updated February, 2003
Main Gear Bearing Failure
and moderate horsepower applications generate substantial lateral movement
of the inner drawn cup bearing, which can eventually work its way out
of the main drive gear bore, resulting in catasrophic transmission failure.
close look at the little details that make a big difference
in reliability and capacity.
exclusive caged roller bearing is securely retained in the
by snap rings over washers at both ends. Only Johnson Engineering
provides performance details like this.
SportGear cross section below. Washers between snap rings
and bearing shell allow bearing to float freely without axial
movement for even longer life.
ring retainers on both ends put an end to bearing "walk"
and possibility of failure. Details like this keep your tranny
alive and well.
Our bearing can't shift laterally thanks to retainer
snap rings over washers. Big and beefy design ends radial
Caged roller on left, drawn cup needle bearing on right illustrate
major differences in load capacity where it counts.
Engineering's helical main (output) gears replace the inexpensive
end drawn cup bearing (not shown) with a high performance caged roller
(top left) that's capable of much higher load and torque
OE or aftermarket bearings.
We've also added snap rings (top, middle drawing) over washers on both
sides of our roller bearing, as well as on the sprocket end needle
bearing, to eliminate lateral movement in either direction.
bearing failure can also occur when the bearing dings the sheet
drawn cup that retains the OE needle bearings. The small diameter of
the needle bearings, coupled with the relatively soft drawn cup
metal, allows the drawn cup to become dimpled under heavy loads. And
nobody thinks dimples are cute when bearings are the issue.
massive caged roller bearing features 3.5 mm diameter heavy duty
30% larger and with three times the load capacity of standard 2.5 mm
diameter needles. They won't crush down under heavy use, and can't
walk because of our exclusive snap ring retainers.
entire main gear assembly results in a much stronger gear
Notice the snap rings on both ends of our stout caged roller bearing
on the driven end. Our new SportGear (shown) main gear oil seal is
retained by another exclusive,
with a wobbly, unsecured oil seal.
check out our four-point bearings
for Big Twins and Sportsters!
and TwistGear® are trademarks of Johnson Engineering, Inc. Buell™,
Dyna™, and Sportster™ are trademarks of the Harley-Davidson
Motor Company. No affiliation with the Harley-Davidson Motor Company
is implied or inferred.