Camilo

I'm moving the parts from my old Cannondale CAAD7 frame to my new Felt ZC frame. The front derailleur is braze on type on the new frame. My components are Shimano 9 speed/triple, 6503.

I mounted the front derailleur and it doesn't have enough clearance with the seat tube to eliminate chain/derailleur cage rub when on the inner/small chain ring and the largest couple of sprockets in the back.

The cable is not attached, so it's not a cable length problem

The inner limit screw is backed off so it is not limiting derailleur movement at all. What is stopping the derailleur is the seat tube itself - the derailleur simply cannot move enough inward to get to the correct position over the inner chain ring.

I have fiddled with it and there is no way that I can mount the derailleur to increase inner movement enough.

The bottom bracket is Octalink with the triple spindle length.

Looking at it, the only solution I picture: if the spindle was longer, the entire crank would move outward, therefore the derailleur wouldn't have to move inward so far to be properly positioned.

As far as I know, there is no Octalink BB with a longer spindle though.

Any thoughts, ideas solutions?

Thanks.

DaveSSS 

The only other way to change the chainline would be to install 1-2mm of spacer behind the BB cup on the right side. You should check the chainline anyway. Measure from the side of the ST to the tip of a tooth on the middle ring, then add half the ST diameter. The total should be 45mm. Some other brands specify 46-47.5mm. Campy goes as far as 47.5mm and it's done so the FD will work on bikes with larger seat tubes.

I would unscrew the right cup by 1mm (one full turn is barely more than 1mm). Verify that the crank actually moved to the right after unscrewing the cup. If that doesn't do it, then try one more turn. That way you can figure out the spacer required without removing and reinstalling the crank.

Camilo

I did install spacers - it took 3 (didn't measure them, I'm thinking 3 or so mm). Chainline is approximately 48-49 mm. I can't get it to work any other way. The shifting seems OK. I've ridden it about 30 miles. I have definitely noticed that I have less "range" in the rear cogs when on the outer/big ring. I used to be able to fine tune it so I could get 6 or 7 of the rear cogs easily without rubbing. Now it's probably 5 or 6.

Middle ring still has full range in back.

Inner/smallest ring now has full range in back too. I think that's were the "missing" cog range from the large/outer ring went. I used to get about 6-7 (or even more) of the 9 rear cogs on either of those rings, now it's changed. To me, this makes sense because of the shift of the chain line.

Also, some of the "normal" drive train noises seem different. This could be my imagination or because of the change in the sound transmitted/amplified by the different frame. But, this has never been the quietest drive train in the world... I use SRAM cassettes and chains, and that could have something to do with it. But even on the old frame it wasn't as quiet as my commuter which has a shimano LX triple crank and XT derailleurs and the same type of SRAM 9 speed cassette and chain and is much quiter - always has been.

All of the above is tentative. Still dealing with tweaking the front and rear shifting w/ new cables and figuring out the subtle differences in what the changed chainline has caused.

Also, I "think" there's some front ring noise that I'm not familiar with. Not der. cage noise, not rubbing on adjacent ring, but somthing different, and not in all combinations. Just sounds like the chain is making noise on the chain wheel itself. Could be just need more rear der. tweaking, could be a sound that has always been there, but just sounds different and/or amplified with the new carbon fiber frame vs. the old aluminum one.

I'm going to try to ride it w/ tools in hand on as quiet and smooth a road as I can find so I can really listen and try to see how much is just normal drive train noise which just sounds different and how much can be tweaked away.

But really it works fine - I rode a brisk 30 miles and really enjoyed it and except for being preoccupied with the above a little, there were no missed shifts and the shifts were normal in terms of smoothness.