The e*thirteen TRS Plus 12-Speed Cassette Keeps an Ace in the Hole With Its 9-Tooth Cog

e*thirteen has taken 1X MTB gearing range a small step further by cutting the smallest cog to just 9 teeth, allowing us to pedal faster when the throttle is fully open.

When was the last time you saw a driveside photo of a bike where the brake-rotor was visible beyond the dinner-plate-sized cassette? With modern 46-51t climbing cogs, your answer is likely; “it was a downhill race bike.” The massive range of those low cogs and super sprinty high gears has allowed us to ditch finicky front derailleurs altogether while arriving at nearly the same gear range we had with a pair or triad of chainrings.

e*thirteen has taken that range a small step further by cutting the smallest cog to just nine teeth, allowing us to pedal faster when the throttle is fully open. My initial complaint with 1X drivetrains was that the 12-tooth highest cog was too large, and the then-36t lowest gear didn’t allow me to use a larger chainring to speed things up. While that may not matter to everyone, for folks who race XC or enduro it’s a vital drivetrain consideration. Just as narrow-wide chainrings gobbled up my chain guide woes, wider cassette ranges have handily taken care of the sprint vs. ascent capabilities for cassettes. With a whopping 556% gear range spanning 9-50t cogs with a minor 393g weight penalty, the e*thirteen TRS Plus Gen2 12-Speed Cassette adds a handful of nails to the front derailleur coffin.

Price$319 Available at REI
Weight393g (9-50t tested)
Gearing 9,11,13,15,17,20,23,27,31,36,42,50
Range 9-50t = 556% or 9-46t = 511%
Drivetrain compatibilitySRAM Eagle, Shimano XTR, XT, and SLX 12-speed
Freehub compatibilitySRAM XD driver only

I won’t ramble on about installing the TRS cassette since e*thirteen has done a fine job of explaining that. The install is quick and simple, and I haven’t had any trouble with pieces of the cassette coming loose or making noise during testing. The current Gen2 model only works with SRAM XD freehub bodies, so if you have a Shimano HG or Micro Spline style freehub you will need to swap it out.

In the wild

Photo: e*thirteen

I have been testing the 9-50t TRS Plus cassette on e*thirteen’s LG1 Race Carbon Enduro Wheelset, and the company’s graphics certainly sit well together. I shifted through the cassette with a new Shimano XTR drivetrain on my personal bike, and with a SRAM XX1 drivetrain on another bike, both using the correct level chain from their respective brands, and with 32t chainrings.

Jumps between gears across the cassette feel fairly natural, and after a couple of rides, the small differences in tooth numbers between the TRS Plus and other cassettes I have used were unnoticeable. The only gearing selection that truly stands out is the 9t cog that allows you to out sprint your friends, provided you have the same chainring size. I expected the tiny cog to drop or slip the chain more often than 10t or 11t versions, but there was no issue with it whatsoever. In fact, once the drivetrain was dialed the chain stayed steady on the gear it was assigned to.

If you have multiple bikes with different drivetrains and you want to be able to swap wheels, this cassette will work with SRAM or Shimano, after a few tweaks. It’s definitely worth checking the limit screws if you throw the rear wheel in a frame with a different drivetrain, as the cog spacing differs slightly. According to e*thirteen, “Shimano 12-speed spacing is a little different than SRAM. Our cassettes were largely designed around SRAM spacing since that’s all that existed when we started.” In short, it works with both, but it will require a little more fine-tuning with Shimano drivetrains.

The one issue I did have with the TRS Plus cassette centered around the lowest two cogs. With the Shimano XTR drivetrain and chain, it was difficult to shift into a higher gear from the lowest cog. I had to shift past the gear I wanted, and then shift back to it. I have had this same issue with a SunRace cassette that I sometimes use to pair XD freehubs with Shimano drivetrains. e*thirteen recommends using some other chains in combination with a Shimano drivetrain to make the whole system compatible with their cassette.

I rode with this same cassette on a friend’s Shimano XT equipped bike, and it shifted beautifully, so likely I need to swap the chain out for a KMC or e*thirteen’s recommended YBN chains that they sell with their 12-Speed Upgrade kit.

In conclusion

The TRS Plus 12-speed cassette from e*thirteen will give you a wide gear range and a wicked sprint cog to spice up the party. It requires more derailleur tinkering than a cassette made by your derailleur’s manufacturer, but once it’s dialed it works well. If you care about weight savings and gearing range, this cassette is certainly worth considering.

⭐️ Find the e*Thirteen TRS Plus 12-speed cassette at REI, Wiggle, and other online retailers.

Thank to e*Thirteen for providing the TRS Plus cassette for testing and review.

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