If you just picked up an ARRMA Grom or Typhon Grom, you’re holding one of the most fun micro bashers on the market right now. But here’s something nobody tells you at checkout: certain parts on these little trucks will break, and when they do, you don’t want to be waiting two weeks for shipping while your new toy collects dust. Knowing which ARRMA Grom spare parts to buy before your first bash separates the frustrated newbies from the prepared hobbyists who keep running all weekend.
The Grom platform launched as ARRMA’s entry into the 1/18 scale micro segment, and it’s been a hit because it delivers legitimate bashability in a backyard-friendly size. The 2S power system, full ball bearings, and oil-filled shocks give it way more capability than most micro RCs. But that capability means you’ll push it harder, and harder pushing means broken parts. We’ve run both the standard Grom buggy and the Typhon Grom 4×4 extensively since their release, and we’ve learned exactly what fails first.
This guide walks you through every spare part worth stocking, organized by how likely you are to need it. We’ll cover the high-frequency breakables, the “nice to have” spares, the upgrades that actually matter, and the stuff you can safely ignore. By the end, you’ll have a shopping list that keeps your Grom running through 2026 and beyond.
Why the Grom Breaks Differently Than Larger ARRMA Models
The ARRMA Grom breaks in predictable ways because of its 1/18 scale physics. Smaller parts experience proportionally higher stress loads during impacts, and the lightweight chassis means less inertia to absorb sudden stops. Understanding this helps you predict failures before they happen.
At 280 grams ready to run, the Grom is light enough to catch air off the smallest bumps. That’s part of the fun. But it also means landings generate forces that concentrate on tiny plastic components rather than distributing across larger, beefier parts like you’d find on a 6S platform. The front diff gears on a Kraton 6S might last a year of hard bashing. On a Grom, those same style gears might last a month if you’re jumping aggressively.
The 2S 850mAh battery pack delivers around 20 minutes of runtime, which sounds short until you realize that’s 20 minutes of nearly continuous full-throttle action. Most bashers don’t pace themselves with a micro car the way they might with a $600 truck. You send it harder, more often, with less recovery time between runs. This accelerates wear on every moving component.
Temperature also plays a bigger role at this scale. The Grom’s motor and ESC sit in a tighter chassis with less airflow than larger models. On hot summer days, we’ve seen motor temps climb above 160°F during extended pavement sessions. Heat softens plastic, and softened plastic wears faster. Keep this in mind when planning your spare parts inventory.
→ ARRMA Grom, The standard Grom buggy remains the most popular variant, and its parts availability reflects that popularity with better stock at most hobby retailers.
Tier 1: Parts That Will Break on Your First Bash
Front differential gears top this list because they fail on nearly every Grom within the first few sessions. The stock plastic diff gears can’t handle repeated hard landings, especially nose-first impacts from jumps. Order part number ARA310977 before you even charge your battery for the first time.
We covered the front diff gear issue extensively in our Grom durability and diff gear replacement guide, but the short version is this: the front diff takes the brunt of landing forces because the Grom naturally nose-dives during jumps. The stock gears strip within 10 to 20 hard landings. Having two or three spare sets on hand means you’re never sidelined.
Steering knuckles come next. Part number ARA310975 covers the front knuckles, which crack or shatter during side impacts. Clip a curb at speed, catch a rock wrong, or land sideways off a jump, and you’ll hear that distinctive plastic snap. The knuckles are load-bearing components that connect your wheels to the suspension, so a broken knuckle means immediate stoppage.
Body clips seem trivial until you lose three of them in tall grass and can’t secure your body shell. The stock clips are small, dark colored, and practically invisible once they ping off into the wild. Order a pack of 20 or more. Some bashers switch to body clip retainers or use bright orange aftermarket clips for visibility. Either approach works.
The front bumper mount takes hits on every forward crash. It’s designed to flex and absorb impact, but repeated stress causes fatigue cracks. The mount itself is cheap, under $5 for OEM replacement, so grab two while you’re ordering other parts. You’ll appreciate having it when the original finally gives out.
Tier 2: Parts That Break Within the First Month
Spur gears wear out faster than you’d expect on the Grom, especially if you run on pavement. The stock 54-tooth spur gear meshes with a small pinion, and that mesh point generates significant heat during acceleration. Pavement running compounds this because there’s no slip, just pure grip and pure drivetrain load.
Check your spur gear after every few sessions by removing the body and inspecting the teeth. You’ll see wear patterns developing before catastrophic failure. A worn spur gear makes a distinctive whining sound and eventually strips completely, leaving you coasting to a stop. Stock replacement is ARA310969, and you should have at least one spare ready.
The pinion gear wears alongside the spur but lasts slightly longer due to its steel construction on most Grom variants. Still, inspect it when you check the spur. A worn pinion accelerates spur wear, so replacing both together ensures optimal mesh and extends the life of your new parts.
Turnbuckles bend during crashes. The Grom uses thin aluminum turnbuckles for camber and toe adjustment, and they’re not designed to withstand direct impacts. A bent turnbuckle throws off your alignment, causing uneven tire wear and unpredictable handling. Straightening them works once or twice, but metal fatigue sets in quickly. Spare turnbuckles are cheap insurance.
Shock shafts can bend on hard landings, especially if you bottom out the suspension. The Grom’s oil-filled shocks are impressive for the scale, but the shafts are thin. A bent shock shaft causes binding, which you’ll notice as inconsistent suspension travel or a shock that won’t fully extend. Replacement shocks are available as complete units, which is often easier than rebuilding with new shafts.
→ ARRMA Typhon Grom, The Typhon Grom 4×4 variant shares most spare parts with the standard Grom but adds a rear diff that creates additional maintenance considerations.
Tier 3: Wear Items to Stock for Long-Term Running
Bearings don’t fail dramatically, but they degrade over time. The Grom uses full ball bearings throughout, which is excellent for a micro at this price point. However, dust, dirt, and moisture work their way in during bashing. After several months of regular use, you’ll notice increased drivetrain resistance and rougher wheel spin.
A complete bearing kit runs around $15 to $20 from aftermarket suppliers. You don’t need to replace all bearings at once. Focus on the wheel bearings first since they see the most contamination, then the diff output bearings, then everything else. Cleaning and re-lubing bearings extends their life, but eventually replacement becomes necessary.
Tires wear down, obviously, but the rate depends heavily on your running surface. Pavement eats through stock rubber in a few sessions. Dirt and grass are much gentler. The Grom’s stock tires are surprisingly good for general bashing, but you’ll want spares on hand regardless. Some bashers run through a set of tires every month during heavy use periods.
The servo saver spring can weaken over time. This spring allows the steering linkage to flex under impact rather than transferring all force to the servo. A weak servo saver spring means your steering feels vague and unresponsive. It’s a $3 part that makes a noticeable difference in steering precision.
Motor brushes don’t apply to the Grom since it runs a brushless system, but the motor bearings do wear. If your motor develops a grinding sound or increased resistance when spun by hand, the bearings are going. Replacement motors are available, though bearing replacement on small brushless motors requires some skill and proper tools.
Upgrades That Actually Improve Durability
Metal diff gears solve the front diff problem permanently. Aftermarket steel or hardened metal diff gears cost more than plastic OEM replacements but last exponentially longer. The tradeoff is slightly increased drivetrain noise and a bit more weight. For most bashers, that tradeoff is worth never stripping diff gears again.
The installation process is straightforward. Remove the diff, swap the gears, reassemble with fresh diff grease. We recommend applying a thin layer of silicone diff oil to the gear faces during assembly. This reduces initial wear-in noise and helps the metal gears mesh smoothly.
Aluminum steering knuckles exist for the Grom platform, though availability varies by region. These replace the stock plastic knuckles with machined aluminum versions that can survive impacts that would shatter the originals. The downside is cost, typically $25 to $40 for a set, and the fact that aluminum transfers impact forces to adjacent components rather than absorbing them through breakage.
Some bashers prefer to keep plastic knuckles as sacrificial components. The logic is sound: a $6 plastic knuckle breaking protects a $30 steering rack or $50 servo from damage. This philosophy works if you’re willing to carry spares and perform trailside repairs. If you’d rather just drive without worrying, aluminum is the answer.
→ Metal Gear Servo, Upgrading to a metal gear servo prevents stripped servo gears, a common failure point when running aluminum steering components that no longer flex on impact.
A metal gear servo upgrade makes sense if you’re also upgrading to aluminum steering components. The stock Grom servo uses plastic gears that can strip under heavy loads. With plastic steering knuckles, the knuckles break before the servo gears strip. With aluminum knuckles, that protection disappears, and servo gear stripping becomes the new failure point. A metal gear micro servo rated for 3kg-cm or higher torque solves this permanently.
Upgraded shock springs allow you to tune suspension stiffness for your running style. Stiffer springs reduce bottoming out on big jumps, protecting shock shafts from bending. Softer springs improve traction on rough surfaces. Having a range of spring rates lets you dial in the setup for different terrains.
Parts You Don’t Need to Stock Immediately
The chassis plate rarely breaks unless you’re doing something extreme. The Grom’s composite chassis is flexible enough to absorb most impacts without cracking. In two years of running multiple Groms, we’ve never broken a chassis plate during normal bashing. Save your money for parts that actually fail.
The ESC and receiver unit are integrated on the Grom, and they’re remarkably reliable. Electronic failures happen occasionally, but they’re rare enough that pre-stocking a replacement doesn’t make financial sense. If your electronics die, order a replacement then. The few days of downtime won’t kill you.
Motor mounts almost never fail. They’re simple, sturdy, and well-designed. The same goes for the battery tray, body mounts, and wing. These parts exist in the spare parts catalog, but you’ll likely never need them unless you experience a truly catastrophic crash.
Diff cases are another “order when needed” item. The cases themselves are tough. It’s the internal gears that fail, not the housings. We’ve seen stripped diff gears in perfectly intact cases dozens of times. Stock the gears, not the cases.
Battery and Charging Considerations for 2026
The stock 2S 850mAh battery gets the job done, but runtime is limited. Many bashers pick up a second or third battery to extend sessions without waiting for charges. The Grom uses a JST-XH balance connector and XT30 main connector, which is standard for this class of micro RC.
Aftermarket 2S packs in the 1000mAh to 1300mAh range fit the Grom’s battery tray with minor modifications. Larger capacity means more runtime but also more weight. The performance tradeoff is minimal at this scale, and the extra runtime is usually worth it. Just ensure any aftermarket pack you buy has the correct connectors or be prepared to solder adapters.
Our 2026 ARRMA battery compatibility guide covers voltage and capacity considerations across the entire lineup, including specific recommendations for the Grom platform. The key takeaway: stick to 2S packs rated for at least 25C continuous discharge. Lower C-ratings can cause voltage sag under load, which triggers the ESC’s low voltage cutoff prematurely.
→ LiPo Balance Charger, A quality balance charger handles both your Grom’s 2S packs and future 6S batteries if you expand your fleet, making it a smart long-term investment.
Charger selection matters more than most beginners realize. The stock USB charger that comes with the Grom is slow and lacks balance charging capability. A proper hobby-grade balance charger not only charges faster but also maintains cell balance, which extends battery lifespan and ensures consistent performance. Look for a charger that handles 2S through 6S so you’re covered if you eventually move up to larger ARRMA models.
We’ve documented USB charger issues across the mini ARRMA lineup in our charger problems and solutions article. The short version: upgrade your charger early. It’s one of the best investments you can make for any LiPo-powered RC.
→ 6S LiPo Battery, While the Grom runs on 2S, having 6S capability in your charger prepares you for larger ARRMA trucks like the Kraton or Typhon when you’re ready to scale up.
Building Your First Spare Parts Order
Here’s the practical shopping list, organized by priority. This assumes you’re buying before your first bash and want to be prepared without overspending.
Essential items for your first order: two sets of front diff gears (ARA310977), one set of steering knuckles (ARA310975), 20 body clips, one spur gear (ARA310969), and one front bumper mount. Total cost runs around $35 to $45 depending on retailer pricing in 2026. This covers the most common first-session failures.
Second-tier additions if budget allows: one set of turnbuckles, one complete shock set, one pinion gear, and a bearing kit. This adds another $40 to $50 but prepares you for the failures that typically occur within the first month of regular bashing.
Upgrade path for serious bashers: metal diff gears, aluminum steering knuckles, metal gear servo, and upgraded shock springs. This represents a $100+ investment but transforms the Grom from a fun basher into a nearly unbreakable micro machine. Most bashers work toward this setup over time rather than buying everything at once.
Skip these until you actually need them: chassis plate, ESC/receiver, motor mount, diff cases, body mounts. These parts fail so rarely that pre-stocking them wastes money better spent on consumables.
Terrain-Specific Part Considerations
Pavement running accelerates drivetrain wear but is gentler on suspension components. Stock extra spur and pinion gears if you primarily run on smooth surfaces. The lack of slip means every bit of motor torque transfers directly through the drivetrain, which wears gears faster than dirt running where wheels can spin freely.
Dirt and gravel running reverses this pattern. Suspension components take more abuse from bumps and debris, while drivetrain wear decreases because loose surfaces allow wheelspin. Stock extra shocks, springs, and steering components for off-road focused bashing.
Grass running is surprisingly hard on the Grom. Tall grass wraps around axles, generating heat and resistance. It also hides rocks, roots, and other obstacles that cause unexpected impacts. Bearings contaminate faster in grass due to moisture and organic debris. Clean your Grom thoroughly after grass sessions and inspect bearings more frequently.
Skate parks and concrete features represent the highest stress environment. Hard landings on unforgiving surfaces break parts faster than any other running style. If you’re building ramps or hitting skate parks, double your spare parts inventory across all categories. You’ll go through components quickly.
Side-by-Side: Grom vs Typhon Grom Spare Parts
| Component | Standard Grom | Typhon Grom 4×4 |
|---|---|---|
| Front Diff Gears | ARA310977 | ARA310977 (same) |
| Rear Diff Gears | N/A (2WD) | ARA310978 |
| Steering Knuckles | ARA310975 | ARA310975 (same) |
| Spur Gear | ARA310969 | ARA310969 (same) |
| Chassis Plate | Buggy specific | 4×4 specific |
| Shock Length | Identical front/rear | Identical front/rear |
| Turnbuckles | Shared part numbers | Shared part numbers |
| Body Shell | Buggy body | Typhon body |
| Wheel Hexes | Shared 7mm hex | Shared 7mm hex |
| Drivetrain Complexity | Single diff | Front and rear diffs |
The Typhon Grom 4×4 shares most spare parts with the standard Grom buggy. The major difference is the addition of a rear differential, which means Typhon Grom owners need to stock rear diff gears alongside front diff gears. The rear diff sees less stress than the front since the Typhon doesn’t nose-dive as severely on landings, but it still wears over time.
Body shells and chassis plates differ between variants, but these rarely need replacement. The drivetrain, suspension, and steering components that actually break are largely interchangeable. This parts commonality is intentional on ARRMA’s part and makes stocking spares easier if you own both variants.
Where to Source Parts in 2026
Horizon Hobby remains the primary source for OEM ARRMA parts. Their online store stocks the complete Grom parts catalog, and shipping times are reasonable in most regions. The downside is pricing, which tends to be full retail without discounts.
Amazon carries many Grom parts from third-party sellers, often at competitive prices. Verify seller ratings and check that part numbers match before ordering. Counterfeit or incorrect parts occasionally slip through, especially from overseas sellers with limited feedback.
Local hobby shops stock varying levels of ARRMA parts depending on their focus. Shops that carry the Grom usually stock common consumables like diff gears and body clips. Less common parts may require special ordering. The advantage of local shops is immediate availability and the ability to inspect parts before purchase.
Aftermarket suppliers fill gaps in the OEM catalog. Companies like Hot Racing, RPM, and various smaller manufacturers produce upgraded components for the Grom platform. Quality varies, so research specific products before buying. User reviews and forum discussions provide the best guidance on aftermarket part quality.
Frequently Asked Questions
What ARRMA Grom parts break most often?
Front differential gears break most frequently, typically within the first few bashing sessions. Steering knuckles rank second, failing during side impacts. Spur gears wear out over time rather than breaking suddenly. These three components account for the majority of Grom repairs and should be your first spare parts purchase.
Are Grom and Typhon Grom spare parts interchangeable?
Most spare parts are identical between the standard Grom and Typhon Grom 4×4. Steering components, front diff gears, spur gears, shocks, and bearings share the same part numbers. The Typhon Grom adds a rear differential not present on the 2WD Grom, requiring additional rear diff gear spares.
Should I buy metal diff gears for my Grom?
Metal diff gears are worth the investment if you bash frequently or jump aggressively. They cost more than plastic OEM replacements but last significantly longer. The tradeoff is slightly increased drivetrain noise. Most serious Grom bashers consider metal diff gears an essential upgrade rather than optional.
How many spare parts should I order before my first bash?
Order at minimum two sets of front diff gears, one set of steering knuckles, and a pack of body clips. This covers the most common first-session failures for under $40. Add a spare spur gear and turnbuckles if your budget allows, bringing the total to around $60 for comprehensive coverage.
Do I need a better charger for my ARRMA Grom?
Yes, upgrading from the stock USB charger is highly recommended. A proper balance charger charges faster, maintains cell balance for longer battery life, and provides safety features the stock charger lacks. Look for a charger handling 2S through 6S to accommodate future RC purchases.
What causes the Grom’s front diff gears to strip?
Nose-first landings from jumps concentrate impact forces on the front differential. The stock plastic gears can’t withstand repeated stress and eventually strip. Running on pavement accelerates wear due to increased traction. Metal diff gears or gentler landing techniques extend gear life significantly.
Where can I find ARRMA Grom spare parts in 2026?
Horizon Hobby stocks the complete OEM parts catalog online. Amazon carries many parts through third-party sellers at competitive prices. Local hobby shops vary in stock levels but offer immediate availability. Aftermarket suppliers provide upgraded alternatives to OEM components for durability-focused bashers.
Final Verdict: Your Essential Grom Spare Parts List
The ARRMA Grom delivers incredible fun for its size and price, but it demands preparation. Stocking the right spare parts before your first bash transforms the ownership experience from frustrating downtime to nearly uninterrupted running. The investment is modest compared to the cost of the truck itself, and it pays dividends every time you snap a part and keep bashing instead of packing up early.
Your absolute minimum purchase should include two sets of front diff gears, one set of steering knuckles, and plenty of body clips. This covers roughly 70% of first-bash failures for around $35. If you can stretch the budget to $60, add a spur gear, pinion gear, and turnbuckle set. This expanded kit handles nearly everything you’ll encounter in your first month of ownership.
For bashers who know they’ll push hard, the upgrade path is clear. Metal diff gears eliminate the most common failure point permanently. Aluminum steering knuckles paired with a metal gear servo create a nearly indestructible front end. These upgrades cost more upfront but save money and frustration over the long term.
The Grom platform has proven itself over several years now. Parts availability is excellent, the aftermarket support is growing, and the community knowledge base is deep. Whether you’re running the standard Grom buggy or the Typhon Grom 4×4, the fundamentals of spare parts preparation remain the same. Stock the consumables, consider the upgrades, and skip the parts that rarely fail.
Preparation separates hobbyists who bash all weekend from those who spend half their time waiting for parts. Make your spare parts order today, and you’ll thank yourself the first time something breaks mid-session. Because on the Grom, something will break. That’s not a flaw; that’s just what happens when you build a micro basher capable of real performance. The parts are cheap, the fixes are easy, and the fun is worth every penny.
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