Popular Mechanics - USA (2019-03)

TECHNOLOGY

ILLUSTRATION BY TYSEN JOHNSON

↓ HOW IT WORKS

The Polaris 850 PRO-RMK 174 is one of the latest, combining low weight

with big power. Here are some highlights.

/ BY EZRA DYER /

Tr a c k The 174-inch track has

116 three-inch paddles for flota-

tion and traction. The chassis design

tucks the engine and drivetrain up high,

helping the track climb up on top of the

snow rather than sink into it.

SLS Springs The front sus-

pension stance is adjustable

from 36 to 38 inches, so riders

can tailor the degree of lean

in deep powder. The Walker

Evans Monotube Impact-

Extruded Shocks use steel

coil springs that, thanks to a

patented production process,

are three pounds lighter than

the previous steel springs, or

even titatnium springs.

Body Making the

sled narrow allows

riders to lean into

steep hills without

dragging the cowl-

ing in the snow.

Running boards give

the rider leverage

when standing.

Pro-Lite Seat Mountain sleds

need a long track, but use a

short seat so it’s easy to move

from one side to the other.

Dashboard A GPS-linked speedometer automati-

cally logs top speed. Check it later, when you’re

Weight By

chipping away

at ounces here

and there,

the entire sled

weighs only

449 pounds.

AXYS

RMK Rear

Suspension

Sixteen inches

of travel and a

coil-over shock

maximize

rear weight

transfer.

Carbon-Fiber Reed Valve Petals

Reed valves, partic-

ular to two-stroke

engines, allow the

air–fuel mixture into

the cylin

flex millions of times over an

engine’s life cycle, so they need

to be light, springy,

and durable. The

850 Patriot engine’s

reed valves use carbon

fiber—expensive, but the per-

fect material.

12 March 2019 _ PopularMechanics.com