Each wheel weighs about 360 to 375 lbs. the pipe is 18" with a 1/2" wall weighs right at 100 lbs. /ft. The concrete is about 1.65 cubic feet at 150 lbs./cu ft. Plus some steel bracing and rebar inside the wheels, about 5 lbs. The center of these rollers have a piece of 2 7/8" pipe, the axles are 2 3/8" pipe. The axle tubes are closed each end with grease zerks between the rollers and I drilled holes to allow the grease to run inside the rollers. To reduce the amount of grease to fill the 2 3/8 pipe I put a piece of 1 1/4" pvc with caps glued each end inside. I used freeze plugs to close up the ends of the tubes.
With frame and seven rollers the total weight is close to 2800 lbs, I have not weighed it yet so this is a guess. My 4520 is rated for 2500 lbs lift, it was not a problem to lift to full height. I did have to use the split brakes a few times and found this to be a good place to use float on the top link.