More Front Derailleur Funkiness

[jack1]

I just switched my road bike to a more upright/flat set of handle bars. My old handle bars had STI shifters on them (Deore) and my new ones have Shimano V Brake Index Shifters on them.

I found by raising the FD higher than normal I was able to get my "trim points" back (they didn't work at the 2cm distance).

I was able to use Alex's video to get my travel screws all set. But then comes the problems.

I shift to the big cog in the back, the small cog in the front, and then I move to the middle cog on the front. It makes all kinds of racket. So I adjust it (a lot) with the barrel adjusters, and the noise goes away. But then I shift to the lower sprocket on the front again and I get a very loose FD cable hanging from my frame.

Not sure what to do about this.

Thoughts??

Thanks in Advance.

[Bill]

Are the two shifters compatible? Maybe I mean to say is the replacement shifter compatible with the rest of the FD assembly?

[Joe_W]

Yeah, those are probably not really compatible, they might pull a different amount of cable, might still work on the FD, though. Read the specs, if there are any available for that.
Your problems come possibly from the trim function, many (not all) shifters have that. Grab 06) at http://bike.shimano.com/publish/content/global_cycle/en/us/index/tech_support/tech_tips.html to learn more.

Are you sure that "rising the derailleur" did not just shorten the cable enough to make it work? I'd rather keep the FD cage 2 mm (that is millimetres not centimetres!) above the large ring. Otherwise shifting performance will decline. If the cage was in fact 3cm above the ring you should not be able to make it work at all.
Oh, and there are no Deore road bike components....
If you had a flatbar bike (in my opinion not really a road bike), you might have had Deore stuff installed, though. But I wonder why they did apparently work and the new stuff doesn't.

[cyclerUK]

Joe your correct.
MTB shifters (rapidfire) pull a lot more cable than STI.
STI pull about 1/2" compared with 3/4" of Rapidfire per click, so that is why there is a lot of slack.
You would have to fit a Deore or similar FD to be really compatible.
The possible problem with MTB front derailleurs is the curve of the cage might not match larger ring sizes.
The maximum ring size is stated as 48T so if you have a 50T or above it may not function properly.

JACK,
From what you are saying do you have a double chainset?
The front triple MTB shifter does not have a "trim" setting. It's 3 positions for the 3 rings.
Even if you fit a MTB derailleur you wouldn't have a proper trim except by luck.

The pull on both STI & MTB for the rear derailleur is the same so will work any Shimano Road or MTB system.

P.S. Joe, Flat bar road bikes where around a long time before MTBs were invented.
I had one back in the fifties (Trent Tourist).

[Joe_W]

Hm, ok, maybe that shows I'm "quite young" ;-) Glad to be corrected (these bikes seem to be called "fitness bikes" in the catalogues here at the moment, though). Oh, and I know that MTBs are quite new, I believe road cyclists used to put wider tyres on their bikes in winter, race in the mud and thus "invented" cyclocross... though there might exist other stories (and this has now gone way too OT, bad boy Joe!)

[DaveM]

Sorry to be the bearer of bad tidings, but I think you also have a brake issue. V-brake levers are not supposed to be used with road brake calipers. The brakes will function, but you may get degraded performance because v-brake levers also have a different cable pull than road levers. I think it means that you have to apply more force at the levers to get the same braking force at the wheel. You can get adapters that will fix that cable pull issue, but I don't know about the fr derailleur.

Bikes ain't as simple as they used to be...

[jack1]

(02-05-2010, 05:40 AM)cyclerUK Wrote:  Joe your correct.
MTB shifters (rapidfire) pull a lot more cable than STI.
STI pull about 1/2" compared with 3/4" of Rapidfire per click, so that is why there is a lot of slack.
You would have to fit a Deore or similar FD to be really compatible.
The possible problem with MTB front derailleurs is the curve of the cage might not match larger ring sizes.
The maximum ring size is stated as 48T so if you have a 50T or above it may not function properly.

JACK,
From what you are saying do you have a double chainset?
The front triple MTB shifter does not have a "trim" setting. It's 3 positions for the 3 rings.
Even if you fit a MTB derailleur you wouldn't have a proper trim except by luck.

The pull on both STI & MTB for the rear derailleur is the same so will work any Shimano Road or MTB system.

P.S. Joe, Flat bar road bikes where around a long time before MTBs were invented.
I had one back in the fifties (Trent Tourist).

First, thanks for your thought and energy. The STI shifters were Tiagra, but that isn't important.

It sounds like I need to investigate a new FD. I have a triple on the front. The bike is a Specialized Allez Comp. I've been commuting on a "hybrid" but I would like to get back on my lighter, faster, more agile road frame. I've got a hip that is giving me issues and I like being a little more upright, that's why I changed the handlebars. I was hoping this would be easy but....

Might have to head to the LBS after all.

Not too worried about the brakes right now, they actually feel great.

Any other suggestions are welcome.

Again, thanks!