Singlespeed & Fixed Gear - Wheel wobble

I have a Raleigh Rush Hour that I haven't really screwed around with since I bought up until a couple days ago. I flip-flopped the wheel and used the bike on my trainer as a single speed (freewheel), and noticed when I took it off to flip it back that my wheel was wobbling. I've only ridden the bike maybe 40 miles since I bought it, so I can't imagine that the wheels have become untrued. My question is, how do I check to see if the wheel is just not on the drop out correctly, or if the wheel isn't true anymore?

If it is a loose bearing hub, also check to make sure that there is no play in the cones. It is a long shot but had one of my front wheels giving me the creeps for a while. Just hold the wheel by the axles and see if the hub has any side to side movement.

being crooked in the dropout won't make it wobble.

If it's not straight in the dropouts, the front of the wheel will be closer to one chainstay than the other, but the relationship won't change as the wheel spins. If it is "wobbling" getting closer to one chainstay at a certain point in the rotation, then it is out of true. I suppose one other cause for a different sort of wobbling might be a loose axel, but I think it's most likely out of true.

If it is a loose bearing hub, also check to make sure that there is no play in the cones. It is a long shot but had one of my front wheels giving me the creeps for a while. Just hold the wheel by the axles and see if the hub has any side to side movement.


Edit: More to your questions, take your chain off. Bottom the axles out in the dropouts and see if there is wobble. that will remove the option of not being in the dropouts correctly. You can move it to the front fork for testing purposes if the rear dropouts allow the tire/tyre to rub the seat tube.

If it wobbles, it's out of true, or the bearings need to be adjusted. Putting it in the dropouts crooked won't affect how it spins, it will still spin true, just at a weird angle.

You can move it to the front fork for testing purposes

Rear hubs are spaced 110-135mm depending upon the type and vintage of frame. front forks are almost universally 100mm.

Rear hubs are spaced 110-135mm depending upon the type and vintage of frame. front forks are almost universally 100mm.

I wasn't even thinking about it spinning true even if it was crooked. How am I supposed to keep track of spacing? (heads back to caffine dispencer) Definately not thinking well this morning.