Front derailleur narrow cage - bit of a pain
Simontheintrepid
Posts: 128
Hi Internet
I have a Tiagra spec bike and broke the derailleur recently. Needed another one quickly and as the Tiagra replacement (34.9 diameter) was hard to find, got a 105 derailleur instead. I noticed that the cage is considerably narrower on the 105 and now I have to be really precise with the tension and if it changes at all I get immediate chain rub, which is annoying at the start of a 50+ mile ride. Also, there's a gear in the middle of the cassette that rubs the inside of the cage in the big ring and the outside of the cage in the small ring. It's the gear I tend to fall into on gradual inclines.
So, do I need a narrower cassette on the back (standard Shimano Hyperglide at the moment) which I guess requires replacing the whole shifting system? Should I just STFU and get the bike serviced properly/replace with Tiagra, or should I just be less incompetent adjusting the tension?
Not a big problem, just worrying about chain rub all the time is beginning to get on my nerves.
Thanks Internet
I have a Tiagra spec bike and broke the derailleur recently. Needed another one quickly and as the Tiagra replacement (34.9 diameter) was hard to find, got a 105 derailleur instead. I noticed that the cage is considerably narrower on the 105 and now I have to be really precise with the tension and if it changes at all I get immediate chain rub, which is annoying at the start of a 50+ mile ride. Also, there's a gear in the middle of the cassette that rubs the inside of the cage in the big ring and the outside of the cage in the small ring. It's the gear I tend to fall into on gradual inclines.
So, do I need a narrower cassette on the back (standard Shimano Hyperglide at the moment) which I guess requires replacing the whole shifting system? Should I just STFU and get the bike serviced properly/replace with Tiagra, or should I just be less incompetent adjusting the tension?
Not a big problem, just worrying about chain rub all the time is beginning to get on my nerves.
Thanks Internet
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Comments
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sounds like you fitted a 10spd mech to a 9spd set up."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
Yes I was aware of 105 being 10 speed stuff but I thought it wouldn't matter for a front derailleur, plus it got me out of a sticky situation as I needed something for a big ride quickly.
Besides, a 105 derailleur would in theory need to accommodate an extra gear on the cassette. Why would it be narrower?0 -
the chain is narrower so the cage has to be narrower."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
Oh right, didn't know chain sizes varied much. That solves that one then.0
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The cassettes are the same width, so with 10 speed the sprockets have to be closer together, hence a narrower chain.
I have a mavic 10 speed chain on my 105 triple which is marginally fatter than the shimano chain it replaced. I now get chain rub in some combinations, and some sluggish gear changes. It's amazing the difference it can make.
That'll tech me for being a cheapskate; couldn't resist the idea of a 10 sp chain for a tenner!0 -
keef66 - yes road bikes can be surprisingly fickle like that. It's all a learning process, usually an expensive one but all the same good to know.
Just so happens to be a Tiagra 34.9 on eBay so I'll get that instead - wish it had been there a week ago. Don't know why these are so rare. Anyway problem solved
Thanks0 -
dont forget to check that is is right for your set up. there is more than one version."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
It's a double and the right diameter, has the same part no: FD-4500. What else could go wrong?0
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Sounds like the correct one then!0
