|Welcome to Ultramax Support
at Ultramax Racing Chassis, we put a tremendous amount of effort
into each and every product we put on the market. However, we
realize that it is not enough to give you the highest quality
product that we can produce...
That is why we are dedicated to making sure that you get the
most out of our product through our technical support programs
and online owners manual area offered on this site.
Owners Manual Page 5:
Setting Your Weight Percentages continued...
Nose weight is also proportional to the
amount of bite in a track as well as front-end settings, rather than
driver size. For a track with a lot of bite and speed you can generally
get by with the least amount of nose weight that we recommend, 43.5%.
This is due to the strong influence of the high biting track conditions
on the front end of the kart. On the other end of the spectrum, a
track with a low amount of bite can generally take on a little more
nose weight, 45% or so, due to a lack of track bite to help the kart
turn. In this case, you will generally have to tighten the kart up
a bit to keep the rear end underneath you at the apex of the corner
however, once this is done you will generally have an overall better
handling kart. We are now ready for the always debatable, cross weight
Over the last several years cross
weight has become an increasingly complicated topic that has had many
different cases of debate to go along with it. So for this section,
we will primarily give you a set of constraints that we feel are a
safe range to stay in. This is an area of chassis setup that you will
just have to play with and learn what you and your driver likes for
different situations. For the 2003 Blaze we recommend a minimum of
55% and a maximum of 65% cross weight. Yeah, I know, we really helped
you out there didnt we? This is simply one of those areas that
you are just going to have to work at and see what works best for
you. We have found that generally a track with a lot of bite and high
speed tends to like a lot of cross weight for two reasons: 1) excessively
loading the right front tire making it carry all of the work and thus,
pivoting the kart very quickly in the center of the corner and 2)
relieving the right rear tire from excessive tire temperature and
stress. Given the previous two reasons, it should be obvious to you
that cross weight is very dependent upon other settings in the kart
such as front end geometry (remember, we said that a lot of cross
weight loads the right front tire excessively) left side weight, as
well as and most importantly, driver preference. With this brief explanation
of weight percentages we are now ready to go to the track and tune
on those miscellaneous chassis settings.
7 At the Track Tuning
In this section we will simply discuss
several different chassis tuning techniques such as axle lead and
air pressure. This section is simply designed to familiarize you with
the rest of your 2003 setup options.
Axle lead has become quite a hot setup-tuning
tool over the past several years for all of the top karting manufacturers
and riders. Your chassis is leading the way of top manufacturers by
giving you that same tuning tool. Axle lead is designed to assist
the kart in turning from the apex to corner exit much like a fork
lift turns. Maximum axle lead will generally be ran during those fast
hard biting track conditions where the kart tends to get tight from
the apex to corner exit and becomes very hard to steer under other
karts to make that all important pass getting into the next corner.
Be careful with axle lead, as it will tend to give the driver a sensation
of spinning out on corner exit. This sensation varies depending on
track size and condition but is definitely something that takes a
little getting used to. We recommend running no less than the standard
axle lead of 1/8" for most all track conditions.
Tire pressure is yet another thing that
greatly depends on track conditions and situations. However, for dirt
and pavement we recommend starting with 1psi less air pressure in
the left side tires than the right and working on your own from there.
On dirt, race air pressures can vary anywhere from 5psi to 11psi depending
on the amount of speed and bite in the track. The more bite a dirt
track has, generally the more air pressure you need to run to keep
the kart free. On pavement, we recommend starting around 10psi for
most all track conditions. Going up in air pressure will tighten the
kart along with making it "come in" quicker (which is good
for qualifying) and having the long lasting effect of "locking
down" late in a run. We recommend going no lower than 9psi and
no higher than 13psi for most pavement conditions.
This is a touchy subject that can rarely
be simplified as we are trying to do here. However, We will lastly
try to give you an idea of what to do when you see that dirt track
go through a "face lift" or that pavement temperature go
up or down 25°.
A dirt tire is primarily dependent on two things; spring rate and
rubber thickness, both of which tie into one another. The thinner
the rubber the less natural spring rate a tire has and the more air
pressure you would have to run to get "x" as a desired spring
rate. Likewise, the thicker the rubber on a tire the more natural
spring rate a tire would have requiring you to run less air pressure
to get the desired spring rate "x." Now, we arent
saying that you have to calculate spring rates and rubber thickness
for every track condition; we are simply trying to give you an understanding
of the basis behind the following statements.
The more speed and bite a racetrack has, the more tire temperature
that will be developed which will require you to run a thinner amount
of rubber to dissipate that excessive temperature build up. Running
a thinner amount of rubber will require you to run a little bit more
air pressure to get the necessary spring rate needed for that particular
tire and those particular track conditions. As speed and bite decrease
in a track, tire temperatures become less and less and you need more
and more rubber on a tire to create bite in the tire. Because of the
larger amount of rubber, you need to run a little less air pressure
to get the desired amount of spring rate for those particular conditions.
The more speed and bite that is produced in a track, the harder the
track is on tires requiring a harder tire selection. This can be compared
to sand paper being rubbed on bare skin versus sand paper being rubbed
on wood. The bare skin, like the soft tire, is too soft for the sandpaper
and just gets ripped away while the wood is harder and therefore cannot
be torn up by the sandpaper as bad. In the same way, the harder tire
can resist the harder biting track conditions better than the softer
tire, producing better overall grip.
Pavement tires have all of the same conditions as mentioned above.
However, the one thing that is generally most important on pavement
is a new tire. With this being the case, we dont have near as
much influence over the spring rate of one tire versus another due
to each new tire having roughly the same thickness of rubber as the
other. This is an issue that many tire manufactures has already taken
care of and calculated for while building their tires for pavement
conditions. So, that leaves us with the easier, yet in some financial
ways harder, job of just bolting on a new set of tires and picking
the right air pressures.
For most pavement conditions, either Firestone YGFs or YGHs
will be ran with the F being the softer of the two. The more rubber
that is laid on a racetrack, the less and less abrasive the track
becomes, allowing you to generally run the softer tire. This is likely
opposite of the way you would think it would be. With this being said,
for most pavement conditions we recommend running the YGF with a DAM
Dunlop on the left front and a DAH Dunlop on the left rear.
In closing, we would like to thank you for your purchase of the Ultramax
chassis and hope that you get as much out of it in your racing seasons,
as we have put into it. We hope that in some way this setup tutorial
has helped you become more familiar with your chassis as well as becoming
better acquainted with chassis preparation and analysis in general.
Here at Ultramax Racing Chassis, we try very hard to give you the
very best product and customer support that we can and we look forward
to helping you in any way that we can for the 2003 racing season and
GOOD LUCK from, Ultramax
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