2x9

A 3x9 is a typical setup for mountain bikes. Three chainrings in front (at the crankset) and 9 cogs of cassette at the rear tyre, hence the 3x9 or 27 gears. However, not all combinations can be used.

A 2x9 has the cassette but only 2 chainrings at the crankset. It only has 18 gears. Is sounds like having less gear is of no good. But, 2x9 setup is reportedly to have better chainline that allow all combinations. It is also lighter.

My riding buddy, Jimmy Kok, swapped his trusted Shimano XT 3x9 crankset with a KCNC 2x9 crackset last month. He said he is happy with the performance, where he is now gathering more traction rather than more wheel spinning when the trail is pointing upwards.

I tried the crankset on one of our Saturday morning rides (on Jimmy's bike, of course), and I'm liking it. It is true that the traction is well within control and the legs opening & spinning are more natural.

However, his KCNC has a 42/29T setup. Personally, this is slightly heavy for me. I would prefer a 40/27T. Since KCNC has only one setup, so I started searching for other options.

After searching from the Net, these are the options that are available:

1. KCNC - Chainring setup at 42/29T. BCD 94mm.

2. SRAM XX - Chainrings setup options at 39/26T, 42/29T and 44/32T. Each has propritery BCD bolt setup.

3. FSA - Chainring setup at 42/29T and 40/27T, with their own BCD bolt setup.

4. Rotor Agilis - Chainring setup at 40/27T. BCD 110/74mm.

For compatability purposes, I like the KCNC and Rotor BCD setup.

Personally, I want the Rotor Agilis 40/27T. As bonus, it comes with Q-ring eclipse rings.