Motorcycle suspension technology has moved beyond the era when a pair of limp, price-point rear shocks was state-of-the-art, and nobody is happier about that than me. The problem is that now I expect modern suspension performance from every bike I ride, including my 2012 Triumph Bonneville, which came with a pair of limp, price-point rear shocks. It’s an unrealistic expectation, I know, but with Progressive Suspension’s 444 Series rear shocks I’m closer to realizing it.
The 444 Series shock is an update of Progressive’s 440 Series. That update is Frequency Sensing Technology (FST), which “dynamically adjust[s] damping as you ride.” There’s an animation on Progressive’s website that shows how this works, but here’s the short version:
A piston that moves through the oil in the shock body provides damping. There are two paths through the piston. One results in very little damping; the oil moves through it freely so that when you’re riding on a smooth road, the ride is soft. Hit a big bump, though, and the oil speeds up, moving an O-ring that closes off the low-speed path and diverts the oil through a set of flexible shims that deflect more or less according to how big the bump is. The bigger the bump, the higher the oil velocity, and the more damping you get.
The result is just as advertised. On smooth roads and on the highway, the 444s give a soft ride, so much so that when I installed them and took off on a test run I thought I had a rear tire going down. On twisty and bumpy back roads, they stiffen up and keep the rear wheel under control to a degree the stock shocks could never approach.
Spring preload on twin-shock bikes is usually easier than on single-shockers, which typically require you to reach into the frame and turn a collar with a tool that’s too long to fit in the tight space. The 444s have threaded collars on top of the springs that you turn by hand. The threads are very fine so it doesn’t take a lot of effort, and there are index marks on the shock body so you can set both sides the same. This arrangement is more precise than the old ramp-type adjusters with only four or five settings.
Installation is about as easy as it gets. I put the bike on the centerstand and replaced the shocks one at a time. They come with bushings to match different diameters on the mounting lugs for a tight fit. I put a thin layer of grease inside each one to keep them from corroding over time just as a precaution.
The 444 Series shocks put my Bonneville a step closer to riding like a modern motorcycle. They come in black or chrome with matching standard or heavy-duty progressive springs for a suggested retail price beginning at $624.95 per pair. Available eye-to-eye lengths are 11, 11.5, 12, 12.5, 13 and 13.5 inches.