Northern California - climbing out of sausalito killed my bike

Well actually It killed my rear derailleur hanger, snapped it clean off and put my RD in my spokes seizing up the back wheel... which was fun.
http://img.photobucket.com/albums/v217/tylerc13/P4040039.jpg

Thankfully I was able to coast/walk to A Bicycle Odyssey who got me back on the road.
I must say that I was quite overtaken at the amount of people who stopped to ask if I was ok or needed anything while I was on the sidewalk breaking the chain to get the RD out of the spokes. You should all give yourselves a pat on the back.

Wow, that's bad. Must have made one heck of a noise. Very nice that they had the right derailleur hanger just waiting for you.

Oof - that must have put a nice spike in your heart rate.

Maybe I'm missing something but I don't really understand why climbing would have pushed it over the edge - I always assume that its the teeth on the cassette and your chainring that are handling the bulk of the power/load when climbing and that the RD is passively "feeding" the chain to your cassette rather than bearing any of the load itself? Either way, glad you're OK- assume no other problems with your bike?

I had something similar happen on my first death ride - the only theory I've heard that makes any sense as to the cause is that if you shift (especially mulitple cogs) under load, sometime the RD moves sideways, but either the chain doesn't move as quick or the springs can't deal with the sudden change in tension, and it briefly locks up your driveline. If you keep pedaling, something's got to give - the RD is the weakest link, so to speak. If your drivetrain is dirty, it makes this more likely. It's not the most common thing, but it does happen.

Beaker has it right, though, if you're not shifting there shouldn't be any undue forces on your RD. I'd definitely shifted twice pretty quickly as I started to climb a hill when it happened to me.

JB

That is a good one. Marin County is the only place where I had to get emergency bike repairs done (though my bike shop was in Fairfax after coming down from Mount Tam.

Another theory that could be plausable is that there could have been as simple as there was a stick that got jammed of a stiff link that attributed to jonathans theory.

Wow. Maybe it's just that you are too flippin' strong and no lightweight shifting gear can handle that sort of power. I'm sure that's it!

kool man, i had that happen to me while i was in a mountain bike race, but the RD didnt get stuck in the spokes. it hella sucked though when that happened, damn our super strong legs

Sometimes when you shift into the large cog the derailleur cage catches on a spoke. Then the wheel pulls the derailleur around and twists it into a pretzel, breaks it off, or breaks the hanger if you are lucky.

I have been next to riders on steep hills and hearing their derailleur cage pinging the spokes... all it takes is a bit more wheel flex and the derailleur is going to hook a spoke.

I think it was that the chain seized and pulled it off, I was shifting but I wasn't in my lowest gear so I don't think it would have been close enough to catch a spoke, plus I looked and felt all the spokes on my rear wheel and they seemed fine.

I'm off to conzelman rd. If you see a guy pushing a bianchi across the bridge, it happened again.

Geez, glad you were able to get some quick help.

Wow. Now we get to see how good the "lifetime" warranty is! Good luck.