rat_factory

Okay I have an 3.0 aluminum Cannondale SM500 frame and the rear derailleur hanger is bent inwards. Judging from the attatched pic, does this have a replacable derailleur hanger? My LBS said they had never seen it (they don't sell cannondales) and wouldn't touch it because the aluminum might break. I gently tried to bend it out, but I didn't want to stress the aluminum, and it didn't budge. It also appears to have allen bolts, but they are an odd size, even SAE doesnt fit. this frame is one of those Cannondales with the derailleur hanger positioned a little far out beyon the rear triangle. any tips?

mcoine

Yep its replacable.

cascade168

Try these guys:

https://derailleurhanger.com/

Guess what they specialize in?

rat_factory

great! where do i get one?

rat_factory

okay i found a match. but i'm assuming they are made of steel or cro-mo, which means i can try and bend it back, right? or should i just buy the new one?

mcoine

I have two in my toolbox, and I think they are alloy!

rat_factory

hmm, he site does say 'billet', i guess as in billet aluminum. aren't they supposed to be steel so people can bend them? argg

FXjohn

it can certainly be bent back....

mcoine

No, its got to be weaker than the frame, so you replace the hanger, not the frame, thats the whole point.

rat_factory

but im putting sooo much force on it and it barely yields when i do it. i guess it if snaps i'll just get the replacement

cascade168

Ideally, you need two special tools to do the job correctly. You need a derailleur alignment tool and a dropout alignment set. First, you check your dropout alignment. If it's off, fix it. Even with Al frames, if the misalignment is not severe you can cold set it. If the dropouts are aligned correctly then you move on to the derailleur alignment. If it's off you have two choices. One, you can just replace the hanger and, of course check it's alignment. The other choice is to use the derailleur alignment gauge to bend the hanger (yes, it is used to bend as well as check the alignment). The problem with this choice is that you might bend the frame rather than the hanger. Then you'd have to go back and re-align the dropouts. I'd guess that this is what your LBS was concerned with. I'd say trying a new hanger is a better course of action.

RD misalignment is one of the most common causes of poor shifting performance and the only way you can accurately check it is with a derailleur alignment tool.

If you could post a picture, or two, that are directly behind (i.e. from behind the bike) it would be a lot easier to help you with a course of action. If it's clearly the hanger that's bent, and not the dropout, then, again, you're probably best off to just replace it. If you do, take the old one and get a big hammer and an anvil and flatten it out. Then you have a spare. I suppose you could even try this before buying a new one. It should be pretty obvious if it's flat, or not, once you get it off the frame and set it on a flat surface. Any time a bike falls on the drive side or the derailleur bangs something during a ride, a bent hanger can result.

DieselDan

There's more to it then just the hanger. The lower part of the dropput is part of the derailluer hanger on a Cannondale. Wheels Manufacturing makes them, or has them made, and can be purchased from any bike shop that has Hawley as a vendor.

cascade168

Here's a funny quote from Sheldon Brown about what a "billet" is:

"Billet:
pretentious word for "lump of metal," used by machinests and marketeers to confuse outsiders."

Another quote from him that's appropriate here is about "cold setting":

"The process is commonly referred to as "cold setting" which is a fancy way of saying bending the rear frame apart so that it is wider."

As I said earlier, aluminum dropouts can be cold set if the misalignment is only slight. Trying to respace rear dropouts on an Al frame is not good because then you are trying to "cold set" the Al tubing in the seat and chain stays. Al tubing does not bend well.

Whether the OP's derailleur hanger would bend before the Al frame is the $64 dollar question and it would seem that his LBS did not have a definite answer.

mcoine

I had a similar frame ('91 beast of the east) and I am about 100% sure that the hanger will bend or break before the frame. The frame would crack before bending permanently. More pics would be helpfull. By the way, why was the frame repainted?

rat_factory

actually the frame was not repainted. thats the original blue powdercoat with decals and everything. maybe thats why my allen wrenches wont fit.

as far as the derailleur alignment is concerned, i dont have that tool nor do i know anyone that does. my lbs already told me to 'upgrade to newer technology' and somethings tells me the price of derailleur alignment is more than that of the hangar. maybe i can find a used derailleur alignment tool on ebay or something. or maybe i can bend the derailleur itself? i'm not gonna spend big bucks here and if it turns out the dropouts are not aligned then i'm really not gonna spend more $ to get that cold set as well, if it the triangle doesn't crack first. maybe thats why my LBS gave me the simplified 'upgrade' solution.

oh and more pics to come in the morning. i'm tired

Retro Grouch 

Sure looks replaceable to me.

My 2005 QBP catalogue lists a hanger for 91-2004 Cannondale mountain bikes. The picture looks alot like, but not quite identical to yours. It definitely looks like it's designed to hand off behind the seat stays like on your bike. An LBS will probably charge you between $25.00 and $30.00 for the part.

You also might try derailleurhangers.com. It's an aftermarket Wheels Mfg. part so my bet is they'll have it.

HillRider

Your LBS, not a Cannondale dealer as you said, has an interest in selling you a new bike, not repairing yours. If you really want an excuse to buy a new bike, go ahead and follow his advice. Otherwise, find a real Cannondale dealer that knows the product.

rat_factory

okay here are some pics:







i don't know if they are aligned, they seem pretty straight i guess.

phoebeisis

Buy the replacement 1st-make sure you have it in hand(not just on order) and then try to bend the hanger back in place.
Take it off-put the new one in place to make sure it is correct and will fit-and then you can bang away at the old hanger.
Clamp the old hanger in a vice-mark(a scratch with a screw driver) where you want the hammer to hit it while it is still on the bike.It is easy to get turned around,and hit it the wrong direction(don't ask) if you don't pre mark it.Clamp it in a vice( Harbor freight-$10-you don't even have to mount it if it is reasonably heavy).Hit it gently with a heavy hammer(1.5-3 lbs).You can initially just let the hammer fall-no added force.Check the alignment-redo hit-recheck-etc until you are satisfied.Don't just haul off and give it your best hit at the beginning.You have to 1st get an idea just how much force it takes to bend it.Luck,Charlie