Finished the 3 month Centurion Prestige build. Adjusted everything on the stand. Test rode up and down the block, brifters and brakes, it's working nicely so I go to end of the block, turn left uphill and stand on the pedals. I didn't finish the second rotation when it came apart violently.

This was a tough lesson; when building on an old frame with unknown history, build and test before any cosmetic work.

Only 10 minutes to live


So, the worst has happened; n-1, and this will be rectified soon!

What a shock!

Ugh. I feel your pain! I've never seen a failure like that. I wonder what kind of forces, and in what direction(s), caused such a failure.

Get it fixed. It will be worth it.

Holy crap, never seen that before. Hopefully you came out of it unscathed.

My guess is the dropout had been bent back and forth in its life and was weakened at the thinnest section, at the threaded hole.

Definitely. A good frame guy can braze you in a new dropout for not much drama, and the repaint for that section only shouldn't bee that pricey either. That's too gorgeous a build to abandon.

Glad to read that.

Awful... Though the half a dropout is proof positive of the enormous wattage that you clearly put out. If it were mine, I'd hang it on the wall and recount the story to houseguests. Good luck finding your n+1!

I would think the force exerted would tend to pull the axle towards the front of the dropout, along the slot. What caused it to force the bottom part of the dropout (I'm guessing), down, vertically?

Usually it happens as a result of the chain jamming and pulling on the derailleur. This could have happened under a previous owner, who straightened the damage. A subsequent hard shift may have been enough to cause the failure in that previously weakened spot.

That build came out pretty nifty. Sorry that happened.

Well, all the old books say that a great benefit of steel frames is that they can be relatively easily/cheaply repaired. Time to place that ancient wisdom into practice!

1. Likely bent in shipping and bent back.
2. Worth fixing.
3. Take the picture, frame it, mount that on the wall as proof of your wattage.
4. Refine the story to generate swoonage.

Long drive, but...
Come to Harvard and I'll MIG it for you.
Bring a nice Calvados or green chartreuse and be prepared for an evening of fun.
My prior dropout work is here. I'm confident I can do this. Super easy, especially if you can forego the adjuster. I can redrill and tap the adjuster as well, just a bit more work.

You would weld the two parts together?

Sure I would. For a bottle of green chartreuse and some agreeable company. Would also consider aņejo mezcal or tequila. You know, the stuff that's been aged on oak. Come over on the megabus, tell them it's a folding bike, they won't know!

I'd rather do that than try to source another dropout, melt and grind and file the old one out, prep everything, and braze it. The bottom of the dropout doesn't see much stress. This is way easier than the one I just did, linked to above. Only risky thing is trying to drill through the weld and tapping that hole for the adjuster. Much easier and stronger if you forego the adjuster on that side. But I can drill it too, if you must.

This is the one argument in favor of stamped dropouts over forged.

It is also possible that the dropouts were not properly aligned, or that the previous owner had broken a rear axle and stressed the drive side dropout in the process.

"...so there I was, rolling easily along at about 8/10ths when I decided to pour on the coal..." Etc., etc.

Any signs of corrosion in the threads of the adjuster hole? Just grasping at straws here.

That's gonna be a pretty build once it's back together.

Sam, a welder and tequila... what could possibly go wrong!

Hahahahahahaha
Good one !

I've seen that before. In those cases, it was from putting a longer OLD axle in frame designed for 120/126mm without cold setting and making sure the dropout faces were parallel to each other. Mind you, that's not what I'm saying is the case here.

Hmmm. I wonder.

I will very closely check the DOs after fixing.

I did not successfully cold set because the stays were like spring steel (wouldn't hold a mm of bend, even after spreading to 165mm, yet relatively easy to spread by hand) and now my check for parallel with a homemade tool feels cursory.

Edit PS
Wouldn't that misalignment become evident while setting up the RD?

I'd get that MIG or TIG welded for sure. As said, welding would fill in the tapped hole, but it could be drilled out and tapped after. If MIT is too far, maybe someone at RPI?