Claris/2400 vs 2300

[Dogtrousers]

Can I just check that a Shimano Claris RD-2400-GS 8 speed rear mech is compatible in cable pull terms with a 2300 shifter, ie ok to replace an RD-2300 . I'm 99.9% certain that it is but I just wanted to double check as I'm specifying parts for a friend so I don't want to get it wrong.

(Another bottom gear lowering project ... replacing the 12-26 cassette with 11-32 on a Giant Avail 5)

 

[mcshroom]

I'd expect so. Shimano at 8 and 9 speed level used identical cable pulls for rear mechs, even between MTB and Road. I can tell you from experience that an Altus or Alivo rear mech is directly compatible and allows a 34t sprocket, as I've used this set up for years on my tourer

Sora 9sp front and rear mechs also work with 2300 shifters, which I have on another bike.

 

[Dogtrousers]

Great stuff, thanks. I thought so, but as it's not my money that will be buying the bits I wanted a bit of reassurance, so that (a) my friend doesn't waste money and far more importantly (b) so that I don' t look like an idiot (more than usual).

 

[Drago]

The answer is 'yes'.

 

[DCLane]

@Dogtrousers Yes - I run 2300 shifters / crank / front mech and have a 2400 rear mech.

You'll need the long cage rear mech though if you're moving to a much wider gear range.

 

[Dogtrousers]

@Dogtrousers Yes - I run 2300 shifters / crank / front mech and have a 2400 rear mech.

You'll need the long cage rear mech though if you're moving to a much wider gear range.

Thanks for the reassurance, nice to hear from someone using this exact setup. Chances of me appearing to be a complete idiot are reduced!

Yes to the long cage bit. In fact, that's the only reason I'm planning for the existing RD-2300 to be replaced with a RD-2400-GS.

 

[Nigelnaturist]

I'd expect so. Shimano at 8 and 9 speed level used identical cable pulls for rear mechs, even between MTB and Road. I can tell you from experience that an Altus or Alivo rear mech is directly compatible and allows a 34t sprocket, as I've used this set up for years on my tourer

Sora 9sp front and rear mechs also work with 2300 shifters, which I have on another bike.

Can't be as the spacers are different.
@Dogtrousers the pull is controlled by the shifter, almost any RD will work providing it has the capacity i.e. max tooth eg 32th and the total amount to accommodate the range i.e. front 22th rear say 11-34=23th total front and rear 45th not many road RD's have that yet. on a 50/34 16 front 23 rear total 39th this will fall with in many current GS (medium cages) RD's, also an option is to fit a MTB RD for extra range.

 

[mcshroom]

Can't be as the spacers are different.
@Dogtrousers the pull is controlled by the shifter, almost any RD will work providing it has the capacity i.e. max tooth eg 32th and the total amount to accommodate the range i.e. front 22th rear say 11-34=23th total front and rear 45th not many road RD's have that yet. on a 50/34 16 front 23 rear total 39th this will fall with in many current GS (medium cages) RD's, also an option is to fit a MTB RD for extra range.

That's the shifters not the mechs. The shifters pull a different amount of cable per click, but the mech moves the same distance per unit length of cable pulled

The mechs don't care, it's the shifters that are speed dependent. This changed with 10sp when the MTB and Road rear mechs moved different distances for the same amount of cable.

 

[Dogtrousers]

Thanks.

The RD-2400-GS has max sprocket of 32 and a capacity of 41.
The proposed setup (50/34 11-32) needs a capacity of 37, so that's fine.
It's not my bike so I don't want to get into the realms of exotic solutions involving MTB mechs - I'd rather keep to the same/similar Shimano series road components that are already there. If there was such a thing as a 2300-GS I'd be using that. I think this is the most conservative approach that will do the job required.

The bike itself as sold has a range of 35"-111", which as an entry-level bike, does seem rather high. (esp one targeted at women who, while on average lighter than men may not have the same leg strength). Inadvertently, by putting an 11T sprocket into the mix I'll be increasing the top to 121", which is a bit bonkers. If I could find a 12-32 8 speed cassette I'd spec that, but they seem to be fairly uncommon, and I want to be careful to reduce the risk of things being incompatible to the absolute minimum,

But I can feel myself inching towards my soap box so I'll stop there.

 

[Nigelnaturist]

That's the shifters not the mechs. The shifters pull a different amount of cable per click, but the mech moves the same distance per unit length of cable pulled

The mechs don't care, it's the shifters that are speed dependent. This changed with 10sp when the MTB and Road rear mechs moved different distances for the same amount of cable.

Again the RD is dumb as you say, and I used my RD5701 fine with both 9 and 8sp.

@Dogtrousers you can always split two cassette and make one of your own choosing, I briefly ran a 13-32 9sp on my RD5701 front was 52/40/30 on an FD3303, but might not be what your looking for, 8sp cassettes are cheap enough to do it though.

 

[cyberknight]

i use a sora mech with 2300 and 2400 shifters with no issues.