It's easier to put a new rim on an old hub than to put a new hub on an old rim. You would essentially have to have the whole wheel relaced, and would probably need different sized spokes, the flange on the dyno hub is a lot bigger than on most conventional hubs. It would be a good time to upgrade your rim, if you so desired. Peter White Cycles on the web sells a lot of dyno hubs, and they'll build the wheel for you.