Does anyone have experience in replacing rims on Raleigh three-speeds? I have a circa 1977 Raleigh Sports and am considering replacing at least the rear steel rim, which has a slight hop to it. I believe that there is an aluminium rim available in the correct size. I would like to reuse the original three-speed hub which works fine. Are there any pitfalls in doing this and is there anything special to consider in selecting spokes, etc?