Sora and 105 compatibility

[Dangermouse]

Can a 10 speed 105 rear mech be used with 9 speed sora shifters, after all the mech only moves as far as the cable allows it to, or is there something else determining the travel.

 

[HLaB]

I'm not sure 100% but my old Sirrus (now pernamently on the turbo) worked fine with an 9sp tiagra derailleur and 8sp sors shifters.

 

[Sittingduck]

Reckon it can. The mech is just a dumb unit, innit. All the intelligence lies in the costly STI's...

 

[Dangermouse]

Exactly what I wanted to hear.........cheers

 

[fossyant]

Yes, same pull ratio !

 

[Dangermouse]

Thanks Fossy..........

 

[Koga]

I thought the chains are different and therefore the index (travel space for each gear chain) is different. In which case it depends on what cassette you are using (9 or 10).

 

[HLaB]

I thought the chains are different and therefore the index (travel space for each gear chain) is different. In which case it depends on what cassette you are using (9 or 10).

They are but its the shifters that pull the mech by the appropriate amount for 9 or 10sp I believe, just the H. & L screws need adjusting. FWIW, a 9sp mech on an 8sp cassette with 8sp shifters worked for me anyway.

 

[Koga]

They are but its the shifters that pull the mech by the appropriate amount for 9 or 10sp I believe, just the H. & L screws need adjusting. FWIW, a 9sp mech on an 8sp cassette with 8sp shifters worked for me anyway.

I agree some combinations work, or work good enough. But I am pretty sure 9 gear shifters and 10 gear shifters are not compatible. In which case if you use a 9 gear Sora for shifting the cassette should also be 9 gears as otherwise the index does not match the spacing of the gears.

 

[HLaB]

I agree some combinations work, or work good enough. But I am pretty sure 9 gear shifters and 10 gear shifters are not compatible. In which case if you use a 9 gear Sora for shifting the cassette should also be 9 gears as otherwise the index does not match the spacing of the gears.

I must admit I havent tried it, but if the OP is using 9sp shifters pulling a 10sp deraileur over a 9sp cassette, as per the other posters above say I wouldn't have thought it would matter. If they are looking to match up 9sp shifters with a 10sp cassette that is almost certainly incompatible

 

[fossyant]

The pull ratio is the important thing and 8 9 and 10 speed mechs will work with any shifter. Only one exception and thats Dura Ace 7400.

 

[Koga]

I must admit I havent tried it, but if the OP is using 9sp shifters pulling a 10sp deraileur over a 9sp cassette, as per the other posters above say I wouldn't have thought it would matter. If they are looking to match up 9sp shifters with a 10sp cassette that is almost certainly incompatible

That is what I thought.

 

[Koga]

The pull ratio is the important thing and 8 9 and 10 speed mechs will work with any shifter. Only one exception and thats Dura Ace 7400.

I am no expert in this, but I though the chain width is different on a 10 speed chain, which would indicate to me the pull ratio will be different.

 

[HLaB]

I am no expert in this, but I though the chain width is different on a 10 speed chain, which would indicate to me the pull ratio will be different.

It is but as said if they are using the same speed of shifters and cassete is shouldn't matter if the deraileur has a greater capacity as Sittingduck says "The mech is just a dumb unit, innit. All the intelligence lies in the costly STI's". If the OP is using a mis match of shifter and cassette there is a different pull ratio there

 

[Dangermouse]

The setup will be 9 speed shifters 105 mech and 9 speed cassette, hopefully this should work fine