Bicycle Suddenly Unstable??
 

Riding home from work on Friday, my bike all of a sudden felt a little unstable. I thought it may just be me, but I rode it today again and it is still doing it. If I take my hands of the bars while moving, it feels like it is going to tip right over. Very difficult to ride with one hand as well...

The tires are up to pressure, tires are in good shape. Anyone have any thoughts??

Simple check list I'd run down, check your handle bar to fork allignment, check your wheels positions mounted in their drop outs... and I guess (although I think it's unlikely) the crankset/BB to make sure they're tightened properly but I'm guessing you'd notice either of those with your feet already. Pictures might also help but who knows :D

cracked fork/frame or axel

:/ that's my fear too, but we can pray it's a quick simple fix no?

Since I can feel it while riding, would it be noticeable? Visible to the eye?

Spoke check time!! IMO, I'm 99.9 % sure that you have one or more broken spokes in your rear wheel.

Check for a loose headset. Also, grab the top of the front wheel at the top of the forks and push it left and right to check for loose wheel bearings or cracked axle.

So I just walked downstairs and checked out the bike. No noticeable cracks in the frame or the fork. The spokes are all tight and in great shape. Wheels spin true.

The headset is not loose but it does look like fork is tilted forward a bit... just slightly...

The gap at the front of the headtube looks good, but at the back it gets slightly larger. New bearings needed?

Hold the bike up on it's wheels, apply the front brake and try to rock the bike forward. Feel a click? If you do, that's it. Hopefully a headset adjustment will fix it.

Yeah. Rock it back and forth with some force and listen, look, and feel for movement where the top of the fork abuts the head tube. Sometimes there might be some play or looseness in the brake caliper that might feel similar to a loose headset.

Well, I got home and checked the fork, frame and axel. All good.

Then I pulled the fork out and the bottom headset bearing was destroyed...

Glad my frame isn't cracked! Thanks for the help everyone!