 Its rear suspension adapted the A-arm suspension design from sports car racing, and was the first four-bar linkage in mountain biking.This design reduced the twin problems of unwanted braking and pedaling input to the rear wheel, but the design wasn't flawless.Problems remained with suspension action under acceleration, and the RS-1 couldn't use traditional cantilever brakes since the rear axle, and thus rim, moved in relation to the chainstays and seatstays.