According to SURLY…(info on tyre widths).
The Knard 3.0 tire on a Rabbit Hole 50mm rim will be 75.8mm/77.7mm (casing/tread) wide and will have a diameter or 779.4mm (at 19psi).
The Knard 3.0 tire on a Velocity P35 will be 72.6mm/76.7mm wide and have a diameter of 778.6mm.
A Schwalbe Racing Ralph 2.4″ tire will be 66.0mm/59.2mm wide and have a diameter of 752.2mm when mounted on a Rabbit Hole rim (at 35psi).
A Continental Trail King 2.4″ tire will be 65.5mm/57.1mm wide and have a diameter of 759.5mm when mounted on a Rabbit Hole rim (at 35psi).
Cant get over the price of those Rabbit Hole rims…£140ea !!!
The Dually at £110 looks ok, but given its lighter, & only results in a 3mm difference in a mounted Knard tyre, I think the P35 at £67 looks a goer for my rebuild.