Looking for suggestions, information, and experience. I have a full 7 speed Super Record Merckx and when I am in high gear I get chain rub against the inside of the outer face of the FD when pedaling hard at the very top of the stroke on the drive side (from 12:00 o'clock to 3:00 o'clock). When pedaling very hard in high gear, I can look down and see the chain move slightly to the right during this quadrant of the pedal stroke. It only occurs during extremely hard pedaling, but that is rather normal for me and I don't want to change my pedal stroke to accommodate the bike. The FD has been adjusted out as far as it can go without coming into contact with the inside of the crank arm and there is still a little rubbing in high gear. Is this likely being caused by crank flex or frame flex or is there some other issue that could be a factor? Is this a bit of a Super Record design problem? I was thinking of trying a narrower chain (9 speed) to see if this might resolve the issue, but I was concerned that a narrower chain might not work so well with the Sachs freewheel. But even if that does resolve the issue, should these clearances normally be this tight? Thanks for any input!

A 9 speed chain will work fine on a 7 speed freewheel. However, since the wider 7 speed FD cage will require a longer throw to move the chain up the the big ring, you still may have the same rubbing issue. A 9 speed FD in addition to the chain might be what's required to truly fix the problem.

Another possibility is adjusting your chainline to move the crankset away from the bike slightly. This would net you some clearance without requiring any expensive component changes (and keep the bike original). You should only need a thin spacer (0.5 - 1mm) to get the clearance you need based on your description.

Thanks for your response. You have some good ideas and I will consider them carefully. Is this problem I am having the result of outdated design (do other riders experience this on vintage SR drive trains) or could this issue be caused by a crankset with execssive flex? Are there any other possible causes I should investigate? Could I also simply resolve this by moving to Chorus 7 speed? I have a Bianchi with late 80's Chorus 7 speed and it has none of these issues.

As materials have improved, every part of a bike has become stiffer and that includes cranks and chainrings. Your problem could be any number of things including the frame, crankset, front derailler, bottom bracket, and chainrings. I would tend towards the cheapest solution which is first making sure what you have is tuned properly and only then looking to replace parts.

I just had another thought. Try grabbing your crankset by each arm and see if it will wiggle back and forth towards the frame. If it does, your bottom bracket needs to be adjusted. That play alone could cause the rubbing you are experiencing. Also check to make sure your chainrings aren't bent.

As I previously suggested, a simple bottom bracket spacer which will move the crank away from the frame should cure your problem and only cost a few dollars. If you have the upgrade itch, I won't try to stop you but there's no way I can guarantee you won't experience the same problems requiring the same solution as if you had kept the original parts in place.

Thanks again for your post! I definitely don't have the upgrade itch. I would like to retain everything I currently have. Just so I understand, are you suggesting that moving the crank slightly to the outside will provide some additional clearance because the angle of the chain will be changed slightly? I'm not sure that will resolve the issue because I am going to have to adjust the limit of the derailleur farther out as well to eliminate the rubbing and that will put the outside face of the derailleur into the same relative position with the crank arm. Or are you saying that I won't have to adjust the derailleur limit quite as far because the angle of the chain has been changed just a tiny amount? My ability to get the derailleur away from the movement of the chain in high gear is limited by the crank arm. My thoughts about moving to Chorus is that I believe the design of the newer cranks provided more clearance between the crank arm and the front derailleur. But I might be wrong about that. I have to check it out.

Sometimes I just don't know what's going through my head when I post something like the above. I think I had in my head that your issue was similar to when the front derailler can't move in far enough to clear the chain on the inner ring and big cog. But, as you've so patiently pointed out to me, it's definitely not. Sorry for the confusion.

So, we're back to changing the chain and derailler or moving to a different crankset. Given that yours is a rare issue, I'd be inclined to recommend just about any modern crankset as a solution to your problem. I've never had an issue with the derailler hitting the crank and I've installed quite a few different cranks though none of them Campy. If there was an issue like yours with the modern cranks, I'm sure we'd hear a lot more about it on these forums.

Its older stuff so you really have to deal with it. Its mostly the BB and crank flex, but a little bit of frame flex. You really can't do anything other than buy newer stiffer cranks.

IMO newer sealed type BBs tend to reduce that flexy feeling a bit. Also, are your chainrings nice and straight and tight?

I swapped a Zeus crank, but not the BB, out and put in a 10speed Chorus crank on my old steelie. I was really surprised by how much less flex there was afterwards. Even if you don't want to permanently change the crank you should try a more modern one to see if that is the issue you are having, although that isn't always so easy or cheap. I had the crank already sitting on a cracked frame.

I have a bunch of cranks lying around, at least a couple of them are new 7 or 8 speed Chorus and Record vintage that I was planning on using elsewhere and I think I will definitely give that a shot! I've got a feeling that will have some effect.