maypo

I have been out of cycling for a few years and want to get a bike i have running better than when i was riding it-and start riding again. I bought it used the summer before i stopped riding.
It is Campy Record 8 speed ergo (the Davidson impulse steel frame was not built for 8 speed and you do need to spread it to get it in there). The front double chainrings are a 53-39, the rear 8 spd cluster is a 12-25 if i counted right. The rear derailler has aftermarket idler wheels and never seemed to be able to be properly tuned or stay in tune. I have no idea if this was a 7 spd set up put together to become 8 spd or what.
I am thinking that my easiest course of action is to buy a used campy record 8 spd rear derailler as i have no idea what other issues the already modified derailer might have.
Based on the set up i think i am looking for a short cage 8 spd.???
Can someone give me an idea of what my chain length should be in case that is a contributing issue??

FBinNY 

Chain length has little (or nothing) to do with the derailleur.

It must be long enough to loop the big/big combination with an inch to spare.
It should be short enough so that the RD can take up slack when in the small/small combination.

Anything in between is fine.

BTW- unless there's a specific reason to replace the derailleur, you probably won't benefit from doing so.

Al1943

Are you sure that the shifters, cassette, and rear derailleur are Campy 8-speed? Can you use the model numbers or serial numbers to confirm this? Campy changed the derailleur actuation ratio in 2001, later models are not compatible with 8-speed.
Are you sure that the shift cable is connected on the correct side of the pinch bolt?

Andrew R Stewart 

The Op might try an upper pulley with some float in it if it isn't already that way. It's been too long for me to remember whether the stock upper pulleys had float or not. Even prior to indexing the after market pulleys often ran rougher/noisier then the OEM ones. Many being made of metal and not the OEM plastic didn't help this.

My 8 spd Ergo stuff is/was Sachs. The Success ders came with both types of pulleys. For those of you who don't know, the Sachs Ergo levers were Shimano 7 speed or Campy 8 speed cog spacing compatible but pulled the cable with a Shimano der spec. Andy (who never ran metal pulleys after his Huret days).

FBinNY 

Campagnolo never (until maybe recently -- since 2003 or so) used floating pulleys. Their shift system relied on over travel and return to trim to make shifting happen. Pulleys were sold in pairs, and both were the same.

Andrew R Stewart 

IIRC Campy wanted the cable/index adjustment to be done with the chain on the middle cog. So as you went up or down the cassette the errors were balanced over the range. I have done a few pulley replacements, years ago, using Shimano pulleys with float on customer Campy systems with good results. Another aspect of those early Ergo systems is that the frames and cable fittings were often not best for indexed systems. Campy was less often found, OEM, on brands that could/would change their minor frame specs with each model year. When Shimano first brought out index shifting they claimed there were something like 17 specs that had to be right for good performance. Some of these could be fudged a bit, others less so. But fudge a few then the errors added up. Andy.

FBinNY 

Campagnolo RDs can be trimmed in ANY of the sprockets except for the end ones in either direction. Ergo levers are built with a large overshift to the outermost sprocket to make it easier to assemble the levers at the factory. This is OK because the outer sprocket position can be trimmed via the limit screw. You don't set trim on the innermost sprocket, not because you can't, but because the limit screw position might be affecting the position.

Most people experienced with setting up Campy RD trim do so on the 2nd to 3rd high sprockets, but in the final adjustment, end up balancing shift response in both directions rather than worrying about trim per se.

zacster

And one thing to check is the derailleur hanger alignment. If it is not straight you would also have a lot of noise.

I'm the original owner of a 1981 custom built Davidson, before they started selling them pre-built at Elliot Bay. It is also 126 rear spacing, but I have a 10sp/130 wheel on it for over 10 years now. It hasn't caused any problems. I use the original Campy friction shifters and derailleurs too, and it works a lot better than you'd think.

Dave Mayer

Since you have Campy 8-speed Ergopower shifters, any 8-speed Campy rear derailleur should be index compatible with your levers. That is, the slant parallelogram derailleurs produced from around 1992 to 2000. The later (and current) derailleurs will still work, but not as well.

I suggest you work on improving your current shifting. I would replace all of the shifter cables and housing, and start the derailleur adjustments from scratch. And buy a new chain - in my experience the Shimano IG and HG 7/8 speed chains shift the best.

The pulley wheels should not make a difference, as long as the bushings indside are not worn out, making them sloppy. If you really need to replace the pulley wheels, some aftermarket units such as Tacx work fine. You can pay 5 times more for the ceramic ones, for no benefit.

Campy Record 8-speed rear derailleurs go for hideous prices on Ebay. Plus, many of the Record units seem to have a casting flaw that causes them to crack near the top pivot. Check Ebay - a high percentage of these units (Record only) for sale share this fatal flaw. In terms of shifting, the (much cheaper) Athena or Veloce units from the same generation work just as well.

Chain length will have only peripheral effects on your shifting. Too long, and it will droop when you are in the small-small ring/cog option. Too short, and the chain will break, or it will tear the derailleur off of the frame the first time you shift into the big-big combo.

Andrew R Stewart 

It is interesting that there are different views/experiences in dealing with components so long around. Perhaps the lack of Campy market share and the tendency to view Ergo through Shimano eyes is some of the reason. I take issue with some of the comments made in this thread but none are absolutely wrong, just in my experience not completely correct. The OP certainly has a range of suggestions and understandings to go with.

The one bit I will revisit, and not because i think it's incorrect, is Francis's use of the term "trim' when talking about a rear shifter. But i do wonder why he uses this term. Many people have come to understand this as the feature of front shifters allowing small cage repositioning to relieve chain/cage rub. I have not heard it used WRT rear shifting since friction levers. Do you (Francis) mean the overshift movement of the down shifting direction that Ergo (and STI) levers have is this trim you refer to? Please educate me. Andy.

FBinNY 

I use the term trim in many ways but the meaning is usually obvious from the context. I could say fine tune, or dial in, but I prefer to say "adjust trim" when speaking of RDs. It's just a language quirk of mine.

It's like my having to grit my teeth every time I have to say "adjust cable tension", when I mean adjust cable length. So to prevent expensive dental work I'll often say use the barrel adjuster to adjust trim.

Andrew R Stewart 

Francis- Thanks for your explanation. Andy.

maypo

I thank everyone for their comments especially those that answer the questions that were posed. I think i should remove my rear derailer and examine it for cracks as well as try to replace the anodized red aluminum idlers that are in it before anything else.

Mr Stewart-you are likely within shouting distance.

maypo

With only 2 posts i can not send nor reply to private messages. The county seat is Batavia NY. I live west of Byron NY and North of Elba NY. I work in downtown Rochester.

Ex Pres 

Just a thought here. If the bike started it's life as a 7s, and was converted to 8, they may not have changed out the RD. I've tried using a 7s Chorus RD (with unit with the A/B selector) with Ergo - and it works, sort of, and then it feels out of adjustment. So you readjust it. And you can go through this cycle over and over, but it's never quite right. All was well when I installed a "newer" (8-9s) RD. The 7s units just aren't quite right for Ergo. But close enough to trick you.

Kimmo 

First thing I'd do would be to ditch the noisy metal pulleys for some plastic BB ones. $20.

Hard to diagnose the more subtle shifting issues when there's extra noise...

Some pics would go a long way too.

maypo

Yup. This is what i was thinking. It always seemed like i had it fine on the stand and once i started riding and shifting i was back to having to play with the adjuster on the down tube or try and tweak the lever a bit.
It was not like the shimano indexing on my touring bike-once it was set up it was just a snick into each and every gear. I remember now thinking that i should convert the gearing to a shimano system - I should look through my boxes, i may have bought some...