|
















 |
Unless you also race in some
high-end track events, or you have a friend who does, you’re unlikely to
have
a set of levelling pads and electronic scales. Perhaps you’ve tried the
four short planks and four bathroom scales approach, with varying results?
Fear not! The following method of balancing a buggy is so simple even I can
do it, and it’s really quite accurate.
All you need to do the job are
some lengths of RHS steel, a bit of steel angle, a couple of boards, and a builder’s
level.
Weld the steel balance frame
together as in Drawing 96, and tack weld the piece of angle in place. Take
care not to get too much heat into the centre of the frame, which could
cause the frame to bow. Make up the wheel cradles too. Select a few boards
just longer than the buggy’s track. Spend a few minutes and find a level
area on the floor to represent the wheelbase, and track of the buggy.
Lay a board on the floor, and stack a few on top, to the same overall
height as the balance frame you’ve made.
Before you begin the balancing process you should make sure that the buggy
is race-ready; fluid levels need to be topped up, tyre pressures checked,
ride height adjusted, caster and camber set, and the toe checked.
Last, but not least, the fully kitted driver will also
need to be in the driving seat.
Grab your “C” spanners, and slack off the locking rings on the shocks’
spring seats. While you’re at it, give the shock threads a light spray of
WD40, so the spring seats will turn nice and easily.
Jack the rear of the buggy up,
and slide the stack of boards under the rear tyres. Check the top board is
absolutely level, and shim if necessary.
Now jack the front of the buggy up, and slide the balancing frame under the
front tyres. Drop a plumb line from the centre mark on the front of the
buggy, to ensure it’s sitting centrally on the frame. Very gently, bounce
the front of the buggy a few times, to insure that there is no suspension
bind, and the shocks are not hanging up. Try to do the settling procedure
consistently as this will help you obtain repeatable results. From this
point on, avoid disturbing the buggy; no sitting on it, or leaning up
against it, otherwise you could possibly get false readings.
It’s more than likely that the
wheel weights are all different. It’s of no concern if both axles don’t
weigh the same, but it’s important to try and achieve equal weights on the
same axle.
When adjusting the wheel weights, it’s important not to lose sight of the
ride height. It’s very easy to wind the spring perches down so the wheel
weights are equal, but in the process, the ride height may be increased.
The balance frame will tip down
on the side of the heavier of the two front wheels.
If you raise the ride height at
one corner, the weight on that corner will increase, as will the
weight on the diagonally opposite corner. The weight on
the other two corners will be reduced.
The idea is to adjust
the spring seats until the balance frame is level. Start with the
lightest of
the four wheels, and screw the spring seat down, thereby
preloading the spring and increasing the pressure
on the wheel. Check the top edge of the balance frame with the builder’s level
frequently. Make only very small changes at a time, as
any changes will affect the other wheel weights.
Every so often, check the ride
height, and if it’s rising, raise the spring seat of the heaviest
wheel to compensate for screwing down the lighter one. Keep adjusting the
spring seats until the balance frame is dead level. Do not tighten the
locking rings yet!
Repeat the whole process
on the
rear end, and then check the front again one last time. When you’re
satisfied with the results, tighten all the locking rings against their
spring seats.
Note: The
buggy will need to be balanced again after any alterations or repairs are
made to the suspension.
|
|