Razorback vs Mach Frame: FM-A Kits Compared
Razorback 18713 and Mach Frame 18714 both emerged from Tamiya's 2018 Mini 4WD Design Contest and both come on the FM-A front-motor chassis. Their bodies could hardly be more different: Razorback draws on wild-boar and hot-rod forms, while Mach Frame breaks a motorcycle-and-jet-inspired shell into separate frame components. They also leave the box with different gears and tyres. That makes this a useful parts comparison as well as a design choice.
Same front-motor foundation, different contest stories
Razorback took the contest's Top Award; Mach Frame took its Merit Award. Those are design-contest distinctions, not racing placements. Tamiya gives both kits 156 mm length and 97 mm width, includes a motor, and calls for two AA batteries separately. Both use the FM-A chassis, whose motor sits near the front and whose underside gives access to the power unit and setup. FM-A takes a standard single-shaft motor, not a double-shaft PRO motor for MA or MS. The FM-A kit guide surveys the wider family; these two items deserve a closer look because their stock running packages differ.
Razorback: boar-inspired shell and 4.2:1 gearing
Tamiya's Razorback body is gunmetal ABS with metallic stickers, shaped around a ridge-like upper profile and hot-rod cues. Under it sits a black FM-A chassis with light-green low-friction A parts. Dark-silver six-spoke wheels wear low-profile tyres. The official product page lists a 4.2:1 gear set and 46 mm completed height. It does not identify the tyre as super-hard, so do not transfer Mach Frame's tyre description to it. For a first run, assemble this exact configuration and note how the shell clears the front skid and stays. That gives you a usable baseline if you later try other compatible FM-A tyres or gears.
Mach Frame: separate pieces and 3.5:1 gearing
Mach Frame uses a main body plus three separate frame elements to create its open mechanical look. Its chassis is metallic grey with black A parts, while white A-spoke wheels carry super-hard low-profile tyres. The official kit-specific gear ratio is 3.5:1 and the published height is 36 mm, ten millimetres below Razorback. Its more complex shell invites careful test fitting: make sure each frame piece is fully seated and remains clear of turning tyres before a track run. Do not read “frame” as a different chassis construction; both models use the same FM-A family beneath the shell.
How to choose and compare fairly
Choose Razorback for its compact hot-rod body, gunmetal colour and 4.2:1 starting ratio. Choose Mach Frame for the multipart body, lower published height, super-hard stock tyres and 3.5:1 gears. A lower numerical gear ratio changes wheel revolutions per motor revolution, but actual acceleration and lap outcome also depend on tyre diameter, grip, motor load, assembly friction and the course. The gear and motor matching guide explains why “3.5 beats 4.2” is not a universal race result. If you later want to compare the bodies themselves, fit equal motors, tyres and gears only after checking correct part compatibility and event rules. Neither award title establishes an on-track winner.
Keep the supplied gears and wheels labelled if you experiment. Because both cars use FM-A, it is tempting to swap parts and then remember the result as a test of Razorback versus Mach Frame. That would be a test of two changed setups. Record the initial tyre, wheel and gear combination for each before making changes, and compare one variable at a time on the same course. Those simple notes are more informative than attributing a run to the silhouette alone.
Frequently asked questions
Are Razorback and Mach Frame just two shells on an identical box setup?
No. They share FM-A, but Razorback lists 4.2:1 gears and generic low-profile tyres, while Mach Frame lists 3.5:1 gears and super-hard low-profile tyres.
Which kit won the 2018 contest?
Razorback received the Top Award; Mach Frame received a Merit Award. These are design honours, not lap rankings.
Can a Mini 4WD PRO motor be used in FM-A?
No. FM-A uses a single-shaft motor; PRO motors are double-shaft for midship PRO chassis.
Sources checked 26 September 2026: Tamiya Razorback 18713 and Tamiya Mach Frame 18714.