Replacing a rear Tiagra derrailure
1964johnr
Posts: 172
I need to replace my rear Tigra derrailure which runs on a 9 speed Shimano cassette. I seem to be looking at a lot of 10 speed Tiagra derrailures, but can't seem to find a 9 speed one. My Giant SCR 2 is 8 years old now. Can I replace the Tiagra with a 10 speed, even though my Shimano cassette is a 9 speed? I ave a triple chain set. I also see that derrailures seem to be short or medium. Not sure which one I need. Any help would be appreciated.
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http://www.ribblecycles.co.uk/sp/road-track-bike/derailleurs-rear-shimano-sora-3500-9-speed-rear-derailleur/shimgrrr211
The number of "speeds" determines how much the derailleur moves with each index (click) of the shifter. Fitting a 10spd derailleur to a 9 speed shifter means that the spacing will be out of line and you MAY struggle to get a smooth movement of the chain through the jockey wheels.
Agreed, I have a '9 speed' sora derailleur mixed with 10 speed 105 shifters and a 10 speed tiagra cassette. As long as the shifters and cassette match you can use 9/10/11 speed derailleur.
I would go with medium, it gives you more flexibility on the cassette.
Not so fast with lumping 11 speed in with the others. Shimano changed the geometry of the rear mech with the move to 11 speed, so you'd have problems using an 11 speed mech with 10 speed shifters, or the reverse.
8, 9 and 10 speed Shimano mechs will work with 8, 9 and 10 speed shifters etc. In terms of speeds, the shifters, chain and cassette need to be the same.
To the OP, I'd go for the 10 speed Tiagra mech. Since you have a triple you should go for the longer cage version (medium)
I would agree with this. All a deraiileur is , is a big spring with a couple of jockeys on it really. Its the shifters that dictate how it moves. The only real difference in say a Tiagra RD and a Dura Ace is weight and materials. They all work exactly the same way (less Di2 Obviously) So long as the spring has the same range of movement as that of the cassette width it will work fine.
Jockey wheels can be changed you know. Thet are only bits of plastic on bearings.
Yeah I know. What I dont know is whether different sized jockies would work in a derailleur made for a different number of gears. I was also curious as to whether there is greater tolerance in the jockies with regards to chain size.
A 10sp Tiagra derailleur would most probably work with a 9 Sp cassette and shifter.
The cage width would restrict any wider chains going through but a 10 sp would work ok.
I have a 10sp Tiagra groupset less crank I just removed from my VN7 that I ugraded to 105 for less than £100 (front, rear derailleur shifters + cables) for sale if anyone wants it!
If you have the cash its well worth ipgrading the lot. The step from Tiagra to 105 is bug and you get the cleaner cockpit with better shifter cable running
It will be fine.
Shimano, for some reason stopped calling long cage mechs 'long cage', now it's medium. Maybe long cage sounds uncool???
Giant TCR Alliance Zero
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No, no, no! It's not just about the range of movement. You are quoting keef, agreeing with him and then contradicting him! A derailleur is more than a big spring with a couple of jockey wheels on it. It is a big spring with a couple of jockey wheels on it and a lever. The lever is important but fortunately a constant for the OPs options. Of course, probably the only real reason for the lever to vary whatever the number of speeds is to sell more mechs but that's another cynical story.........
So. NO, NO, NO....Actually yes you are right just I elaborate a bit more on what you said by adding in a little more detail. Point for the OP is what he is asking will work. Thats all that matters in the end.
Absolutely! I was more making the point to avoid confusion for the next person who comes along wanting to swap is 11 speed mech for a 10!