2010-2012 PRO-RIDE RUSH Switchback RMK Service Manual, Page 334Get this manual
Steering and Suspensions Heavy Duty Rear Track Shock Spring-RMK Coil-Over
An optional HEAVY DUTY spring is available if adjustments to the factory-installed springs are not sufficient for riders over 300 lbs(136kg)The part number for the HD spring is 7043741-067Reference the RTSS Setup-Heavy Duty Spring Table below
RTSS Setup-Heavy Duty Spring (Measure spring length with suspension off the ground
RIDER WEIGHT
(WITH GEAR) LBS250-300 300-350 KG 113-136 136-159
INSTALLED SPRING LENGTH
(REAR SUSPENSION OFF THE GROUND) INCHES CM 25.7 25.4
RMK PRO RMK 155163 RMK ASSAULT