Tiagra, got 2 need 3, how easy is the change?

[BenScoobert]

I have a genesis Croix de Fer, it has this spec according to the genesis website

Transmission
ShiftersShimano Taigra STI, 9-speedRear DerailleurShimano 105Front DerailleurShimano Tiagra bandChainsetShimano Tiagra compact 34 / 50TBottom BracketShimano external bearingChainShimano HG-53FreewheelShimano HG-50 12/25 9-speed
Does anyone know if this will switch for the 3 ring here

https://www.cyclechat.net/

I don't NEED 3 rings, but it would help me a lot as I live on the pennines. So for £30 it is a good upgrade for me, but I don't want to spend too much more to fit them.

My shifters need 2 clicks to go from 1 ring to the other and I guess its just an adjustment to make it line up on 3.
Are tiagra standard sized cranks etc, is it just a case of remove, refit and set up right?

Any help greatly appreciated.

 

[TheDoctor]

It's more expensive than you think - you can't just adjust a double STI to make it work a triple.
You'll need triple STI levers, a new front mech and long-cage rear mech, as well as the triple chainset. Around £300
Personally, I'd either MTFU and get fitter, or get a 9 speed MTB rear cassette with a 34T big sprocket, and an MTB rear mech. That'll get your gearing down lower than a triple would, and be shedloads cheaper.

 

[BenScoobert]

It's more expensive than you think - you can't just adjust a double STI to make it work a triple.
You'll need triple STI levers, a new front mech and long-cage rear mech, as well as the triple chainset. Around £300
Personally, I'd either MTFU and get fitter, or get a 9 speed MTB rear cassette with a 34T big sprocket, and an MTB rear mech. That'll get your gearing down lower than a triple would, and be shedloads cheaper.

Thanks for the response doc.
I was under the impression these levers were originally designed for 3 rings, which is why I need 2 clicks to go 1 gear, or am I wrong?

I'm trying to MTFU but the 25% gradients keep SMTFD.

 

[TheDoctor]

The extra click is a 'trim' position, so you can move the front mech a little bit if the chain rubs on it.
Shimano, in their wisdom, make different STI levers for doubles and triples.
Even going for a 12-27 cassette would give you one gear below your current lowest, which may be enough. Normally I'd suggest a smaller inner ring, but 34T is about as small as the inner rings on compacts will go.
Well, you can get a 33T, but the difference this will make is unnoticable.

 

[redddraggon]

Low end Shimano shifters do Double and Triple, Tiagra are triple and double compatible.

 

[MacB]

you will get fitter and stronger quite quickly, but the cheapest option is a new rear mech and a wider range cassette up to 34t. 34x34 would give you a low gear of about 27 gear inches compared to your current 37.

 

[jimboalee]

The problem with a 34 ring to a 25 sprocket is its way too big at 37".

When you get to an 18% hill, you are only riding at 3.2 mph at 30 rpm giving 320 Watts.

What you need is some gearing a lot lower than this, OR, you could grit your teeth.

 

[BenScoobert]

this is looking like a much bigger job than I thought

I've not had a bike 2 weeks yet and my fitness has improved ten fold

so I feel the short germ gain ain't worth the hassle
if it had been a quick plug and play fix then I would have gone for it

thanks to all for the advice

 

[redddraggon]

this is looking like a much bigger job than I thought

I've not had a bike 2 weeks yet and my fitness has improved ten fold

so I feel the short germ gain ain't worth the hassle
if it had been a quick plug and play fix then I would have gone for it

thanks to all for the advice

All you need is a triple crank, triple front mech, and likely a longer chain. It's not really that big of a job.

 

[Number14]

All you need is a triple crank, triple front mech, and likely a longer chain. It's not really that big of a job.

Or just replace the rings in the double at the front with two smaller ones. Middleburn make replacement rings of differnt sizes and dropping to a 44/46 and a 26/28 may be feasible. ou'll have to lower your front mech a bit but it should be ok. Of course you lose the gears at the top end .....

 

[redddraggon]

Or just replace the rings in the double at the front with two smaller ones. Middleburn make replacement rings of differnt sizes and dropping to a 44/46 and a 26/28 may be feasible. ou'll have to lower your front mech a bit but it should be ok. Of course you lose the gears at the top end .....

How do you reckon you'll be able to fit a 26t or 28t chainring on a 110mm bcd spider?

 

[TheDoctor]

Low end Shimano shifters do Double and Triple, Tiagra are triple and double compatible.

Wrong. Tiagra STIs come in double or triple.
They've got a different part number, and they're different. Linky.

 

[TheDoctor]

Can I just add that it's not terribly helpful to offer advice that is plain unworkable. As I said earlier on, the smallest chainring for a compact is 33T, so suggestions of a 28T chairing are not going to work.
No road mech will work with 46T/26T chainrings so you'll need an MTB front mech, which won't work with road STIs - the cable pull is different.
Et cetera, and so on and so forth.
For a cheapish fix, get a 12/27 cassette, or an MTB cassette and rear mech.
Either of these will work
Or walk up the stupid steep bits. There's no shame in that.

 

[MacB]

It does make you wonder though, something billed as a Cross bike with 50/34 and 12-25, that gives you ranges of, 54-113 gear inches in the outer and 37-77 in the inner. Change the setup to a 46/30 and 12-27 and you get 46-104 outer and 30-68 inner.

Certainly SRAMs new 10 speed double for MTB and Cross comes with 45/30 rings.

 

[redddraggon]

Wrong. Tiagra STIs come in double or triple.
They've got a different part number, and they're different. Linky.

A genuine mistake I ensure, I don't generally find myself looking at low end Shimano stuff, so I may not be as familiar as other people.

However 4400 only come in one version, and 4503 are Triple and Double compatible. Of course SRAM and Campagnolo make things simple, All SRAM road stuff is only double, and all Campag stuff is triple and double.