It ran on dust or sand and now something is gritty, noisy or dragging
Dry grit grinds rather than corrodes, so the damage is mechanical and the obvious first move makes it worse. How to spot it and what is still saveable.
It ran on dust, sand or dry dirt, and now something is gritty, noisy or dragging.
Dry grit does not corrode anything — it grinds. That means the damage is mechanical, it is usually already done by the time you can feel it, and the obvious first move makes it worse.
> ⚠️ Do not wash it first. Water turns dry dust into a grinding paste and carries it straight past the bearing shields. Blow it out dry before any water touches it.
How to tell that is what happened
- A wheel spins rough or short compared to the one opposite it at the same end. Compare sides — the difference is the finding, not the feel on its own.
- A whine that rises with road speed, which usually means grit has changed the gear mesh.
- A shock has started weeping after the session. Grit sitting on the shaft cuts the seal on the next compression.
- The diff oil feels gritty rather than milky — that is dust, not water.
- The motor runs hotter than usual, because dust packed around it stops it shedding heat.
What to do about it now
Spin-test all four wheels with the motor disconnected and compare left against right at each end. Gritty is cleanable; notchy — catching at the same point every turn — means the races are already carved and it needs replacing.
After sand specifically, do not rely on the spin test. Sand is harder and more angular than ordinary dust and it does not announce itself early. Pull and clean regardless of how it feels.
Stopping it next time
Full procedure, in order: after a dry, dusty or sandy run.
If you run dust or sand regularly, sealed (rubber) bearings rather than shielded are the single biggest improvement available. The small extra drag is nothing next to contamination.
> Came home wet or muddy instead? That is the other job — see wet runs.
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Add what you know. Run a beach, a desert, a dusty track? Know which bearings on a particular chassis go first, or a body that actually keeps grit out? Add it — this page is meant to grow.
Source: https://rctechtips.com/rc-cars/how-to-clean-your-rc-car/; https://amazingcarsanddrives.com/how-to-clean-rc-car/ + RC Crash Crew knowledge base