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Helix Race 13-52T + Helix Race 9-52T
Experience the advantages of e*thirteen’s all-new Helix Race cassettes.


As pedal assist bikes have become more popular, we set out to engineer a close-ratio cassette specifically for e-MTBs. Enter the Helix Race 13-52T—a new 12-speed close-ratio cassette specifically engineered for steep terrain with high climbing speeds and gravity-powered descents.

The 13T, combined with a 32T chainring at 85rpm cadence, will deliver speeds of 30kmph/19.2mph, right at the speed-limited assistance of most e-bikes. The new 52T lowest gear and closer steps help riders clean the most technical climbs with newfound ease.

Most mountain bike riders spend at least 70% of their time climbing or traversing, not utilizing the smallest cogs of the cassette. We’ve moved those wasted gears to the big cogs, giving you smaller gear steps starting at the 25T cog all the way through to the 52T. With this gearing, you can optimize cadence for e-bikes and bio-bikes alike.

While the Helix Race 13-52T was conceived with e-bikes in mind, it can improve the ride experience for all types of riders, allowing them to optimize their cadence on steep climbs and let gravity do the work on descents.

Like all e*thirteen Helix cassettes, the Helix Race 13-52T delivers seamless cross-compatibility with SRAM™, Shimano™, and TRP™ 12-speed drivetrains, along with improved shifting precision and wear life. Weighing in at 467g, the cogs are reinforced for high-powered e-bikes yet light enough for weight-optimized trail bikes.

Experience the advantages of a close-ratio cassette on your next ride, with the Helix Race 13-52T.

– Close ratio gearing cassette for better cadence and improved shifts under load
– Lower fatigue and extended range (Bio or Battery) with sweet spot cadence for max efficiency
– Helix Race Close Ratio 13-15-17-19-22-25-28-32-36-40-45-52 vs Eagle™ 10-12-14-16-18-21-24-28-32-38-44-52
– Cross-compatibility with Shimano, SRAM, and TRP drivetrains and chains
– Aluminum and Steel clusters can be replaced separately to reduce service costs and lower environmental impact versus buying a complete replacement cassette
– Patented two-piece aluminum/steel construction for strength, stiffness, light weight, and durability
– Reinforced for e*spec strength: 467g
– Five bold anodized or PVD color options
– Tested extensively for bio and e-bike use


Helix Race 9-52T Cassettes are engineered to deliver precision shifting performance with Shimano, SRAM, and TRP 12-speed drivetrains equally with an industry-leading 578% gear range.

e*thirteen’s proprietary 9T smallest cog combined with the new 52t largest cog enables the use of a smaller chainring for improved clearance, lighter system weight, and a lower bail-out gear ratio while offering an even higher top gear.

The unique two-part design, with its 7075 aluminum two large cogs and 10-cog heat-treated steel cluster, uniquely supports replacing the individual clusters as they wear, lowering cost and waste while maintaining optimal performance.

Forged and CNC machined from steel and AL-7075, the Helix Race 9-52T cassettes are light enough for weight-conscious trail bikes at just 392g, yet tough enough to take the abuse of high-powered e-bikes. Future-proof your ride and expand your range with the Helix R 9-52T. Available in the full Helix color range, including long-wearing Intergalactic PVD.

– Widest range in the galaxy at 578%: 9, 11, 13, 15, 17, 20, 23, 27, 31, 36, 43, 52
– Cross-compatibility with Shimano, SRAM, and TRP drivetrains and chains
– Two-part design provides ease of assembly/service and reduces waste
– Two largest alloy cogs cluster or 10 steel cog cluster can be replaced separately and affordably
– 43-52t cluster can be retrofitted to upgrade Helix 9/50t cassettes
– Unique 9T high gear allows use of smaller chainrings for clearance and weight savings
– Heat-treated Steel and AL-7075 construction for strength, stiffness, light weight, and durability
– Five anodized or PVD options to coordinate with colors and components to match your dream build
– Tested extensively for analog and e-bike use


The complete range of 11 and 12-speed cassettes solves compatibility woes and allows riders to optimize gear selection for any riding style, terrain, or bicycle. The e*thirteen team understands the limitations of a one size fits all approach, so the brand created the Helix cassette range for the best performance and value in a variety of sizes.

12-speed cassettes are available in four gear configurations from the Close Ratio 13-52T to the 9-45T that can be fitted to eke out a little more range on a gravel bike.

For the diehards sticking with tried and true 11-speed, Helix cassettes run the gamut from 9-46T Wide Range for MTBs to the Wide Road 9-34T. You chose to stick with 11-speed; now you can choose more range and easier, lower-cost service.

Mon 22nd May, 2023 @ 9:30 pm

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