2x9 Cranksets for XC Mountain Bike Racing
2x9 Setup for XC Mountain Bike Racing
In most situations in Cross Country (XC) mountain bike racing, you don't need a little chainring. You are simply riding too fast for a granny gear to make sense.
To save weight, one thing you can do is switch from a standard triple chainring to a "2x9" setup, which means you have two chainrings instead of three (and the customary 9 cogs on the cassette.)
Here is what you need to know to make the switch:
Benefits of a 2x9 Setup
Why you should use a 2x9 setup.
There are three main reasons you should switch to a 2x9 crankset setup for XC racing.
1. Weight Savings
Two chainrings are lighter than three, so you save a little bit of weight. This can be a pretty big deal these days, with the availability of 20 pound full-suspension racing bikes.
2. Improved Chainline
With just two rings, you can have a straighter chain line in a wider range of gears. With some setups, you could use the small ring and small cog without the chain rubbing the front derailleur cage.
(With a triple chainring, or 3x9, setup, you can get crazy cross chaining going on, which is not a good idea.)
3. Lower Q-factor
This isn't a guarantee, but with some 2x9 setups, you can achieve a lower Q-factor. This means your feet will be closer together when pedaling, which can allow you a better feel and better power delivery to the pedals.
2x9 Crankset Options
Companies that offer 2x9 cranksets.
The biggest obstacle to a 2x9 conversion is finding a crankset. (You could just remove the small chainring, but that gives you a smaller gear range and doesn't improve chain line.)
So here are some options for you:
Cannondale offers a fancy 2x9 crankset made of carbon fiber. It comes standard on some of their finest bikes, like the Scalpel Team with the BB30. 29/44 rings.
Aftermarket, expect to pay about $1000 for one of these carbon 2x9 cranksets.
FSA K-Force Light
FSA makes two 2x9 cranksets. The K-Force Light is the fancy carbon fiber one. It's available for regular and BB30 bottom brackets.
This one costs about $850 or more.
This is an aluminum 2x9 crankset from FSA. It is similar to the other one, but cheaper since it's aluminum.
The 2x9 Afterburner will set you back about $300.
The Middleburn Duo, whether you choose the RS7 or the RS8, is a popular 2x9 crank that has been around for a while. It has strong aluminum arms and is fairly light.
(The RS8 is basically the same crank arm as the RS7, expect it has some more metal machined off, giving it a slightly lighter weight.)
It's not too expensive either. The crank arms and rings (no BB) come in at $240.
Ring options include 27/40, 29/42, and 29/44. There is also the option to get either square taper or ISIS compatible arms.
*Also, a "Shimano Spider lockring tool" would come in handy for the crank.
Stronglight Oxale Two
The cheapest option I've seen for a 2x9 crankset is the Stronglight Oxale Two. It is an inexpensive aluminum crank that has gotten mixed reviews, but Stronglight is a good company, so it is probably worth a shot if money is tight.
More Tips for 2x9 Riders and Racers
Tips and tricks for setting up a 2x9 crank.
A few more things you should know:
Front derailleur setup
For the most part, you are using a standard front derailleur, but adjusting the limit screws and shortening the cable to where you just use two stops.
Then you just have to worry about the shifting issues caused by having a large gap between chainring sizes. With some setups, there is a good size jump/drop between the chainrings.
For example, in a 3x9 setup, the 32/44 jump is 12 teeth, but use a 29/44 on your 2x9 and you're dealing with a 15 tooth difference.
The Cannondale and FSA cranks may include a bottom bracket, but with the other cranks, you probably need to buy a BB separately.
Make sure you get a BB that matches your frame. Mountain bike frames typically use a 68 or 73mm BB shell. A long spindle (such as 113mm) is usually required due to the wide chainstays.
One popular option is the Crank Bros Cobalt BB (ISIS compatible) for under $100.
You can see it here:
For square taper cranks, the Phil Wood BB is popular, although very expensive.
2x9 Links and Resources - Blog posts and forum threads about 2x9.
Check this list of blog posts and forum threads to see more details and personal experiences with 2x9 crank setups.
- Complete 2x9 Discussion at MTBR.com forums.
Good info with crank options, setup tips, BB widths and styles, etc.
- Weight Weenies discussion of Stronglight Oxale Two
Some debate about the Stronglight Oxale Two crankset.
- Pics and info on new 3-bolt FSA 2x9 cranksets
Info on FSA K-Force Light and Afterburner 2x9 cranksets. Includes photos.
- FSA K-Force Light Review
A neat review at BikeHugger.com
- FSA K-Force Light 2x9 Review
Another review of the FSA cranks, this one on Bicycling.com.
- Looking for 2x9 cranks, soon!
A discussion of current 2x9 offerings and those that may show up at the end of 2009, for the 2010 season.
2x9 Cranksets on eBay - Find a good deal on a new or used 2x9 crank.
eBay can be a great resource for finding 2x9 cranks. Considering some cost over $1000 new, buying used could be a good idea!
2x9 or 3x9? - Which is best for XC mountain bike racing?
So you're an XC mountain bike racer... do you choose the standard triple crank, or do you go with a 2x9 setup?
Do you use 2x9 or 3x9?
Now you know all about 2x9 cranks. Do you ride 2x9? Want to make the switch?
Or do you still prefer 3x9?
Or... maybe you're waiting to go 2x10 with the SRAM XX group?