Assembly, fitting and cutting guide.
This is a mounting platform that sits between an SCX30-class chassis and a body you supply or build yourself — a plastic model kit body, a paper body you fold, a sculpt, or a structure you build on top.
It is not a body. It's the bridge between the chassis and whatever you put on it.
Fits: Axial SCX30 — 1/30 scale, 99 mm wheelbase, 161 mm long, 77 mm wide.
This is a hands-on build project. Cutting, fitting and gluing are the activity, not a defect. If you want something that clips on and is finished, this isn't it.
Most 1/25 kit bodies will not fit. Not "some" — most. Kits sold at the same nominal scale vary enormously in length, width and interior volume, and a scale number on a box is a class label rather than a measurement. Assume a given kit won't work until you've measured it or seen it in the tested list below.
And essentially every kit body needs its wheel arches opened up. Crawler tyres are far larger in proportion than the wheels a static display model was drawn around, so the arches will foul them. Plan for this on every build — it's the normal first job, not a sign something went wrong.
Check the numbers below rather than trusting a scale label.
Kit boxes are sealed, so you can't measure the body in the shop. You can still get a useful answer from a spec sheet, because the one number that predicts whether the arches will line up is the wheelbase.
real car's wheelbase in mm ÷ kit scale ≈ 99 mm
99 mm is the chassis's wheelbase. The closer the kit lands to it, the better your wheels sit in the arches. Here's how that played out on cars we've actually built:
| Body | Real WB | Scale | Works out to | Off by | Result |
|---|---|---|---|---|---|
| Suzuki Jimny | 2250 mm | 1/24 | 94 mm | −5 | arches line up well |
| 1940 Willys pickup | 2642 mm (104″) | 1/25 | 106 mm | +7 | worked |
| 1967 Mustang | 2743 mm (108″) | 1/25 | 110 mm | +11 | visibly wrong |
Rule of thumb: within about ±7 mm and you can make it look right. 10 mm or more and the arches will sit ahead of and behind the wheels no matter what you do — that gap can't be sanded out.
Hunt small cars. Japanese, European and pre-war American designs have short wheelbases. Post-war American cars mostly don't fit — the Mustang above is a fairly typical example, not an unlucky one.
Note the Willys is a truck and still worked: it's a 104″ pre-war car, so it's short despite the body style. Being a truck doesn't help or hurt; being short does.
Scale is a smaller lever than the car itself. The same Willys at 1/24 would come out at 110 mm and fail like the Mustang — so 1/25 helped, but only by about 4 mm. Choose the car first, the scale second.
Asking an AI assistant for a car's wheelbase is a fast way to run this check while standing in a shop. Two cautions:
This test only predicts one thing. Wheelbase tells you about arch alignment. It says nothing about rear deck height, body width, or a pointed nose — and any of those can still rule a kit out. Use it to reject bad candidates cheaply, not to confirm good ones.
Forget measuring our parts — what matters is the chassis envelope: the hardware your body has to swallow. Three numbers cover it.
| Number | What it is | What it decides |
|---|---|---|
| 99 mm | Wheelbase, axle to axle | Whether the arches line up with the wheels. The only one you can check before buying — see the wheelbase test above. |
| ~67 mm | Across the wheels, outer wall to outer wall | Whether the wheels sit inside the body line or stand proud of it. A body much wider than this swallows the wheels and looks wrong. |
| ~132 mm | Front of the front light housing to the outer face of the rear light housing | Whether the tail clears. A body shorter than this runs into the rear light housings and needs cutting back there. |
Measured with calipers, rounded for use. Treat them as minimums with a little margin rather than exact targets — if your body is within a millimetre of any of these, assume it needs work.
Only kits physically built are listed. Nothing here is predicted.
| Kit | Fit | Notes |
|---|---|---|
| AMT 1940 Willys Pickup, 1/25 | Fits — with work | Front and cabin are straightforward. The tail is the hard part: the chassis's rear light housings force it, and the moulded rear profiles and the bed floor both had to be cut away to clear them. Plan on real surgery back there. |
| MGB, 1/24 TBD — maker | Fits | Built on the short shell. Notably needed no rear cutting — it sits slightly high on the frame, which puts the rear light housings just under the boot instead of into it. Wheel arches still had to be opened. |
| 1967 Ford Mustang, 1/25 TBD — maker | Fits — but looks poor | Honest verdict: it goes on, and we wouldn't build it again. The kit's wheelbase is longer than 99 mm, so the arches never line up with the wheels, and the body ends up riding about a tyre-radius high. It needed no rear cutting — but only because it sits so tall that the light housings pass underneath. |
| TBD | TBD | TBD |
Not listed doesn't mean it won't fit — it means we haven't tried it. Use the measurements above.
The bodies below are simply set on the chassis — nothing cut, nothing mounted, no arches opened. That's the raw starting point, and it's the fastest way to see whether a kit is worth the effort. All four are photographed the same way so you can compare them directly.
Look at two things first: where the wheels sit inside the arches, and how far the body floats above the tyres.
Then check two more that a side-on photo won't show you:
No verdicts on the unbuilt ones. Three of the four above haven't been cut or mounted, so we're not claiming they work — only showing the starting point. A promising drop-on is where the work begins, not proof it will succeed.
Kits are listed by body, not by livery. The same tooling gets reboxed with different graphics and licensing — the plastic underneath is identical, so any boxing of the same kit fits the same way. Buy whichever version you like the look of.
Brand names appear here only to identify kits. Not affiliated with, sponsored by, or endorsed by any kit manufacturer.
| Version | Contains |
|---|---|
| Spine rail | Centre rail · front socket plank + registration keys · rear hook · front arms + spares · pins |
| Shell (long) | Long shell (front socket plank integrated) · rear hook · front arms + spares · pins |
| Platform kit | Everything in Spine rail · long shell · pre-cut short shell |
| Advanced kit | Everything in Platform kit · fully enclosed platform |
TBD — exact spare counts per version.
Everything ships unglued. That's deliberate — where you glue the rear hook is a decision only you can make, and it's permanent. See below.
| Tool | For |
|---|---|
| Rotary tool with a sanding drum | Opening wheel arches. If you're fitting a kit body, treat this as required — see below |
| Razor saw / fine-tooth hobby saw | Cutting the shell |
| Flush cutters | Trimming small parts |
| Hobby knife | Cleanup |
| CA or E6000 / contact cement | Gluing — see below, the wrong glue won't hold |
Saw — don't snap. The shell is 3D printed, and printed plastic splits along its layer lines. A scored-and-snapped cut will crack somewhere you didn't intend.
Cut slowly with a sharp saw. A worn or coarse blade will grab and break the part. If you don't own a razor saw, use the pre-cut short shell instead — that's exactly why it exists.
Model cement will not work. Plastic kit bodies are polystyrene, and modellers' styrene cement bonds styrene to styrene — it does nothing to the PLA our parts are printed in.
Use CA (superglue) or E6000 / contact cement. Scuff both mating faces first; glue grips a scratched surface far better than a smooth printed one.
Keep CA away from the arm flex zones. CA wicks. If it runs into the flexible section of a front arm it makes the plastic brittle, and the arm will snap later under a load it should have survived. Apply sparingly, and keep it off TBD — name the exact zone.
Three lengths, one interface. All of them use the same front arms and rear hook.
Each of the builds below is a real one, on the version named.
Fendered vintage bodies, narrow hoods, scratch-builds — anything where you want as little as possible imposed on the body. It needs only a slot around the front plank rather than having to swallow a whole frame.
Shorter bodies. Comes pre-cut, so no tools needed.
Full-size bodies. Can be cut down yourself if you have the saw.
For building something on top rather than fitting a body over. It closes the deck and seals the electronics underneath.
Cutting is one-way. Cutting a long shell gives you a short one — but then you no longer have a long one. If you want both sizes, you need both shells.
TBD — arms plug into the socket plank holes. Needs: orientation, whether glue is required, how to tell they're correctly seated.
Read this before gluing anything. This decision is permanent.
The rear hook can be glued in two positions, and the position determines what your shell can become:
| Position | Result |
|---|---|
| Back | Full-length shell. The rear section stays. |
| Tail (forward) | The wide rear section can be cut away later, converting the shell to short. |
If you're not sure which you want, glue at the tail position — it keeps both options open. TBD — verify there's no downside to the tail position on a full-length build.
TBD — DIAGRAM. Annotated photo of the shell showing both hook positions AND both cut zones. Probably the single most-needed image on this page.
TBD — how the assembly attaches. Pins? Which chassis mounting points? Anything to remove first?
Only if you're shortening a long shell. Skip this if you have the pre-cut short one.
The shell has fine scribed lines moulded into it marking where to cut. You don't need to measure — the lines are the guide. They are cut guides, not score-and-snap lines. See the saw warning above.
Spare shells are available TBD — link. It happens; it's a cheap part and not a disaster.
Expect to cut the body. On most kits the interior has locating pins, floor pans and detail moulding that has to come out before the body will drop over the frame.
On most kit bodies this is the longest job — though not all of them need it. The chassis's rear light housings cause two separate problems:
On the Willys that meant losing the moulded rear profiles and the bed floor entirely.
The rear cut is the price of sitting low. Both bodies that needed no rear surgery avoided it the same way — by sitting high enough for the housings to pass underneath. The MGB sits slightly high and gets away with it. The Mustang sits far too high, which is exactly why it looks wrong.
So "no cutting needed" is not automatically good news. If a body clears the housings without work, check why — it may be telling you it's riding too tall.
Do this before anything else. There's no point opening arches or trimming an interior on a body that turns out to sit 5 mm too high at the back.
TBD — photo: the rear light housings on a bare chassis, and a body cut back to clear them. This is the single most consequential fitting problem and there's no picture of it.
The front socket plank has to sit high enough to do its job, and on most bodies the underside of the hood is in the way. If you don't clear it, the body can't drop far enough and you're back to the floating-too-high look.
The fix is to cut through the hood where the plank lands. On the Willys that meant two holes in the hood — after which the body finally sat low enough to look right.
This is the one place where our part is the obstruction, not the chassis. And you can't avoid it by picking a different version — the spine rail has a front plank too. It's narrower, so it needs a smaller opening, but it still needs one.
A low, pointed nose is the hard case. Where the hood tapers to a narrow point, even the rail's slimmer plank can be wider than the space available. If that's your body, check this first — it can be the thing that rules a kit out entirely.
Style the cut rather than hiding it. Holes in a hood are what bonnet vents, scoops and louvres look like anyway. A cut you shaped deliberately reads as a design choice; a ragged one reads as damage. Same hole, different impression.
TBD — photo: the Willys hood from underneath, showing the two relief holes and the plank sitting through them.
This is the job you will do on essentially every kit body, so it's worth having the right tool before you start. Crawler tyres are much larger relative to the body than the wheels the kit was designed around, so the arches have to be cut back until the tyre clears at full suspension travel.
Use a rotary tool with a sanding drum. The drum's diameter roughly matches the curve you're cutting, so it follows the arch naturally instead of fighting it — you sweep along the opening and the shape stays smooth. A knife leaves facets and chatter, and files are slow and hard to keep symmetrical.
Take material off in passes and offer the wheel up repeatedly. You can always remove more; you can't put styrene back.
TBD — photo: an arch mid-way through being opened, and the drum bit itself. This is the single most-repeated task in the whole build and there's no picture of it.
Paper is a good material here: near-zero weight, no glue chemistry problems, and you can make a new one next weekend.
TBD — attachment method. Double-sided tape? Velcro? Tabs?
The enclosed platform closes the top and seals your electronics underneath, giving you a flat deck to build on. What you build is entirely up to you — glue a base plate on and it's a brick platform; glue something else on and it's something else.
Keep your build low. The chassis is small and weight up high tips it nose-down and hurts how it drives. Building bricks in particular are heavier than they look.
The deck isn't a brick-standard width — the chassis is 77 mm wide, which doesn't divide into brick units — so a base plate will fit but you won't get symmetric walls on both sides without an extra step. TBD — describe the extra step, or drop this if it's more confusing than useful.
| Part | Why you'd need one |
|---|---|
| Front arms | The designed-to-fail part. Cheap, and meant to be replaced rather than the whole assembly. |
| Shell | If a cut goes wrong |
TBD — links