mrblue

I have an older (2000) LeMond Tourmalet. I have upgraded most of the components to Shimano 105, except the front derailleur and cassette, which are what came with the bike (non-original). Anyway, I've been thinking about replacing the front derailleur (which just says "Shimano 9-Speed" on it, no specific model) with a 105 because it doesn't seem to shift as "crisply" as I'd like.

The problem is this: I have a 9-speed cassette on the bike. All of the 105's I've looked at online say it is for a 10-speed. I don't really want to replace my cassette as it's still pretty good, and if I did that I'd also have to replace my shifters (which are 105 2x9, also in really great shape). So my question is, will the 10-speed 105 front derailleur work all right with my current set up, or should I look for a derailleur which is intended for a 9-speed (something like Sora)? If I do install the 105, 10-speed derailleur with my current 9-speed cassette what sort of issues can I expect to face?

Thanks.

e_guevara

The 10s 105 FD will work fine with your otherwise 9s setup.

headloss 

10speed FD is fine. It might rub a little more in the extreme cross-chained gearing combos... using a 10speed chain would eliminate that if it's a problem.

mrblue

Thanks!

So, if I were to use a 10-speed chain to accommodate for any chain rub on the front derailleur, would that then cause issues with the 9-speed cassette?

headloss 

No.

The only potential problem would be that the chain could fall between the rings on the crank, although this is unlikely if the crank is a true 9-speed crank. If that were an issue, however unlikely, you can get different spacers to put between the rings and narrow the gap.

gregjones

I used a 9 speed chain through a "10 sp" 105 for about 600 miles without problems. Try the chain you have, it will probably work fine.