Buying guides
How to choose a crawler chassis.
Wheelbase, skid angle, material, transmission — in the order they lock you in.
A chassis is the one upgrade that changes everything else: it sets your wheelbase, your skid clearance, where the motor and battery sit, which transmission you can run, and whether your truck is legal in the comp class you want to enter. It is also the easiest upgrade to buy wrong — a beautiful set of rails that doesn't match your transmission or your wheelbase is wall art. This guide works through the decisions in the order they constrain you, using the chassis actually on sale right now — every one of them is in our Chassis Kits category with a verified price. Prices verified Oct 13, 2026. Or skip the shelf entirely and build your own tube chassis from raw stock — our DIY metal chassis & roll bars guide covers brazing, bending and the full starter kit.
First: do you even need a chassis?
Be honest about the complaint, because a chassis swap fixes a specific list of problems and does nothing for the rest. It fixes: a tall sprung center of gravity that tips the truck over sideways, a flat skid that high-centers on breakovers, front/rear weight bias you can't tune out, a lack of shock and link mounting options, and a truck that's illegal in the comp class you want to run. It does not fix tire grip, weak steering, poor low-speed motor control, or missing low weight at the axles.
The build cases bear this out. Capra owners who documented their fix order got their wins from a stronger servo, low portal weight and a shock mod — the skid and motor were called "not necessary." A SCX10 III case study fixed the truck in two rounds — tires, inserts and weighted wheels, then bumper clearance and a free shock-mount relocation — and never touched the chassis. So: if your complaint is grip, steering or control, spend there first (our first upgrades guide and weight balance guide cover that order). The strongest candidates for a chassis swap are comp entrants whose class demands it, ground-up builders — for whom the chassis is the first decision, because it dictates everything downstream — and trail owners whose specific complaint is breakover, CG height or weight bias.
Start with your wheelbase
Wheelbase is the first filter because links, driveshafts and the body all have to agree with it. The factory 1/10 numbers: SCX10 III at 312mm (the same class of truck is often quoted as 313mm — that difference is rounding, not a different truck), VS4-10 Phoenix at 313mm, the Capra 1.9 UTB at 318mm, the VRD Mullet comp kit at 320mm, and the TRX-4 depending on body — about 312mm for the Sport and early Bronco, 324mm for the Defender and 2021 Bronco. WRCCA Sportsman and Pro classes cap wheelbase at 12.5 inches (317.5mm), measured at any point in the articulation — a long-wheelbase trail truck is not a Sportsman truck no matter what rails it wears.
Two traps live here. First, a chassis swap can change the wheelbase on you: wheelbase is set by link lengths and mount positions, and a skid that moves the lower-link mounts can shorten it noticeably unless you rebuild the links to suit. Second, driveshafts often need to be cut to length after a forward-skid swap. Notice how INJORA's TRX-4 LCG kit ships both 313mm and 324mm link sets — that's the manufacturer admitting the two TRX-4 wheelbases are different builds. Budget links and shafts alongside any rail swap, not just the rails.
Pick your skid angle
The skid is the plate under the transmission, and its angle is the single best shorthand for what a chassis is for. A flat or near-flat skid keeps a truck scale and Class 1-friendly but hangs up on ledges; an angled skid ramps the belly over breakovers instead of high-centering, at the cost of scale looks and body fit. The angles actually on sale tell the story: INJORA's 1/10 kits run 5°, a Powerhobby SCX10 kit 6°, GSPEED's GS-FS 8°, and they climb from there through the comp world — one chassis maker's comparison chart puts flat-skid scale designs around 7° of rake, angled designs at 15°, performance cuts at 19.5° and full proto/comp geometry at 22.5°, with dedicated comp chassis reaching 26°.
Read it as bands: ~5° is trail/scale LCG — lower than stock, still looks like a truck. 8–15° is the Class 2 crossover zone — real breakover gains, body fit gets tight. 19° and up is dedicated comp territory. For a sense of what wheelbase and overhang do to the same numbers, compare two factory TRX-4s: the 312mm Bronco posts a 58.9° breakover angle, the longer 324mm Defender 57.0° — length costs clearance before you change a single part.
Material: carbon vs aluminum vs steel vs titanium
| Material | Character | Where it shows up |
|---|---|---|
| Carbon fiber | The LCG/comp default. Lightest and stiff for its weight — a pair of 3mm carbon comp rails is roughly 68g — but it snaps or delaminates where metal would bend, and it's the priciest rail material. | Most aftermarket LCG kits: INJORA, MEUS, GSPEED, CCW, the VRD Carbon. |
| Aluminum (6061/7075) | Heavier than carbon in the same design, but it bends instead of snapping and machines well — the default for skids, mounts and budget mini rails. | Budget TRX4M/SCX24 rails, skids and mounts everywhere. |
| Steel | The factory trail standard — SCX10 III C-channel, TRX-4 ladder frame, VS4-10 C-channel. Heaviest and stiff, cheap and durable; OEMs pick it for cost and toughness, not for center of gravity. | Stock trail trucks. |
| Titanium | The premium at micro scale, where an INJORA SCX24 titanium kit ($53.99) sits above its carbon equivalent ($34.99). Nobody publishes a 1/10 titanium rail weight comparison, so treat any such claim as marketing. | SCX24/TRX4M kits, links, hardware. |
| G10 / Delrin (POM) | G10 is GSPEED's budget rail material — the same geometry for less money. Delrin/POM isn't structural; it's the slippery plastic skids and sliders are made from because it glides over rock. | Budget rails; skids and sliders. |
The transmission decides your skid
Here is where buyers get burned: the skid's bolt pattern is a transmission choice. The de-facto comp standard is the Axial 3-gear pattern paired with a compact transmission, and a chassis drilled for it will not simply accept a big 2-speed. GSPEED states the GS-FS fits the Axial 3-gear and Dlux narrow transmissions on its 78mm or 67mm skids, while a TGH 2.low needs an adapter plate and wedge shims on the 78mm skid — that's the normal shape of compatibility in this world: pattern first, adapters second. Dlux's portal transmission is the extreme case: 29.5–36.5g, forward motor, and fabrication required on everything except Dlux's own Capra Sporty — and its gearing doesn't suit non-portal axles.
Platform trucks are their own exceptions. The TRX-4's two-speed and locking diffs are platform-specific, which is why INJORA sells its TRX-4 LCG kit separately from the SCX10 kit — it's built around stock TRX-4 running gear. And features like the Capra's dig or the SCX10 III's optional dig live in the transmission, not the chassis; no rail swap adds them.
The servo layout is decided in this same step. A chassis-mounted servo requires a 3-link front plus a panhard bar; a servo on the axle allows a true 4-link front and puts the servo low. INJORA sells one chassis family both ways — the INC-10C with a center transmission for axle-mounted servos, the INC-10F with a front-mounted transmission for CMS — so pick your layout before you pick your chassis, not after.
Weight bias and motor placement
The recurring comp pattern is a forward motor: Element's Stealth XF, Vanquish's VFD and INJORA's INC-10F all put the motor ahead of the skid, because nose weight is what keeps a truck planted on steep climbs instead of looping out. Chassis comparison data quantifies the target by tier: about 60/40 front bias for scale trucks, 65/35 for performance builds, 70/30 for proto/comp. GSPEED's GS-FS shows the geometry version of the same idea — its skid sits 26mm further forward than the V3/V4 it replaces. Whatever chassis you pick, the battery goes low and as far forward as the layout allows; a big pack mounted high undoes everything the rails bought you. Our weight balance guide and overdrive guide go deeper on both halves of this.
Comp legality check
If you might enter an event, the class rules pick your chassis before you do. Under SORRCA's Living Rules (June 2024 revision): every class bans motor-on-axle and requires a single chassis-mounted motor. Class 1 allows a full rail or pan chassis only; Class 2 adds truggy-back; Class 3 adds tube chassis. Class 1 is the strict one — chassis-mounted servo mandatory, no rear steer, no dig, the skid parallel to the rocker panels (which makes angled-skid LCG chassis Class 1-illegal), cab and bed required, bumpers front and rear. Class 2 allows axle- or chassis-mounted servos and a cab-only body but still bans rear steer and dig; Class 3 is the only class with rear steer and dig, and bumpers become optional. Tire ceilings run 4.19" in Class 1, 4.20–4.75" in Class 2 and 4.76–6.0" in Class 3, and pin-pattern comp tires are banned outright.
WRCCA frames it differently: Sportsman — the class a 313mm LCG shaft-driven truck targets — caps wheelbase at 12.5", requires a body that resembles a real truck, one motor, one ESC, one servo, a chassis-mounted motor and at least three links per axle. Pro keeps the 12.5" cap but allows up to two motors (motor-on-axle is legal there). Mini caps wheelbase at 9" with no dig; Super runs 16–18" wheelbases on 3.2"+ wheels; Performance Scale requires the chassis to cover every axle centerline with a chassis-mounted battery tray, tires at 4.8" or under, and no dig or MOA. Local clubs adjust both rulebooks, so treat this as the shape of the rules and confirm with your organizer.
What the tiers really cost
| Tier | What you get | Live examples |
|---|---|---|
| Budget — $16.79–$65.99 | Rails and braces; you solve fitment, links and mounts. Mostly mini/micro kits plus entry 1/10 girders. | INJORA TRX4M 5° kit $16.79 · INJORA SCX30 kit $24.99 · INJORA SCX24 carbon $34.99 · INJORA SCX10 girder $52.99 · INJORA TRX-4 kit with both link sets $65.99 |
| The rails-only trap | A $44.98 set of GSPEED GS-FS rails still needs a skid, spacers, mounts and links — a US comp brand's true entry cost is far above the rail price. | GS-FS rails $44.98 (reg $78.98) → roughly $250 as a rolling chassis |
| Mid — $85–$199.99 | A complete box, sometimes with a transmission included, and fitment the maker has already solved. | INJORA INC-10C $89.99 · INC-10F $99.99 · Dlux La Perra Loca $99.99 · MEUS Gold Rush V2 $139.99 · Dlux Mercenary $140 · Dlux Madhouse $199.99 |
| Premium — $350+ | Bought à la carte or as complete vehicle kits: transmission-specific skids, forward-skid geometry, real support. A Dlux portal transmission alone is $154.99 — premium is a build cost, not a shelf price. | MEUS MB18 Pro $349.99 (TRX4M) · Vanquish VRD Mullet $420.69 · Vanquish VRD Carbon kit $429.99 |
One honesty note on the premium Vanquish entries: most Vanquish "kits" are complete vehicle kits — axles, transmission and chassis together — not chassis-only products. That's why they're priced like trucks. The chassis-only Vanquish item in the category is the VRD S25 carbon rail set at $74.69.
Picks by platform
Everything below is live in the Chassis Kits category right now:
- SCX10 II / III: the budget answer is INJORA's carbon girder at $52.99; the solved-fitment answer is the MEUS Gold Rush V2 at $139.99 with its transmission, or the same chassis bundled with MEUS portal axles at $249.99. Parts pages: SCX10 II · SCX10 III.
- TRX-4: INJORA's dedicated TRX-4 kit at $65.99 (both link sets in the box), or the INC-10F at $99.99 if you want the front-motor CMS layout. Parts page: TRX-4.
- Capra 1.9 UTB: the INC-10C at $89.99 is the first Capra-compatible chassis kit we've carried — it's explicitly Capra-rated and includes the transmission. Parts page: Capra.
- SCX24: INJORA carbon at $34.99, the MEUS MD24 titanium kit at $59.99, or INJORA's Rockover titanium at $69.99. Parts page: SCX24.
- TRX4M: from INJORA's 5° kit at $16.79 through IERC's Merge 18M conversion at $70 to the MEUS MB18 Pro at $349.99 — the widest spread in the category. Parts page: TRX4M.
- Ground-up comp: GSPEED GS-FS rails at $44.98 if you're piecing a build together, Dlux Madhouse at $199.99 for WRCCA Sporty, and the Vanquish VRD kits at the top.
Still deciding between whole trucks rather than chassis? Start with the best 1/10 crawlers guide and the fitment guide.
Chassis FAQ
Will any aftermarket chassis fit my truck?
No — the skid plate's bolt pattern decides which transmission the chassis accepts, and that is the gate most buyers hit. The de-facto comp standard is the Axial 3-gear pattern with a compact transmission. A chassis drilled for that pattern will not simply take a big 2-speed, and platform trucks like the TRX-4 keep their own running gear. Match the chassis to your transmission first, then to your axles and wheelbase.
Should I swap my chassis before tires, weight and a servo?
Almost never. In the documented build cases we researched, the wins came first from tires and inserts, low brass, a stronger servo and even free fixes like relocating the stock shock mounts — a chassis swap fixed none of those trucks' original complaints. A chassis swap pays when your actual problem is a tall center of gravity, a flat skid hanging up on breakovers, bad front/rear weight bias, or a comp class your current chassis is illegal in.
What is the difference between rails only and a full chassis kit?
Rails only is exactly that: two frame rails. The skid, spacers, shock and body mounts, links and sometimes the transmission are all separate purchases, so a $45 set of rails can become a $250 rolling chassis before it turns a wheel. A full kit bundles rails with the skid and hardware — and the mid-priced INJORA INC-10 kits and MEUS Gold Rush V2 even include a transmission. Compare total build cost, never the rail price alone.
Can I run an angled-skid LCG chassis in SORRCA Class 1?
No. Under SORRCA's June 2024 Living Rules, Class 1 requires the skid to sit parallel to the rocker panels, a chassis-mounted servo (axle-mounted servos are banned), a full rail or pan chassis, a cab and bed, and bumpers front and rear. Angled-skid LCG chassis are Class 2 or Class 3 trucks. Local clubs do vary their rules, so check with your event organizer before you build.
Do I want a chassis-mounted servo or a servo on the axle?
Decide before you buy the chassis, because the chassis is built around the answer. A chassis-mounted servo (CMS) needs a 3-link front suspension with a panhard bar — it is the scale-legal layout SORRCA Class 1 requires, at the cost of some panhard bump-steer. A servo on the axle (SOA/AMS) allows a true 4-link front, kills the bump-steer, and puts the servo's weight low and unsprung. INJORA sells the same chassis family both ways — INC-10C for axle-mounted, INC-10F for CMS — for exactly this reason.
A quick note on links
Some links on this page are affiliate links. If you buy through them, the retailer may pay us a commission at no extra cost to you — it keeps the lights on and the deal verification going. Prices were verified Oct 13, 2026; the live deal pages always show the current verified total. RC Crawlers Seek currently tracks 3,545 hand-verified deals.