Jkdolan Posted May 5, 2019 Report Share Posted May 5, 2019 (edited) Just started full timing to see the country. Did a Smart Weigh with Escapees. Chevy 2017 3500 HD. Winnebago 39FB 5th wheel. B&W Hitch is installed in GM factory pucks/holes. Airlift Airbags Smart II System Truck only individual wheel weights. Front Left 2850 Front Right 2750 Rear Left 2300 Rear Right 2300 (Dually) Pretty even unloaded. Weight in truck distributed evenly. Truck and Trailer Front Left 3000 Front Right 2500 Rear Left 3900 Rear Right 4600 Truck is cockeyed/unbalanced 500 lb heavy on Front Left 700 lbs Heavy on Rear Right Logically if 5th wheel is putting weight on one side both front and back should be heavier on one side. If frame was bent it should show up in unloaded also. Any thoughts? Edited May 5, 2019 by Jkdolan Quote Link to comment Share on other sites More sharing options...
Garyp4951 Posted May 5, 2019 Report Share Posted May 5, 2019 What side is your fuel tank, and def tank on? Those are strange weights. Quote Link to comment Share on other sites More sharing options...
Jkdolan Posted May 5, 2019 Author Report Share Posted May 5, 2019 (edited) Thanks for question.Fuel tank spans the truck drivers side to pax side. Evenly distributed. DEF is only 30 or so pounds or so. Weight in truck distributed evenly. If not would show up in unmatched weight. Edited May 5, 2019 by Jkdolan Quote Link to comment Share on other sites More sharing options...
Second Chance Posted May 5, 2019 Report Share Posted May 5, 2019 Were you in the driver's seat for the weights? Just askin'... Rob Quote 2012 F350 CC LB DRW 6.7 2020 Solitude 310GK-R, MORryde IS, disc brakes, solar, DP windows Full-time since 8/2015 Link to comment Share on other sites More sharing options...
Jkdolan Posted May 5, 2019 Author Report Share Posted May 5, 2019 14 minutes ago, Second Chance said: Were you in the driver's seat for the weights? Just askin'... Rob Rob - Yes. I aint that heavy!!😎😎 Part of Smart Weigh is normal passenger configuration and full fuel. Quote Link to comment Share on other sites More sharing options...
mptjelgin Posted May 5, 2019 Report Share Posted May 5, 2019 A fifth wheel hitch sitting over the rear axle should have very little effect on front tire weights. Like less than 100 pounds. To add 250 pounds to one and subtract it from the other would take a heck of a twisting moment from the hitch. If everything was sitting on level ground, as I imagine it was, I would question the validity of those weights. Quote Mark & Teri 2021 Grand Designs Imagine 2500RL, 2019 Ford F-350 Mark & Teri's Travels Link to comment Share on other sites More sharing options...
Jkdolan Posted May 5, 2019 Author Report Share Posted May 5, 2019 Mark - Thanks. I agree on twisting part. They were doing multiple Smart Weighs that day. Scales should be good. But anything is possible!!! Quote Link to comment Share on other sites More sharing options...
jblo Posted May 8, 2019 Report Share Posted May 8, 2019 (edited) I would think that moving the hitch forward any amount would add weight to the front axle--just about every weight I have seen has been higher on the front axle when hitched over unhitched. But should never add weight to one side only--bad numbers. Also, DEF is 9.1 lb/gal--heavier than water--if I remember, that year GM DEF tank is close behind the right front tire? Edited May 8, 2019 by jblo Quote Link to comment Share on other sites More sharing options...
mptjelgin Posted May 8, 2019 Report Share Posted May 8, 2019 1 hour ago, jblo said: I would think that moving the hitch forward any amount would add weight to the front axle--just about every weight I have seen has been higher on the front axle when hitched over unhitched. With a 164" wheelbase (probably close) moving the hitch forward 1" in front of the rear axle CL will shift 0.6% of the pin weight to the front axle. So with a 3000 pound hitch weight, the total amount transferred is 18 pounds, or 9 pounds per tire. Most hitches installed into factory pucks place the CL of hitch within an inch or two of the rear axle CL. Even at 3" forward you would only be looking at 55 total pounds, or around 28 pounds per tire. Quote Mark & Teri 2021 Grand Designs Imagine 2500RL, 2019 Ford F-350 Mark & Teri's Travels Link to comment Share on other sites More sharing options...
jblo Posted May 21, 2019 Report Share Posted May 21, 2019 Mark, Not questioning the numbers, but wonder about the process of how you came up with them? Seems every fiver I have ever moved the hitch position forward, affected the front axle weight more. Been a long time since I messed with levers/fulcrums... Joe Quote Link to comment Share on other sites More sharing options...
mptjelgin Posted May 21, 2019 Report Share Posted May 21, 2019 This is a pretty simple calculation. The ratio of load transferred to the front axle matches the ratio of distances from the hitch to the rear axle and the wheelbase. That is to say that if the hitch is directly over the rear axle (a distance of 0" from the rear axle) the ratio of pin weight shifted to the front axle is (0"/164") for a 164" wheelbase vehicle. You can imagine that if a load was added halfway between the rear and front axles (82" in this case) the load would be split 50/50, or (82"/164") going to the front. In my calculations, assuming a hitch set 1" in front of the rear axle, the ratio of loaded shifted to the front axle is (1"/164") or .006. With a pin weight of 3000 pounds, the load shifted forward is 3000 x .006 = 18 pounds. At 3" forward of the rear axle, the ration becomes (3"/164") or .018. With the same pin weight, 3000 x .018 = 54 pounds. Mark Quote Mark & Teri 2021 Grand Designs Imagine 2500RL, 2019 Ford F-350 Mark & Teri's Travels Link to comment Share on other sites More sharing options...
Lloyd Posted May 24, 2019 Report Share Posted May 24, 2019 I don't know if you've figured out your weights yet, but I just had to comment. In a previous life I set up race cars. What your hitched numbers look like is a ride height/ weight jacker issue. With your bags inflated, my theory is, your right rear bag is over inflating or your left rear is under inflated or deflating causing your RR to carry too much weight. This will in turn transfer extra weight to your left front. Hope I helped, Lloyd Quote Link to comment Share on other sites More sharing options...
jblo Posted May 26, 2019 Report Share Posted May 26, 2019 Never thought about that possibility... Quote Link to comment Share on other sites More sharing options...
MNRon Posted July 17, 2019 Report Share Posted July 17, 2019 I agree those numbers aren’t very believable. Did you have the truck in gear and foot on the brake? That will affect numbers. Weights should be measured with truck in neutral, and I can’t imagine a valid scenario that would result in front L/R discrepancy Quote Ron and Pat, and 2 Portuguese Water Dogs 2013 Silverado 3500 SRW Duramax w/SuperGlide 2005 NuWa HitchHiker DA 31.5 LK w/MorRyde IS Link to comment Share on other sites More sharing options...
Consolenut Posted October 6, 2019 Report Share Posted October 6, 2019 Is there a big slide on one side up front on the fiver. That will account for some weight. Is there a washer or dryer up there on one side. Quote Link to comment Share on other sites More sharing options...
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