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Sherline Tongue Scale - Using, Storing & Helpful Info

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  • Sherline Tongue Scale - Using, Storing & Helpful Info

    This information was posted in another forum quite awhile ago and think it will be helpful to repeat here. While I started the thread, several members contributed significant information that I've also included in this post, so a shout out to Cate&Rob , Chiefblueman , and gbkims. Hopefully I didn't miss anyone--if I did it wasn't on purpose!

    First: there's going to be a weight difference if you put your scale on the coupler or on the powered tongue jack. From the manual:

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    The first time I tried it on my 315RLTS (almost two years ago!) these were the results: the tongue weight with the scale under the power jack (1075-lbs) was higher than the tongue weight measured at the coupler (950-lbs). It is easier (IMO) to weigh using the power jack than to weigh at the coupler.

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    Another feature of the Sherline is the gauges can be swapped. (There are two different ranges available--the exact model of gauge depends on the model scale owned. See https://www.sherline.com/product/800...acement-gauge/ )

    Finally, here is how I store my scale. (Box is from Harbor Freight. Make sure and store with the scale vertical per the owner's manual!)

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    Questions? Fire away.

    -Howard



    Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

    Howard, 2017 Ford F-350 DRW, '19 315RLTSPlus

  • #2
    Forgive me if I'm not understanding all this but here goes.

    Most people are towing with a WDH and in my case I'll never tow my trailer without it...... So seems like the information from this type of scale is sort of useless since this only gives you a tongue weight without a WDH.

    Am I missing something?
    Charles and Susan
    2021 Ram 3500 6.4 Hemi, 4x4 CCSB
    Equalizer w/ 1,000 lb bars
    2020 Imagine 2600RB

    Comment


    • #3
      Originally posted by ckreef View Post
      Forgive me if I'm not understanding all this but here goes.

      Most people are towing with a WDH and in my case I'll never tow my trailer without it...... So seems like the information from this type of scale is sort of useless since this only gives you a tongue weight without a WDH.

      Am I missing something?
      A WDH does not, will not, and cannot correct a trailer that does not have enough tongue weight. I'm exaggerating, but a 10,000 lbs trailer with a tongue weight of 200 lbs will quickly turn into accident. (200 / 10000= 2% tongue weight)

      Going the other way isn't good, either. With 5,000 lbs on the tongue (50% tongue weight) the hitch will likely bend right off the tow vehicle or the front "A" frame of the trailer will fail. Again, an exaggeration but the point is valid.

      So what's the "right" tongue weight? According to almost every tow website, a percentage 10-15% of the trailer's gross weight (5vr's, which have a pin weight, are different) is the right value.

      So how do you know if your trailer's tongue weight is in this zone?

      Weigh the trailer. To do that, go across a CAT scale with your trailer hooked up to your tow vehicle (TV) and get the total weight. Park somewhere safe and disconnect the trailer from the TV. Go back across the CAT scale with just the TV to get it's weight. Subtract the second gross weight from the first gross weight. Voila'--you know how much your trailer weighs.

      Example: Gross Weight of just the TV is 9280. Gross weight of TV+trailer is 20160. The trailer weighs 10,880 lbs. (These are actual numbers from old weight slips.)

      I could do more math to figure out the tongue weight from the CAT scale slips but that's not what this thread is about, so I'm going to skip that part. Let's stay with knowing the trailer weighs 10,880 lbs.

      Back in the driveway, unhooked from the TV, what range should the Sherline show for a tongue weight? Assuming the measurement is taken with the scale under the tongue jack, ideally I'd be looking for a measurement between 1,300 and 1,500 lbs (12-14%).

      It is easy to experiment with loading your trailer and verifying the results on the tongue weight using the Sherline scale.

      So what is the purpose of the WDH? It doesn't change the actual tongue weight, but it does distribute where it is carried to the front axle of the TV (lowers front end to improve braking and headlight aiming) and also back to the trailer's axles, alleviating some of the load "felt" by the hitch. Think of it like trying to lift and hold up a heavy board by the end. Now a friend comes and helps carry some of the load. Doesn't change the weight of the board, but some of the load has shifted to your friend from yourself. Not an exact analogy, but it's close. (I hope.)

      Does that make any sense?

      If you want an example of calculating tongue weight from CAT scale slips, let me know and I'll add it to this thread.


      Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

      Howard, 2017 Ford F-350 DRW, '19 315RLTSPlus

      Comment


      • #4
        That makes sense sort of - but here is what I found....

        Truck and trailer loaded for camp. Equalizer with 1,000# bars and 4 washers (as setup by dealer). Took to CAT Scale and put the weights through the Travel Trailer Towing calculator as linked to on this forum. My tongue weight ended up at 1080#'s. Basically 15.7%

        When I readjusted to 5 1/2 washers I went back over the CAT Scale. I now had a tongue weight 840#s 12.5%. Also my drive axle weight went down and my steer axle and trailer axles both increased. So yes the WDH did shift some weight off my hitch and drive axle and put that weight onto my steer and trailer axles.

        So I guess using a scale like that to help readjust your trailer loading would work but in the end with a properly setup WDH your effective tongue weight will be less. Am I right?

        Charles and Susan
        2021 Ram 3500 6.4 Hemi, 4x4 CCSB
        Equalizer w/ 1,000 lb bars
        2020 Imagine 2600RB

        Comment


        • #5
          Originally posted by ckreef View Post
          That makes sense sort of - but here is what I found....

          Truck and trailer loaded for camp. Equalizer with 1,000# bars and 4 washers (as setup by dealer). Took to CAT Scale and put the weights through the Travel Trailer Towing calculator as linked to on this forum. My tongue weight ended up at 1080#'s. Basically 15.7%

          When I readjusted to 5 1/2 washers I went back over the CAT Scale. I now had a tongue weight 840#s 12.5%. Also my drive axle weight went down and my steer axle and trailer axles both increased. So yes the WDH did shift some weight off my hitch and drive axle and put that weight onto my steer and trailer axles.

          So I guess using a scale like that to help readjust your trailer loading would work but in the end with a properly setup WDH your effective tongue weight will be less. Am I right?
          No, the tongue weight doesn't change. I know that doesn't sound right but read on!

          I posted about the Sherline in respond to this thread: https://gdrvowners.com/towing-and-hi...y-while-towing and this one https://gdrvowners.com/towing-and-hi...-towing-2800bh

          The OP of the second thread, MikeG90 , asked a similar question in post #34 and I responded in 35. I'd always assumed the tongue weight changed due to the WDH but didn't know so I did some research. I consider etrailer's technical responses reliable (usually) and this was their response to a similar question about tongue weight and WDHs:

          Weight distribution works to distribute the tongue weight of a trailer up to the front axle of the tow vehicle so that it will sit more level and handle/brake better. That being said the systems do not "reduce" tongue weight or allow you to tow beyond the capacities of the vehicle. The tension on the spring bars essentially lifts up on the tongue, figuratively "holding" some of the tongue's weight. This causes a shift in the distribution of the weight off of the vehicle's rear axle to all of the axles in the entire setup.

          What I conclude from their response is you can not determine the actual tongue weight using CAT scale weights with the WDH engaged. Either remove the bars (or release all the tension on them) prior to weighing on the CAT scale or use the Sherline to get the actual tongue weight.

          I just recently came to this conclusion--and there's a lot of individuals on this forum that know a lot about this stuff--so someone chime in if you think I've gone off a cliff here.

          -Howard
          Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

          Howard, 2017 Ford F-350 DRW, '19 315RLTSPlus

          Comment


          • #6
            I know that calculator I used required 3 weights. Truck only. Truck and trailer/no weight distribution bars and truck and trailer/weight distribution bars installed. I don't know the formulas behind all that I just know the results.

            Just trying to understand all this.

            Later tonight I'll read the links you posted. TY for trying to educate me properly.



            ​​​
            Charles and Susan
            2021 Ram 3500 6.4 Hemi, 4x4 CCSB
            Equalizer w/ 1,000 lb bars
            2020 Imagine 2600RB

            Comment


            • #7
              A Sherline scale can also be used to measure individual wheel weight.

              Measure the distance from axle tube to ground at the position to be weighed. You will need to return to this measurement to make sure that you are measuring exactly what that tire was carrying with all four tires on the ground. Lift just this axle end at the U bolts and remove the tire. Lower this supporting jack to just below your original measurement to the ground. Now, lift with another jack and the Sherline scale until the axle end just lifts off its supporting jack and returns to the original distance from the ground.

              I made a hardwood lifting block that slides over the two lower wheel studs to make this lift more secure, but you will only be lifting 1/8" or less off the supporting jack.

              To make this weight as accurate as possible, the front of the trailer should be supported at the hitch ball or 5th wheel pin (this is more important on 5th wheels where the front legs are well back from the pin location).

              Just another project to keep us busy while we all stay home .

              Rob
              Attached Files
              Cate & Rob
              (with Border Collies Molly & Angel and their kitty Gracie)
              2015 Reflection 303RLS
              2014 Ecoboost F150 with Heavy Duty Payload Package
              Bayham, Ontario, Canada

              Comment


              • #8
                Very interesting Rob! I always wondered how you could get a weight at each wheel. The Cat Scale has no provision for this.

                Comment


                • #9
                  howson have you checked that scale? I saw this video and he was having issues getting the scale to repeat measurements. https://www.youtube.com/watch?v=XBYy6qIcEkQ
                  Tow Vehicle: 2018 GMC K2500 Denali Diesel
                  Coach: 303RLS Delivered March 5, 2021

                  Comment


                  • #10
                    Originally posted by Jlawles2 View Post
                    howson have you checked that scale? I saw this video and he was having issues getting the scale to repeat measurements. https://www.youtube.com/watch?v=XBYy6qIcEkQ
                    You beat me to it. I was going to post the same thing. I have a regular Sherline 5000Lb scale and I get different Pin weights every time. The way I use it is I stack all of my Lynx Levelers under the Pin and then put the scale on top of them. Then I lower the pin down onto the scale. It ends up being a good height so when the pin is on the scale, the RV is pretty close to being level. Because I know the scale will give me different weights, I will raise and lower the pin several times onto the scale and then take the average of the weights and call it good. The readings are usually from 50-150 pounds different. I don't believe you can get really accurate rates with those scales. They're just too small and weights we're checking are heavy but they're better than nothing especially if a CAT scale is a long distance away.
                    2020 Silverado 2500HD LT, CC, 4X4 6.6 Duramax 3310LB Payload
                    2021 Grand Design Reflection 311BHS

                    Location: Southern Tier of Western NY

                    Comment


                    • #11
                      Jlawles2

                      I have used my Sherline scale extensively to measure pin weight, and individual wheel weight. All readings seem reasonable and repeatable. The Sherline measurement of my unloaded Reflection pin weight exactly matched the UVW number on the paperwork from Grand Design. Further to this, I used the Sherline as the "load cell" for measuring spring load vs deflection (on a fixture built with my hydraulic press . . . see picture) across an assortment of OE and aftermarket springs. What I measured, closely matched manufacturer's specs for each of these different springs. (This was part of a project that several forum members worked on to figure out how to match spring strength to weight carried for trailers with significantly different left-to-right weight balance).

                      All this to say that a Sherline scale is accurate if handled properly. As noted in the video that you linked . . . if you pick up the scale by the top (the piston) you can introduce an air bubble into the hydraulic chamber which will cause readings to be varied and inaccurate. Sherline specifically warns of this in the literature that comes with the scale.

                      Rob

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                      Cate & Rob
                      (with Border Collies Molly & Angel and their kitty Gracie)
                      2015 Reflection 303RLS
                      2014 Ecoboost F150 with Heavy Duty Payload Package
                      Bayham, Ontario, Canada

                      Comment


                      • #12
                        Cate&Rob Nice setup Rob. I just wondered if you had seen differences. I'm guessing your scale is older than the one he was showing. Wonder if that has anything to do with it's accuracy. I also wondered about it possibly getting side loaded when he was using the forklift which threw it off.

                        I've 50,000 psi gauges get knocked off by the pump when only going to 1/2 the pressure, so they can be quite delicate things.
                        Tow Vehicle: 2018 GMC K2500 Denali Diesel
                        Coach: 303RLS Delivered March 5, 2021

                        Comment


                        • #13
                          Jlawles2

                          A Sherline scale is a pretty simple hydraulic device. As long as the two O rings don't leak and there is no air in the system, readings should be repeatable. I know that I often cycled the same spring several times and saw readings within the 2% accuracy claimed by Sherline. There is the possibility of gauge calibration error and this might skew the readings but should not cause random variation. Sherline does caution against side loading. To measure pin weight, I use a rigid tripod and the Sherline scale. I can see where using the hitch adapter and the rear suspension of the truck could introduce variation.

                          Rob

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                          Cate & Rob
                          (with Border Collies Molly & Angel and their kitty Gracie)
                          2015 Reflection 303RLS
                          2014 Ecoboost F150 with Heavy Duty Payload Package
                          Bayham, Ontario, Canada

                          Comment


                          • #14
                            Originally posted by Cate&Rob View Post
                            Jlawles2

                            A Sherline scale is a pretty simple hydraulic device. As long as the two O rings don't leak and there is no air in the system, readings should be repeatable. I know that I often cycled the same spring several times and saw readings within the 2% accuracy claimed by Sherline. There is the possibility of gauge calibration error and this might skew the readings but should not cause random variation. Sherline does caution against side loading. To measure pin weight, I use a rigid tripod and the Sherline scale. I can see where using the hitch adapter and the rear suspension of the truck could introduce variation.

                            Rob

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                            X2 on the introduction of air causing error. Even a small bubble will skew the measurement.

                            Jim
                            2017 Imagine 2600RB
                            2015 GMC Sierra 4x4

                            Comment


                            • #15
                              Jlawles2

                              As Rob mentioned, it's not only the handling but storage. Cate&Rob "saved" me when I showed how I stored mine lying flat in a case. (Wrong!) Now it stands up in the case as the manual (yep--I didn't read the manual...) states is required.
                              Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

                              Howard, 2017 Ford F-350 DRW, '19 315RLTSPlus

                              Comment

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