e*Thirteen Helix Plus 12-speed cassette review – more gear range with less weight

e*Thirteen boosts your MTB gear range with its 9t equipped Helix Plus 12-speed cassette

e*Thirteen Helix Plus 12-speed cassette
(Image: © Graham Cottingham)

BikePerfect Verdict

The e*Thirteen Helix Plus cassette is an excellent aftermarket cassette that squeezes even more performance out of your 12-speed drivetrain.


  • +

    Increased range

  • +

    Lower weight

  • +

    Cheaper than SRAM GX alternative

  • +

    E-bike approved

  • +

    Compatible with SRAM, Shimano, and TRP 12sp


  • -

    Large jump between 11t and 9t

  • -

    XD only

  • -

    Not SRAM T-Type compatible

Why trust BikePerfect Our cycling experts have decades of testing experience. We'll always share our unbiased opinions on bikes and gear. Find out more about how we test.

It doesn’t matter how good drivetrains get, there is always some form of aftermarket upgrade to eke out a little more performance. Most of these usually involve increased maintenance and high costs for marginal gains.  

e*Thirteen’s Helix Plus 12-speed cassette not only manages to better the main players' cassettes with a wider gear range, but also saves weight while doing so. Not only that, but it's potentially a cheaper option when it comes to replacing a worn cassette. But surely all this is too good to be true?

e*Thirteen Helix Plus 12-speed detail

Dropping from a 10t to 9t cog ups the cassette's range to 556 percent  (Image credit: Graham Cottingham)

Design and build

As 1x MTB drivetrain ranges have increased, we have seen larger and larger cassettes. e*Thirteen has opted to go the other way, squeezing a 9t sprocket onto the end of a SRAM XD driver to offer a huge 556 percent range. That’s a considerable jump when compared to Shimano’s 510 percent 10-51t and SRAM’s 520 percent 10-52t MTB cassettes, giving you more winching power without sacrificing your faster gears. 

For those that are interested, SRAM’s XG-1275 cassette features a cog spread of 10, 12, 14, 16, 18, 21, 24, 28, 32, 36, 42, 52, while Shimano’s M8100 cassette has 10, 12, 14, 16, 18, 21, 24, 28, 33, 39, 45, 51. In comparison, the Helux Plus’s starts lower with 9, 11, 13, 15, 17, 20, 23, 27, 31, 36, 42, 50, which is how it achieves the extra range. On paper, the difference in ratios at the easier end of all three cassettes is very similar. It's when you reach the mid-point of the Helix cassette that ratio jumps start to ramp up a little. On the trail, the marginally larger gaps aren’t noticeable until the last two sprockets.

The cassette is built in two sections with two larger cogs made from aluminum and the rest of the cassette using steel. These separate clusters are also available individually as well – in case you need to replace just one section. Our review cassette weighs in at 415g, which is a decent saving over Shimano and SRAM’s quoted weights of 470g and 452g respectively. If you wish to save more weight, e*Thirteen has a Race version with a quoted weight of just 384g which comes in a range of bright colors.

e*Thirteen Helix Plus 12-speed cassette fitted to a MTB

Helix Plus 12-speed cassette is compatible with both Shimano and SRAM drivetrains, but not SRAM Transmission (Image credit: Graham Cottingham)


Fitting the cassette is a simple process although a little different from a standard XD/XDR cassette. The alloy carrier with the two largest cogs is fitted first and tightened with a 3mm pinch bolt. The steel cluster is then aligned and locked into the alloy carrier, then finally, a 3mm hex set screw is tightened to hold everything in place. All the parts are well finished and everything went together as expected.

e*Thirteen recommends running the cassette with a chainring two teeth smaller than you would usually use. This effectively gives you a lower gear and more weight savings with a smaller chain ring. I fitted the cassette to a fast downcountry build with a 32t chainring to give me a higher top speed at the cost of slightly larger ratio jumps than if I was running a 30t or 28t chainring.  

The Helix Plus cassette was paired with a SRAM GX AXS derailleur and the shifting has been impressive. The setup was simple and gear changes have been quick and slick across the full block. I found shifting performance was still precise when changing under power or when the cassette was coated in slop. 

Cogs with a lower tooth count are mechanically less efficient due to their smaller size, but I never felt any grumbling or increased resistance in the 9t gear. It’s a big jump between the 11t and 9t sprockets though, so expect to go from spinning to grinding when you engage the smallest sprocket. I didn’t find this to be an issue though as big jumps in cadence are more tolerable at high speeds. Even with a 28t chainring you will still need to be doing well over 30kph before you start thinking about deploying the 12th gear.

e*Thirteen Helix Plus 12-speed cassette

e*Thirteen's other cassettes come in a range of colors although the Helix Plus only comes in black (Image credit: Graham Cottingham)


e*Thirteen’s Helix Plus cassette offers a genuine upgrade in performance with its wide range and lower weight. Shifting is tight and precise as well so there is no loss in performance there either. 

For SRAM users, upgrading to this cassette is a no-brainer as it will improve performance and save you some cash at the same time. For Shimano riders it's not quite as clear cut though. Shimano’s XT cassette can’t match the range and weight, however, it’s still considerably cheaper, especially if you need to factor in a Micro Spline to XD freehub switch too.

Tech specs: e*Thirteen Helix Plus 12-speed cassette 

  • Price: $229.95 / £229.95 / €241.97
  • Sizes: 9-50t
  • Options: XD only freehub
  • Colors: Black
  • Weight: 415g
Graham Cottingham
Senior reviews writer, Bike Perfect

Graham is all about riding bikes off-road, based in Edinburgh he has some of the best mountain biking and gravel riding in the UK on his doorstep. With almost 20 years of riding experience, he has dabbled in downhill, enduro, and gravel racing. Not afraid of a challenge, Graham has embraced bikepacking over the last few years and likes nothing more than strapping some bags to his bike and covering big miles to explore Scotland's wildernesses. When he isn’t shredding the gnar in the Tweed Valley, sleeping in bushes, or tinkering with bikes, he is writing tech reviews for Bike Perfect.

Rides: Cotic SolarisMax, Stooge MK4, 24 Bicycles Le Toy 3, Surly Steamroller

Height: 177cm

Weight: 71kg