What is Frequency Sensing Technology (FST)?

Frequency Sensing Technology (FST) is a patented system that allows the shocks to automatically adjust damping. It senses the frequency of bumps and distributes oil through ports accordingly to absorb impacts, improving ride comfort.

How do I adjust the preload on these shocks?

The shocks feature a top mount threaded preload adjuster. You can fine-tune the spring preload by simply twisting the cap by hand, without the need for any special tools.

What are the different spring rate options available?

These shocks are available in three configurations: Standard Weight for typical loads, Heavy-duty for riders over 250 lbs, and Super Heavy Duty specifically for touring models with riders over 350 lbs.

Progressive Harley 444 Series Shocks 13.0in - Chrome

Specifications

Brand: Progressive
Part #: 444-4020C
UPC: 444-4020C

Progressive Harley 444 Series Shocks 13.0in - Chrome

Name: Progressive Harley 444 Series Shocks 13.0in - Chrome
Brand: Progressive
Price: 860.95 USD
Availability: InStock

$860.95

On Backorder — Expected to ship by Apr 22, 2026

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

Progressive Harley 444 Series Shocks 13in - Chrome

Key Features

Fits a wide range of Harley-Davidson motorcycles including Road King, Electra Glide, and Street Glide models.
Features patented Frequency Sensing Technology (FST) for automatic damping adjustment.
13-inch length with a chrome finish.
Top mount threaded preload adjuster allows for easy, tool-free fine-tuning.
Available in standard or heavy-duty spring rates to suit rider weight.
Includes progressive rate springs and deflective disc valving for improved control.

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Will this fit your vehicle?

Product Details

These Progressive 444 Series shocks feature a patented Frequency Sensing Technology (FST) that automatically adjusts damping based on the frequency of bumps. This means the shocks distribute oil through internal ports to effectively soak up both small and large impacts, leading to a more comfortable ride. The 13-inch length and chrome finish offer a classic look for a wide range of Harley-Davidson models, including the Road King, Electra Glide, and Street Glide.

The top-mounted threaded preload adjuster allows you to fine-tune the suspension by hand, without needing any special tools. You can choose between standard or heavy-duty spring rates, depending on your riding weight and style. These shocks also incorporate a progressive rate spring and a deflective disc valving system, working together to provide a responsive and controlled feel on the road. They are built in the USA and come with a limited lifetime warranty, reflecting their well-built construction.

When considering these shocks, think about your typical riding load. Progressive offers standard weight, heavy-duty (for riders over 250 lbs), and super heavy-duty (for touring models over 350 lbs) spring configurations to match your needs. Ensuring you select the correct spring rate will maximize the benefit of the FST technology and the overall ride quality for your specific setup.