Head to head
Traxxas TRX-4M vs TRX-4 Sport
Traxxas sells two very different trail crawlers with almost the same name. One works on a living room floor and arrives ready to drive; the other is a full-size rig that needs terrain and a battery you have not bought yet.
By Ryder M. · Published October 10, 2026 · Last reviewed
Shock & Servo is reader-supported. If you buy through a link on this page we may earn a commission, at no extra cost to you. It never changes which products we pick or the order we rank them in — the full rules are on our methodology page and our affiliate disclosure.
Buy the [TRX-4M](#traxxas-trx-4m) unless you have somewhere genuinely rocky to drive, in which case buy the [TRX-4 Sport](#traxxas-trx-4-sport). The TRX-4M is an eleven-inch 1/18 crawler that arrives complete — a 7.4 volt 750mAh LiPo and a 2-amp USB charger are in the box — and it works on a rockery, a flowerbed, a gravel pile or a living room floor. The TRX-4 Sport is nearly twenty-two inches long with portal axles, locked differentials and no battery or charger at all, and it is only interesting on real terrain.
Short version: the TRX-4M is the better gift and the better first crawler, because it is complete in the box, waterproof, and small enough to use indoors in winter. The TRX-4 Sport is the better vehicle if there are rocks, streams or a trail involved — portal axles give it clearance no standard axle can match — but it needs a battery, a charger and terrain before it makes any sense.
The two crawlers compared
| TRX-4M | TRX-4 Sport | |
|---|---|---|
| Scale and length | 1/18, 11 inches | 1/10, 21.9 inches |
| Axles | Solid axles, four-link suspension | Portal axles — housings lifted clear of the rocks |
| Differentials | Standard | Spool-locked front and rear |
| Motor | Brushed | High-torque Titan 21T brushed |
| Electronics | Waterproof ECM-2.5, Sport / Trail / Crawl modes | Waterproof XL-5 HV speed control and receiver box |
| Battery and charger included | Yes — 7.4V 750mAh LiPo and a 2A USB charger | No |
| Where it works | Indoors, rockeries, flowerbeds, gravel | Rocks, trails, streams — needs real terrain |
| Pavement behavior | Fine | Locked diffs scrub the tires; not a driveway car |
| Best for | A gift, a first crawler, small spaces | A full-size trail rig for someone with a trail |
Size is not a specification here, it is the decision
Crawling is a slow hobby. Nothing crashes, nothing goes fast, and the entire appeal is picking a line over an obstacle and getting the truck to take it. That means the obstacle has to exist, and the size of the truck decides what counts as one. At eleven inches, the TRX-4M treats a stack of books, a curb, a flowerbed or a gravel pile as a course — which is why it is the crawler that actually gets used, including in February when nobody wants to stand in a field. At nearly twenty-two inches, the TRX-4 Sport needs rocks to be interesting; on a lawn it just drives across it.
There is a related trap worth naming. The TRX-4 Sport's spool-locked differentials give it maximum traction on rock, and the cost is that the tires scrub on pavement — it fights you on a smooth driveway in a way that feels like something is wrong. Nothing is wrong; it is a terrain vehicle. If the only available surface is a driveway, neither of these is the right purchase and the best RC cars for pavement is the better page.
What portal axles actually buy you
On a conventional axle, the driveshaft runs straight into the center of the wheel, so the axle housing hangs at hub height — which is the lowest point of the truck and the thing that grounds out on a rock. A portal axle adds a gear set at the wheel end, dropping the drive down to the hub and letting the housing sit much higher. The result is ground clearance in exactly the place a crawler needs it, and it is the single biggest hardware advantage the TRX-4 Sport has over the TRX-4M.
It is not free. Portal axles add weight, cost and a set of gears that can be damaged, and they only pay off when the obstacles are tall enough for clearance to be the limiting factor. On a flowerbed, they do nothing the TRX-4M's solid axles cannot. If scale engineering is the appeal in its own right, Axial SCX24 vs FMS FCX24 covers two very small crawlers that also run them.
How we judged the pair
- Where will it actually be driven? Crawling needs obstacles. The smaller truck finds them everywhere; the larger one needs rock. This decides the comparison more than hardware does.
- Is it complete in the box? A crawler with no battery and no charger is two purchases away from working, and that is the most common way an RC gift fails.
- Then clearance. Portal axles are a real advantage on tall obstacles and irrelevant on small ones.
- Then waterproofing. Both have sealed electronics, which matters more in crawling than in bashing — wet rock, streams and damp leaves are the native habitat.
- Then the surface penalty. Locked differentials scrub on pavement. If the only surface is smooth, neither truck is right.
- Honest cons on both. The TRX-4M's 750mAh pack is small and its licensed bodies scuff; the TRX-4 Sport needs a battery, a charger and terrain.
The crawlers
| # | Product | Best for | Score | Price |
|---|---|---|---|---|
| 1 | Traxxas TRX-4MThe small Traxxas crawler that arrives complete: battery, charger, waterproof electronics and a licensed body. | Crawling, complete in box | 9.0 | |
| 2 |  Traxxas TRX-4 SportThe 1/10 crawler for someone who wants the real thing: portal axles, locked differentials and waterproof electronics. | A full-size trail rig | 8.8 | |
| 3 |  Axial SCX24Under eight inches long, four-wheel drive, and it turns a living room floor into a trail. | Indoor crawling | 8.6 |
Illustrative photo — not this exact model.
#1 · Crawling, complete in box
Traxxas TRX-4M
The small Traxxas crawler that arrives complete: battery, charger, waterproof electronics and a licensed body.
9.0/10our score for this use
A 1/18 scale trail crawler eleven inches long, built on a steel ladder frame with solid axles and a four-link suspension — the layout of a real truck, shrunk. Traxxas fits its waterproof ECM-2.5 module with Sport, Trail and Crawl modes, and the box includes a 7.4 volt 750mAh LiPo and a 2-amp USB charger, so nothing else is needed on the day.
- Size:
- 1/18 (11 inches long)
- Drive:
- Solid-axle 4WD
- Motor:
- brushed motor
What it does well
- Battery and USB charger are in the box, which almost nothing else in the Traxxas range can say
- Waterproof electronics and LED lights, so wet grass and after-dark driving are both fine
- Small enough for a living room, a rockery or a stack of books — no field required
What it does badly
- Crawlers are slow by design. If the recipient wants speed, this is the wrong shape entirely
- The 750mAh pack is small; a second battery is the first thing most owners buy
- The licensed bodies are ABS plastic and will scuff on rock
Specifications from the Traxxas TRX-4M product page.
Illustrative photo — not this exact model.
#2 · A full-size trail rig
Traxxas TRX-4 Sport
The 1/10 crawler for someone who wants the real thing: portal axles, locked differentials and waterproof electronics.
8.8/10our score for this use
Nearly 22 inches long, driven by a high-torque Titan 21T brushed motor through a steel-geared single-speed transmission. Portal axles lift the axle housings clear of the rocks, the differentials are spool-locked front and rear for maximum traction, and the XL-5 HV speed control and receiver box are waterproof.
- Size:
- 1/10 (21.9 inches long)
- Drive:
- Portal-axle 4WD
- Motor:
- brushed motor
What it does well
- Portal axles give it ground clearance that no standard axle layout can match
- Waterproof electronics, so streams, snow and wet rock are all in bounds
- The full Traxxas parts and upgrade network behind a crawler platform
What it does badly
- No battery and no charger in the box, so the real spend is meaningfully higher
- Locked differentials scrub the tires on pavement — this is not a driveway car
- Large and slow: it needs terrain to be interesting, not space to be fast
Specifications from the Traxxas TRX-4 Sport product page.
Illustrative photo — not this exact model.
#3 · Indoor crawling
Axial SCX24
Under eight inches long, four-wheel drive, and it turns a living room floor into a trail.
8.6/10our score for this use
A 1/24 scale crawler — smaller than a shoe — sold as several licensed bodies including Jeep, Ford Bronco, Chevrolet C10 and a Power Wagon. It is a complete ready-to-run package with a small LiPo battery and USB charger, and it crawls over table legs, stairs and garden rockeries at walking pace.
- Size:
- 1/24 (under 8 inches long)
- Drive:
- Full-time 4WD
- Motor:
- brushed motor
What it does well
- Small enough to use indoors year-round, which no other hobby-grade car on this site can claim
- Slow, so crashes barely exist — the failure mode is tipping over, not breaking
- A huge aftermarket of upgrade parts if the hobby sticks
What it does badly
- Tiny. If the person you are buying for wanted something impressive to look at, this is not it
- Not fast, and it never will be
- The included battery is small, so a spare pack is an obvious early purchase
Specifications from Axial's brand pages at Horizon Hobby.
The smaller alternative worth knowing about
The Axial SCX24 is smaller again — under eight inches, 1/24 scale — and it is the crawler to buy if the hobby is likely to stick, because it has the largest aftermarket in the category. Brass weights, metal axles, better servos, different wheels: there is always another upgrade to fit, which is a different kind of appeal from driving. It also arrives complete, with a small LiPo and a USB charger. The honest criticism is that it is tiny, and the aftermarket is a cost as much as a feature. The best RC crawler brands compares the field properly.
Which to buy
- A gift, or a first crawler: the TRX-4M. Complete in the box, waterproof, and usable in a living room.
- There are rocks, a stream or a trail: the TRX-4 Sport, with a pack and a charger budgeted on top.
- Indoors, year round, in a small apartment: the TRX-4M, or the even smaller SCX24.
- Upgrading is the hobby, not driving: the SCX24 and its aftermarket.
- Only a smooth driveway is available: neither — locked diffs and crawler tires are the wrong tools. See the best RC cars for pavement.
- Speed is secretly the requirement: neither. Crawlers are slow by design. The best RC trucks for adults is the right page.
What to buy alongside
On the TRX-4M, a second battery — the 750mAh pack is small, and a spare is the cheapest change that doubles the afternoon. On the TRX-4 Sport, a pack and a charger before anything else, because it will not move without them; the best RC battery chargers covers buying one charger that will still be right in two years. For both, a set of hex drivers that will not round off, and on the TRX-4 Sport a spare set of tires eventually, since crawler compound is soft by design. What else do you need is the longer list.
How we assessed this
By reading both models' Traxxas product pages for published specifications and inclusions, then ranking them on the question that decides whether a crawler gets used: whether there is somewhere to crawl. Every figure above is Traxxas' own and linked in Sources, and anything Traxxas does not publish has been left out rather than estimated. No price figures appear anywhere on this site. We do not test these products first-hand; our methodology page sets out what that means.