RMU launches the Nighttrain, a 170mm dual-chain enduro bike from a Colorado ski brand

RMU, the Colorado ski brand best known for its small-batch alpine skis and Whistler-rooted mountain culture, has launched the Nighttrain — a 170mm aluminum enduro bike that is, by some margin, the most technically ambitious debut from a ski brand crossing into mountain bikes. RMU built the Nighttrain in collaboration with suspension designer Dave Weagle, and the headline feature is a patented dual-chain, dual-idler drivetrain layered onto a new variant of Weagle's Orion suspension. It is the first production enduro bike to ship with two chains and two idler pulleys.

Weagle's Orion design has shown up before in Esker's all-day trail bikes as a four-bar, single-chain layout tuned for efficient pedaling. The Nighttrain version is something else entirely. RMU and Weagle have rebuilt the platform around a six-bar flex-stay rear triangle with a mid-pivot main pivot, which Weagle says targets the support and damping behavior of a World Cup DH bike rather than the supple long-day feel of earlier Orion implementations. Three short links and a flexing seatstay drive the rear travel, and visually it shares a family resemblance with the Pivot Phoenix that Weagle also designed — but the lower links co-rotate where the Phoenix's counter-rotate, and there is no DW6 branding here. Weagle is keeping the two suspension trees separate.BlisterPinkBikeBikeMag

The dual-idler layout is the part that is genuinely new on a production enduro bike. A first chain runs from a 27-tooth chainring at the crank up to an inner idler pulley, and a second chain runs from an outer idler back to the cassette. The two-step gearing lets RMU use a smaller chainring for ground clearance while preserving normal cassette range, and Weagle claims more drivetrain efficiency than a single-idler layout because of the increased chain wrap. Pinkbike notes a 57.5mm chainline and a 157mm Super Boost rear hub to make space for the second chain, with frame compatibility for either Race Face Cinch or SRAM 8-bolt cranks.PinkBikeBlister

Geometry is straight modern enduro: a 63° head tube angle, 77.5° seat tube, and four sizes from S1 to S4 with size-specific chainstays growing from 427mm on the S1 to 438mm on the S4. Reaches run 440mm, 465mm, 485mm, and 510mm. The Nighttrain rolls on dual 29" wheels only — there is no mixed-wheel option, no flip chip for geometry adjustment, and no shock rate tuning, which Pinkbike flagged as unusual at this price point given how many enduro competitors now offer those tuning tools.BlisterPinkBike

Three complete builds and a frameset are available, all in a Midnight Onyx colorway. The $4,999 Deore build comes with a Marzocchi Super Z fork, Fox Float X2 Performance shock, Shimano Deore drivetrain and brakes, Race Face Turbine eMTB wheels, and an SDG Tellis V2 dropper. The $6,999 XT Di2 build steps up to electronic shifting, a Fox 38 Factory fork, and Fox Factory damping front and rear. There is also a park-focused $6,499 Saint build with a 190mm Fox 40, Shimano Saint drivetrain and brakes, no dropper, and DH-casing Maxxis tires. The frame kit, including a Fox Float X2 Performance shock and the 27-tooth chainring, is $2,499. A complete size M XT Di2 weighs 16.32 kg / 36.0 lb. The Maxxis Assegai/DHR II tires come in light-duty Exo+ casings on the enduro builds, which Pinkbike called the only questionable spec choice on what is otherwise a well-sorted parts list.PinkBikeBikeMagBlister

Ski brands have crossed into mountain bikes before — Rossignol, Commencal, and Scott all started in alpine — but the Nighttrain is the most ambitious debut of that crop in recent memory: a small-batch boutique brand teaming up with one of the most established suspension designers in the industry to launch a six-bar dual-idler platform from scratch. Weagle has said the Nighttrain is the first of a planned RMU lineup, suggesting more bikes to come. Pre-orders are open now, first shipments are expected in July 2026, and the frame is backed by a lifetime warranty.BlisterBikeMagPinkBike