Tire Selection - Honda CRF450R Owner's Manual

CAUTION:
• Unless you have the required mechanical knowhow,
tools, and an authorized Honda Service Manual,
sprocket changing should be done by your autho-
rized Honda dealer.
Some outdoor tracks may be watered heavily prior to
the first race, then lightly or not at all during the day.
This results in a track that is slippery during the first
few races, changes from good to great then back to
good traction for part of the day, then may end the day
with a slick, rock-hard consistency. Ideally, your gear-
ing should be adjusted to suit all these conditions.
• Wet and slippery or sandy conditions: use less teeth
than the standard sprocket to keep the engine rpm
down, and avoid unwanted wheelspin. The engine
may bog in certain corners so you'll need to slip the
clutch to compensate; downshifting may be too
drastic a change in speed.
• Average conditions: use the standard sprocket.
• Hard (but not slippery) track conditions: use more
teeth than the standard sprocket to keep the engine
rpm high where the engine produces the most
power. This may require an extra upshift on certain
sections or perhaps you can just rev it out a bit
Ionger.
Another example of the benefits of proper gearing
for soil conditions is experienced when riding on a
sand track. Of course, you want to keep the front
end light so the front wheel virtually floats from the
peak of one whoop to another. Generally speaking,
with higher than stock overall gearing it is easier to
maintain that perfect attitude of maximum rear
wheel traction and a light front end because you
remain in the powerband longer in each gear.
If you've ever run too low overall gearing in the sand,
you've noticed that you are tapped-out very quickly
and the front end feels very heavy. You don't want
to be steering the bike with the front wheel much in
soft sand. The taller gearing allows you to steer more
efficiently with throttle control and body English.
Sometimes alternate gearing can help even if track
conditions are consistent throughout the day. If there
are sections of the track on which you must consis-
tently over-rev the engine (rather than losing time
by upshifting), perhaps "taller" gearing (a smaller
driven sprocket) will help.
Whenever you change gearing, have someone check
your lap times (before and after) to get an honest ap-
praisal of the changes. Use a stopwatch for consistency.
"Seat-of-the-pants" feelings can't be trusted since elimi-
nating wheelspin can make you feel like you're going
slower, but in reality you've decreased your lap time
by increasing your speed a little bit in each section of
the track.
But everything is a compromise, so sometimes you'll
have to sacrifice performance on one section of the track
to gain a better overall time. You should shoot for the
lowest lap times and not worry about some sections
where the gearing feels wrong. Of course these recom-
mendations must be tempered against your ability the
actual layout of the track (long, short, hilly, etc.), and
your riding style. But generally, these recommendations
will suit most conditions and most riders.
Whether or not it's worth the effort and time it takes to
swap to gearing that might help you pick off a position
or two at the finish of your next moto is up to you.

9. TIRE SELECTION

Choosing the correct tire tread pattern and rubber
compound can make the difference between finishing
first or somewhere in the pack. The tires your CRF
comes equipped with are a perfect "happy medium"
for the variety of soil conditions the majority of riders
are likely to encounter.
Motocross tire design has developed into an extremely
intense area of study. The descriptions given here offer
CRF riders a very basic knowledge of the factors in-
volved in tire design so the proper tires can be utilized
and the best possible competition result achieved. More
tire information is available in the Maintenance section,
page 10. The most complete information should be
obtained from the various tire manufacturer represen-
tatives and dealers.
• Hard, Slick Terrain requires tires with many relatively
short knobs that are close together in order to ob-
tain the largest possible contact patch on the sur-
face. The rubber compound needs to be softer for
hard ground in order to hook up, but not so soft
that the knobs easily roll over and keep you from
holding your line. These tires tend to wear more
quickly than some because of the combination of
soft rubber and hard terrain.
• Very Tacky Soil or Muddy Courses require a more
open tread pattern to avoid clogging. The rubber
compound for these conditions can be harder to pre-
vent the relatively long knobs from bending back
under acceleration or wearing quickly.
• Loose and Sandy Soil conditions are best handled
with a tire that is similar in construction to those
needed for tacky soil and mud, but with a few more
knobs.
Don't stray from the factory recommended sizes since
this may affect handling and even acceleration.
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