I have an old two-seater recumbent trike with coaster brakes. One of the rear hubs rumbles terribly when the bike is coasting. When the brake is on, or when pedaling, it doesn't make a noise. I assume it's some bearing giving out, but it just had all the bearings replaced not long ago. Also, it's impossible to tighten up without making at least a slight grumble, so the wheel is slightly loose on the hub. What to do?
I don't know that I have the wherewithal to just replace the wheel... it's a bicycle hub with thick motorcycle spokes and rim and motorcycle tires. 20". I'd likely have to have a custom wheel built from scratch, plus find someone to cut small spokes.