Polygon Cozmic CX3.0: SRAM NX Eagle 1x12 Speed

Not too long ago, I installed the 1x12 speed S-Ride groupset onto the Polygon MTB to test it out. It was always intended to be a temporary installation, until the next interesting groupset comes along. As you may have realized, my Polygon MTB is being used as a test bike, where I will install new setups on it for test riding, before swapping it for other components later on.

It came stock as a 3x10 speed setup, which I changed to 2x10 speed. After that, I tried 1x11 speed, followed by 1x10 speed and then the S-Ride 1x12 speed. Now, I shall try the SRAM NX Eagle 1x12 speed upgrade kit!

Installation is straightforward, very similar to the S-Ride 1x12 speed upgrade kit. The 11-50T 12 speed cassette also uses the standard Shimano spline design, which means it goes straight onto the stock rear hub without any issues. That is the benefit of using the original spline design, which makes it really easy to upgrade older bikes such as mine.

SRAM NX Eagle rear derailleur, with a clutch. The clutch mechanism is not very strong though.

SRAM NX Eagle 12 speed cassette, 11-50T. Plenty of range and gears!

Drivetrain setup, still using the front single Shimano SLX M7000 34T crankset.

SRAM NX Eagle 12 speed shifter, paired with the Shimano Deore M615 hydraulic brake levers.

Shifter clamp band position is adjustable, and I had to set it up this way as there will be interference between the shifter and brake lever clamp bands.

The upgrade kit consists of the rear derailleur, cassette, chain and shifters. All other components such as the crankset or the brakes are unchanged as they are still compatible.

At the same time, I decided to swap the brake rotors, from the previous RT81 rotors to the nicer looking RT99 brake rotors. These RT99 brake rotors were taken from the Avanti Inc 3 when I changed to the Fabike C3. Before the Avanti Inc 3, these RT99 brake rotors came stock with the Canyon Endurace road bike. As you can see, it is nice to have cross compatibility across different bikes as it is easy to swap components without fuss.

160mm RT99 brake rotor on the front wheel

Similar 160mm size brake rotor on the rear wheel.

View of the full bike with SRAM NX Eagle 1x12 speed components!

Once again, with a different 1x12 speed setup, I can test out the components and compare it with the S-Ride 12 speed groupset.

On the first ride off road, something strange happened to the SRAM NX Eagle shifter. The first click of the shifter could not engage, meaning that to perform a shift, I had to push the main lever a long way until the second click, before it could shift.

After dismantling the shifter, I could not find anything wrong with it. Upon reassembling, it worked normally again. Seems that something inside was misaligned or jolted out of place when I went off road, and the reassembly aligned everything properly again. Not ideal as a MTB shifter needs to withstand off road riding without malfunctioning.

Other than that, everything else worked fine. The new and slightly wider Maxxis tires work well, while the new ODI Rogue grips also feel comfortable. Overall, the shifting feeling and performance of the SRAM NX Eagle groupset feels better than the S-Ride groupset.