I'm getting ready to order a 77 inch axle. (tip to tip)
My calcs (repeated many times) say this will give me enough clearance for my extended floor width.
The springs mount directly under a 55 inch wide frame.
So each side the axle will stick out 11 inches.
I want to stick with the 1.53 inch diameter round axle if possible. I then wouldn't need to add new u-bolts, and weight increase would be minimal.
The 39mm/1.53inch axle is considered a 750kg / 1650 lb axle over here.
My target weight is about 900 -1000 lbs loaded, and current indications (estimating ply weights from the density labels on the sheets, weighing bits as I fabricate them, etc) are that I'll make it.
So the question is, "Is 11 inches of overhang outside the spring too much? Does it allow too much leverage, how much does it de-rate the axle?"
Opinions?