Jamis Helix 27.5″ Comp Mountain Bike 2016



Building great recreational-level bikes for both men and women that ride much like our hi-end bikes is a passion at Jamis. And no bikes showcase our commitment to do just that better than these. The 27.5” wheel size is not a compromise between 26” or 29”: it’s the best of both worlds. The Helix chassis emphasises all-day performance and quick handling without being overly darty. Low standover, short reach stems and brakes, wide range gearing and gender specific saddles are just some of the features of the highly capable Helix lineup.




Lightweight and strong 6061 series aluminium tubing, featuring oversized & tapered tubing for increased frame stiffness.


The aluminium frame of the Trail X and Helix is beefed up to include a larger 34.9mm seat tube, which allows us to spec an oversized 31.6mm seat post. The larger diameter post flexes less, providing a firmer pedalling platform.

Top Tube Cable Routing

Running the cables up under the top tube keeps cables and housing out of the muck for more precise and reliable shifting performance.

ZERO STACK Internal Headset

A Zero Stack internal headset places both the cups and bearings inside the head tube instead of outside. This reduces the total stack height (including the head tube), which is beneficial on larger wheeled bikes. The larger diameter head tube also provides a larger weld interface at the critical head/top/down tube junction.

Dual Water Bottle Mounts

Most of our Trail X sizes offer two water bottle mounts located inside the main frame. This provides excellent hydration capacity in an easily accessible position.

Replaceable Derailleur Hanger

Because it’s much easier and much less expensive to replace a derailleur hanger than it is to repair or replace a frame, every Trail X and Helix frame offers a replaceable derailleur hanger designed to yield in a crash before the frame does.

Full Shimano Shifting System

Fully integrated shifting systems offer the most precise and reliable performance. That’s why our Trail X and Helix models all offer Shimano shifters, Shimano front and rear derailleurs and Shimano cassettes or freewheels.

Alex TD26 Disc-Specific Rims

Disc hubs twist during braking. This twisting increases “pull” load on the nipples in the spoke bed. The Alex TD26 spoke bed on the rims specified on Expert, Comp and Sport is cleverly reinforced to resist disc brake torque and prevent spokes & nipples from shearing.


Frame 6061 aluminum main tubes, over-sized seat tube, zero-stack head tube, over-sized stays, replaceable derailleur hanger
Fork RST Blaze TNL 27.5″”, coil spring with Turn-n-Lock hydraulic lock out, external preload adjustor, 30mm stanchions, aluminum lowers, 100mm travel
Headset Zero-stack internal cup threadless, 15mm cone spacer
Wheels Alex TD26 27.5″” rims, 32H, alloy 6-bolt disc hubs, stainless spokes
Tires CST Patrol, 27.5 x 2.25”
Derailleurs Shimano Acera rear and M190 front
Shift levers Shimano M310, 3×8-speed
Chain KMC Z7, 8-speed
Cassette Shimano HG20, 8-speed, 11-32T
Crankset Shimano TY501, 42/34/24T, 170mm (14″”/16″”) 175mm (18″”)
BB Set Sealed cartridge
Pedals ATB platform, hi-impact resin
Brakeset Tektro M286 hydraulic disc, 160mm rotors
Handlebar Jamis XC riser, 31.8 x 20mm rise x 660mm
Stem Jamis XC alloy threadless, 31.8 x 10º rise x 70mm (14”), 70mm (16″”), 90mm (18″”)
Grips Kraton
Seat Post Jamis alloy micro-adjust, 31.6 x 350mm (14″”) 400mm (16″”/18″”)
Saddle Jamis ATB Sport Women’s, SL cover, protective front and rear guards
Sizes 14”, 16”, 18”
Color Gloss Black
Weight 31.25 lbs


14 21.2 / 540 70˚ 72.5˚ 17.1 / 435 40.5 / 1029 1.8 / 46 4.1 / 105 26.3 / 668
16 22.1 / 560 70˚ 72.5˚ 17.1 / 435 41.3 / 1050 1.8 / 46 4.3 / 110 27.7 / 704
18 22.9 / 580 70˚ 72.5˚ 17.1 / 435 42.1 / 1070 1.8 / 46 4.7 / 120 28.9 / 731