When the time came for Alistair Philander to replace the drivetrain on his Trek, he thought it would be the best opportunity to drop some weight and gain simplicity. After consulting with the team at The Bike Park, he decided to go for SRAM’s 12-speed GX Eagle drivetrain. With its wide range 10-50 cassette and several chainring options, it was a simple enough task to give him the range he was used to in the process.
Crankset
The GX Eagle crankset has forged aluminium crank arms that are stiff, strong and reliable. Completes its performance mission with the new X-SYNC2 direct mount chainring. With numerous Eagle X-SYNC2 direct mount chainring size options, we thought it best to discuss the rider’s needs first. A 32T was decided upon to give him the range he was used to and prefers. Coming from a 2×10 speed drivetrain with 38/24T chainrings and an 11-36 cassette the Eagle drivetrain gave him a slightly lower granny and top gear – perfect for his needs. Check the gear ratio charts at the end of the article for further details on this.
TRUVATIV’s crank engineers threw away the old standards and developed a new chainring geometry from the ground up. They precisely paired the different-sized chainrings and redesigned where and how the chain engages with the rings. By aligning the chainring pick-up rivets to the chain pivot pin—rather than the middle of the chain link—you get double the shift opportunities.
XD driver
SRAM developed the XD driver for their 1x 11 speed XX1 drivetrain to allow the use of a 10T sprocket on the cassette. Up and until that point the smallest sprocket that would fit over a freehub was an 11 tooth. On paper, it seems small, but that one fewer tooth out back has the same result in ratio jump as going two chainring sizes smaller in front. (E.g. dropping from 24T to 22T). This gave the drivetrain the extra range needed to suit the bulk of riders. That was of course before they launched the 12 speed Eagle drivetrains available today.
The XD compatible driver body design is an open standard available to any hub manufacturer interested in producing a driver body compatible with the XX1 10-42 11-speed or 10-50 12-speed cassettes. The cassette slides on much like the existing cassette, which interlocks with a spline system at the rear of the driver. From here, a standard Shimano-type cassette lockring tool (with a spline length of 7-8mm) is used to tighten the cassette onto the body.
Cassette
The GX Eagle cassette is made up of pressed steel cogs held together by stainless steel pins. The largest 50 tooth cog is made of aluminium. The material costs and manufacturing process are far cheaper than the XX1 and X01 cassettes that are machined out of a solid piece of steel and results in a cassette that is only 95 grams heavier. The first eleven cogs match the sizes of the familiar 11-speed cassettes (10, 12, 14, 16, 18, 21, 24, 28, 32, 36, 42) with the addition of the larger 12th 50 tooth cog for added range.
The open design aids in mud clearance, giving you cleaner shifting performance and longer component life. Although the manufacturing process is simpler, the cassette is not short on technology.
X-GLIDE 2 is next generation of SRAM X-GLIDE technology optimized for the Eagle 12-speed cassette. It provides quick, precise, power-on shifting performance throughout the gear range, and increases chain retention on larger cogs. Flawless shifting means you’ll never again compromise your speed and power in unpredictable off-road terrain.
Chain
The GX Eagle chain features solid pin construction and smooth, efficient shifting that you can count on every time. Ultra-smooth chain inner-plates are completely devoid of square edges, resulting in a chain that engages the cassette and chainring with far less friction, for quieter performance and better wear life. The design allows a narrower overall profile that can withstand greater angles, and also allows for a flatter outer-plate, which means more consistent chain riveting and enhanced overall strength.
Shifter
Superior ergonomics and adjustability let you shift quickly, comfortably and intuitively with GX Eagle’s trigger shifter. It carries with it all of the enhancements and improvements that the XX1 and X01 Eagle trigger shifters received, improving trigger feel, precision, and durability in a forged aluminium body.
Weight savings
With the upgrade in drivetrain, the bike’s overall weight dropped from 12.29 kg down to 11.91 kg for a total saving of 380 grams.
The finished product
Gear range comparison
