ME Chassis Tuning Guide
The ME chassis is Tamiya's newest midship platform in the Mini 4WD PRO family, alongside the older MS and MA chassis, as a double-shaft, dual-motor-drive layout rather than the single-shaft, propeller-shaft arrangement of standard rear- or front-motor kits. Because it is the youngest chassis in regular production, most "known-good" tuning shortcuts that circulate for MS and MA have not been fully re-tested on it. This guide works from Tamiya's published dimensions and current race regulations, then lays out a build order that treats ME as its own platform rather than a drop-in replacement.
ME chassis specifications at a glance
Tamiya's chassis and compatible-parts catalog publishes dimensions for low-profile tyres and alkaline batteries as fitted; a different tyre, wheel or battery choice will change these figures. The table below places ME next to the other two PRO double-shaft chassis for context.
| Spec | ME chassis | MS chassis | MA chassis |
|---|---|---|---|
| Length | 156mm | 152mm | 156mm |
| Width | 97mm | 92mm | 97mm |
| Wheelbase | 80mm | 80mm | 80mm |
| Tread (front/rear) | 60mm / 66mm | 67mm / 69mm | ~59.5mm / ~59.5mm |
| Weight (bare chassis) | 117g | 124.7g | 125.9g |
| Ground clearance | 2.5mm | 4mm | 2.2mm |
| Gear ratio (as supplied) | 3.5:1 | 4:1 | varies by kit |
| Motor layout | Midship, double-shaft | Midship, double-shaft | Midship, double-shaft |
| Standard rollers | Six | Not published | Six |
Two things stand out. ME is the lightest of the three by a clear margin, and its stock 3.5:1 ratio sits at the fast end of the gear ladder, beyond MS's stock 4:1. Ground clearance is also tighter than MS, which is worth checking against your track's transitions and bumps before assuming an MS setup will translate directly.
What actually makes ME different to tune around
The clearest structural difference from earlier PRO chassis is that ME's front and rear bumpers are separately molded, user-removable pieces held on with truss screws, rather than parts moulded as one piece with the main frame. That is convenient for swapping bumper types or running a bumperless build, but the mounting screws and surrounding plastic become a wear point that older one-piece-bumper chassis do not have. After a hard wall hit or jump landing, check those screw bosses for stress marks or a bumper that no longer sits flush — a loose or cracked mount shifts front-end geometry in a way that is easy to misdiagnose as a roller or wheel alignment problem.
The six-roller layout and double-shaft PRO motor mean ME follows the same basic tuning grammar as MS and MA: motor and gearing set top speed and acceleration, rollers and stays set cornering line, brakes and dampers set jump and braking behaviour. What is genuinely new is ME's lighter bare-chassis weight combined with its shallower ground clearance, which cuts the margin before the underside contacts track surface irregularities compared with the taller MS.
Building a reliable ME baseline before chasing speed
Because published community data on ME is thinner than on MS or MA, treat the first several packs as data-gathering rather than optimisation. Assemble to the kit instructions exactly, confirm the gearbox turns freely with no binding, and seat the double-shaft motor squarely before adding option parts. Fit stays and bumper hardware without overtightening — the truss screws on the removable bumper strip more easily than a moulded mount would forgive. Run the stock or a first-step Tuned-class PRO motor for the initial sessions, record how the car handles the specific jumps and corners on your track, then start layering changes.
Change one variable per test run: roller height, brake sponge, gear ratio. ME's lighter weight is a genuine asset once the car finishes consistently, but on an unproven platform a hard landing can unsettle it more than a heavier MS build would, so validate braking and mass-damper placement before assuming the weight saving is free. If you're new to roller and stay tuning, the roller setup guide and MS chassis tuning guide cover the same principles on a more established double-shaft platform — borrow method, not settings, from them.
Motors, gearing and race-legal limits
ME is a PRO chassis, and Tamiya's official regulations restrict PRO chassis (ME, MA and MS) to the kit-included motor or motors specifically designated for the PRO line — standard single-shaft Tuned or Dash motors built for rear/front-motor chassis are not the correct part for a double-shaft mount. Pair the motor to your track with the same logic as any other Mini 4WD build: a torque-biased PRO motor and lower gear ratio for technical or hilly layouts, a higher ratio with a faster PRO motor for long straights, re-tested after every change rather than assumed. The motor and gear ratio matching guide covers that pairing logic in more detail.
Chassis modification itself is limited under the official regulations to cutting away plastic material or cutting holes in the stock chassis — adding material, fabricating a homemade chassis, or using non-Tamiya Mini 4WD/R/C Mini 4WD/Dangun Racer parts is not permitted, and the original part shape must stay identifiable after any cutting. Stock Class tightens this further: no cutting or shaving of the chassis at all, no new screw holes (existing holes may only be countersunk), and a "forbidden zone" between the front and rear axles where only the body and driver figure may be mounted. None of this is ME-specific, but a new bumper or stay bought for ME should still be checked against whichever class you're entering.
Frequently asked questions
Can I fit MS or MA option parts onto an ME chassis?
Some FRP and carbon stays are cut to fit a specific chassis outline, so fitment is not automatic even between chassis with similar overall dimensions. Check the part's listed compatibility and the ME kit's instruction sheet before assuming a stay, bumper or roller set designed for MS or MA will bolt straight on.
Is ME's lighter weight always an advantage?
Not automatically. A lighter chassis needs its braking and damper setup validated separately — the same jump or braking zone that an MS build absorbs at 124.7g can unsettle a 117g ME build differently. Confirm the car lands and brakes predictably before treating the weight saving as a straight speed gain.
What motors is ME legal to run in official events?
As a PRO chassis, ME is restricted to the kit-supplied motor or PRO-series designated motors under Tamiya's official regulations — not the standard single-shaft Tuned/Dash range built for rear- or front-motor chassis. Regulations can change, so verify the current official rules and, for Stock Class entries, the Stock Class restrictions before an event; on-day technical inspection has final say.