My beloved Schwinn World Sport broke its rear axle a few months ago, and I've been riding one of the extras my housemates and I have. I finally got around to replacing it and repacking the rear hub. I jubilantly rode the old girl for about 20 minutes, then ¡snap! went the axle, and I ground to a halt. It went just like the last time - it was not at a pothole or anything, just a sudden jolt on the road and suddenly a whole lot of resistance in my no-longer-aligned rear wheel.
I wasn't terribly far from Kraynick's at the time, but it was late, so I locked it up and I'm going to walk it the rest of the way there later today. I imagine Jerry will know what's up, but just so I have an idea what to expect, how the HELL did I break an axle in 20 minutes?
Wish I knew what to tell you about the axle... but I don't have the first clue unfortunately.
However - you have a Schwinn World Sport! That was my first "10-speed." I got mine when I was 14 or 15. Light blue paint, foam grips on the bars. Lost track of it post college. Thought ex-brother-in-law might have it stashed in a garage somewhere, alas it is gone.
Glad to hear someone else has appreciation for the model. Really hope the axle thing works out.
Please don’t take offense at this question; did you replace the broken axel with the correct size replacement? Or did you use something very close you thought would work.
I have a Shwinn Sport and I recall the axel is a weird size 9.5x1.0x164mm.
If this were autumn I'd suggest it might be the cold November Rain.
ejwme: I'ma give you a Rose for that lovely pun.
Greasefoot: No offense at all. I assume it's the right size, as I used the old cones and nuts and things on it, and they wouldn't have threaded on if I used the wrong size. But otherwise I didn't pay size too much attention; I took the wheel and broken axle into Kraynick's and Jerry just pulled out a new one for me. The old pieces fit, and it went onto the frame.
Maybe it's relevant to note that I have to pull the drops apart just a tad to fit the wheel in there. This has been true for all the years I've had this bike, though, even before it was breaking axles like crazy.
If this were autumn I'd suggest it might be the cold November Rain.
the slash-and-burn technique you use for your puns is making me dizzy.
Yea I do remember the last time I had the back wheel off that bike it was a tight fit…The axel would snap if it’s binding up (alignment issue). Check your hub and make sure you don’t have a bad bearing. Also take close look at your dropouts to make sure one is not bent.
Good Luck!
Edit:
Don't forget to coat your next axel with anti-seize compound.
20 minutes is some kind of record. You must have monster quads, and horizontal dropouts...
Ditto on the bent dropout. Or maybe it's badly worn. Slightly spreading the frame is probably not an issue. I've been riding a frame with 126mm hub spacing, using a 130mm hub, forever.
Don't cross-chain, and don't ride down staircases.
You know, now that I'm thinking about my old World Sport - I used to love it, but I had to kill it.
So what's the prognosis if it is a bent dropout? Is there anything I can do, doc? Or will that mean it's time for a new frame? 
In related news, Sheldon Brown told me:
With horizontal dropouts, it is possible to mis-align the wheel in the frame if it is installed carelessly. The axle nuts or quick-release must be tightened quite securely, or the chain tension may pull the axle askew.
I thought I tightened my axle nuts fairly tightly, but I didn't go nuts on them (pun half-intended). Should I have?
bent dropouts can be straightened, by someone with the right tools. If that's not it, you will probably get more mileage out of a Shimano freehub instead of that freewheel.
The dropouts on that bike are not forged so they can bend. If this is the case it all depends on how much you want put into the bike. I’m sure you can find a shop that could fix or replace the dropouts but people might think “your crazy” to put a lot of money into a Japanese (Giant) Schwinn.
20 minutes is some kind of record.
if only the bike had just a little patience.
Something similar happened to me a long, long time ago, I would break axles again and again. I don't remember exactly what was going on, but I something was wrong with my wheel bearings, and as my wheel was turning, a bolt would unscrew and it would exert pressure on the axle, extending it until it breaks.
Just a thought.
So in case folks were wondering, it turned out I was a paranoid idiot. My axle did not break this second time. BUT, the wheel did get pulled out of alignment, which had the same symptoms as when I broke my axle (wheel mis-aligned in frame, rubbing chainstay, resisting turning), which is why I assumed the worst and decided not to touch it until I could show someone who knew better.
But, the drops were indeed mis-aligned - likely the reason for the old axle breaking anyway - and I fixed them using some neat re-alignment tools at Kraynick's. And my axle ain't broken. And I rode my lovely old bike all weekend long, the end.
