Bicycle Mechanics - Ultegra 6603 crank, 9 speed set up: What FD?
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02-01-07, 09:28 AM
I am currently converting my wife's Burley McKenzie from 105 9 speed double crank to Ultegra 10 speed triple (to make it easier to go uphill during pregnancy). I am facing two issues:
1) What front derailleur to install for the Ultegra 6603 which is 52/39/30? I am trying to choose between a 7703 (Dura Ace 9 speed model) and the 105/Ultegra 10speed models. From Sheldon Brown we know that all of these are 'optimized' for 13 teeth between largest and middle chainring. Since the rest of the Burley set up is 9 speed (including the chain) I am leaning towards the DA 9 speed FD, as presumably that is more compatible with the slightly wider 9 speed chain. Or should I got with a 10 speed 105/Ultegra FD (which costs about the same as 9 speed DA)? Any suggestions or experiences you can share?
2) The 6603 crank is currenlty missing the little spacer that goes between the BB and the non-drive crankarm (spacer is for 6603 crank only, not for the 6600). Do I really need that, or can I install it without (for a short while/forever)?
02-01-07, 10:22 AM
1: It depends. I'd lean towards the 9 speed FD, myself. You could use the 10sp as well, it would just be more difficult to adjust. I've done 9 speed FDs with 8 speed drivetrains without much difficulty but I've never done a 10 on a 9.
2: It shouldn't be a huge issue as long as you can get the non-drive side cap to preload the bearings properly. The only thing that would be affected at that point is the chainline, once again leading to minor difficulties in adjustment.
Felix, I think you're wasting $$ going with the 10-speed crank. $300 is about the best you're going to do on the crankset and cups. Yet CBO (http://www.cambriabike.com/) has the 9-speed FC-6503 crankset and BB-5503 BB cartridge for $115.
If you insist on going 10-speed, then I'd use the matching FD: "The Ultegra 9-speed triple front derailleur is designed for 52-42-30 chainrings, a ten tooth difference, large to middle. The Ultegra 10-speed triple front derailleur is designed for 52-39-30 chainrings, a 13 tooth difference, large to middle." - Al19434
CBO has the FD-6603 braze-on on sale for $40.
02-01-07, 04:43 PM
DMF, it sounds like he already has the crankset. Could be wrong but that was the impression I got from the OP. That said the 10 speed crank has a lot of advantages in terms of overall reliability and servicability... Whether that's worth all the extra money is another matter but if he's already got it might as well work with it.
My vote's still to go with your gut instinct. Personally now that I've pondered it some the 10sp will be worth the extra aggrivation of setting up now in that later you can more easily switch to 10 speed if the time ever comes.
02-03-07, 03:46 PM
Thanks for your different opinions. Yes, I already have the crank - in 165mm length to match my favorite rider's legs...
Since I only paid $130 including BB cups for the 10 speed 6603 triple it wasn't hard to decide whether to go with nine speed cranks ;-)
I think I will go DA 7703 as FD once I find a cheap one. Just feel that it will work better with the 9 speed chain.
My second question has also been solved, as I now have the extra spacer.
I agree that the D-A 9-speed derailleur should work better with the 9-speed chain. The D-A 9-speed triple is 53-39-30, a 14 tooth difference, but one tooth's not likely to matter. I suspect that a 9-speed 105 or Ultegra FD would also work.
BTW, the 10-speed 105 is a 50-39-30, so the derailleur is spec'd for an 11 tooth difference, I suppose.
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