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Was helping a mate upgrade his gearing on his Tiagra equipped bike. Pointed him to the cassette and longer cage mech he needed. I installed the parts for him and for the life of me I couldn't get the indexing dialled in. I've done a bit of digging and it seems in its latest iteration Shimano have changed the pull ratio to be the same as that of the 11 speed components. So new shifter is needed.
Am I correct in thinking a 105 11 speed shifter would work? obviously the 11th index would not be used but other than that should work fine? Lots of second hand 105 shifters out there but not many new Tiagra ones.
thanks
4700 tiagra is different to all the other Shimano road 10 speed. It does indeed use the same pull 'ratio' as 11 speed, but the actual amount of cable it pulls is different to both traditional Shimano 10 speed road and Shimano 11 speed road.
This basically means you can't use new tiagra mechs on old tiagra (4600) 10 speed shifters.
(As an aside, it means you can run new tiagra 4700 mechs with Shimano 11 speed road shifters and cassettes, or 11 speed mechs with new tiagra 10 speed shifters and any 10 speed cassette).
New tiagra 10 speed cassette spacing is identical to previous 10 speed cassette spacing.
So I assume you've got 4600 tiagra shifters. Easiest thing to do is put a Shimano road 8/9/10 speed mech on or an MTB 8/9 speed mech. Don't use an MTB 10 speed mech... That won't work.
Thanks, so if we wanted to keep the shiny new mech we could get a second hand 105 shifter and be OK? Cant return the mech now as its been used so would prefer to get a shifter to suit.
Assuming you bought a tiagra 4700 mech then no, you wouldn't be able to use 105 11 speed or 105 10 speed shifters. If you went with an 11 speed shifter you'd also need to change to an 11 speed cassette and chain.
I realised I’d made this mistake recently. Bought a 10spd Tiagra mech to replace a 10spd Tiagra mech and apparently it doesn’t work right. Irritating. In practise it just means I lose the smallest sprocket so I’m living with it (on my commuter). But it’s annoying.
Yes it’s kinda my fault for not checking, but FFS Shimano.
So what shifters does he currently have?
Whay speed block?
Assuming a 10 speed block and 4600 Shifters then he needs a 4700 shifter to work with a 11 speed mech
Am I correct in thinking a 105 11 speed shifter would work? obviously the 11th index would not be used but other than that should work fine? Lots of second hand 105 shifters out there but not many new Tiagra ones.
Not unless you had an 11 speed block. The gears are physically closer in 11 speed. Rather than the block being wider
I think 10 speed grx is the same pull
10 speed Grx shifters are compatible with 4700 rear mech, and vice versa IE a Grx rear mech (10 or 11 speed) will work with 4700 shifter.
Why not buy an older Tiagra GS mech?
https://www.ebay.co.uk/itm/Shimano-Tiagra-Rear-Derailleur-RD-4601-GS-10s-/254702490399
Ah ok. Incorrectly assumed that since the pull ratio was the same I could use an 11 speed shifter and loose one indexing position but thinking again it won’t work.
So looks like cheapest option is to go for the 4600 mech.