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First off... Congratulations on your purchase of the Ultramax
Racing Chassis! And welcome to the Owners & Setup Area of
the Ultramax website.
We'll help you get started off with your chassis the right way.
Even if you are an experienced racer, you should be able to
go even faster! |
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Start Owners Manual
Area:
This setup tutorial
is designed to do just that by familiarizing you
with your Ultramax Chassis and giving you the
necessary information on chassis preparation and
setup analysis that will put you ahead of the
pack for the next racing season. Although this
tutorial Mentions just one of our chassis designs,
the instructions do apply generally to all of
our chassis. In the following pages we are going
to break down the process that we have found to
be most successful in assembling a chassis once
it is received from the factory. We will cover
topics like squaring and alignment, front end
geometry, seat and body mounting, at the track
setup analysis and several other important issues
that are necessary to keep you out front for future
racing seasons and beyond.
1 - Out of the
Box
The first thing that should be done when you receive
your chassis is to make sure that you have received
all of the necessary equipment from the factory.
We try very hard to include everything needed
to put the finishing touches on your chassis once
you receive it but hey, we tend to make mistakes
from time to time just like everyone else. So,
keep us in check and go over this quick check
list to make sure that you have all of the necessary
equipment to make your assembly process a quick
and easy one. The following things should be included
in every chassis purchase:
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•
Left
and right side seat strut along with 4
bolts and nuts for each strut and seat
hook up point.
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Steering
wheel with hub, three bolts, three nuts
and three cotter keys.
•
12
wheel nuts and 6 sprocket hub nuts.
•
Steering
column lock and pin.
Once you have made sure that all of the
necessary components are there, you are
ready to move on to step two which many
consider to be the most important step
in assembling a new chassis.
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2 – Squaring and
Alignment
One of the most important parts of assembly on
a new chassis is making sure your chassis is square
from front to rear and that all of the front end
geometry is set to your desired specifications.
It is very important that a certain process is
followed when setting your front end geometry
and squaring your chassis. If the process is not
followed, your front end may get out of align
with itself and the rear axle giving you poor
scaling consistency and on track performance.
In this section, we will outline this step-by-step
process, breaking down each step for a better
understanding of its roll in your chassis on track
performance.
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Step
1 – Leveling your Chassis
It is a good
idea to level your chassis when setting
your front-end geometry so you can take
accurate measurements when setting up your
front-end. A surface plate used when scaling
a chassis works well in completing this
step.
Simply level your surface plate and leave
the scale plates off. Without wheels or
tires, place the chassis flat on the surface
plate and make sure that it is stable and
level on the plate.
You are now ready to move on to step two.
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Step
2 – Setting Your Pitman Arm
Front-end geometry consists of a series
of angles that set your caster, camber,
king pin inclination and Ackerman. Each
angle must be set correctly and work together
with one another in order for your front
end to work at its optimum level. The first
step in doing this is making sure your pitman
arm is set perpendicular to your level surface
as shown in the picture on the left.
A digital smart level that can be found
in any hardware catalog is a good tool to
have when completing this step. To check
its alignment, simply place the smart level
parallel to the pitman arm on each side
and turn the steering shaft the necessary
direction to get the two angles to equal.
The angle that you are looking for is around
4° - 5° on each side. Once this
is completed, lock your steering lock down
on the steering shaft and place the locking
pin in it. You are now ready for step three.
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Step 3 – Setting
your Caster
Each chassis comes with the right front caster
set at 10° and the left front caster set
at 8°. These settings are obtained when both
sides have the center notches lined up on the
caster blocks as shown with the left front in
the center picture below. For almost all conditions,
these caster settings will be a good starting
point. However, there are certain situations where
a different setting may be desired for a better
weight jacking effect. For this case, both the
right front and left front caster blocks come
equipped with three lines both forward and backward
from the original notch. Each line forward or
backward is a 2° change in caster. Therefore,
on the right front you can go as low as 4°
of caster or as high as 16° of caster. Similarly,
on the left front you can go as low as 2°
of caster or as high as 14° of caster. The
following figures illustrate how this works using
the left front as an example with the picture
on the left set at 6°, the middle at 8°
and the right at 10°.
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Caster
is built into a racing chassis to promote
weight transfer, which is a major factor
in producing the bite necessary to negotiate
each corner on the track. Generally, more
caster will produce more weight transfer
and more bite and less caster will produce
less weight transfer and less bite.
So, on high speed, hard biting racetracks,
less caster will be needed since the racetrack
itself will be producing most of the necessary
bite. Similarly, on low speed, low biting
racetracks, more caster will be needed
in order to produce the necessary amount
of bite in the chassis.
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Running more caster
in the right front than the left front assists
the kart in turning left on corner entry, this
is known as caster split. The more caster split
that is ran, the more the chassis wants to pull
to the left thus, helping the kart turn on corner
entry. In a situation of too much caster split,
the kart will generally turn in very well on corner
entry but pick up a push at the apex of the corner
due to an insufficient amount of weight jacking
by the left front. If there is not enough caster
split in the front end, the driver will have to
apply a lot of input to get the kart to turn getting
into the corner, making the kart feel tight in
the front, or possibly twitchy in the rear, on
corner entry.
A few good rules of thumb on caster for those
who are less experienced with it are as follows:
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2° of caster split is a safe amount of split
for most all conditions. If you are not experienced
with caster or simply don’t like to adjust
it much, this split will be the best overall setting
for you. It is our recommendation that you don’t
exceed 4° of split and never run less than
a 0° split.
• Using the right front as a baseline,
we have found that you will generally not need
to run more than 14° of caster. Most times
if you run more than this you will create too
much weight jacking to quick and will be unable
to keep the kart consistent. Likewise, 6°
of caster is the least amount we recommend running.
Lower settings than this tend to cause a pushing
condition due to a lack of weight jacking.
Naturally, these are simply guidelines to follow.
Every racetrack is different and may require caster
settings outside of the parameters we have outlined
above. However, if you stay within these parameters,
we feel confident that your front-end settings
will be within a safe range and should be sufficient
under most conditions. Now that your Caster is
set, we are ready to move onto step 4.
Go Page Two... or
Go Back to Start
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