Sturmey-Archer 3-spd -- Bad wobble in rear wheel
 

Yup, this is an old bike. I use it as my commuter, since no one will bother messing with it.

It's got a Sturmey Archer 3-spd hub on it and it's been riding fine up until a few weeks ago, when I noticed that the rea wheel had developed a really bad side-to-side wobble. As I ride it, the rear wheel shifts about 1-inch sideways with each revolution, always at one point, sort of like how a wheel would react if a bunch of spokes at one point were really out of tension.

I finally had a chance to look at it this past weekend.

I took the wheel off and the bolts were tight and secure. I spun the wheel in my hands and it spun smoothly and with no wobble at all; the wheel is perfectly round and true, even when back on the bike.

I re-attached the wheel and adjusted the shifting.

But the wobble is still there!

What could it be? It seems to only occur with a bit of speed. It happens while pedaling or coasting. It feels as if the wheel isn't bolted on at all. But since I know the wheel is on tight, I've continued to ride it like this.

I'd appreciate any tips you can give me. TIA.

It sounds like the bearings are out of adjustment. Adjusting them isn't any different from conventional bicycle hubs as seen here: http://parktool.com/repair/readhowto.asp?id=105 . For all the details of adjusting Sturmey-Archer hubs, consult the guru: http://www.sheldonbrown.com/sturmey-archer/adj.html

It is simply impossible to tell if the wheel is true by spinning it in your hand.

+1 on checking the bearings.

Replace broken or missing balls, add grease and adjust. Read the article by Sheldon Brown on servicing SA hubs if you are new to this.

I know you said the wheel is true, but with your desciption I'd be looking for a broken spoke. If a bearing problem was allowing up to an inch of movement at the rim, that thing would be flopping and wobbling all over, not just one specific spot.

If the bearings are tight and the wheel spins true when you have it off the bike, I would check the rear frame for cracks, which would also cause the rear wheel to wobble.

Possibly a wobble only when your weight is applied? Broken rim? Broken nipples?

That actually sounds to me like a cracked frame. Check the bearings anyway — it makes a big difference in the performance of the hub — but if that doesn't fix it, see if the frame's cracked.

These are all great suggestions. The wheel spins true in my stand. I didn't specifically look for a broken spoke; it just didn't occur to me. Cracked frame(!), I'll have another look this weekend. That's definitely not safe. I'll report back with my findings.

Thanks guys!

+1 on cone adj. definatly inspect the frame and everything else. i own like 5 3speeds, all s.a. and those bearing cones can get you. good luck.

Another vote for a close inspection of the frame's rear triangle. Check all the other stuff too. Good luck.

ok, I figured it out. I feel stupid!

It turns out that the tire on the rear was [likely] original and was so badly worn out that it was down to the casing and threads in some spots. My theory is that under load, the tire was collapsing under my weight. That would explain why I couldn't feel anything when the bike was in the stand or in my hands.

A few weeks ago, while leaving work, the tire gave up on me and I literlly had a blow out. A loud pop and my tire basically disintegrated.

When i got it home, I saw how bad the tire was. I probably just never noticed it because the fender was always covering it.

Anyway, I ordered some new Kendas and got them on the bike a few days ago. Hey, no more wobbling!

Enough crap on the roads in Nevada so I inspect tires at least as part of every pumping them up. Riding on worn tires is just not safe!