вот метаюсь в выборе сиситемы и решил забибенить обзорчик:

SRAM X.0
The professional's choice.
Experience SRAM® X.0™ - the pro-ready rear derailleur that's lighter, stiffer, smoother and flat-out better looking than anything out there. With a potent mix of high-grade metals - forged aluminum and titanium - reinforced carbon composite, advanced engineering and smart design, SRAM® X.0™ is the ideal upgrade for your current SRAM® system.


SRAM X.0
Rear Derailleur

Technology:: 1:1® actuation ratio & Direct Route Technology for lighter effort shifting.
Speeds:: 8 or 9
Weight:: 210g long /197g med. /192g short
Material:: Forged alloy links and B-knuckle, High Strength Grilon® P-knuckle, Machined and heat treated oversized pivot pins, sealed cartridge bearing pulleys, CNC long-cage / Carbon Fiber on med. and short
Compatibility:: SRAM 1:1 shifters (triggers and twisters)
Other:: Available in long, medium and short cage lengths.

SRAM X.0
Trigger Shifter

Performance:: Competition
Technology:: 1:1® Actuation Ratio for precise indexing and control
Speeds:: 9
Weight:: 225g / pair
Indicator:: N/A
Materials:: Alloy body with Carbon Fiber upper cover, Stainless steel hardware
Pull Lever:: Alloy
Compatibility:: SRAM 1:1 rear derailleurs, SRAM or Shimano® front deraillers
Other:: Teflon coated cables, On the Bar Cable Change.

SRAM X.0
Twist Shifter

Technology:: 1:1® Actuation Ratio & SRS technology for light, precise indexing
Speeds:: 8 or 9
Indicator:: Quick View
Body:: 50mm Shorty w/ lightweight Grilon®, carbon finish and ergo tornado style grip
Compatibility:: SRAM 1:1 rear derailleurs, SRAM or Shimano® front deraillers
Other:: Teflon coated cables w/ tethered never lose port cover for quick cable replacement, Index and Micro-adjust front shifter options

X-Generation
Front Derailleur

Technology:: Super Stiff wide pivot design
Speeds:: 44/32/22T 8 or 9 Speed
Cage:: Chrome Plated Steel
Clamp:: Forged Alloy
Clamp Size:: 34.9, 31.8, and 28.6 (with adaptor)
Cable Pull:: Top or Bottom Pull
Other:: Silver or Black Finish option