Bicycle Mechanics - Broken rear derailer, broken chain, bent wheel - good start to the season.

Last year I did a frame swap on my bike. I swapped all my ultegra parts from BD over to a cannondale CAAD 9. I rode it a ton on the trainer and once when it was nice outside during late winter.

Today I took it out for the first time this season. Pumped the wheels, spun the tires. Hopped on and slow pedaled down the driveway. Out into the street - started pe]eling -- and bam. Rear wheel is locked up and I'm stopped. Quick un clip and look back. First thing I see is a 4 foot skid mark left in the road.

Then I look down. :twitchy: My Ultegra rear derailer is snapped at the small part between the hanger and the rest of the derailer. The thin part - please see picture. It's bent and lodged in the spokes. Only one spoke looks bent. I walk back to the house and unlodge it. Yep, only one spoke but the wheel is out of true or bent. The derailer little black gears are broke in half too.

Next I see the worse part. A dent in the inside of the chain stay on the drive side. Also one of the pins in the chain is sheered, so that made it easy to take off....

Why did this happen? It was undisturbed, nothing was wrong with it last season. Now I need to spend what - $300? And that's if this dent isn't too bad. Please see the pics, tell me what you think. I guess I wont be riding this season, after all that time saving up for it.

I'm upset. I guess it'd be ok if I just had to buy a new derailer. But now my brand new (to me) frame is damaged. Is a dent in a chainstay enough to kill a frame? :(

Off season damage to RD went unnoticed?

What kind of damage are we talking about? Family members say nothing happened, but if they dropped the bike or moved it hard, are you saying it could have bent it and caused this?

Upon further looking, the dent isn't too big, maybe between a quarter and a nickle. Hoping it isn't too important. I can live with getting the wheel trued and a new derailer. Anyone selling one?

Cambria Bike has new Ultegra rd for $40

Awesome. Thanks, do I need a certain kind? There are 3 on that page and I don't know what the differences are, except for the prices. Also, how do I know if I need long or short? If I need short will long work?

I've also found a small dent on the seat stay, very near but not touching the weld. Are these two dents (this and the one on the chain stay) likely frame killing? I don't care if it looks bad, I just want to ride it :(

It sure sounds to me like the rd was set a little too close to the wheel and you sucked it into the spokes. You say that you've only ridden it once on the road since swapping it over, right? The frame and wheel flex differently on the road than on the trainer. Maybe you never shifted into the largest cog on the back on that one road ride. I do not know your mechanical proficiency, but if you forgot to set the low limit screw when swapping over I could definitely see the rd hitting the spokes.

I wouldn't worry about the dents. Especially not on the rear. Even if they do fail catastrophically, you'll just end up needing to walk home. If it were damage to the front of the bike like the fork or head tube I'd be a little more worried as failure could result in a faceplant, broken neck, and large dental bills.

A long cage will work with pretty much anything, it's required with triples.

one bad part is that after sucking the derailure into the spokes most likely you will need to get the hanger straightened. that meens a trip to the shop and you will have to deal with them trying to sell you a new bike because yours is damaged. I hate hard sell's . I have had one shop refuse to perform said services after a similar incident, to try an up the drama. went somewhere else no big deal. its cost me $15.00.

Cambria Bike has new Ultegra rd for $40



And here's the link to it:

http://www.cambriabike.com/shopexd.asp?id=68265&page=SHIMANO+ULTEGRA+RD-6500+REAR+DERAILLEUR

What kind of damage are we talking about? Family members say nothing happened, but if they dropped the bike or moved it hard, are you saying it could have bent it and caused this?

If it dropped from standing on to the right side, that could have bent the RD enough, especially if the low limit was set a little loose already. If you don't have a "dork disc", that again increases the odds.


Cambria Bike has new Ultegra rd for $40

This is the 6500 long cage. It is a generation older then the 6600 series, and the 6700 series should be out soon. However there is no reason you can't use it. You can use long cage whether you had a short or long cage previously.


one bad part is that after sucking the derailure into the spokes most likely you will need to get the hanger straightened. that meens a trip to the shop and you will have to deal with them trying to sell you a new bike because yours is damaged.

Or hangar repleacement if it's a bolt-on hangar.

As to the frame damage, aluminum can't be bent back and keep it's strength. You can find people to weld aluminum, but aluminum welds are ususally stronger then virgin aluminum. That could effect handling, I don't know.

I've said it before, but you're very lucky you didn't have a dork disk, it would have been scratched for sure!

I can see the use of them. I've never taken one off before, but alas, this bike didn't come with one.. :(

With the type of damage you describe you can be pretty much guaranteed that the hanger is at least out of alignment if not completely destroyed.

I can see the use of them. I've never taken one off before, but alas, this bike didn't come with one.. :(

Was your bike part of the recall due to lack of dork discs?
Joking aside, you're going to need a rear derailer. 6500,6600,6700, you'll be fine. If you have a double and a small cassette, a short cage will do. A triple will require a long cage, and a medium cage will work on something in between. Having a cage that is too short causes problems. Having a cage that is too long will work for you. You can also go down in the Shimano line to 105 or lower, the parts are still compatible. Additionally, you will probably need a derailer hangar, maybe one new spoke, need to true your wheel (easy if you are mechanically inclined), and spend $5 on a dork disc in case you don't get the derailer adjustment right the second time.