I just installed 2 new axles on my Argosy 26'. The original axles were rated at 2800# each with 10" brakes.
I upgraded to 3000# axles with 12" brakes.
The overall track is about 3" wider, but poses no clearance problems. As a matter of fact it has improved the clearance on the inside between the tire and frame. I was always uncomfortable with how close the tires were to the frame.
I felt the 400# increase in axle capacity would help with the riding height of the trailer, but not make the ride too stiff. That's 200# per axle increase.
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