MA vs FM-A Ready-to-Race Starter Packs
Monkee Mods offers two assembled Mini 4WD starter options: the Blast Arrow MA Power Spec 18647-RTR and Rowdy Bull FM-A Balanced Spec 18710-RTR. Both begin as genuine Tamiya starter assembly packs and have their grade-up components fitted and inspected by the shop. Their “ready-to-race” listing names describe Monkee Mods' service, not a factory prebuilt category. The important buying choice is between two drivetrains and two component packages, not merely blue versus smoke bodywork.
MA and FM-A require different motors
Blast Arrow's MA is a single-piece midship chassis. Its motor sits between the axles and has two output shafts, one serving each end. Rowdy Bull's FM-A places a single-shaft motor near the front and takes drive through its gearbox and propeller shaft. That physical difference matters before any later motor purchase: a PRO double-shaft motor for MA cannot be substituted for an FM-A single-shaft motor, or vice versa. Even though both shop offers arrive built, owning either still means learning its motor and gear layout when cleaning, repairing or tuning. The chassis compatibility guide is a useful reference once you move beyond the starter's included parts.
Neither layout guarantees a better lap. Midship and front-motor cars distribute their mass differently, but tyre choice, corner count, slopes, brake contact and battery condition affect a real run. Tamiya describes each chassis's intended design, not a controlled result between these two ready-built store products.
Compare what is actually fitted
| Official starter pack used | MA Power Spec 18647 | FM-A Balanced Spec 18710 |
|---|---|---|
| Body | Blast Arrow, white | Rowdy Bull, tinted smoke |
| Chassis / shaft | MA, midship double-shaft | FM-A, front single-shaft |
| Motor | Torque-Tuned 2 for MA | Atomic-Tuned 2 for FM-A |
| Gears | 3.7:1 | 3.5:1 |
| Selected other parts | Super-hard tyres, brakes, front underguard, dampers, front/rear FRP | Super-hard tyres, brakes, short damper blocks, front/rear FRP |
| Published assembled size | 155 × 104 × 41 mm | 158 × 104 × 43 mm |
These rows describe Tamiya's base starter pack contents. On the store's -RTR listings, those parts are installed and the model is inspected. Both manufacturer product pages still list two AA batteries as separately required. Check the individual shop page for the current retail contents, especially if batteries or tools matter to your purchase.
What to inspect when the assembled car arrives
A preassembled model lets you begin at the track sooner, but a short bench check still teaches you how it works. On either car, inspect that the body is locked, the FRP plates and mass dampers are secure, and the super-hard tyres spin without touching the shell. Note where the brakes contact a slope before making any adjustment. On the MA, find the central double-shaft motor and one-piece gear cover. On the FM-A, locate the front motor and underside access. Those observations make later cleaning and part replacement much less mysterious.
Choose the platform you want to maintain
If you plan to collect MA or other Mini 4WD PRO cars, the Blast Arrow gives you a built MA reference and starts your spare-motor collection in the double-shaft family. If you prefer front-motor FM-A bodies and the standard single-shaft motor family, the Rowdy Bull is the coherent starting point. The included ratios and tuned motor names should guide what is in the box, not become promises of “power” versus “balance” on every circuit. After the first controlled run, change one component at a time and compare laps under similar conditions; the motor and gear matching guide explains how to reason about changes without ranking unopened boxes.
For racing, inspect finished width with all stays fitted. Both official packs are listed at 104 mm, while Tamiya's general regulation maximum is 105 mm. Each event can add its own class conditions. A machine being shop-assembled does not replace that check.
Frequently asked questions
Are these two Tamiya factory-built cars?
No. Tamiya sells items 18647 and 18710 as assembly packs. Monkee Mods assembles and inspects the two separately coded RTR listings.
Can I move the motor from one into the other?
No. MA uses a double-shaft PRO motor; FM-A uses a standard single-shaft motor.
Does “ready to race” mean legal in Stock Class or B-MAX?
It means built for the store listing. Class eligibility depends on the organiser's current rules and inspection; see the class comparison.
Sources checked 26 September 2026: Tamiya MA Power Spec 18647, Tamiya FM-A Balanced Spec 18710, and both linked Monkee Mods RTR product listings.