minicoopers05

My Sun EZ Speedster AX has all X9 components except the front derailleur, which is Shimano. And I know you can't mix SRAM with other stuff.

So I'm upgrading all my SRAM to XO and I just don't know which version of XO front derailleur to get. I see on eBay 2x10, 3x10, etc some which say direct mount and others clamp and they list teeth.

I'm going with standard mountain bike triple rings up front for more power on inclines and a 12x36 cassette. My current setup version is cranks forward with derailleur tube.

Any ideas or suggestions? Thanks.

Retro Grouch 

Front derailleurs have several characteristics to look for:

1. Clamp size vs. direct mount. Look at the front derailleur that you have now. If it has a band that encircles the derailleur mast, your new derailleur has to have the same clamp diameter. It'll be marked on the inside of the derailleur clamp. If it bolts directly to a little bracket on the derailleur mast, get a direct mount front derailleur.
2. Top pull vs. bottom pull. Look at how the shift cable connects to the derailleur that you have now. On some the cable pulls up, on others it pulls downward. You'll want to mimic that direction.
3. 2X10 and 3X10 refer to 2 sprockets in front 10 in back and 3 sprockets in front 10 in back. A derailleur for 3 front sprockets will probably have a deeper inside blade on the derailleur cage. A derailleur for 10 sprockets in back will have a very slightly narrower cage to function better with the narrower 10 speed chain.
4. It probably won't come up but how many teeth do you have on your biggest front chain ring? If it's more than 48 (which I doubt) you might have to do some fooling around with front derailleurs to get one that will match your chain ring arc.