Rowdy Bull Kit vs Ready-to-Race Starter
Rowdy Bull buyers can choose the standard 18707 assembly kit or Monkee Mods' 18710-RTR ready-to-race listing. The second car uses Tamiya's item 18710 FM-A Balanced Spec Starter Pack, then the store assembles and inspects it. Tamiya's own 18710 is still an assembly kit. These are not merely two states of an identical Rowdy Bull box: the motors, tyres, tuning parts, body finish and published completed width differ.
What standard Rowdy Bull 18707 includes
Tamiya's ordinary Rowdy Bull places its motor ahead of the battery compartment on the FM-A chassis. It has the muscular bonnet and wide rear fenders that define the model, marking stickers, silver-plated A-spoke wheels and low-profile tyres. The included motor drives 3.5:1 gears. Tamiya's assembled dimensions are 156 × 97 × 43 mm. Four rollers and a front skid feature belong to the chassis configuration. You assemble the kit; two AA batteries are needed separately. This version is sensible if you want the original body finish and prefer to learn the front-motor gearbox before deciding which brake or mass damper to buy.
Front-motor does not mean a special double-shaft motor. FM-A belongs to Tamiya's single-shaft family, with a propeller shaft taking drive to the other axle. If you already own MA or MS cars, don't assume their PRO motors fit. The motor guide separates those two families.
The Balanced Spec pack is a different parts starting point
Tamiya's 18710 starter pack keeps the Rowdy Bull name and FM-A layout but supplies an Atomic-Tuned 2 motor, black super-hard tyres, a brake set, short mass damper blocks and FRP plates for both ends. Its product page also specifies 3.5:1 gears, a wrench and rubber tubing. Unlike some other starter packs, there is no published gear-ratio change to cite against standard 18707: both pages say 3.5:1. The differences that can be stated confidently are the tuned motor, tyre compound and fitted hardware. The 18710 body is tinted smoke ABS rather than the standard kit's finish, and its assembled dimensions are 158 × 104 × 43 mm. The wider measurement is relevant for setup and technical inspection.
Buying the store's 18710-RTR listing means the Balanced Spec grade-up parts are fitted and the model is inspected before shipment. It is not a Tamiya factory assembled line or a guarantee that an event will accept its configuration. Monkee Mods' product page is the authority for its retail assembly service; the Tamiya 18710 page is the authority for the manufacturer's kit contents. Keep those two claims separate when comparing prices or explaining the product to a new racer.
Think through future parts purchases
Because both use FM-A, the chassis label alone does not tell you which parts you still need. An owner of standard 18707 who later wants the Balanced Spec may need to source the Atomic-Tuned motor, tyres, brakes, dampers and FRP plates individually. An owner of 18710-RTR already has those pieces fitted and might instead need consumables or spares. Check mounting instructions and permitted parts for the exact race class before adding a second plate or moving a mass damper. More hardware can also change the completed width from the box figure.
Which Rowdy Bull should you choose?
Pick the standard kit when the building process and original simpler setup matter. You can run it as a baseline, then choose an Atomic-Tuned motor or brake parts later after seeing how it behaves on your track. Pick the RTR listing if you want the smoke-body Balanced Spec with its motor, tyres, dampers, plates and brakes already assembled. Inspect every fastener and wheel before a first run even on a prebuilt car, and provide the two AA cells specified by the manufacturer. A local event may have extra requirements beyond Tamiya's general regulations, so check the race inspection guide and the organiser's latest sheet rather than reading “ready to race” as automatic approval.
Frequently asked questions
Is the starter pack's gear ratio higher than the standard Rowdy Bull?
No published difference appears on these two official product pages: both list 3.5:1 gears. The pack's motor and included tuning parts change.
Does 18710-RTR arrive unassembled like Tamiya item 18710?
No. Monkee Mods' separately coded 18710-RTR is sold assembled and inspected. Tamiya's own 18710 remains an assembly kit.
Can the Balanced Spec be used in every race class?
There is no universal answer. The organiser's current rules and inspection of the finished car decide eligibility.
Sources checked 26 September 2026: Tamiya Rowdy Bull 18707, Tamiya FM-A Balanced Spec 18710, and the linked Monkee Mods 18710-RTR listing.