WHAT IS IT? The WP 6500 cartridge kit allows you turn the stock XACT AER air forks on your KTM, Husqvarna or GasGas into coil-spring forks.

WHAT’S IT COST? $1299.00 (Pro 6500 kit), $135.00 (fork springs).


WHAT STANDS OUT? Here’s a list of things that stand out with the WP XACT Pro 6500 cartridge kit.

(1) Fork performance. Most MXA test riders are pleased with the current production WP air fork, largely because they understand how it works and how to fine-tune it. But, not all riders like the learning curve of air forks. For those riders, WP has introduced a drop-in kit that turns the WP air fork into a coil-spring fork (with damping cartridges and springs in both legs). This kit eliminates the constant fiddling with air pressure and delivers a much more planted feel throughout the fork’s stroke. Most MXA test riders felt that it gave them a better feel for where the forks were in the stroke. Overall, the 6500-equipped fork stayed consistent for the test riders on multiple different tracks, allowing them to just show up and ride.

(2) Weight. The 6500 closed-cartridge fork kit adds 3.5 pounds over the standard AER air fork. The difference between the WP XACT air fork and the heavier WP 6500 closed-cartridge fork is very noticeable on the track. The extra oil, cartridge rods and coil springs make the front end feel slow and ponderous. The added weight affects the maneuverability of the bikes, as the lighter-feeling air front end was easier to maneuver when changing lines to set up for the corners. 

The WP 6500 cartridge kit offers more comfort in small bumps, follows the ground better and doesn’t have the ramp-up in damping force late in the stroke of the air forks, but it does give the bike a heavier front-end wiggle when off the gas. Riders with slower turn-entrance speed liked the coil-spring kit with more rebound damping to help with tire-to-ground feel.

(3) Installation. The WP 6500 kit has three different damping configurations to choose from. Your WP authorized dealers can assemble your 6500 cartridge kit to suit your taste or add a custom setting for the kind of riding you do. MXA had AEO Powersports in Temecula, California, valve our 6500 forks and add in 5.3 N/mm springs.

(4) Setup. When we had the forks working to our liking—holding up initially and better damped from the crust to the mid-stroke in the fork—this setup gave the rear shock a lower feel, which expressed itself as a tendency to hop in throttle-off situations. Our solution was to stiffen the high-speed compression by a quarter turn.

WHAT’S THE SQUAWK? We were pleased with the performance of the WP 6500 drop-in kit, but, as with most drop-in spring kits, the overall cost—when you add up the cartridge kit, installation, oil, bushings and valving—is pushing close to $1500. If you like the plusher feel of coil-spring forks over the lightness of air forks, the WP 6500 cartridge is an expensive upgrade.

MXA RATING: The WP 6500 cartridge fork kit is drop-in plushness.




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