Large-diameter tires put more load on the belt and CVT.
Modern CVT covers are vented like this one is.
This lower-powered machine doesn’t require a heavy-duty
belt like a powerful UTV does.
Sand, a heavy and powerful machine, and a hill to climb—
all together they make a CVT belt cry for mercy. Breaking
in the belt properly, keeping belt temp in mind and driving
smart will help the belt live.
don’t clear it, it will work its way back
into the CVT area and raise havoc.
Some experts claim that belts are
directional. Always install the belt so
that the writing on the belt is facing
you. That way, if you end up using a
used belt for a spare, you will install
it in the same direction it was run
before. If you find a belt that has
been installed “backwards,” don’t
rotate it; leave it running the same
Never power-brake a CVT vehicle.
Even at the start of the race, when you
do that, the rpm is up but the belt is not
spinning, and it puts flat spots in the
belt. Check your machine’s sheaves.
If they have wear or grooves, you
won’t get optimum performance, and
you’ll prematurely wear the belt.
CHOOSING A BELT
Most stock CVT belts are of very
high quality. Often they are expensive compared to aftermarket belts.
Many customers choose to stick with
the stock belts, but others swear by
aftermarket brands. Some perfor-
mance companies have their own
belts (usually private-labeled from
a belt manufacturer), or they recom-
mend a specific belt. Belt technology
has had to accelerate as the power
output of CVT-equipped machines
rises. Did you notice that extreme-du-
ty belts appeared shortly after
high-horsepower UTVs did? ATVs do
need replacement belts, but not at the
rate that UTVs do.
The belt is made from rubber (
usually fiber-reinforced) that is rigid across
but flexible along the length. The
“cog” or toothed look on the inside
helps the belt resist the extreme compression and allows a greater traction
surface yet still bend easily. The cog
on top aids bending around the pulleys, adds side traction, makes the
cross section strong and generates
cool air in the CVT case. Between the
top cog and the inner cog is the cord.
The cord gives the belt the strength
lengthwise. The cords are bound into
the fiber-reinforced rubber of the cogs
with adhesive. The face of the cogs
has a fabric cover.
HEAT IS THE ENEMY
The consensus in the industry
is that belt temperatures over 200
degrees are bad and 400 degrees is
critical. Some racers use a belt-temp
gauge, and they drive the race car
while watching the belt. If temps rise,
they back off to allow the belt to cool.
High-end SxS racing, high-horsepower machines with paddle tires and
mud boggers with tall, aggressive
tires are the hardest machines on
Engine mods, big tires and a heavi-
er machine all add to the heat that
the belt must endure. If you start to
make changes like these, then you
need to make changes to the clutch-
ing to keep the heat down. You want
to avoid extended running at one
throttle position. If you’re rolling down
a graded road for miles, you want
to cycle the belt up and down the
sheaves a bit. Basically, throttle up
and down as you are rolling along.
Extended wide open is even worse.
When the clutch finally shifts all the
way out, it loses pressure on the belt,
and that can lead to slipping.
Changes in the most modern
machines, more available knowledge
about belt issues and more educated
drivers are all helping belt life. Follow
the advice from the experts on how
to avoid belt issues. Most of the problems noted occur frequently only in
extreme use or, as in the case with
riding too slow in high range, from
improper riding technique. There is
a reason that the CVT is so common:
it works. If you are having serious
and frequent belt problems, check
that the clutches are working as they
should mechanically. Consider an
extreme-duty belt, and check into
having the clutches fine-tuned for
your riding conditions. Make sure that
the belt deflection is inside the manufacturer’s specifications. Keep belt
cooling in mind, and make sure that
the factory vents are not hampered in
any way. Then, have fun! ❏