Progressive Monotube Front Suspension
Bob LaRosa & Mark DiPietroDescription
Thanks to Progressive Suspension, high performance front suspension is now finally available for 2014 and newer Harley Davidson touring models. The Progressive monotube has combined ride smoothing Frequency Sensing Technology (FST) damper with a progressive rate spring to create a state of the art fork cartridge assembly for the late model Harley Davidson Baggers.
The Progressive monotube assembly works by having an asymmetrical layout that places a progressive rate spring in one leg and an aluminium bodied, sealed cartridge damper in the other leg. This FST valve is designed with an internal bypass which allows for superior dampening. The overall design truly sets a new benchmark for high performance front suspension.
This Progressive monotube fork kit replaces your stock fork caps, preload spacers (if present), fork springs and damper rods. The lowered kit contains components for two different fork configurations – approximately one inch or two inch lowered. Or you can retain your original, stock height with that specific kit. With this FST cartridge design comes improved resistance to front brake “dive”, improved front end stability, improved cornering, and improved bottoming control.
Baggers are really under sprung and poorly dampened. In a corner, lack of control translates to chassis oscillation. That means, the front suspension compresses and rebounds an inappropriate amount while cornering. Imagine entering a corner at a steady speed. Apply a little brake and tip into the corner. You have now transferred weight to the front of the motorcycle. The stock suspension will typically compress far too much which forces the rider to correct his hold line. The poor dampening will then allow the fork to return too quickly forcing the rider to correct again. That’s considered oscillation. Something we all get used to on Harley Davidson’s but certainly not preferable.
Take the same corner with the Progressive monotube suspension. A little braking and you’ve set your line through the corner. The motorcycle will now hold that line as you accelerate out of the corner. Bob and Mark will be installing the Progressive monotube cartridge assembly into a beautiful set of Performance Machine lower sliders. Watch the next video of these two excellent products from two of the top American companies in the motorcycle industry come together. This FLH is going to handle and look amazing!
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