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Hi
I have an xtr triple chaninset and nine speed cassette. I am fed up with not being able to use all of the cassette cogs with any of the x3 chainrings (before the chain rubs on the front mech) and believe this is one of the benefits of converting/changing to 2x9/10?
What I am not clear on, is if I converted my chainset to 2x9, how suddenly the chainline would be improved, when the chainrings are in the same position as they are now?
Or am I missing something!?
Or is it only until you use a proper 2x10 chainset (with reduced q-factor) and a x10 speed cassette that this issue improves?
Thanks!
The chainline would be the same as it is now bar the omission of the third ring.I guess the only difference would be if you were to fiddle with the bb spacers to bring it closer to the bb.I`m assuming that dedicated 2 x 10 chainsets allow for this.
From my expereince on my road bike its probably still not a good idea to use low front with high rear or vice versa.regardless.
2x9 just looses the outer chain ring and saves some weight - chain line is the same.
It is, but the 'outer' ring is in the middle ring position. So big/big has an equivalent chainline to middle/big on a triple.
You're still not supposed to go big-big or small-small, I think the avantages are in the chainring sizes, 26-38 seems to mean less shifting as you can use the 26t for 3or 4 gears more at the back where a 22 need to be 2 gears smaller at the back for the same ratio so it's less crossed in that respect. Ditto the 38t is more usable than a 44t which would spend a lot of it's time at the big end of the cassette a 38 would be better at the mid/small end of the cassette.
Edit: depends whether you mean a double like SLX had double+bash with 24-34 rings or double like on an XC bike with 26-38 (or 28-40). The former has no gearing advantages but imporves ground clerance, the latter is for more usable gears.
It would be a double like an XC bike..
Ok - so basically you might gain a few more usable gears but still can't use all of them. Good to know, Thanks.
So there is little point in buying a new chainset etc rather than converting, other than to get 10 gears instead of 9, perhaps...
When converting a triple to a double is there a limit to the size of the larger chainring. Can you for example go 38/24?
Mine is a fairly bastardised system but with 22/ 34 chainings and a 7sp front mech on a nine speed system I get 9 usuable gears in the 36 and 6 in the 22
Shifting is rubbish - but I don't shift that often tending to go into the 22 at the bottom of any significant climb ad using the bottom 6 gears to climb.