Traxxas 4902, Owner'S Manual

T-MAXX 2.5R

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35

Tuning Adjustments

Suspension Tuning

Adjusting the Pivot Ball Caps

The pivot ball caps should be adjusted 
so that the pivot balls operate freely in the
axle carriers with no excess play. Use the
provided four-way suspension multi-tool
to tighten or loosen the pivot ball cap.

Caster Adjustment

The T-Maxx 2.5R offers the ability to adjust the caster angle of the front

suspension. Caster adjustment may be used to influence the understeer/
oversteer handling characteristics of the T-Maxx 2.5R. Increasing the caster
angle will increase the tendency of the truck to oversteer (less traction on
the rear tires, more traction on the front tires), while decreasing the caster
angle will cause the truck to have a tendency to understeer (push in the
turns). This effect becomes more pronounced at higher steering angles and
higher spring rates. Caster is adjusted by repositioning the shims on the
pivot point of the upper suspension arms.

The stock caster setting is 7-degrees with one shim at each end of the arm.

Reduce the caster angle to 4-degrees by removing the rear shim and
inserting it next to the front shim. The caster angle can be increased to 10-
degrees by removing the front shim and inserting it next to the rear shim.

Fine Tuning the Shocks

The eight  shocks  (oil dampers) on your T-Maxx 2.5R have tremendous
influence on its handling. Whenever you rebuild your shocks, or make any
changes to the pistons, springs or oil, always do it carefully and in sets (front
or rear). Piston head selection depends on the range of oil viscosities that
you have available. For example, using a two-hole piston with lightweight oil
will give you the same damping as a three-hole piston with heavier oil. 

We recommend using two-hole pistons with a
range of oil viscosities from 10W to 40W
(available from your hobby shop). The thinner
viscosity oils (30W or less) flow with less
resistance and provide less damping, while
thicker oils provide more dampening. Use only
100% pure silicone shock oil to prolong seal life.
From the factory, the T-Maxx 2.5R uses 30W oil. 

The ride height for the T-Maxx 2.5R can be
adjusted by adding or removing the clip-on
spring pre-load spacers. Note that changes in ride
height will occur when changes in shock angle or
spring rates are made. You can compensate for
ride height changes by changing the pre-load
spacers on the shocks

Shock Mounting Positions

Big bumps and rough terrain require a softer suspension with the

maximum possible suspension travel and ride height.  Racing on a
prepared track or on-road use requires a lower ride height and firmer, more
progressive suspension settings. The more progressive suspension settings
help reduce body roll (increased roll stiffness), dive during braking, and
squat during acceleration. 

Upper shock mounting position (A)

should generally be used with lower
shock mounting positions 1 and 2.
Upper shock mounting position (B)
should be generally be used with
lower shock mounting positions 3
and 4. The innermost upper shock
mounting position (0) can be used
for tuning with the inner pair of
lower shock mounting positions on
the arm (1,2). It is not compatible
with lower shock mounting positions
3 and 4. Other combinations may be
used to achieve individualized
suspension settings.

Caster adjustment shims (1 Front, 1 Rear)

Caster adjustment shims (2 Front)

Caster adjustment shims (2 Rear)

Vertical

4

Ground plane

7

Vertical

Ground plane

Vertical

Ground plane

10

For easier access to the

rear-most shock mounting
screw, remove the one end
of the rear turnbuckle. In
the front, remove the
suspension pin from the
lower front suspension arm
to gain easier access to the
lower shock mounting
screws.