Mods & Custom Builts

Sort by Date Hits Rating

PT-425 Wheel Motor Upgrade - 5/11/2008 - Hits: 65
I upgraded my old-style PT-425's White RS Series 12.5ci wheel motors to Char-Lynn S Series 22.7ci ones.  This essentially doubled the torque while reducing the top speed to half of the stock motors.  I custom-ordered the Char-Lynn motors, adding the optional Low-Speed Valving and High-Pressure seals, in addition to specifying the 1" tapered shaft and 1/2" NPT hose connectors.  Three additional modifications were required: (1) grinding out the PT's tub to clear the motors which are about 3'8" wider in diameter than the width of the rectangular White RS stock motors; (2) grinding the Char-Lynn's Woodruff key down slightly, making it "stepped" to match the keyway on the original wheel hubs which used a slightly smaller bar-type key, and (3) adding washers between the wheel hub and the retaining nut so that it would torque up tightly -- the Char-Lynn motors have a slightly longer shaft.  It was about a 10-12 hour mod, overall, with most of the time spent grinding out the tub with a small air-driven cutoff tool.  Now, this PT (which didn't have the higher-torque 14.7ci White CE wheel motors that the new ones have) can readily climb 20-25 degree slopes and is limited only by traction, not wheel motor torque.  However, the top speed is just slightly above 5MPH, so take that into consideration before you do something similar.  It may be TOO SLOW for your uses...