1. Roulette Derailleur Sram X9 Rear Derailleur
2. Roulette Derailleur Sram X9 Crankset
3. Roulette Derailleur Sram X9 Axs

SRAM X9 Rear Derailleur. SRAM Exact Actuation for precise and dependable 10-speed performance; Carbon and alloy cage makes it light and tough - 204 grams for medium cage; 3 cage lengths available: short, medium and long. SRAM Derailleurs - Lowest Prices and Free shipping available from the worlds largest online bike store - Chain Reaction Cycles.

When looking for replacement jockey wheels for SRAM derailleurs, there is a lot of conflicting compatibility details, particularly for SRAM X9. I've written this to help X9 owners.

SRAM X9 (2009/2010) jockey wheels

Roulette Derailleur Sram X9 Rear Derailleur

My X9 (2009 model) jockey wheels were seizing up after every winter ride. I had to remove the wheels, clean them (where I noticed that that rust would come from the bearing), and grease them after every ride. I found the bearings on the X9 wheels would give problems after just a few weeks from new. I only ride at weekends, so I found that after just 2 or 3 rides, the bearings went stiff. I tried greasing them or just using TF2 spray and neither helped. Some people recommend not greasing as this can attract dirt and make it worse. I had to buy a new derailleur (for another reason) and got another X9, but a 2010 model. This was exactly the same and again the jockey wheels then went stiff and were seizing after just two rides.
Genuine SRAM jockey wheels are £23 from CRC. I started looking for alternatives, as I'd proved that the SRAM bearings were hopeless, but soon found that none seemed to be compatible with the X9 derailleur.
Then a fellow BikeRader forum user (thanks 'glennpro09') confirmed that the KCNC wheels fitted his 2010 X9 long cage derailleur, even though sites list the KCNC's for only SRAM X0 and some specifically say 'not X9'.
The KCNC jockey wheels get excellent reviews, but are quite expensive. They do 10,11,12 & 13 teeth versions and all available with either a stainless steal bearing or a ceramic bearing. I opted for the ceramic version of the 11T at £37.99 (delivered) from Ready to Ride Cycles via eBay. The benefits of a ceramic bearing may be wasted in a jockey wheel, but for the £11 premium I decided it was worth buying the 'best'.
They are a perfect fit for the 2009/2010 X9, as you can see from these photos...

They've now been fitted on my bike for last four rides and so far are still running as smooth as they were when new (and the ceramic bearing is soooo much smoother than the SRAM wheels were when new) and not needed cleaning, apart from the normal hose down I give my bike after each muddy ride. My new SRAM wheels were stiff by this time, so so far they've proved to be superior. Only time will tell, but build quality and the way the bearings are sealed, these look like they will work and prove to be far better than buying genuine SRAM jockey wheels. By fitting these, the time I need to spend cleaning the bike has certainly reduced considerably. Although these KCNC wheels were expensive, it was money well spent. Just wish SRAM could make their bearings cope with the UK conditions.
Update: My 2009 X9 rear derailleur is stamped 'DEC2009', is actually a 2010 model. After referring to the SRAM parts lists, it seems that these KCNC jockey wheels will fit the following SRAM 3x9 models:

Roulette Derailleur Sram X9 Crankset

• X0 2006-2011
• X9 2010-2011
• X7 2010-2011

Roulette Derailleur Sram X9 Axs