The car drifts right, so you add left trim. After the next run, you need more. Eventually the transmitter adjustment is near its limit and the steering no longer feels balanced.
Trim can make a small correction, but repeated large adjustments deserve an inspection. A bent linkage, loose component or incorrectly centred servo can hide behind what initially looks like a radio setting.
Start with the power safely disconnected
Follow the model’s safety instructions, disconnect the drive battery for mechanical inspection and support the vehicle securely. Check for obvious damage, binding, loose hardware and unequal wheel alignment. Keep fingers clear of moving parts and do not force a servo through its travel.
Traxxas’s steering-trim guide explains adjustment and the need to address centring when a large correction is required. Its procedure is for the relevant equipment; use the manual for your own radio, servo and vehicle.
Distinguish centring from alignment
The transmitter’s neutral setting, the servo’s centre position, the horn’s installation and the linkage geometry are related but separate. Changing a turnbuckle to compensate for every other issue can create a setup that looks straight at rest but behaves poorly through its travel.
Record the existing settings before making changes. If you recently replaced a servo or repaired crash damage, return to that installation’s instructions rather than assuming the previous trim value still applies.
Use controlled checks
Any powered centring or endpoint procedure should follow the manufacturer’s directions, with the vehicle safely supported and the drive system managed as instructed. Do not improvise a live test on a crowded workbench or in a public path.
After the mechanical setup is correct, use a suitable open area for a low-speed check. Surface slope, tyres and suspension can also affect tracking. Repeat in a way that distinguishes a consistent vehicle issue from the particular patch of ground.
Stop chasing the symptom
If the steering binds, behaves unpredictably or requires continued extreme correction, stop running and seek competent help. Replacing parts at random can cost more than identifying the source.
A short setup record—what changed, neutral settings and the result—makes the next repair easier. The goal is not a trim knob permanently fighting the chassis. It is a mechanically sound car that needs only the adjustment its design expects.