Free Up Your Progressive Shocks For a Buttery Ride
Mr. Detail VROC 16664
Many of you have replaced your OEM rear shocks with units from Progressive Suspension. These are some of the best shocks on the market, their quality of materials and finishes are second to none.
I replaced the shocks on my 2000 Classic 1500 with Progressive’s 440 units. When I received the shocks they had a handful of steel bushing sleeves to help you get the right fit, right? Not necessarily and the reason for this article. Only one set of steel bushing sleeves was the right diameter to fit the bike mounting studs. These bushing sleeves were shorter than the width of the rubber bushing. I had to trim the rubber bushing with a razor knife otherwise when I bolted on the shocks the rubber bushing was being squeezed to the point that with the nuts and washers properly torqued, the shock was bound at both pivot ends. I had learned from my RC gas racing days that shocks, while needing to be properly attached, also need to be free to pivot when the suspension worked its magic soaking up the bumps and potholes.
After trimming the rubber bushings, I installed the shocks thinking I had the binding issue solved. Too many things were working against me. First, the originals were so worn the ride was sloppy and would bottom out at the slightest bump riding two up. Second, I had ordered the 440 heavy duty springs because of my weight, with that of a passenger, I could easily exceed the carrying capacity of the bike. With the installation done I went for the first ride I thought the shocks were a little stiff but would loosen up with some miles.
Fast forward to 18 months later and now 65 lbs lighter. The stiff ride was killing me. I had the shocks set on full soft (no preload) and yet I could feel every bump like I had struts on the rear. I decided to call Progressive and order the standard springs. When I changed the shock springs I inspected the hardware as I took them off and found a groove had been worn on the inside of each of the chrome flat washers. Apparently the steel sleeves were a bit too long and had been binding up and cut the grooves.
THE FIX: I bolted the flat washer and lock washer onto their respective studs and using a caliper, measured the space between the flat washer and the bike frame mounting boss and in my case it was 0.78”. The sleeve measured 0.784”, just a tick to long and enough to bind up the shock action. Using a flat mill file clamped to my work bench I drew each of the bushings over the file till I could fit each of the bushings between the frame and flat washer that I had left bolted in place. That done I slid the sleeves into the rubber bushings and test fit each end of each shock to be sure they would pivot freely with the mounting bolts firmly torqued in place.
All I can say is this is the ride quality I was looking for and I wish I had been more thorough the first time and noticed the slight differences. The ride now is buttery smooth and the bike much more enjoyable.
PLEASE NOTE: The measurements I have indicated are from my Vulcan Classic. Given manufacturing differences, these measurements may be different on your Vulcan. The object is to get the best fit and best possible ride quality for your bike.