SUSPENSION TUNING: MR. KNOW-IT-ALL

TINY DANCER

Dear Mr. Know-It-All,
I have a ’20 KTM 300XC, and because of my size (240 pounds), I went to a much stiffer rear spring. My problem is that now it returns way too fast. I added rebound damping to slow it down, and all it seemed to do was wreck the feel in the rear end. Now it’s harsh and still feels very quick. Can you help?
Tiny Dancer
via [email protected]

Good query, Tiny. We called in suspension specialist Dick Wilk from Dicks Racing to give you the proper sage: “Whenever changing the rear spring rate more than one size from stock, I have found that it’s important that the rear damper’s internal valving matches the spring used on the machine. In your case, the stock KTM rear coil is a 42 N/mm spring, and for your size you require a 5.2 kg unit. In stock trim, the KTM’s damper has barely enough damping to handle the stock coil. By turning in the rebound adjuster to slow down the response, it works with the system’s low-speed compression circuit as the adjuster works in both directions. This results in harshness during initial travel, which affects traction, control and feel in cobby off-road terrain. Once the WP damper is valved properly, you can address the quick return via the rebound adjuster without making the shock’s response to input harsh and unyielding.” 

 

FOR AN ARCHIVE OF MR. KNOW-IT-ALL QUESTIONS AND SOLUTIONS, CLICK THE IMAGE BELOW:

Comments are closed.