VOLUME 59 ISSUE 7 FEBRUARY 15, 2022 P89
slow out of the hole. It would be
the worst street bike, but that's
what you need for flat track."
Smith and Howerton backed
up the contrasting nature that
separates the FTR from its
competition by actually laying
parts out on a table. Smith said,
"You can tell people the inertia
numbers all day, but until you
see it with parts and pieces—
looking at the Kawasaki's crank,
for example, and comparing that
with the flywheel on the Indian...
it's pretty eye-opening to see the
hard parts in front of you."
The "2" in I = mr
2
is critical to
understanding the advantage
that a larger flywheel provides.
The exponential impact of posi-
tioning mass farther away from
the center of the flywheel means
having an extra inch or more
in the right places will deliver a
monumental impact on its ability
to put power to the ground.
As a result of the differing de-
sign philosophies, the FTR750's
engine generates considerably
more MOI than its challeng-
ers. It's not a huge leap to think
that could directly translate into
other big numbers, such as
overwhelming win and podium
percentages.
Smith said, "It'd be like having
a MotoGP bike in AMA Super-
bike. That's a pretty drastic
difference, but that's about like
what it is. How long do you
allow that one off bike to kick
everybody's ass before you do
something?"
It's important to note that the
engine is far from the sole reason
the FTR750 has been as phe-
nomenally successful as it has. It
also features a perfectly bal-
anced chassis, and it has several
the sport's smartest tuners and
most talented riders accumulat-
ing more and more data while
continually pushing it to its limits.
That said, the MOI difference that
separates it from its rivals makes
it nearly impossible to understand
exactly how important those
other factors have been in con-
tributing to its stranglehold over
the premier class.
This is not a new develop-
ment. "Moment of inertia" has
been a buzzy phrase in the AMA
Pro Racing offices for some
time and the aforementioned
'21 midseason rule adjustments
were made in part to address
that difference, reducing the
weight of the rear wheels on
bikes with "race-only engines"
(i.e. the FTR750) while also
stripping them of the ability to
add additional mass to their base
flywheels.
However, at minimum a more
thorough understanding of the
concept provided AMA Pro Rac-
ing a better grasp of the very
difficult task ahead.
HISTORY LESSON
Single-bike dominance is not a
new development for the series
either. Over a five-decade run,
the Harley-Davidson XR750
racked up 37 Grand National
Championships and 502 premier
class main event victories.
Towards the end of that reign,
however, it had become notori-
ously expensive to maintain, with
parts in short supply and en-
gines needing a rebuild following
every national.
Meanwhile, it's been a long-
standing initiative of the sport to
make street bike-derived ma-
chinery viable options for com-
petitors at the top of the sport.
The production-based big-
bore "Supertrackers" were
Fans are the bloodline for most
sports, especially flat-track
racing. And fans like diversity
when it comes to brand
participation.
