Mini 4WD Lubrication Basics
Tamiya sells exactly two dedicated Mini 4WD lubricants: F Grease for gears and shafts, and Bearing Lubricant Oil for ball bearings and eyelets. Almost everything else about "lubing a Mini 4WD" is really about using those two products correctly, and knowing where lubricant must never go. The stakes are higher here than on most hobby vehicles: a Mini 4WD has no gearbox casing to contain a mess, minimum race weight is only 90g including battery and motor, and grease reaching the track or a tyre is treated by the official regulations as a rule problem, not just a tuning mistake. This guide covers both products, how to apply each, and what the regulations say about keeping lubricant off the course.
The two official Tamiya lubricants
The two products are not interchangeable, and mixing them up is the single most common lubrication mistake. F Grease is a thick fluoropolymer compound for the sliding, meshing contact of gear teeth and shafts. Bearing Lubricant Oil is a thin, low-viscosity liquid for the free spin of a small ball bearing or metal eyelet, where any real film thickness only adds drag. A third item, the Oil Applicator, is not a lubricant at all — it is a fine brush-tip tool for placing F Grease precisely instead of squeezing it straight from the tube.
| Product | Item # | Contents | Target parts |
|---|---|---|---|
| Mini 4WD F Grease (Fluoropolymer Compound) | 15383 | 3g | Gears and shafts |
| Mini 4WD Bearing Lubricant Oil | 15531 | 5ml, plastic drip nozzle | Ball bearings and eyelets |
| Mini 4WD Oil Applicator | 15465 | Fine brush-tip tool | Precise placement of F Grease on gears, rollers and small parts |
Greasing gears and shafts
F Grease (15383) is a PTFE fluoropolymer compound that Tamiya states stays smooth across a wide temperature range, working whether the car has sat in a warm pit box or a cooler air-conditioned hall. Tamiya lists it as compatible across essentially the whole chassis lineage — Type 3, Type 4, Type 5, Zero, FM, FM-A, Super-1, Super-II, Super FM, Super TZ, Super X, Super XX, Super TZ-X, VS, MS, AR, MA, VZ and ME — so one 3g tube covers a vintage rebuild and a current VZ or MA build alike. Load a small amount onto the Oil Applicator's brush tip and work it into the meshing faces of the gear teeth and along the drive shaft, rather than dabbing it on with a finger or a bead straight from the tube. A thin, even film is the goal; a visible bead means there is too much on it. Check gear wear before regreasing — the gear maintenance guide covers what a worn tooth profile looks like, and regreasing a gear that should have been replaced just hides the problem for another pack.
Oiling bearings and eyelets
Bearing Lubricant Oil (15531) exists because grease is the wrong tool for a ball bearing. Tamiya describes the formulation as balanced specifically to limit leakage while still delivering smooth rotation and reduced wear — a compromise that only makes sense for a thin oil, not a paste. Apply it exactly as directed on the product: drip a small amount onto the metal eyelet or ball bearing through the bottle's built-in nozzle, then spin the part by hand so the oil works its way around the race before you reassemble it. Resist the urge to substitute F Grease here "for extra protection" — a bearing's clearances at Mini 4WD scale are too tight for grease to do useful work, and the added viscosity shows up as drag rather than protection. For guidance on choosing which bearing to fit in the first place, see the bearing and drivetrain efficiency guide.
What never gets lubricated
Two areas are off-limits regardless of which product you are holding. The first is the tyre: the official regulations permit shaping a tyre's tread but explicitly prohibit changing the material properties of the tyre surface, and any lubricant reaching the contact patch does exactly that, on top of destroying grip. If grease or oil strays near a wheel while you work, wipe the tyre before it touches the track. The second is the outer rolling surface of a roller. The bearing inside takes oil like any other bearing, but the surface running against the guide rail should stay clean and dry; anything on it transfers straight onto the course. The roller guide covers roller selection and maintenance in more depth.
Rules: grease must never reach the track
This is not just etiquette — it is written into the official regulations. The current Mini 4WD Race Regulations (R1) list "lubricant/grease application to track surface" directly among the prohibited modifications, targeting treatment of the course itself, distinct from routine lubrication of your own car. The Stock Class regulations (R2) put it more plainly still: "Grease must not be allowed to dirty the course," which covers lubricant flung off a car during a run just as much as anyone applying it deliberately. Keeping F Grease to a thin film and Bearing Lubricant Oil to a single controlled drop is therefore a legality habit as much as a performance one. Organiser rules and on-day technical inspection always make the final call, so check R1 and R2 — and any local class supplement — before race day; see the official rules and technical inspection checklist for what an inspector typically checks.
Re-lubrication checklist
- Wipe dust and dirt off gears and bearings before adding any new lubricant — old, dirt-loaded lubricant should be removed before re-application, not layered over.
- Apply F Grease as a thin film to gear teeth and shafts using the Oil Applicator's brush tip, not straight from the tube.
- Drip Bearing Lubricant Oil sparingly through the bottle's nozzle onto each bearing or eyelet, then spin the part by hand to spread it evenly.
- Wipe any stray lubricant off wheels and tyres immediately — do not wait until after the next run.
- Recheck gears and bearings after each race day; lubricant that has migrated or picked up dust is worse than none at all, per the cleaning and care guide.
- Never apply lubricant to the track itself, and keep excess off the course surface — both are explicit rule violations under R1 and R2.
Frequently asked questions
Can I use grease in a bearing instead of oil?
No. Tamiya's Bearing Lubricant Oil is deliberately a low-viscosity liquid for the free spin of a small ball bearing or eyelet, while F Grease is formulated for the higher-load, slower sliding contact of a gear mesh. Putting grease in a bearing adds measurable drag without any corresponding benefit — the opposite of what lubrication is supposed to do. See the bearing and drivetrain efficiency guide for more on why bearing choice and lubrication go together.
Does applying grease or oil to my own car break any rule?
No — routine lubrication of your own gears and bearings is standard maintenance. The restrictions apply to letting grease reach the track (R1), dirtying the course (R2) and altering tyre surface material (R1); organiser rules and on-day inspection still make the final call.
How often should I re-lubricate?
Tamiya does not publish a fixed interval. The practical signal is dust and migration: check gears and bearings before each race day, and always clean off old, dirt-loaded lubricant before adding fresh F Grease or Bearing Lubricant Oil rather than layering more on top of what is already there.