Can anyone tell me how shims work? How do i add to move the weight?
I have them on my trailer. Mine is a ground barring trailer so I lift up the trailer and flip the load legs down. I use metal shims between the legs and the trailer. This will hold the trailer higher.
It depends on the trailer, what kind of trailer do you have? I'm not sure it actually changes the weight though.
Shimming will only charge ground clearance.
Shimming will only transfer weight if you have a spring suspension trailer. For example if you don't put any shims in the front of the trailer it will ride lower to the ground and you will end up with more weight on the front axle. The more shims you put under the load legs the higher the front of the trailer will ride transferring more weight to the back of the trailer. However this won't work on a trailer with an air suspension as the axles will be tied together and receive an equal amount of air pressure in turn balancing the load out on the axles.
Many, many years ago, I pulled around a Trail King 70 ton lowboy with air suspension and a detachable single axle (air suspended) booster that projected out about 15 feet from the rear of the trailer (I think it was a General). In those days in New Mexico, that single axle was worth 20,000 pounds and added to the "bridge" length in Colorado. The way the booster attached to the trailer made it rigid horizontally and in line with the trailer. It had to be shimmed so that it wouldn't carry too little or too much. To set the angle correctly, I got a big load on the trailer--to flatten out the camber--and placed shims at the connection of the trailer and booster to angle the top of the booster for the correct weight distribution. It actually worked quite well once I got used to it. Once I got it set to a 100,000 lb. load (the usual) I didn't set again, although I probably should have. When the trailer was empty, I would have to remove the booster altogether or remove a connecting pin to allow it move vertically independent of the trailer. With the camber of the empty trailer, much of the weight of the (rear of the) trailer would be on that single axle. As I recall, there was air adjustment, but much of the adjustment was done with shims. I hope this makes sense.