Wheel balancing is
important every time tires are mounted on wheels. This eliminate
wheel & tire vibration problems. Wheel balance is controlled by
the minimum radial and lateral run-out of the wheel rim, combined with a
tire and tube assembly, mounted true on the rim and checked after fitting.
Wheel balancing provides a smoother ride by
minimizing tire bounce. This helps improve traction, steering control and
extends the life of the tires. But no matter how carefully wheels and
tires are balanced, they will eventually lose their balance. As the tread
wears, the distribution of weight around the circumference of a tire
changes altering the balance of the tire and wheel assembly. Eventually
the tire may have to be rebalanced because only 1/4 ounce of imbalance can
produce a noticeable vibration.
Problems with out-of-balance wheels
Out of balance wheels are a common cause of uneven
tread wear. The whole wheel unit - tire, rim and drum or disc - must
be in balance, both statically and dynamically for best performance
Dynamic unbalance can only be detected when
the wheel assembly is rotating. Static unbalance maybe detected when
the assembly is rotating and/or stationary.
Static unbalance is usually felt as a
vertical shake or fast vibration at speeds over 70km/hr. The whole
vehicle or parts of its structure can be affected. Commons causes of
static unbalance are heavy or light tread joins, or a flat spot worn by
locked wheel skidding.
With static unbalance the 'heavy' spot will cause a
freely-mounted wheel and tyre assembly to rotate so that the heavy spot
stops at the lowest position. When an assembly with static
out-of-balance rotates on a vehicle it tries to make the vehicle axle move
up and down in time with the heavy spot. A static unbalance is
simply corrected by placing correction weights on the rim flange
diametrically opposite the heavy spot.
Static Unbalance is usually felt as a vertical shake
or fast vibration at speeds over 70 km/h. The whole vehicle or parts
of its structure can be affected. Common causes of static unbalance
are heavy or light tread joins, or a flat spot worn by locked wheel