SRAM Red Carbon Crankset - Double

In most cases if your bike was a little small the long crank could make up the difference in leg extension. Going to a smaller bike and switching to a shorter crank will cause you to change your seat position and raise your handle bars. Proper fitting will dictate the length of the crank.

If the 175 feels good to you then you don't have a reason to change it. I don't feel any difference in cadence, power, and fatigue between a 172.5 or 175; I have to believe the vast majority of us would not notice a difference either.

Someone with a doctorate in exercise physiology will probably tell you different.

This is not available currently.

Yes, SRAM & Shimano are 100% compatible. In fact I run a SRAM Red crank with all Dura-Ace. No issues.

Not recommended for MTB. These are not designed for the kind of forces and impacts put on mountain bikes.

While I hear your confusion from the pull down menu, I would be very surprised if they threw in a bottom bracket. SRAM does not even package the crankset with a BB.Your two BB options are the Red cups with ceramic bearings (cool, spendy) or the SRAM GXP bottom bracket cups (also cool, not even close to as spendy).On my bike that I just built, I managed to snag myself some pre-release '09 Red + Force. While I splurged on a Red cassette (they're just too gorgeous, and yes, a moment of vanity), I could not bring myself to getting the Red cups.The choice is yours:http://www.backcountry.com/store/SRM0016/SRAM-GXP-Bottom-Bracket.htmlhttp://www.backcountry.com/store/SRM0013/SRAM-Ceramic-Bottom-Bracket.html (Ceramic GXP bottom bracket designed for Red)

yes. But ideally try to keep your drive train brand components same brand. In the long run they will synchronize better as a "system".

This item is a 50/34 chainring SRAM red crankset: http://www.backcountry.com/store/SRM0008/SRAM-Red-Crank-Set-Compact.htmlTechnically a 9 speed and a 10-speed system aren't cross-compatible. A 9 speed chain is wider than a 10 speed chain, and while it's possible to get away with it, it can also lead to some messy problems.If you are picking up the Red crankset, don't forget the bottom bracket cups! You can get away with any Truvativ/SRAM GigaXPipe (GXP) bottom bracket, check the items below.http://www.backcountry.com/store/SRM0016/SRAM-GXP-Bottom-Bracket.htmlhttp://www.backcountry.com/store/SRM0013/SRAM-Ceramic-Bottom-Bracket.html (Ceramic GXP bottom bracket designed for Red)