From the October 2023 issue of Car and Driver.
At a glance, Toyota’s IsoDynamic seat looks like a set decoration, a strange contraption built to make a starship’s command perch appear suitably futuristic. But there’s method to this apparent madness.
The IsoDynamic seat is inspired by the Lexus Kinetic Seat, a 2016 Paris auto show concept that featured spiderweb-patterned hammock-like supports instead of cushions. The design allowed an occupant’s torso and hips to move independently in order to keep the head stationary. Toyota developed the Tacoma TRD Pro‘s Iso Dynamic seat to accomplish the same goal in an off-road context.
Think of the IsoDynamic seat as a seat within a seat. The cushions rest on an inner frame that attaches at two points to an outer frame (which itself mounts to the vehicle body). One attachment point is high on the seatback, and the other is a ball joint hidden below the front edge of the thigh cushion. Between these, the seat swings side to side like a hammock, up to an inch in each direction.
To regulate the IsoDynamic seat’s movement, the prominent vertical reservoirs contain pistons that compress chambers of air. The right strut works against lateral swing, and the left one restrains up-and-down motion. Below each piston, oil flows through hoses to pairs of remote cylinders affixed to the seat.
A lockout on each reservoir keeps the seat in a fixed position during normal driving conditions.
The upper attachment point contains a four-bar linkage enabling 1.4 inches of up-and-down movement and a slip joint allowing 0.7 inch of fore-and-aft motion. A coil spring absorbs fore-and-aft hits at the shoulders.
A phone app recommends air-pressure settings based on factors such as terrain and body weight. A hand pump connects to Schrader valves below the pressure gauges.
Behind the plastic trim are four remote cylinders. Two transmit side-to-side movement to the right reservoir, and the other two convey vertical motion to the left one.
Technical Editor
Dan Edmunds was born into the world of automobiles, but not how you might think. His father was a retired racing driver who opened Autoresearch, a race-car-building shop, where Dan cut his teeth as a metal fabricator. Engineering school followed, then SCCA Showroom Stock racing, and that combination landed him suspension development jobs at two different automakers. His writing career began when he was picked up by Edmunds.com (no relation) to build a testing department.
