Sliding ahead will take weight from the drives and put it on the steer. I thought his original question was about his trailer axles being so far apart on weight. Lol
Some of the suggestions were to move the fifth wheel forward, as I am also light on my drives and steer. Hopefully this may shift some of the weight off the back of the trailer. I didn't want to go too far all at once as I found that the air cylinder for my slide needs replaced. It's a pain to unlatch the slide without air and the trailer attached, so just went about 8" to see if it makes any changes. If anyone has an air cylinder for a fontaine fifth wheel I'd be interested. Haven't been able to find any info about the trailer axle weight difference, and if there's something else to look for on the trailer. Thinking some of the weight difference may just be due to the ramp leading up to the scale. Haven't had a chance to axle out on a flat scale.
Set back axle and twin 140 gallon tanks that start just behind the front fender. Usually 9840 empty on the steers and 10400 loaded.
Changing fifth wheel position will not affect trailer axle weight. It will only change the distribution between the drives and steer.
I agree that moving the 5th wheel forward won't do anything to change the axle weight issue. I run a 48ft flat every day, loaded with 45-48k on the deck. While I rarely scale loads, when I do, I've never seen a weight difference like that, that I can recall. Because you're weighing at a scale at the shipper which you said has a slight incline when pulling on, I could see this issue happening. Best way is to get an unloaded weight and then loaded weight on a Cat scale.
Probably a Detroit. Cat or N14 normally more than that. I've ran and owned plenty of them. Mines a 120 classic with forward 120 gal tanks. If I break 11,000 on steers, I'm over 100k gross.
One of the brokers had a 9400 set back with the tanks forward. By the time he had eastern weight on the drives he was 13,500 or more on the front if the fuel tanks were full, no matter where he put the wheel.