Need More Help Understanding Weights

[Pat Cassity]

For those of you that helped me before with this same issue, I can't thank you enough. Now I need your help again. We picked up our new TT yesterday and today I decided to take to the local CAT scale to have it weighed. I was very unhappy with the way it handled on the 400 mile trip home yesterday. There seemed to be much more 'trailer movement' than what I was used to with my other trailer, before the accident. The weigh tickets are attached in order of the weights taken. The total weights are a bit confusing as I would have thought this would stay constant. Hopefully my weighing process was correct. Now I need help under standing the the results. Thanks!

TV - 2014 Yukon Denali - Maximum Trailer Weight Rating 8,500 lbs
TT - 2015 Airstream Serenity 27FB - GVWR 7,600 lbs / Tongue weight ( per Airstream) 791 lbs.

Ticket 1 - TV Steer axle on scale 1, drive axle on scale 2, TT on scale 3. Blue Ox Hitch on link 7
Ticket 2 - TV only. Steer Axle on scale 1, Drive axle on scale 2
Ticket 3 - Same as Ticket 1 except Blue Ox Hitch on link 8
Ticket 4 - Same set up as tickets 1and 3 but with weight distribution bars not attached.



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[A W Warn]

Those are some pretty large discrepancies in the gross weight totals. Obviously, the first photo includes a passenger that was not weighed in the last two photos. The last two photos puzzle me, since I've never notice more than 20 lbs difference of the gross in any weighings that I have done.

[SSquared]

Originally Posted by Pat Cassity

For those of you that helped me before with this same issue, I can't thank you enough. Now I need your help again. We picked up our new TT yesterday and today I decided to take to the local CAT scale to have it weighed. I was very unhappy with the way it handled on the 400 mile trip home yesterday. There seemed to be much more 'trailer movement' than what I was used to with my other trailer, before the accident. The weigh tickets are attached in order of the weights taken. The total weights are a bit confusing as I would have thought this would stay constant. Hopefully my weighing process was correct. Now I need help under standing the the results. Thanks!

TV - 2014 Yukon Denali - Maximum Trailer Weight Rating 8,500 lbs
TT - 2015 Airstream Serenity 27FB - GVWR 7,600 lbs / Tongue weight ( per Airstream) 791 lbs.

Ticket 1 - TV Steer axle on scale 1, drive axle on scale 2, TT on scale 3. Blue Ox Hitch on link 7
Ticket 2 - TV only. Steer Axle on scale 1, Drive axle on scale 2
Ticket 3 - Same as Ticket 1 except Blue Ox Hitch on link 8
Ticket 4 - Same set up as tickets 1and 3 but with weight distribution bars not attached.
Attachment 229971Attachment 229972Attachment 229973Attachment 229974


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I see some surprising things here.

For the three tickets that include the trailer, the total combined weights are 12,720, 12,400, and 12,460. That is too big of a range to be right. The scales read to the nearest 20 pounds, and when I have done multiple weighings like you did, my totals have all been +/- 20 pounds. Did you get all these weights at the same time, with the same people in the car? Could it be that you had the front axle touching the front of the scale, or the rear at the back, so that the full weight was not seen?

Comparing your Yukon-only weight of 6120 with the others, I see the Drive + Steer values of 6980, 6920, and 7220. That gives tongue weight of and 860, 800, 1100. You said one of the weights was with the bars not attached. When the bars are not attached, the front axle is the lightest, and the drive axle the heaviest. That would be the first ticket (2840 + 4140 + 5740 = 12,720).

Is your Yukon the short wheelbase version? If so, your numbers should look similar to some of mine. I have a 2010 short wheelbase Yukon Denali and a 2013 25FB Airstream. I used to use a Blue Ox Sway Pro.

Here are some numbers from our second outing. This was coming home from a rally with empty black and gray tanks, some water in the fresh tank, and camping gear aboard. Two adults in the Yukon.

Yukon solo: 3080 Steer, 3040 Drive, Total 6120
Combined with bars not attached: 2600 Steer, 4420 Drive, 5160 Trailer axles, Total 12180
Combined with bars at link 7: 3000 Steer, 3880 Drive, 5300 Trailer axles, Total 12180

Comparing the first with second, you can see the Yukon axle sum went from 6120 to 7020: A 900 pound increase, which says the tongue weight is 900 pounds. (at the rally, the tongue was weight with a portable scale, which showed 950 pounds, with some water in the waste tanks).

The front axle got lighter by 480 pounds, which is 53% of the tongue weight.
If you have the short wheelbase Yukon, you should see about the same percentage lightening of your axles.

The more I look at your numbers and compare them with mine, the more I think there is something funny about them--empty vs full fuel tank in the Yukon, empty vs. loaded trailer, passengers vs. no passengers, or something.

I will say that we were new to towing larger trailers when we got our Airstream, and the trailer seemed to move around more that we liked. It did improve when we cranked the Blue Ox bars tighter. I suggest you try that, and maybe go to heavier bars if you do not already have the heaviest.

Good luck.

[cwf]

Pat.. congrats!
Looks like you LOST 320# from 1-3 and but gained back 60# by #4.. Weird.

on #1 it looks like you transferred weight to the trailer...??

Weird... not making sense to me...

[SteveSueMac]

Hi there. So I'm not 100% sure I've got this right, but if the order of the tickets shows up in the app the way you identified them you're saying the steer axle on the TV went up 80# (3040 to 3120) when you attached the trailer with no WD applied. That doesn't make sense to me. Attaching the trailer without WD should lift weight off the steer axle.

When you applied 7 links, the total weight of the rig went up 260# (12460 to 12720) that also doesn't make sense to me. You have 3 different total rig weights and they should all be the same (+/- 20# scale tolerance).

When you applied 8 links you added 100# back to the TV steer axle from 7 links (2840 to 2940) which is 100# lighter than TV steer alone (3040) but it's hard to say how much you've actually restored to the steer axle because your ticket for connecting the trailer without applying WD ADDED 80# to your steer axle rather than lifted weight off....

So - I'm a little confused and don't know how accurate this will be but using your 8 link ticket, it looks like your trailer is 6280# (total weight of 12400 - weight of your TV 6120). That 6280 less the 5240 weight of your trailer on the no WD ticket might indicate a 1040# tongue estimate (not at all accurate - that's a rule of thumb - and because of the weight fluctuations in the total rig across tickets, I think something didn't happen correctly at the scales - were you always in or out of the TV the same time the same way each weighing? I did that wrong and Ron G accurately guessed my personal weight from the tickets I posted :-) ).

Do I have any of that right? If so - let's see if we can figure out how any of that affects sway.

[Pat Cassity]

I have the short wheelbase Yukon Denali. I had a feeling that there was going to be a problem because the person operating the scales inside was unsure of how to process the weights for what I was trying to accomplish. Also, I just realized that when I removed the bars for ticket no. 4 I placed them on the scale instead off to the side. So, the drive axle weight on ticket 4 includes the weights of the bars. Probably around 30 lbs. I also think that she didn't give me enough time on one of the weighs, if not more to get back into the Yukon before weighing. I think that the most accurate ticket is no. 1. If 3 and 4 do not include my weight, that would be approximately 175lbs added to each drive weight, correct? It appears to me that the steer weight on tickets 1 and 3 are extremely light and could be why I had such poor handling on the drive back yesterday. Would you agree?


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[Pat Cassity]

Steve, you are correct about the order of the tickets.


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[SteveSueMac]

Pat - if you weigh 175#, first - mazel tov - I haven't been there since 3rd grade and second - if you're in the vehicle, that's split on both steer and drive axles - if you're outside the TV and standing on the steer axle plate then yes, all 175 would be shown there.

I don't think it's problem having the bars on the scale - they'd be there when you apply 7 or 8 links - so when applying 0 you'd still want to have their weight included.

Does your Yukon want 100% of whatever's lifted off your steer axle to be replaced? If so - it's possible you're only 100# off but it's hard to say with the tricky scale tix.

[Pat Cassity]

If one was to use only ticket numbers 1 and 2 and 4, and added approximately 182 lbs to ticket no. 4 to compensate for my weight ( and my clothes weight, which I didn't include when I stated 175 before) that may have been omitted, what would be your conclusion?


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[Pat Cassity]

Ok, I think we have the weight discrepancies figured out. My wife also exited the Yukon to help me remove the WD bars for the last weigh. The operator must have started the weighing before the both of us returned the vehicle. Our total weight is 315. That would put the total weight on ticket 4 at 12715.


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[A W Warn]

Since you do not really know how that missing weight would have been distributed, the only way to know is to weigh the vehicles again. Use the tow vehicle manufacturer's owners manual recommendations for weight transfer to make your plan/goals before you go. And, make sure the scale weigh master knows to wait for you to re-enter the tow vehicle.

[SSquared]

Originally Posted by Pat Cassity

Ok, I think we have the weight discrepancies figured out. My wife also exited the Yukon to help me remove the WD bars for the last weigh. The operator must have started the weighing before the both of us returned the vehicle. Our total weight is 315. That would put the total weight on ticket 4 at 12715.


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I picked up a pointer about using the CAT scales from an old thread. Get a stick like a broom handle, at least four feet long, five is better. Put a rubber cap on one end, or wrap it with something sticky (I used repair tape). Then when you are positioned on the scales, lean out and press the button with the sticky end of the stick. That way there is no getting in or out while on the scales. My stick is only four feet, and I have to open the door and stand with one foot on the running board to reach the button.

By the way, I never unhook or adjust bars on the scales. I drive off and on for each weigh.

[SteveSueMac]

Pat - I was in the middle of a LONG response which I lost when I exited the app to search for a piece of info ... Rrrrr. :-)

I'm going to guess that's good news since I remain confused - even more so with your latest info. The scales work in 20# segments so let's round up to 320# to be added to ticket 4 - this is your trailer attached without WD applied. As printed, ticket 4 doesn't make sense because it's saying you added 80# to the steer axle when you connected the trailer with no WD. What should happen is your steer axle should lose weight when you do that (drop 1000# of tongue weight on the rear of the Yukon and the front should lift up a bit, not gain 80#). If we add you and your wife back in to the Yukon, your 320# will hit 50%ea to the steer and drive axles adding 160# to each. That would mean your steer axle gained 240# when you added the trailer. Something doesn't add up.

I think a new set it tickets will help for sure - I had to do this 3 times at first to get a foundation I could work from. I actually love the process now - it's just so fun to have the data - your mileage may vary 😀

But for now - let's say my earlier guess based on the tickets says your trailer is about 6300#and your Yukon is about 200# lighter. I don't know whether that relationship has more to do with sway than the effectiveness of your WD system (though I'm sure others here have a more informed view they can share).

[Pat Cassity]

Yeah, you are correct. ticket 4 makes absolutely no sense. I will certainly re-weigh in the near future. Ssquared, love your suggestion about using the stick for the call button. I really believe getting in and out of the vehicle added to the problem. For the time being I am going to use the info. from tickets 1 and 2. I feel they are fairly accurate. If I am correct this would give me a tongue weight of 860 lbs. However, it also appears that I may have a problem with the way my Blue Ox hitch was setup by the dealer. They told me before I left that they struggled setting the head at the correct height because the Denali's automatic load control kept moving the rear of the vehicle up and down as they were trying to complete the installation. I do know that I have the recommended 1000lb WD bars. For my next weigh, I believe I will start on link 9 and see if that returns the steer axle to approximately 3040. However, if it does I am now concerned that I may be exceeding the maximum weight rating of the Denali of 7100lbs.


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[ROBERT CROSS]

Yep....re-weigh.

TV alone loaded for camping.

TV & AS with and without WD set, (with full camping load), rig must be LEVEL when WD set properly.

Notice I'm within 100lbs of the TV alone steering axle weight.




Bob

[SSquared]

Pat, for your reference, here are pictures of my rig with the Blue Ox. You can see how far down the shank the hitch head is attached. This gave me a level trailer.

Notice that the top of the shank is tilted up toward the trailer. This shows how much my Yukon's receiver was flexing under load. I eventually had Andy T. at Can-Am reinforce the hitch. At the same time, I changed to a different brand of hitch, so I can't say whether the reinforcing changed the behavior of the rig with the Blue Ox.

The wide view shows four and a half links exposed between the loop on the end of the bar, and the rotating chain bracket.

[ROBERT CROSS]

SS,

I was always told to install the chains with the open end toward the trailer.



Bob

[paiceman]

I think I'd go to another scale. You stated operator did not seem to know what was going on and the scale may not have been calibrated recently.

[Pat Cassity]

Robert, the information from your tickets are a big help. I used the percentage of weight of each axle from your ticket with WD applied and compared it to my ticket no 1, which I feel is the most accurate of the 4. It indicates that my steer axel was 1% (127lbs) light, my drive axle is 3% (381lbs) heavy, and my TA is 4% (509lbs) light. I am still going to re-weigh but its looking more and more like the setup from the dealer is bad.

[Msmoto]

I love these confusion states....because I do not feel so bad about trying to get the weight distribution gig figured out...

However, I am still in process of getting my unit fully adjusted, so I sent a question to Life As A Trucker asking about when the truck scales are least busy. It is my opinion, that the "set up" should be done by weighing once, driving off the scale and readjusting, then returning to the scale for the next weigh in. There is some "settling in" of the hitch after a few feet of driving and this can be accomplished in the weigh return route at a state inspection site.

If there is minimal traffic at the weigh station no one will get upset. I would avoid trying to cut into a line of truckers.....

More to come when I get this figured out....LOL