Description from manufacturer:
A true sport performance shock at heart with an unbelievable low cost, the new 490 Sport Series Shocks feature a high-pressure monotube with deflective disc damping technology, hand threaded preload and a rebound adjustment to dial in the ride. This technology coupled with a linear rate spring allow for consistent feel through the damper stroke and the ability to withstand extreme temperature ranges and heavy loads. An engineered jounce bumper with a built-in metal cup also help smooth out and control bottoming. From pounding pavement around town to hammering around the tarmac on your next race day, the 490 is the perfect choice for your performance demand! Every shock is hand-built, tuned and dyno’d and come with a lifetime warranty.
Available in 13.5"
Further notes from Progressive Suspension:
Target Ride Length (in) : 12.25
With the shocks selected above installed and the full weight of the rider(s) & gear on the bike as it will be ridden, measure the distance between the upper and lower shock mounts (center to center)***. If your measurement is less than the indicated Target Ride Length, increase the spring pre-load** to raise the bike until you achieve the Target Ride Length. If your measurement is more than the indicated Target Ride Length, reduce the spring pre-load** to lower the bike until you achieve the Target Ride Length. Achieving the Target Ride Length in this manner sets the rear suspension ride sag for optimum performance and comfort.
*** For Adjustable length shocks -Target ride lengths specified are with shock length adjustment set at the shortest length. If adjusting the shocks to a longer length, add the same amount to the target ride length. Example: If you lengthen the shocks by 0.38", be sure to add 0.38" to your target ride length.