DIVERSIFIED MACHINE INC. 2020 PRODUCT GUIDE
XR3-4.12
Bulldog XR-3
4.12 Complete Rear
78lbs.
XR-3 Dimensions:
The Bulldog XR-3 utilizes an 8" 4.12 ring and pinion that saves more than 2.5lbs compared to a conventional
10" gear. The XR-3 was developed using the latest computer F.E.A. technology to develop and engineer the
rear. The rear is a direct replacement utilizing standard 10 spline quick change gears commonly used in full
size rears along with conventional length driveline components. The rear offers an additional 2" of fuel cell
clearance and 1.75" of seat clearance. The ring and pinion has been used successfully in applications up to
800 horsepower on both dirt and pavement. This rear is an excellent choice for RaceSaver®, 305 or 360 sprint
car competitors. New for 2020 - all axles feature 1" increased left side spline length to accomodate deeper
offset wheels.
Standard Features Include:
• O-Ringed Rear Cover
• Billet Aluminum Front Bearing
• Non Twist One Bolt Shifter Mount
• Jack Pad
Housing
• 3 quarts Bulldog Blood Oil
• Increased Oil Reservoir
• Heat Treated Lower Shaft
• Temperature Reducing Cooling Fins
• Breather Assembly
Important Specs
Side Bell Nuts- 30 ft./lbs.
Threaded Ring Gear- 60 ft./lbs. w/ Red threadlocker
Pinion Retainer Bolts- 25 ft./lbs.
Pinion Backlash- .004-.008
Rotational Pinion Preload (No axle) - 25 in/lbs. @ 70° F
Rotational Pinion Preload (Complete Assembly) - 48 in/lbs. @ 70° F
Starting Recommendations for Shims Left- .062" Right - .062"
Weight Savings of Some Popular Options
XR-3 4.12 Std Rear = 78 lbs.
Description Savings
EDM Ring Gear 1.75 lbs.
Titanium Lower Shaft (Internal 10-10) 1.18 lbs.
Titanium Hardware .89 lbs.
2" I.D. Axle 2.27 lbs.
Important Driveline Lengths when using XR-3 with a 40" Engine Setback
Internal 10-10 Driveshaft – 29” w/ U-Joint Spring
DMI Style Swivel Coupler Driveshaft – 26.5” w/ U-Joint Spring
Winters Style Swivel Coupler Driveshaft – 27.5” w/o a U-Joint Spring
Torque Tube – 27”
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