Need Help, Please: Rear Derailleur

[Bak in a Camel]

Hi, I am looking to upgrade my Rear Derailleur from a Shimano Claris 8 speed.

I am wanting either an ultegra or a 105, depending on price.

I cannot find a 105/ultegra 8 speed Rear Derailleur, only 9/10 speed, so my question is, can a so called 9/10 speed by the manufacturer, be used in conjunction with an 8 speed set up?

Because in my head, even though I have an 8 speed Cassette and Chain which have different spacing to 10/11 speed, as long it is suitable for the max teeth (32) on the cassette, it should be just a case of adjusting the cable tension and indexing the gears?


I am 100% not fussed if my understanding is wrong, please, just let me know!

 

[raleighnut]

I use a 105 10spd on an 8 but you need to use the 'alternate' cable position on the mech to get the cable 'pull' right. Indexing is fine.

 

[vickster]

Interested to know why it would be an upgrade if not changing the shifters too?

 

[Ajax Bay]

As @vickster implies, what are you trying to achieve, exactly. Is the Claris RD broken? Do you want 9 or 10 speed? Or do you think a 105 or ultra (sic - it's Ultegra) will give you better shifting on the cassette? Would the best thing be to scratch away the 'Claris' name on the RD and put a '105' sticker on there?
If you want to go to more gears, as well as the RD, you would need to swap out the rear STI (brake/shifter) too, and the cassette.

 

[raleighnut]

I understand, 105 goes 'snick' when you change, Claris can go grumble crunch grumble before it changes.

 

[Bak in a Camel]

I use a 105 10spd on an 8 but you need to use the 'alternate' cable position on the mech to get the cable 'pull' right. Indexing is fine.

Thanks, appreciate it!

 

[Bak in a Camel]

As @vickster implies, what are you trying to achieve, exactly. Is the Claris RD broken? Do you want 9 or 10 speed? Or do you think a 105 or ultra (sic - it's Ultegra) will give you better shifting on the cassette? Would the best thing be to scratch away the 'Claris' name on the RD and put a '105' sticker on there?
If you want to go to more gears, as well as the RD, you would need to swap out the rear STI (brake/shifter) too, and the cassette.

Hi, thanks for our response.
The Claris RD is far from smooth when changing, hence my impulse to change.
Sorry, 'Ultra' was an autocorrect on my mac, I do understand it is calls Ultegra.
But please leave the sarcasm in your being, I really don't appreciate the 'scratching off' comment, it isn't big and isn't clever. We should all get along and try and help each other with our shared hobby/interest/passion.

Scratching the logo off, implying that an 105 RD is the same as a Claris RD, is some what ludicrous, otherwise people would be running Ultegra groupsets with Claris RD's on them to save a few quid.

But to answer your other questions, yes the Claris RD is broken, it's insufferable.
I don't want more gears as of yet.
I will be upgrading the STI's too to enhance a smoother transition in gear change.
I do think the Ultegra will give be smoother shifting on the cassette.

Please do answer my original query, I would really appreciate it... can a so called 9/10 speed RD by the manufacturer, be used in conjunction with an 8 speed set up?

 

[Klassikbike]

For relatively cheap you could go 10 Speed by upgrading to new Tiagra with Shifter, rear derailleur, casette and chain.
An 8 speed derailleur will not work with a 9/10 speed shifter.
Crankset you do not need to change.

 

[Dogtrousers]

Yes, you are right.

There's nothing inherently 8 or 10 speedy about the mech itself - that's dictated by how much cable the shifter pulls.

(Usual disclaimer: I am a random idiot. Do not believe me.)

 

[Ajax Bay]

Answer = 'Yes'.
AASHTA: "Within a given brand/style of rear derailer, all "speed numbers" are generally interchangeable. This applies to all indexable models, basically everything manufactured since the late 1980s."
If you'd said that the Claris RD was not functioning satisfactorily in the first place as opposed to saying you wanted to 'upgrade' then your motive would have been clear. I try to check my posts before submitting to avoid mistakes which undermine any reputation I may have, like 'Ultra' vice 'Ultegra' and do not seek to blame 'autocorrect', ever. And your response was not "our" response, btw (see fourth word of your post).
I think better STIs will make a bigger difference than the improvement gained from the RD.

 

[Bak in a Camel]

Answer = 'Yes'.
AASHTA: "Within a given brand/style of rear derailer, all "speed numbers" are generally interchangeable. This applies to all indexable models, basically everything manufactured since the late 1980s."
If you'd said that the Claris RD was not functioning satisfactorily in the first place as opposed to saying you wanted to 'upgrade' then your motive would have been clear. I try to check my posts before submitting to avoid mistakes which undermine any reputation I may have, like 'Ultra' vice 'Ultegra' and do not seek to blame 'autocorrect', ever. And your response was not "our" response, btw (see fourth word of your post).
I think better STIs will make a bigger difference than the improvement gained from the RD.

Thank you for answering my question, have a nice day.

 

[Ajax Bay]

In my first post I should have said welcome . You have a good ride too.

 

[Arjimlad]

In my experience derailleurs just move up & down the range on their springs. If you disconnect the cable it will just push up & down without any clicks. I replaced a 2011 Sora mech with a more recent 105 one and it has made no difference to shifting quality.

As Vickster says, I think that the main advantage might come from using upgraded brifters as it is these which control how much and how smoothly the rear mech shifts, assuming that cable and outers are doing their job properly.

I have Claris on my Revolt and it has been very good with no shifting problems at all.

 

[cyberknight]

My claris go click not grumble , have you ridden the bike for a while as it might benefit from new cablle inners + outers.

 

[sidevalve]

Cutting out the bull - answer to OP = yes. In essence a rear deraileur doesn't know what it's changing - it does as it's told. You are correct it is the shifters and tension that will do the job [as above though new cables might improve things].