Is the SRAM XX Mountain Group the death of the road triple?
The ten speed SRAM XX cassette. Image courtesy of SRAM.
SRAM has released its latest mountain group, dubbed the XX, which is the first 20 speed mountain drive train on the market (i.e. 10 gear cassette and double chain ring.) For those mountain bikers wanting more info on this latest product release, both VeloNews and BikeHugger have pretty comprehensive first looks at the group covering both the advantages and drawbacks.
So why am I excited by this product roll out? Not only do I not mountain bike, but I have never owned a mountain bike and have done exactly two mountain bike rides in my life, both several years ago. I’ve not felt the urge to do another (although cyclocross is another matter.) No, the reason I am excited by this development has to do with the potential road application for part of this group I noticed when this paragraph in the VeloNews review jumped out at me:
XX uses the same constant cable-pull shifting technology as the road groups, dubbed Exact Actuation. This means that the XX rear derailleur and cassette are compatible with the road shifters.
The SRAM XX rear derailleur built for mountain shifters but compatible with SRAM road shifters. Image courtesy of SRAM.
This is very exciting news for anyone wanting to build up a 10 speed touring bike with a double chain ring crank. Currently, 10 speed cog sets top out at 28 teeth on the back cog. When paired with a compact crank (50/34), you get an excellent bailout gear for extreme grades on a road bike, but this gearing would probably come up short if you are on a loaded touring bike on a similar hill. Mountain cogs with their larger gear range were limited to 9 speed and used different pull ratios so didn’t work well with road shifters. In the past, this left you with a triple chain ring crank as your best solution for a touring setup. Triples definitely gave you a larger gear range, but the additional weight, derailluer complexity, and challenge of avoiding chain rub in certain gear combinations all have been counts against the systems. Add to that the fact that a lot of roadies find the triple to be esthetically displeasing and an indicator of Fredness.
Since the XX rear derailleur is compatible with the SRAM road shifters, you could put a X-Dome cassette (11-36) and XX rear derailleur and get extraordinary range. On a compact double, the 34 front/36 rear combination would give you an extremely good granny gear while the 50/11 combo would give you plenty of gear for flats or down hills. (The 50/11 is more gear than the common 53/12 setup on a standard road crank.)
The only downside of this is you are sacrificing how close the gear steps are in your range. For racing, this would be a real drawback, but for touring this would be less of an issue. This is certainly also an potentially interesting setup for a cyclocross bike with a single chain ring setup.
So, has SRAM killed the high end triple? The compact crank certainly has had an effect with Campagnolo recently dropping the triple option and SRAM not even offering it in their road groups. Only Shimano still offers the triple its top line Dura Ace and who knows how long much longer? If they do kill the triple DA, it looks like the touring bike set will still have options on the table.
on Jun 10th, 2009 at 11:25 pm
This is pretty cool stuff. The only downside to this XX setup is that is will cost mega bucks! That cassette is wicked though! With 32 teeth it weighs in about the same as a lot of road cassettes with much smaller cogs.
on Jun 11th, 2009 at 12:20 am
Interesting. I just went from 11-34 9 speed rear and 48-34-24 front to 11-25 9 speed with the same crank to get a really low granny with smaller jumps on my loaded tourer. I found that most of my road riding was in the three middle cogs of the 11-34 cassette, but I still sometimes used the ends when things got steep. Now I have the same gear range spread out over 5 cogs near the bottom of the cassette and still a decent granny, plus I’m no longer exceeding the range of my derailler and get better chain tension in the granny ring up front. But with the SRAM cassette I could get the same range with just the big ring and the middle ring and much better tension on the chain…
on Jun 11th, 2009 at 5:50 am
Yeah, at $328 for the the cassette and $265 for the rear derailleur, XX is not cheap. I think it’s probably that they’ll come out with a more economically version in the future. Still, it’s good to know those wanting a high quality touring setup will still have options if the triple Dura Ace goes away.
on Oct 5th, 2009 at 4:46 pm
Running this kind of set up has been possible for at least a decade. Only since 10 speed has become dominant on road groups has it been a problem. 8 and 9 speed works fine. i have a 12-34 x 40 on my cross bike, nine speed. What am i missing? It works with an 8 speed set up too, and is less finicky. 10 speed are unreliable for touring and cyclocross applications.