Built to take high horsepower abuse found in late model H-D performance applications while providing elegant shift precision.
- GrudgeBox - Straight 1st, 2nd 3rd, 4th, 5th and 6th gears, design and geared for performance buffs, racers and speed freaks seeking negligible power loss.
- All gears are straight cut for negligible parasitic power loss, providing maximum power transfer to the rear wheel
- Wide-ratio gearing for heavier performance applications
- Built for aggressive take-offs and long distances at above-average speeds
- 250 RPM drop at higher highway speeds (approx. 80 mph)
- Engineering focus on excessive durability
- Bulletproof main drive gear bearing (patent pending)
- Gears up to 40% wider than stock
- Positive dog tooth engagement in gear with pie-shaped shift dogs
- Frictionless linear detent shift system for smooth shifting
- Redundant neutral detent to make it easy to find neutral
- Low effort, single-axis/linear motion ratchet pawl for crisp, tight and easy shifting
- More durable than stock
- No case modifications required for installation
GrudgeBox Installation Instructions for 3.15 1st gear
- 2006-later Dyna
- 2007-later Softail & Touring
OR
- 2017-later M8 Models