Ok I'm a newbie when it comes to in depth bike mechanics. I have a road bike that when I was riding it began making a noise like some thing hitting the frame. I checked and nothing was and the wheel was not banging back and forth. I decided to try and ride it home and look at at it when I got home. I managed about 10 feet when the back wheel seized like the brakes were jammed on. I checked and the brakes were not touching the wheel. I can spin the wheel backwards and the freewheel and chain seems to let it turn like normal but it refuses to go forward. Any suggestions as to what to look at next? Is this a job best left to my LBS?

Thanks

Could be seized bearings. But what helps is to describe the setup, e.g. what type of rear hub? Is it a freewheel? Is it a freehub? Is it an internally geared hub? Shifters/Rear Derailleur? Number of speeds? Can you back pedal freely (not just rotate the wheel)?

If the bearings are seized, then we need to know where/which set, and then check to see if they can be repaired and what else might be broken because usually, seized bearings were caused by some other issue to begin with.

You might have a broken axle inside your rear hub.

Remove the wheel from the frame and it should be fairly apparent if this is the cause. If broken the axle should come out if you have a bolt-on hub, if you have a quick release hub then it should come out after removing the skewer.

If this is the case then the bearing surfaces inside the hub could be thrashed...you will need to inspect them to see if you can get away with a new axle or if you need a new hub altogether.

-j

not op, but I have this problem with my bmx bike. I was using it to commute and began to hear a squeaking noise from the rear wheel. the squeak turned into a grind which turned into a crunch before seizing completely. I pulled the wheel off and the freewheel seems to be in working order, but the axle won't turn at all. is it possible to get new bearings for a hub the same way that you can get new bearings for a bottom bracket or head tube?

Depends on the hub. If it's a cup & cone hub the cups are pressed into the hub and not considered replaceable. They can usually be removed, but w/o a source of replacement cups that won't make you much happier. If you're lucky you can come across a hub that's been scrapped for some other reason and use that as a parts donor. The ball bearings and the cones are readily replaceable though.
Some hubs have cartridge bearings, and these are usually fairly easy to replace. Dunno how common that is for BMX though.

On the good side, if you're not too worried about losing a fraction of performance, cup & cone hubs can usually be returned to working order even if they've been badly abused.

I went back to the bike and checked. Its a Triax Nox2 21 speed road bike. It has a rear derailleur and is not an internal geared hub. I can spin the chain backwards and the gears spin but when I try and move the chain forward it won't budge. I took it off the the chain to see if I could spin it forward by hand but it won't move. I took the wheel out of the frame and it appears to me that the axle is still in one piece (its a bolt on not quick release).

It turns backwards and not forward? That is really odd. Does it feel smooth as it spins backwards? Can you turn the axle by hand now that it's off the bike?

It feels smooth going backwards but when I try an hold the axles and roll the wheel forward, it wont move without trying to move the axles in my hands.

More information:
I was able to remove the axle via the non freewheel side. The axle is in one piece and underneath when I remove the axle, there is metal ring containing bearings on that side. I don't have a chain whip so I can't take the freewheel off yet to see what's on that side. When I put the axle back in, the wheel spins until the nut tightens and then it stops and tries to to spin the axle.
Is it possible that the bearings on the freewheel side have seized or need much lubricant to be able to turn? The freewheel turns smoothly when I spin it backwards.

Sounds like you just need to go to the shop and get a new freewheel.. When you spin it backwards its spinning on the hub bearings but when you spin it forward it wont move because the pawls in the freewheels are seized. Usually happens due to getting water in the freewheel or from sitting a long time. Without having it in hand it's tough to be sure hopefully someone else will come along with another idea.

It sounds like your cones are not tightened against the locknuts correctly.

+1

I think I found the problem. The bearings are caged bearings on the rear. When I got the freewheel off, the caged bearing was twisted and the metal cage had actually risen up. Went and got a new one at the LBS and will assemble tonight. I'll let you know if it works.

That was the issue. Thanks for everyone's help, without it I wouldn't have had the confidence to try this.