Rear wheel causing road bike to vibrate I have a 2019 Giant Contend 3 road bike and I have been having an issue with this bike on and off for the past month. The issue is that when I start pedaling the bike it vibrates. The vibration seems to be coming from the rear wheel. The vibration also makes a squeaking sound, which occurs once each time the rear wheel makes one full rotation. When I speed up the vibration goes away but I still feel some resistance in the rear wheel. Moreover, when I engage the rear break the vibration comes back very strongly.
I went to a bike mechanic when the issue first arose and he told me this was a problem with the bearings in the rear wheel and recommended that I replace the entire rear wheel as he didn't have any spare parts to fix the bearings with due to the coronavirus supply shortage. I went to a different bike shop and they managed to fix the problem. Everything was fine until today when the problem came back.
Does this really sound like a problem with the bearings in the rear wheel? If so, what is wrong with the bearings to produce this vibration and what is the cheapest way to fix this problem permanently?
Yes, a hub that's loose and torn up inside can cause what you're experiencing, and given the evidence you present sounds pretty plausible.
Your experiences with the shops suggest that one or more of your bearing races (cups and/or cones, typically starting with a cone) are damaged. The one that recommended a wheel was cutting to the chase. The one that adjusted it did so because adjusting out the looseness of a damaged cup and cone hub can limp it along, but the nature of cup and cone hubs is that a good adjustment becomes impossible once there's any damage, and the damage perpetuates. So they tightened it, it got more torn up inside, and now it's worse - hence the virtue of cutting to the chase.
If it were just a problem with the cones, they can sometimes be replaced on an OEM wheel such as this. Having a shop do that plus the overhaul labor is often iffy value because the cups, which aren't replaceable, are likely to have picked up some damage at this point too. It's perfectly likely they're heavily damaged, in which case going straight to a new wheel is the only reasonable option.