Thats pretty impressive - if it is only 4 months old then it is probably under warranty (I just had a shifter replaced on a 12 month old bike - LBS was really good with it).

As an asside though, the photo all looks pretty dirty - lots of grit on the chain and grease on the derailleur (I may be a little OCD as far as cleaning and maintaining my bike goes though).

I too, did not know it was possible to put that much pressure on a rear derailer. What brand is it?
It better be under warranty after such a short time. Even if it isn't the LBS should do something about it for no charge.

- we were cranking up a hill
- don't remember shifting at the time
- Ultegra
- i know, it looks really dirty, but i just cleaned the bike and chain 2 rides ago, i got greasy when i was trying to fix the darn thing on the side of the road
- the 2 rides before this were a 50 and 22 miles, with hills, don't remember feeling anything wrong with the bike
- taking it to the lbs later today

That sucks. On the grease/grime topic, you should wipe the excess lube off the chain after you apply it. It only needs to be in the pins, not all over the outside. If you're riding in really dirty conditions, try a wax or dry lube instead.

the LBS joked around with me when i brought it in, they told me that "hammer it" means give it all you've got with your legs, that it does not mean hit your derailleur with a hammer until it breaks.

i just left it there. they called me later and told me that the warranty would repace the derailleur. i guess the wheel was out of whack as well. they fixed that too, my guess is they just "_?_" adjusted the spokes instead of giving me a new wheel, not sure, won't know till i pick it up...