Buying guides
Traxxas TRX4M upgrades.
The right mods, in the right order, at verified prices.
The TRX4M is the 1/18 truck that pulled a huge crowd into small-scale crawling — a proper ladder-frame chassis, portal-style gearing in the axles, and a price that undercuts most of the hobby (the truck itself is $179.95 at AMain). It is also a platform that rewards smart TRX4M upgrades more than almost any other: the stock truck is good, but it leaves obvious performance on the table, and the aftermarket is enormous. Our catalog alone tracks 129 TRX4M-specific listings. The trick is the order. Buy in the sequence below and every dollar makes the truck measurably better; buy in the wrong order and you get a powerful truck that still can't climb.
Why the upgrade order matters
Grip before everything
A crawler can only use the power, gearing, and steering it can put into the ground. Until the tires hook up, nothing else you buy can show its worth — so traction is stage one, always.
Steering second, because grip loads it
Sticky tires and added weight ask far more of the steering servo than the stock setup ever does. Upgrading the servo right after tires prevents the most common TRX4M failure: a steering servo that fades or strips once the truck starts working harder.
Weight low, never high
The TRX4M carries its body and chassis relatively high for its size. Brass at the axles pulls the center of gravity down where it helps; weight on the body or chassis rails does the opposite. Every gram in stage three sits at or below axle height.
Power last of the big four
The stock motor is adequate on stock tires. Once grip, steering, and stability are sorted, a motor or brushless swap becomes a genuine upgrade instead of an expensive way to spin better tires.
Stage 1: tires and beadlock wheels
The single biggest transformation — and the cheapest stage on the list.
The stock tires are a compromise tread meant to look scale and survive the box. On real rock they skate where a soft compound bites. Swapping to a sticky 1.0-inch tire is a ten-minute job, and mounting it on a true beadlock wheel means the bead is clamped mechanically — no glue, no tires peeling off at full lock.
INJORA 1.0-inch All Terrain Tires (set of 4) — $14.39
62x22mm super-soft, sticky all-terrain tires in INJORA's S5 compound, sold as a full set of four. Down from a $15.99 list at HeliDirect — the cheapest meaningful grip upgrade on this page.
JConcepts Landmines 57mm, pre-mounted — $14.99 per pair
A name-brand comp-style tread, pre-mounted and ready to bolt on. Sold in pairs, so budget for two pairs to do the whole truck — still the pick if you want a proven competition tread pattern.
MEUS Racing 1.0-inch Beadlock Wheels — $25.99
Aluminum beadlocks with a brass inner ring and -3.25mm offset, 7mm hex, no glue needed. The brass ring starts your low-weight program at the same time as the beadlock secures the new tires — two upgrades in one part.
Every verified tire option lives on our crawler tires page, and the full parts bin is on the TRX4M parts page.
Stage 2: a steering servo that can keep up
Grip exposes the stock servo. Fix it before it fails on the trail.
The stock steering servo is sized for stock tires on a stock-weight truck. Add sticky rubber and brass, and it starts to fade on climbs, stall against rocks, and eventually strip. The TRX4M's servo bay takes micro servos in the Traxxas 2065 size class, and the aftermarket bench is deep — pick by torque and budget.
MEUS Racing M3280S 8KG Micro Servo — $15.99
The budget fix: 8kg-cm of metal-gear torque on a 25T spline, with a horn set in the box. Fits the TRX4M along with the SCX24 and Ascent-18, so it can move trucks with you later.
INJORA INJS2065 7KG Waterproof Servo + Mount — $29.99
The sensible default: 7kg-cm, IP66 waterproofing, and the correct mount included, so it drops into the stock location without improvisation. Everything most TRX4M builds will ever ask of a servo.
INJORA INJS2065 PRO 9KG Servo + Mount & Horn — $34.99
The go-to steering upgrade for built TRX4Ms: 9kg-cm of waterproof digital torque, with mount and horn included. The extra five dollars over the 7KG buys headroom for heavier brass builds and bigger tires.
INJORA INJS11 11KG Coreless Micro Servo — $49.99
The premium option: an 11kg-cm coreless motor in a waterproof aluminum case. Overkill for a stock-weight truck, exactly right for a heavy brass build that gets driven hard.
Compare the whole field on our crawler servos page — and set your steering endpoints after the swap, so the new servo isn't driving into the stops all day.
Stage 3: brass weight, down low
Stability you can feel on the first sidehill.
With grip and steering sorted, the TRX4M's next limit is its center of gravity — it will lift a tire and topple on sidehills that a weighted truck walks across. The fix is brass at the axles: dense parts that sit at or below axle height and nowhere else. Start at the steering end, where weight also helps the front tires bite on climbs.
MEUS Brass C-Hubs + Steering Knuckles (52g set) — $35.99
Fifty-two grams of brass exactly where physics wants it: at the front wheels. The single most effective stability upgrade on the truck, and it pairs naturally with the stage-two servo swap while the front end is apart.
INJORA Brass High Clearance Links (8pc, 38g) — $19.99
Two upgrades in one box: 38g of low-slung brass and a bent high-clearance profile that slides over ledges the straight stock links hang on. Defender and Bronco fitment.
Hot Racing 20g Brass Differential Cover — $16.88
Twenty grams per axle at the lowest point of the truck. Cheap, invisible once installed, and it protects the diff while it weighs it down.
INJORA 53g Brass Skid Plate / Transmission Mount — $18.99
The heaviest single low-CG brass piece in the catalog: a 53g CNC brass skid that armors the belly and anchors the transmission while it drags the center of gravity down.
Prefer factory parts, or want it all in one box? Traxxas's own brass axle covers (TRA9787, $29.95) are the OEM route, and INJORA's black brass full kit ($58.99) bundles a steering link, C-hubs, knuckles, and diff covers in one order. However you assemble it, the rule stands: brass low, never high — a heavy roof rack undoes everything this stage buys.
The full weight bench is on our brass and weights page.
Stage 4: motor and ESC — brushed value or brushless control
Power is the fun upgrade. It's also the one that pays off least until the first three stages are done.
The stock brushed setup is honest but unremarkable. There are two sensible directions from here: stay brushed and spend very little for more torque, or go brushless and get the near-silent, inch-at-a-time throttle control that transforms technical crawling. What we would not do is spend brushless money before tires, servo, and brass — resolution at the wheels matters more than resolution at the trigger.
INJORA 180 PRO 48T Brushed Motor — $13.99
The cheap thrill: a stronger 180-size brushed motor with a steel pinion that drops into the stock transmission and works with the stock electronics. More low-end grunt for the price of lunch.
MEUS Racing ME25 V2 25A Brushed ESC — $24.99
Swapping the ESC separately from the receiver is how brushed builds grow up: a dedicated 25A mini ESC with proper drag brake behavior, and it keeps your options open for any brushed motor.
INJORA Roverin OR30 + 1721 Purple Viper Brushless Combo — $72.99
The value brushless route: a waterproof OR30 ESC paired with the 2800KV Purple Viper motor, in XT30 or PH2.0 connector versions. Smooth, slow, and sealed — the combo most TRX4M brushless conversions start with.
Furitek MicroSilk 2025 Brushless Power System — $84.99
The premium system: Furitek's MicroPython electronics and Mini Komodo V2 motor, down from a $99.99 list. App-tunable, exceptionally smooth at a crawl, and the setup the no-compromises builds run.
Two more options worth knowing: INJORA's 370 brushed motor with aluminum transmission ($39.99) replaces the whole drive unit in one step, and the Roverin OR30 + 2204 Fat Viper combo ($89.99) is the outrunner alternative to the Purple Viper. And before any motor swap, consider gearing: MEUS's 9.69:1 steel low-range gear set ($13.59) slows the stock driveline down for finer control at a fraction of a power-system swap.
The wider motor field is compared in our best brushless crawler motor guide, and every listing lives on the motors page.
Stage 5: oil-filled shocks
Control the bounce once the truck is heavier and grippier.
Shocks come late in the order on purpose: on a light, stock-weight truck the factory units are tolerable, but a brassed, brushless build moves faster over rough ground and benefits from real damping. Oil-filled shocks keep the tires in contact with the rock instead of bouncing off it, and threaded bodies make ride-height and preload changes a twist instead of a teardown.
INJORA 59mm Long Threaded Oil Shocks (set of 4) — $25.99
CNC aluminum, threaded bodies, two spring rates in the box, and finishes to match your build. A brass-end version runs the same $25.99 if you want a little more unsprung weight in the same part.
Browse the rest of the field on our shocks page.
Stage 6: body, lights, and the fun stuff
You've built the capability. Now make it yours.
A body swap is the one upgrade everyone sees, and it can work as hard as it looks: a hard body adds scale realism, while a cage body sheds the weight and overhang that get hung up on steep transitions. Lights are pure trail joy — with the bonus that the truck stays visible at dusk runs.
INJORA IR60-18 Pickup Hard Body — $29.59
An ABS hard body with a bed rack and front and rear LED lights included, on a clipless front mount. Clearance-priced down from $36.99 — scale looks that work as hard as the truck underneath.
MEUS Racing Ripper V2 Nylon Cage Body — $35.99
An injection-molded PA66 cage body with cockpit and decals included. The comp direction: less overhang, less top weight, nothing to crack on a rollover.
INJORA Headlight & Taillight LED Kit — $6.99
The cheapest smile in the catalog: a plug-in light kit that fits the Defender, Bronco, K10, and F-150 bodies. Six ninety-nine for working lights at both ends.
INJORA 16LED Metal Roof Light (Defender) — $12.99
A metal-housing roof bar with sixteen LEDs, powered from the receiver through the included Y-wire. Trail lighting that survives the rollovers a plastic bar wouldn't.
When the stages are done and you still want more, the next level is the chassis itself: INJORA's 5-degree angled LCG carbon fiber chassis kit ($16.79, down from $23.99) reorganizes the whole truck around a lower center of gravity. It's the gateway to a full comp build — by then you'll know exactly what you want from it.
Stock parts worth keeping
Not everything Traxxas fitted needs replacing, and some stock parts are smarter to keep than to swap on day one:
The stock radio system
The included transmitter and receiver do their job without fuss, and the truck has no aux functions begging for extra channels. A radio upgrade is a fleet decision, not a TRX4M necessity — our crawler radio guide covers when it becomes one.
The stock transmission (at first)
The factory gearbox is durable and appropriately geared for the stock motor. If you want slower, finer control, the $13.59 low-range gear set in stage four gets you most of the benefit without replacing the unit.
The stock body
It's light, it fits perfectly, and it keeps the center of gravity lower than most hard bodies will. Run it until it cracks or until you simply want the truck to look different — there's no performance clock ticking on it.
The stock battery and charger
Perfectly serviceable for the driving most TRX4Ms do. A better charger becomes worth it when run times or a second truck enter the picture — see our crawler LiPo guide for that step.
A sample build, priced
The essential first four upgrades — the ones that change how the truck drives more than everything after them combined:
The core four — $106.36 total
INJORA All Terrain tires ($14.39) + MEUS beadlock wheels ($25.99) + INJORA INJS2065 7KG servo ($29.99) + MEUS brass C-hubs and steering knuckles ($35.99). Grip, steering, and stability, sorted in one order.
The full stages 1–5 path — $166.33 total
Add the INJORA brass links ($19.99), the 180 PRO brushed motor ($13.99), and the 59mm oil shocks ($25.99) to the core four and the truck is, functionally, a different machine from the one that left the box — for less than the price of the truck itself.
Not sure what fits your truck? Our fitment guide covers TRX4M-compatible parts and upgrades.
Lowest Cost Build Sheet
The same stages, re-priced with the cheapest part that genuinely does each job. Two of the core four swap out; the rest of the path was already the budget pick in its slot.
The core four, cheapest route — $69.25 total
INJORA All Terrain tires ($14.39, kept) + INJORA W1049 12-spoke beadlocks ($21.99, in place of the MEUS wheels at $25.99 — the same 1.0" beadlock job in a plainer finish) + MEUS M3280S 8KG servo ($15.99, in place of the INJS2065 at $29.99 — this guide's own FAQ names it the budget servo, and 8KG is still roughly double the stock unit) + Hot Racing 20g brass diff cover ($16.88, in place of the MEUS knuckles at $35.99). Tires at HeliDirect · Wheels at INJORA · Servo at MEUS · Diff cover at Liquid RC
The brass swap, honestly
The diff cover is a partial substitute, not an equal one: it puts 20g on the differential, while the MEUS knuckle and C-hub set puts 52g out at the steering ends, where it resists roll best. There is no cheaper full equivalent for that knuckle set — if you want the full 52g, the slot stays $35.99 and the cheapest-route core four becomes $88.36.
Full stages 1–5, cheapest route — $129.22 total
Add the same three parts as the main sheet — INJORA brass links ($19.99), the INJORA 180 PRO motor ($13.99), and INJORA 59mm oil shocks ($25.99). All three were already the lowest-priced genuine option in their slot, so nothing swaps. That is $129.22 against $166.33 for the main sheet's full path.
TRX4M upgrade FAQ
What is the first TRX4M upgrade I should buy?
Tires. The stock TRX4M tires are a general-purpose tread in a fairly firm compound, and they are the first thing to give up on steep or loose climbs. A soft, sticky set like the INJORA 1.0-inch All Terrain tires ($14.39 for four) grips noticeably harder, and pairing them with real beadlock wheels (MEUS 1.0-inch beadlocks, $25.99) means the tire stays put instead of peeling off the rim. It is the biggest single improvement you can make to the truck.
What servo fits the Traxxas TRX4M?
The TRX4M uses a micro servo in the Traxxas 2065 size class, and the aftermarket is built around that footprint. The INJORA INJS2065 7KG ($29.99) and INJS2065 PRO 9KG ($34.99) are the go-to direct-fit upgrades — both are waterproof and include the mount. On a budget, the MEUS M3280S 8KG ($15.99) also fits the platform. Any of them is a major step up from the stock servo once grippier tires start loading the steering.
How much does it cost to upgrade a TRX4M?
The essential first four upgrades — tires ($14.39), beadlock wheels ($25.99), a proper servo ($29.99), and brass steering knuckles with C-hubs ($35.99) — total $106.36 at current verified prices. Adding brass links, a stronger brushed motor, and oil-filled shocks takes the full stages 1–5 path to $166.33. You do not have to spend it all at once: buy in the order in this guide and each step pays off on its own.
Should I go brushed or brushless on a TRX4M?
Start brushed. A stronger brushed 180 motor like the INJORA 180 PRO 48T ($13.99) drops straight in, works with the stock electronics, and noticeably improves low-speed grunt for the price of a pizza. Brushless is the endgame for throttle control — the INJORA Roverin OR30 + Purple Viper combo ($72.99) and the Furitek MicroSilk system ($84.99) both crawl slower and smoother than any brushed setup — but it replaces your ESC as well, so do it after tires, servo, and brass are sorted.
Do SCX24 wheels and tires fit the TRX4M?
Often, yes. Both platforms run 1.0-inch wheels, and many parts are sold as cross-fitments — the MEUS 1.0-inch beadlock wheels in this guide are listed for SCX24 and TRX4M alike, and several 1.0-inch tire sets cover both trucks. Always check the individual listing's stated fitment before ordering, because offsets and hex details vary between brands.
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 12, 2026; the live deal pages always show the current verified total. RC Crawlers Seek currently tracks 3,545 hand-verified deals, including 129 TRX4M-specific listings.