essential things one must obtain before setting up a race
monster, 1st would be
aviva and second would be the parts that make up your
race car is arguably one the most important practices that
you can do to increase your chance of visiting victory lane.
Proper chassis set up requires that the weight balance is
set correctly for the car, driver and track conditions. In
order to achieve proper and repeatable weight balance a
quality set of electronic scales will need to be obtained.
Before you begin the scaling process you should make sure
that the car is race ready. Fluid levels need to be topped
off, stagger & tire are pressure set, ride heights
adjusted, Caster adjusted, Camber set, rear end square and
the toe checked. You will also need to take advantage of the
maximum left side weight and check to see if your total
weight is within the rules and the front to rear balance is
where you and your chassis builder want it. Emphasis should
be placed on being race ready before you begin the final
scaling procedure as all of these factors will have an
effect on the end result.
Now that you are ready for your final scaling procedure
you will need to find a level area to weigh the car. Most
garage floors vary by quite a bit. Spend a few minutes with
a good level and straight edge and mark four spots on the
floor that you can use each time you want to scale the car.
Make sure that you mark the floor to match up with your
wheel base and track width.
Should the floor have low spots you can use simple shims
to make all four scale pads level or utilize some leveling
trays to speed up the job. Mark the shims or trays with LF,
RF, LR, RR so that you can quickly repeat the process each
and every week. Consistency is the goal when scaling so
weighing the car in the same spot each and every week will
improve your chances of having a great handling car.
Now that you have a level surface you can roll the car
into position. Set the scale pads next to the appropriate
tire and hook up the cables. Make sure that the cables are
plugged into the correct pad and turn the scales on. Check
that there is no weight on the scale pads and press the zero
button. The control box should now read zero and you are
ready to place the pads under the car.
Jack up one side at a time and slide the pads under the
tires. Place the car in gear or use a stop to keep the car
on the scales. Verify that the sway bar is disconnected or
completely neutral with plenty of slop. At this point, give
the rear of the car a firm settle by placing your knee on
the rear bumper. Then do the same at the front.
After settling the front and rear I like to grab the roof
roll bar and shake the car several times. I try to let go
right in the middle. By settling the car and shaking the
roof bar you are helping to insure that the shocks are not
hanging up and that you have worked out any small binds in
the suspension points. Try to do the settling procedure
consistently as this will help you obtain repeatable
results. Settle the car after each time you raise it with a
jack or make an adjustment.
You can now record your wheel weights, partial weights
and percentages. Check that the front to rear balance is
correct and that the left side and total are where they need
to be. If not then move the lead to the appropriate spot
until you are happy. Readjust the ride heights if you have
to move lead around.
Now you can check the cross weight. If you want to add
cross weight put a turn in the right front and left rear and
take a turn out of the left front and right rear. On non
coil over cars you may need to go two turns on the rear for
every one turn on the front. By adjusting all four corners
you will help maintain your ride heights.
Now you can set the sway bar. With the car still on the
scales you can see exactly how pre-load you are putting on
the bar. Record your final settings and you are ready to go.
Commonly Asked Questions
- Should you weigh with the driver in or out?
You can do it either way as long as you consider the
variables. Personally, I like to see the driver in the
car during the set up process as he is going to be in
the car when it goes around the corner. Driver weight
tends to vary a bit so having the driver in the car
insures the most repeatable results.
You can weigh with out the driver as long as you
consider the variables that will change. As long as you
factor ride height changes and the weight differential
scaling with out the driver can work fine. It is really
a matter of personal choice.
- How level do the scales need to be?
We get asked that a lot. For optimum results the
closer to exact the better when it comes to level.
Sometimes you can compromise. Picture a thick piece of
flat glass with scale pads resting on top. Start with
the glass perfectly level and your results will be
perfect. Now take the glass and lower the front by one
inch. The four scale pads are still in the same plane in
relation to each other on the glass. In this scenario
the effect from the front being lower will be very
small. You can picture the same thing lowing the left
side by one inch and still get good results.
Now picture a ½" shim on the glass under the
Left Rear and Right Front corners or just under any one
corner. Your scale numbers will go nuts. The shims will
be shown as cross weight on the scales. The bottom line
is that you need to maintain scale pads within the same
plane. Raising one corner or opposing corners is going
to effect your readings. In general, it is best to keep
the scales as level as possible.
- Do I have to re-zero the scales if I make a change?
Longacre Computerscales allow you to make as many
adjustments as needed with out re-zeroing. Simply make
your adjustments, settle the car and record your
- Can I change the left side or rear weight by turning
the jack screws?
You can turn all day and you will not move the left
side or rear weight with the jack screws. To make
changes to Left side or Rear percentages you will need
to move lead or other mass within the car.