We are going (mainly) road touring on the tandem later this year. Normally we run 22 / 36 / bash chainrings. For road work I think a big ring might be handy. Will it work to have 22/36/48 or is that too much gap? Especially with an 11/ 34 casettee?

It seems a bit daft to end up with 22/36/44 chainrings maybe I should change the granny ring for a 26 as well.

36/46 was std back in the day, if the front mech can cope then go for it, 26 might be more useful also.

Most of the "touring" versions of MTB chainsets are just that- 36/48. You'll be fine.

Most of the "touring" versions of MTB chainsets are just that- 36/48. You'll be fine.

most are 26-26-48 are they not?

is there a rear mech which has that capacity?

thats my concern – will the front mech go from a 22 to a 48? will that bee too much slack for the mech to take up?

That would be my concern too – you'll need a very old std front mech or one to fit the c'sets Luke is on about, even then 26T is a big spread for it.

thats a capacity of 49.

shimano quote 45T as the biggest for rear derraillers.

although there are a few threads on mtbr about exceeding that. and modifying cages…..

Hmmmmm

maybe I'd better put the 26 chainring on as well – we are heading for the low countries so not many hills – but we will have full on camping gear

Ta

Do you really need a 48*11 top gear for tandem touring? Why not just pop on a 32 and 44 ring and use a normal mech, much easier to set up and probably work nicer

I went touring on my Jake with only a 46*13 top gear (on 700*25mm) but it was ok, how fast do you want to go when touring anyway.

I normally run 22/36 on my Inbred and when I take that to New Zealand next year for a road tour I am gonna try 29/42 coz I have a med mech on the back and dont want to buy another to run a triple (plus I have 29 and 42 chainrings in my spares)

If you're already running a 22T inner, then you've probably got a compact front mech. For what you're planning, I think the capacity of the front mech (ie the maximum size of your outer chainring) will be more of an issue than the rear mech capacity – although you might need to look at chain length for the sake of your rear mech.

Have a look at this for more detail – http://www.ctc.org.uk/DesktopDefault.aspx?TabID=%204068

Restless native – I have a 48and a 26 chainring but not a 44 or a 32 I was trying to get the right gearing without buying more stuff. 48/11 is good for flying down hills – but I realize that we are not going to get many of them in the low countries are we 🙂

Birly – I think the bike came with a bigger granny ring originally – maybe 26 / 36 / 48. I seem to remember having to move the mech down to fit the 22.

so the consensus is either go 22/32/44 or 26/36/48 but that 22/36/48 is just going to cause problems

Ta

Ah, yes, a 22T granny. No idea whether that'll work to be honest. If you've got all the bits there's no harm in fitting it and going for a test in the Pentlands?

If you want a 44T I'm going to be back in Embra this week and think I have one knocking about you can gave.

"trying to get the right gearing without buying more stuff"

aha, that I can identify with 🙂

If the rear mech can handle a 45 tooth difference, then if you use a 48:34 big ring/cassette ratio, when you are in your 22 granny you will have a slack chain when you go smaller than the 15t sprocket.

You're never going to be in that ratio anyway, so no need to worry about it.

EDIT – and the if you don't move the mech down, it will only rub when you try to engage the smaller sprockets when in granny, thinking about the chain path.

That makes sense big john.