not_me

So I just had a bike shipped to me. The rear derailleur hanger wasn't as protected as I would've liked, and I'm guessing UPS decided to drop the box at some point. Anyway the impact crushed the driveside dropout just enough to not allow the axle in. You can see the paint is slightly cracked. The derailleur hanger is also slightly bent.

Is it safe to just pry the dropout open and bend the hanger back myself, or should I be taking this to a frame builder to look at? The cracks appear to be just in the paint, but I'm question whether I should try to strip the paint on the dropout to inspect the steel.

What would C&V do?

I'll probably cross post this to the framebuilders forum, but I figured someone in here might have some experience with this type of thing.

edit: The rear adjuster bolts were bent, but I'm not really concerned with that, I'll extract and replace 'em with new.

southpawboston

No problem. Two tools will fix those dropouts. First, the Park Tool dropout alignment tool will straighten the dropouts. (First you will need to pry the opening back out, which you can do with anything that can act as a lever). Next, the Park Tool derailleur hanger alignment tool will get the hanger back in alignment.

If you don't want to shell out the cash for those tools (I use them to check every bike that comes through my stable, so they've paid for themselves), any reputable LBS should have the tools and charge you very little to do this for you. It takes just a few minutes.

While you're at it, you might also want to do a rear triangle alignment check using the Sheldon Brown string method. He illustrated this online, just google it.

Amesja

They can be bent back fairly easily -just like they were bent in the first place. The paint damage will not go away as paint doesn't bend like steel does. It can be touched up though.

Like Southpawboston said there are professional tools for aligning the DO's and the DH. They are expensive. They are not absolutely necessary, and there are expedient methods that work just as well. It's all a matter of how comfortable you are working with your hands, measuring, and thinking outside of the box. Unless one is alighning frames on a daily or weekly basis the tools are really not worth it.

Not listed in the link above is how to make a DH adjuster out of a simple piece of absolutely-straight angle-stock. Just use a bit of angle stock that reaches out to the rim of your wheel on both ends. Drill a hole in the center for the derailleur bolt. Install the wheel and align it and set the dropout set-bolts.

Next install the home-made gauge onto the hanger using your derailleur bolt or better yet an axle bolt that uses the same threading. My own home-made alignment axle bolts from the above dropout alignment procedure are the same threading as this bolt and this also gives me a handle for adjusting the hanger if it needs it.

Measure the distance from the aligned rim to the ends of the angle material. IF they are different from end-to-end then the hanger needs to be tweaked until they are even. You can rotate this "gauge" on the hanger about 70 to 75-degrees without interference with the axle of your wheel and check this alignment at different points. When you are done getting the hanger in the same plane as your wheel then it is good to go. Getting these measurements from your straight-edge to the rim all within a mm or less this pretty good and probably better than the factory got it when the frame was new.

You don't need $500 of special tools to do this job.

If you aren't comfortable doing this yourself your LBS can do it for you using the expensive tools for not too much money ($50-ish sounds about right.)

southpawboston

I got both sets of tools for under $125 new and could have spent less if I waited for used ones to pop up. You can find deals from time to time.

Regardless, as you and I both said, any LBS can do this quickly and inexpensively.

not_me

So is it safe to assume the cracking is just the paint?

Amesja

I spent $2.78 for my home-made set. I'll spend the hundred and change (or more) on tools I really can't make myself.

Some people do not have unlimited funding sources, or can avail themselves of manufacturer sponsorships, and must prioritize on the things they need to acquire to get along through life and their unpaid hobbies.

not_me

I'll be repairing this the cheap way too. It's not bent badly, but I figured it was safer to ask before going at it with a pry bar.

Doohickie

That's not too bad. This is bad.

southpawboston

No need to get agitated over my comments. I was just pointing out that the tools only cost me 1/4 what you claimed. I'm all for DIYing stuff, and I have my own fair share of homemade tools including a DIY headset press, a DIY BB tool, and DIY fender shaping tools. I never actually advised that the OP go out and buy the tools, I merely stated that these are the tools that would get the job done.

Teach me more about these funding sources and manufacturer sponsorships-- I could use them myself.

And to answer the OP's last question, yes, it's safe to assume that cracking is just the paint. The steel dropout is malleable, which is why it bent in the first place and is why it can be bent back. Fortunately it didn't bend too much, or its structural integrity would have been too compromised to repair. Dropouts can be bent and re-aligned several times before they become too stressed, as long as the bending is always slight.

randyjawa 

Make no mistake about it, the rear drop has been traumatized - at its weakest point - where the adjuster screw threads through the drop. It is most likely that the drop is not cracked but one must consider the risk involved with using it. Failure could be dramatic and catastrophic, snapping in half and presenting crash opportunity. That said...

Clean the paint off and eyeball, with a magnifying glass under a really good light, every part of the drop. If you see cracks in the metal, then you know the bike is not safe to ride. If you see no apparent damage, then straighten the piece out, align the drops and check for cracks again. Look very carefully.

You might not see cracks in the metal and the metal might still be cracked. But at least you will have done your best to study the extent of the damage and to use or not to use is still a judgement call.

The alternative is to have the piece dyed and/or X-rayed. That will tell you for sure if the piece is damaged or not. But the process is probably pretty expensive. I used to do this when I had access to the equipment, but those days are long gone now.