Sram: FOR TREK FRAME WITH BB90 and FRAMES WITH ITALIAN THREAD – GXP INTERFACE (NOT DUB COMPATIBLE) Triathlon. Time Trial. Cyclocross. Some disciplines are made for 1x. And while our X-Range™ 2x set up has integrated much of the simplicity of a 1x system, there are still times when a single ring is best. The SRAM RED® 1 crankset offers the most demanding racers the right mix of features—aerodynamics, durability and simplicity.THINGS TO REMEMBERSingle-ring drivetrain simplifies functionality and reduces weight48 and 50t variants feature direct mount aero chainrings for better aerodynamicsNon-aero chainrings can be installed with a single tool, making gearing changes a breezeSRAM X-SYNC™ wide-tooth, narrow-tooth chainring technology provides maximum chain controlLaser-etched chainring finish is more durableDUB™ bottom bracket adds durability and simplicityCan be upgraded to a power meter SPECIFICATIONSPTA_Speeds: 12PTA_BB Compatibility: GXP/PF GXP 68mmPTA_Chainring Size: 40, 46, 48, 50PTA_Crank arm length: 165mm, 167.5mm, 170mm, 172.5mm, 175mm, 177.5mmPTA_Chainline: 45.0mmPTA_BB Spindle Interface: 24mmPTA_Chainring material: AluminumPTA_Guard: No GuardPTA_Bolt Circle Diameter (BCD): Direct Mount (DM)PTA_Crank arm material: CarbonPTA_Color (Crank arm): Natural carbon