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Ultegra - XT compatibility

Posted: 21 Jan 2013, 11:06am
by hayaman
I ride a touring bike with drop handlebars and want a set up with Ultegra 6703 10sp triple STI levers. The trouble is, if I stick to an Ultegra set up, the greatest gear range I can get is a 30T small chainring and 28T largest cassette cog. This just isn't a big enough range for expedition touring over high altitude passes. Mixing in some MTB components, I can get a much bigger gear range. For example, an XT rear derailleur will easily cope with a 36T cog on the cassette, but is it compatible with the Ultegra changers? I know you can make it 'work', but when you are changing up and down gears all day every day (and spending a lot of money on parts), you really want the set up to work perfectly. I have read different things about interchangeability of Ultegra and XT derailleurs, but still can't find a definitive answer. Is the pull ratio the same or is it different?! Any advice would be really really welcome!

Re: Ultegra - XT compatibility

Posted: 21 Jan 2013, 11:47am
by Brucey
XT ten speed rear mech won't work , but XT nine-speed will, so that is what you want. Buy them while you still can!

cheers

Re: Ultegra - XT compatibility

Posted: 21 Jan 2013, 11:52am
by The Mechanic
As above. I have this very set up on my tourer.

Re: Ultegra - XT compatibility

Posted: 21 Jan 2013, 12:12pm
by Big T
You could also go for a non-Ultegra chainset. I have a Deore 26-36-46 chainset paired with STI's and a Tiagra front mech and the shifting is fine. I used to have an XT rear mech but I've swapped it for a Deore because the XT was a low-normal one. I think I have an 11-34 cassette.

Re: Ultegra - XT compatibility

Posted: 22 Jan 2013, 12:08am
by hayaman
Thank you very much for all the replies - very helpful. I couldn't have guessed that the 9sp XT has the same leverage as an Ultegra 10sp. I also like the idea of the XT chainset as I never need a 52 chainring for touring. Combining a closer-range Ultegra cassette with the lower range XT chainset could be perfect.

Just to check, will the following set up work?

Ultegra 6703 10sp lever/shifters
XT M770 (44/32/22) 10sp chainset
Ultegra 6703 front mech
XT M771 9sp SGS long cage derailleur
Ultegra 6700 11-28 cassette

Thanks a lot.

Re: Ultegra - XT compatibility

Posted: 22 Jan 2013, 8:36am
by The Mechanic
The set up you suggest will work fine. The only thing you will have to be careful about is the front mech. As I recall, the 6703 front mech needs a minimum of 13 teeth difference between middle and out ring. Your set up had 12 so you should be OK but may have to have the mech slightly higher than would be optimal. I have a similar set up to you but with a Stronglight Impact triple chainset with 48/38/24 rings. Note the middle to outer diff. is just 10 teeth. This gave me all sorts trouble with the inner plate of the front mech binding on the middle ring when trying to change up to the big ring. I cured this by moving the mech up to create a larger gap between the outer place and the big ring. This gave less than ideal shifting so I reverted to my 6603 front mech (which does not have such a deep inner plate) and that was better but still not ideal. I have yet to get the front shifting perfect although am happy with the rear shifting.

Re: Ultegra - XT compatibility

Posted: 22 Jan 2013, 9:15am
by hayaman
Thanks for the advice on the front changer and the difference between the middle and outer chainring. Would an XT front mech work better? Is that still compatible with the Ultegra shifters? I seem to remember reading somewhere that it is best not to mix road and MTB front mechs.

Re: Ultegra - XT compatibility

Posted: 22 Jan 2013, 9:34am
by 531colin
Mountain and road front mechs. are different cable pull, so you can't mix shifter and mech. if its indexed.
My approach would be 110/74 BCD square taper chainset, available with any rings you choose down to 24T....square taper BBs are generally regarded as very hard wearing, and you can get close to a "road" chainline.

Re: Ultegra - XT compatibility

Posted: 22 Jan 2013, 9:51am
by Brucey
you are right the shift ratio of MTB front mechs is different to that of road mechs in shimano-world.

However there is another reason for being cautious about the front mech; a 'road' front mech is designed to work with a 'road' chainline. An MTB crankset usually installs a few mm further outwards with a wider chainline, and sometimes a 'road' front mech simply doesn't reach outwards far enough on a triple. Not whilst maintaining the indexing accurately, anyway- the shift ratio of the front mech varies with the throw, and even if it reaches, it can be hard work getting that last bit of travel.

For this reason I'd suggest sticking with a road chainline rather than the MTB chainline if there is any doubt.

cheers

Re: Ultegra - XT compatibility

Posted: 22 Jan 2013, 10:21am
by ANTONISH
I've two road bikes with ultegra front mechs working with 46-34-24 triple on Stronglight impact chainsets (I think they are classed as road/touring ). I use bar end shifters on friction so your set up will be different but the mechanism itself works well.

Re: Ultegra - XT compatibility

Posted: 22 Jan 2013, 11:04am
by 531colin
I always regret getting involved in these threads about bloody gears.......as soon as I open my keyboard I'm out of my depth......
This is 10 speed isn't it?
I know Tiagra 9 speed STI & F. mech. work with Impact/XD2 chainset 110/74, because thats what Spa's tourers do....
I never tried 10 sp. OR Ultegra, so I don't know.......if in doubt, assume its more complicated than you think..... :?

Re: Ultegra - XT compatibility

Posted: 22 Jan 2013, 8:08pm
by scottg
Shimano MTB front mechs come in versions for 44 and 46 big rings, double and triple versions.
The 46t triple versions work fine with a Sugino XD with 48/36/24 using bar end shifters.

Re: Ultegra - XT compatibility

Posted: 22 Jan 2013, 8:19pm
by Brucey
but you wouldn't want an MTB front mech with road STIs (a double might be OK, but the pull ratio is wrong for indexed shifting on a triple) and a top swing MTB mech generally won't work with a 'road' chainline triple; the mech often hits the frame before you get onto the small chainring. Fatter seat tubes make this more likely.

cheers

Re: Ultegra - XT compatibility

Posted: 23 Jan 2013, 8:20am
by hayaman
OK, thanks everyone. So much useful information. I wish Shimano would pay attention and make a touring road set up with a sufficient range for big mountain climbing. Anyway, I will stick to a road front mech (probably ultegra) and a 9sp XT derailleur (which I already have). I will go for Ultegra chainset as that is guaranteed compatible with the Ultegra front mech and STI levers. I will run a closer range cassette for daily use and then just put an XT cassette with a 34T cog for the big tours. I cycled over the Himalayas last summer on 30 chainring - 34T cassette and it was just about okay. I could even try a 36T cassette for an extra smidgeon of oomph.

Re: Ultegra - XT compatibility

Posted: 23 Jan 2013, 8:46am
by 531colin
hayaman wrote:OK, thanks everyone. So much useful information. I wish Shimano would pay attention and make a touring road set up with a sufficient range for big mountain climbing...............


Some brakes would be nice, too......and the odd cassette with say 34T but without starting at 11T, 12T, that you don't need.



(they aren't listening...... :wink: )