk before weighing to make sure you can split trailer axles for individual trailer axle weights.  The Petro truck stop on the north side of Las Vegas, NV on I-15 used to have just type.  It's been a couple of years since I weighed there.

 

Assuming you can split trailer axles, pull up to just putting the steering axle on the first pad.  You don't need to be centered front to rear.  This is just a starting point.

 

Look to make sure your drive axle is on the second pad by itself.  Then look at your trailer axles.  Pull forward just enough to get one trailer axle on the third pad all by itself.  Call the scale master and take a weight.  You're looking for the steer axle on pad 1, drive axle on pad 2, front trailer axle on pad 3 and one or two rear trailer axles on pad 4.  If you only have two trailer axles, you're finished with this weigh.  Pull off to the RV parking, drop the trailer, pull the tow vehicle back onto the scale splitting the two axles on the front two pads.  Call the scale master and take a re-weigh of the truck only.  Now you have everything you need.

 

If you have three trailer axles, after you weigh with trailer axles 1 and 2 split, pull forward just enough to split between trailer axles 2 and 3.  Call the scale master to take another reading.  Then pull off, drop the trailer and pull the tow vehicle back onto the scale for a truck only weight.

 

Now that I said that, I'll tell you that just as your steering axle rolls onto pad 1, your drive axle may be well forward on pad 2.  You may only be able to move the rig five to ten feet before one or the other comes off the pad.  This doesn't allow for much flexibility to split your trailer axles.  Remember, these scales are designed for big trucks.  You may have all three trailer axles on pad 3.  In this case, take a weight for the loaded steering axle, loaded drive axle and total trailer axles.  Then pull around and back onto the scale and use pads 3 and 4 splitting trailer axles 1 and 2, take a weight reading, pull forward just enough to split trailer axles 2 and 3 and take another weight reading.  Scratch through the steer and drive axle weights on these scale tickets so you don't use those figures.  You already have made sure you have a good weight for the loaded truck from the first pass on the scale.  On this second pass on the scale, all you're interested in is trailer axle weights.

 

The first weigh may cost perhaps $7 or $8.  Re-weighs might be another dollar or two each.  It's well worth the pocket change if you've not done it before.

 

Before you pull onto the scale, park in the RV parking and go inside to the fuel desk.  Tell the clerk what you'd like to do.  If you haven't called ahead to ask about splitting trailer axles, ask about that now.  If you're told that only the sum of pads 3 and 4 are printed out, don't bother with it.  Call the next truck stop along your route and ask.

 

On every scale, do NOT drop the trailer on the scale for any reason.  Do not back up on a scale.  Move and stop gently on any scale.  Furthermore, do not waste time on the scale.  You may want to have your little radios handy so the wife or co-driver can spot you splitting axles and then get back in the truck quickly before you call the scale master.  I would advise calling ahead the day before to ask questions.  One thing I would suggest is to ask what time of day is their scale rarely used and plan to be there during their slow time.  Depending on the time of day, you may find a line of big trucks waiting to weigh.  You don't want to get in the middle of a bunch of truck drivers trying to weigh and get on the road with their new loads.  That's how they make their money.

 

Dave

[Big5er]

On 5/29/2018 at 11:18 AM, Dave said:

• You need a multi-pad scale found at most truck stops.  But even there, you need to make sure you can "split trailer axles". 

 The problem with truck stop scales is that you get a single weight for each axle. With an RV the weight distribution side to side is just as important as the overall weight. 

The only way to obtain realistic weights for an RV is a good set of portable wheel load scales.