Baker GRUDGEBOX User Manual

PV4-118310
PAGE 2
FEATURES
The GrudgeBox is the most innovative, well executed, robust transmission we have ever
endeavored to design and manufacture. Significant GrudgeBox features include:
1. 6-Speed overdrive design. The 5
th
gear ratio of the GrudgeBox is 1:1 which is
equivalent to the stock transmission 6
th
gear ratio. The overdriven 6
th
gear ratio offers a
250 RPM reduction for highway cruising.
2. Straight cut (spur) gears. Gear School 101. Helical gears are used in most
motorcycles and cars these days because they are quieter than spur gears. However,
there’s a cost for noise reduction because helical gears give up horsepower. The
amount of horsepower given up is proportional to the angle of the helix on a given gear
pair. The stock transmission has helical gears in 2
nd
through 6
th
. The GrudgeBox is
configured with all spur gears and no sacrificed horsepower.
3. Gear width. Stock transmission gear engagement is typically .500”, GrudgeBox is .700”
in 1
st
through 4
th
with nearly twice the circumferential tooth thickness. Generally
speaking, torque capacity of a transmission is the product of the gearset center distance,
gear engagement width, and circumferential tooth thickness at the pitch line.
4. Tapered roller main drive gear bearing. We replaced the problematic self-aligning
stock main drive gear bearing with a tried-n-true opposing tapered roller bearing pair;
patent pending. We did this because any transmission is only as strong as its weakest
link.
5. Dog tooth engagement. The dog teeth on the stock 3
rd
and 4
th
gears have roughly
.200” axial engagement with a less-than 1° undercut. This is a formula for gear hop-out.
For the GrudgeBox we chose 4° undercuts with .250” axial engagement in all positions
to guarantee NO gear hop-out or missed shifts, which translates into NO lost revenue if
you are a Grudge hustler.
6. Direct acting shifter pawl. Upshifting with the stock 07-later shifter pawl is much like
pushing on a rope. To make upshifts crisp and precise, we developed a direct acting
pawl that engages the drum pins with negligible free play and no ropes.
GEAR RATIOS
FEATURES AND GEAR RATIOS
GrudgeBox
1
st
– 3.20
2
nd
– 2.21
3
rd
– 1.61
4
th
– 1.27
5
th
– 1.00
6
th
– 0.92
Stock H-D
1
st
– 3.34
2
nd
– 2.31
3
rd
– 1.72
4
th
– 1.39
5
th
– 1.19
6
th
– 1.00

Baker GRUDGEBOX Specifications

General

Brand	Baker
Model	GRUDGEBOX
Category	Motorcycle Accessories
Language	English