I have had the same problem with wheel bearings. New schwinn bike, but from walmart. The schwinn dealer said the bearing on thoses bikes are built for kids and are junk. I changed them out using lose bearings and seemed to work alot better. Do both sides, I did one at a time and walked home twice. So far I am replacing everything on that bike one part at a time. Fender bracket broke, pedel broke, front wheel was so un-true"my fault for not correcting soon enough" replaced. Next time I will look for an old well built bike to begin with. This one looked strong but cheap hubs and parts, but hey, it was $99.00 new. Good luck with your wheels