When I tried to downshift about 5 cogs in one go, the hollow pin light weight campy chain twisted in the derailleur cage, and bent the Record short cage! The God damn chain didn't break, but two links twisted around about 45 degrees. It also bent the aluminium plate on the back of the derailleur cage!

What the $%$#**********? I am using a 13-26 cog set, which is within the specified range of the short cage derailleur. The chain evidently didn't come off the cog, and jammed against the derailleur inner plate.

&%&*(*!!!!

why were you trying to downshift 5 cogs in one go?

Seriously. I can't imagine such a situation.

The derailleur can handle a series of quick movements of a step, but it isn't designed to move a chain over multiple cogs with one mighty throw. You might be able to get away with moving from large to small, but moving from small to large too quickly will simply torque the chain between the derailleur pulley and the place where it is engaged on the cogs. Hopefully you can recover from your misfortune without it being too expensive a lesson.

p.s. - I doubt the Creator would see fit to expend any special efforts on your chain.

I'm thinking by "downshifted" he meant he used the thumb lever to shift from big -> small across the cassette. I was under the impression that this was possible with Campy.

Otherwise, I thought you could only go 3-at-a-time in the small -> big direction.

Were you pedaling evenly through the shift? Were you standing on the cranks hard? Was it adjusted correctly?

One of the pitfalls of using light weight components. Ironic probably with lower scale Campy components which are also heavier this wouldn't of happened.

I've done before with both my Record and Chorus bikes with zero problems.

You have undoubtedly paid quite a bit for that kit - have you thought about making a warranty claim to Campy? Maybe they will think twice before offering dodgy things like lightened chains....

Let me guess... you came up to a hill and as you lost momentum, you got out of the saddle to keep up the speed. Then finally when you were going way too slow for the current gear with all your weight pushing on the pedals out of the saddle, you shifted into easier gears?

I think anytime you have to shift more than 1 gear, that shift could've been broken up into multiple steps along the way. If you have to shift 5 gears, that could've been broke up in to 5 separate shifts BEFORE you reach the same point where you bent the chain. Sure it could've been 5 shifts every 1/2 a second over the course of 4 feet, but that's still 5 separate shifts and 5 separate events where the chain moved cleanly from one cog to the next with full engagement.

Same thing with cresting a hill and starting down the backside. If you have to shift more than 1 gear, you waited too long.

That was my read on it also. I thought this one of the big advantages of Campy, that you could go multiple steps down in a hurry, as opposed to 5 individual clicks on a shimano shifter.

With a a tight spaced cassette (e.g. 1 tooth different per sporcket) I could see how you'd want to go 5 cogs lower in ahurry in a lot of race situations. For example pack is just lolly gagging and there's a violent attack you have to match.

No, I wasn't standing on the pedal or anything like that. The chain wasn't under any serious load. I crested a hill, then coasted downhill for a short time on the big cog to recover, ater a maybe 20 seconds, I was going about 30 mphs, so I tried to shift up 5 cogs at once to start pedaling again. The chain immediately jammed. I was not standing on the pedal. I was just spinning up.

Yeah, like I thought, big -> small across the back. That should've been no problem.

Not even on a super special Campagnolo chain? I am not asking him to waste time on mere Shimano chains, mind you.

Total repair bill: $215 for the replacement Record short cage, and $50 for a new chain.

Apparently the back plate of the derailleur cage is not sold separately. To get that you need to also the rest of the cage mechanism, including the CF front plate, the tension adjuster, the pulley wheels, the ti bolt holding it to the derailleur body, and the spring.

I can almost get a entirely new derailleur.

Good momentum up a steep hill , stop sign , 5 cogs (+/-) small to big in one go with my ultegra = nice and smooth every time.

Uhem. Ultegra can't manage 5 cogs in one go in either direction. Only 3 cogs going up or 1 cog going down in one go.

You shifted, and then pedaled? If that's how it happened, think about it from the chain's perspective. Derailleur is in the middle of the cassette, and the chain is hooked on the cogs of the large gear. The chainline from the jockey wheel to the cog is horrendous, now you start to pedal and... aargh!! results. All would have been well had you pedaled before shifting.

Sorry to hear it's going to cost so much to fix it. I've bought a couple very nice, entire used bikes for less.

I don't know what to tell ya. It moves from mid cog to the biggest on a 10 speed.

Are the two pulley wheels in the Record cage supposed to be lie perfectly in one single plane? Or is one normally tilted by maybe 3 degrees to the other?

I am looking at mine, and I see the bottom pulley wheel maybe 3 degrees offset from the one on top. The back plate also seem twisted by about 3 degrees. But it shifts perfectly smoothly. So maybe it was suppose to be like this to start with?

The chain is now too short after I punched out the two twisted links, so I can't do big chain ring to big cog anymore. I suppose a new chain is unavoidable.

I dont know what terminology all cyclists use but I would call that "upshifting" since you're moving to a higher gear.

Big chainring/big cog is a NO-NO!

Yes. I know. For some reason I associate shifting to a smaller cog with "down-shifting". What I really meant was shifting to a taller gear ratio.

https://aebike.com/site/page.cfm?PageID=30&SKU=DP9876 You got HOSED...I guess it depends on how much installation cost for the parts though.

I know. But right now were I to put the bike in big-big by accident, the chain is so short it would trace an almost straight path from the bottom of the cog to the bottom of the chain ring, and the derailleur cage would be pulled hard forward, and still the gear would grind against the chain and the derailleur pulley.

That's definitely 2 links too short.

I am doing the installation myself.

I guess I'll chauk that up to "support LBS".