Perhaps a stupid question but I thought the purpose of 10 Speed was to allow greater range at the cassette (not just closer ratios) which allowed you to run a 2 chairing set up? In a similar fashion to my understanding of Sram XX

However all the Shimano Chainsets I’ve seen advertised are 3 ring setups… Am I missing something?

The point is to have tighter ratios so you’re always in the right gear. Also puts less stress on the chain as you’re in a bigger ring more of the time.

XTR double

I personally agree that Shimano have missed the point myself, and that a double makes far more sense! I’ve been running doubles for 4 years though, and there’s nothing to stop you converting any chainset you want!

just re-gearing my 9 speed

11-25 Ultegra road cassette & ordered a 26t inner & 38 middle ring.

ratios will be just as good as 10 speed 🙂

Except you’ll be shifting on the front the whole time, which personally is exactly what I try and avoid. I ran a 12-27 cassette for a while, but found it a real pain!

Thomthumb – Thanks, I have not seen it advertised for XT or SLX… I suppose in typical Shimano fashion it will be in 2012 before this filters down to XT and potentially 2013 before SLX.

Spokes Cycles – Also thanks, I understand the principle… However, less stress is B*llSh*t. Regardless of marketing crap. A thinner chain (ie less contact area) can only increase the stress as the rider is still transmitting the same force. S/S chains are not uber thin for a reason.

Starsh 78 and Njee20. I was under the impression that by only having 2 narrower rings up front you would be able to achieve a better chain line (as oppososed to present 2 plus bashring set ups)and hence changing at the front ring would not be such a great issue as present?

As I see it, it’s more about narrowing the Q factor as they do in road bikes to increase pealling efficiency by limiting pronation. Then adding a few more gear ratios to ease climbs and sustain top end speed.

no, the purpose of ’10 speed’ is to hide the fact that shimano/sram ran out of ideas about 5 years ago.

Having a wider cassette means a more reasonable spread of gears can be achieved with a single or double, which in turn means the chainline is better and you don’t need to shift as much. IMO using a 12-25 cassette is 100% pointless, you could do that with 7 speed, I found such close gearing useless on an MTB, you have to shift multiple gears on the back and you’re shifting on the front a lot more, which in a race at least wastes time. YMMV and that.