What is Frequency Sensing Technology (FST)?

Frequency Sensing Technology (FST) is a patented system that allows the shocks to automatically adjust their damping based on the frequency of road impacts. This means the shocks can better absorb both small, sharp bumps and larger, rolling undulations for a more comfortable ride.

How do I adjust the spring preload on these shocks?

The 444 Series shocks feature a top-mounted threaded preload adjuster. You can easily fine-tune the spring preload by hand with a simple twist of the cap, without needing any special tools.

What is the difference between standard and heavy-duty spring rates?

The standard spring rate is suitable for average rider weights, while the heavy-duty spring rate is recommended for riders weighing 250 lbs or more, or for touring models carrying significant loads. This ensures optimal suspension performance based on your typical riding conditions.

Progressive Harley 444 Series Shocks 12.0in - Chrome

Specifications

Brand: Progressive
Part #: 444-4058C
UPC: 444-4058C

Progressive Harley 444 Series Shocks 12.0in - Chrome

Name: Progressive Harley 444 Series Shocks 12.0in - Chrome
Brand: Progressive
Price: 860.95 USD
Availability: InStock

$860.95

On Backorder — Expected to ship by May 21, 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 12.0in - Chrome. Features Frequency Sensing Technology for an improved, comfortable ride.

Key Features

Fits a wide range of Harley-Davidson models including Road King, Street Glide, and Electra Glide.
Features patented Frequency Sensing Technology (FST) that automatically adjusts damping for improved ride comfort.
Progressive rate spring and deflective disc valving work together to handle various road conditions.
Hand-adjustable spring preload allows for easy fine-tuning without special tools.
Available in standard or heavy-duty spring rates and black or chrome finishes.
Comes in a 12.0 inch length with a bright chrome finish.

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Will this fit your vehicle?

Product Details

When you're out on the open road, the last thing you want is for your suspension to fight you. These Progressive 444 Series shocks are designed to give your Harley-Davidson a more comfortable and controlled ride, whether you're cruising down the highway or navigating rougher patches. They replace your stock shocks, offering a significant improvement in how your bike handles bumps and road imperfections.

What sets these shocks apart is their patented Frequency Sensing Technology (FST). This advanced system allows the shocks to automatically adjust their damping based on the frequency of the bumps they encounter. Hitting small, sharp jolts or larger, rolling undulations, the FST system directs oil through specific ports to soak up the impact, leading to a smoother and more comfortable experience. The top-mounted threaded preload adjuster makes it easy to fine-tune your suspension by hand, no special tools required, so you can dial in the perfect setting for your riding style and load. You can also choose between standard or heavy-duty spring rates to match your needs, and this particular model comes in a bright chrome finish.

These shocks fit a wide range of Harley-Davidson models, including popular bikes like the Road King, Street Glide, and Electra Glide. They are well-built with a progressive rate spring and a deflective disc valving system for consistent performance. Progressive Suspension backs these shocks with a Limited Lifetime Warranty, and they are made in the USA.