Cassettes and will they work?

[robgul]

I have a 10 speed Shimano Tiagra DOUBLE set up on one of my bikes - at present  34-50 at the front and 11 - 34 at the back.

I'd like to get an 11 - 36 cassette just to give me a little bit more help .... but will it work?   [Changing anything at the front or suggesting a triple is a no-no - but see the supplementary question below]

The rear mech is a GS (medium cage).    The official calculation with the chainring and cassette ranges (50 - 34) + (36 - 11)  i.e. 16 + 25 = 41 suggests that it exceeds Shimano's rating of 37 for a roadbike set-up.  So, will it work with a 36?

AND on another bike I use for touring with luggage I have 10 speed Tiagra TRIPLE (50 - 39 - 30) and the same 11 - 34 on the back.  Will that work with an 11-36?

I'm not averse to using a derailleur extender like the Wolf.

Any answers and/or experience appreciated.

Rob

[sojournermike]

I’d just give it a go, but make sure your chains long enough. You might need a lindarets or wolf tooth adaptor. The interesting thing will be small small if you don’t change up to the big ring soon enough.

Alternatively, a 9 speed mtb rear Mech will work well in my experience. pull ratios are the same as 10 speed road, but yo need to check that it works otherwise.


Actually, better check that 10 speed Tiagra has the same pull ratio as the higher groups. There is one group set that uses 11 speed ratio for 10 speed cassettes and shifters. Brucey?

[Brucey]

Tiagra  4600 10s group uses the 'old' rear shift ratio so a 9s MTB mech will work just fine (and so will any 10s 'road' mech other than 4700).

Tiagra 4700 10s group uses the 'new' (11s) rear shift ratio so a 9s MTB mech will not work. The only mechs that will work are 4700 series ones or various 11s mechs.

  IIRC some of these have an 'official' biggest sprocket capacity of 34T but actually accept a 36T sprocket in many cases; the variation occurs because of the length/position of the gear hanger and is also sensitive to the total capacity required with the system; in other words if you are using the full range at the front, you can't always set the system to use as big a sprocket at the rear. In practice things usually work out OK if you are prepared to accept slack running in the small-small combinations (which you need not use; they are duplicate gears anyway).

My advice is that under no circumstances should you set the system up so that the chain is too short to manage big-big.  If it can't do that combination and you accidentally select it, the damage can be catastrophic.

cheers

[robgul]

Tiagra  4600 10s group uses the 'old' rear shift ratio so a 9s MTB mech will work just fine (and so will any 10s 'road' mech other than 4700).

Tiagra 4700 10s group uses the 'new' (11s) rear shift ratio so a 9s MTB mech will not work. The only mechs that will work are 4700 series ones or various 11s mechs.

  IIRC some of these have an 'official' biggest sprocket capacity of 34T but actually accept a 36T sprocket in many cases; the variation occurs because of the length/position of the gear hanger and is also sensitive to the total capacity required with the system; in other words if you are using the full range at the front, you can't always set the system to use as big a sprocket at the rear. In practice things usually work out OK if you are prepared to accept slack running in the small-small combinations (which you need not use; they are duplicate gears anyway).

My advice is that under no circumstances should you set the system up so that the chain is too short to manage big-big.  If it can't do that combination and you accidentally select it, the damage can be catastrophic.

cheers

Tiagra 4700 series on both machines.  My experience is that Mr Shimano usually quotes max rear mech capacities as 2 under what's possible.  Cassette is only £20 to me so I'll give it a go.

Rob

[quixoticgeek]

There's been a number of people who have got an 11-36 cassette working on a tiagra 4700 GS rear mech. I believe Path Less Pedalled did a video about this, either that or it's on there instagram.

J