The best ARRMA Mojave Grom upgrades transform a fun little basher into a genuinely capable micro machine. If you’ve been running your Grom, Mojave Grom, or Mini Kraton stock and wondering why parts keep breaking or why it feels sluggish compared to videos online, you’re in the right place.
These 1/18 scale ARRMA trucks share a common platform, which means most upgrades work across all three models. That’s great news for your wallet and your parts bin. We’ve been running Groms since their 2023 release, and in 2026, the aftermarket support has finally caught up to demand.
This guide covers every upgrade category that actually matters: electronics, drivetrain, suspension, and chassis protection. We’ll tell you which mods deliver real performance gains and which ones are just expensive for the sake of being expensive. By the end, you’ll have a clear upgrade path whether you’re fixing weak points or building a full-send micro basher.
Understanding the Grom Platform: What You’re Working With
The Grom platform uses a 180-size brushless motor running at 8500Kv, producing roughly 70 watts of power in a truck weighing just 340 grams ready to run. That power-to-weight ratio explains why these little trucks feel so fast despite their size.
All three variants, the standard Grom buggy, the Mojave Grom desert truck, and the Mini Kraton monster truck, share identical electronics and drivetrain components. The differences come down to body style, wheelbase, and suspension geometry. The Grom buggy runs a 200mm wheelbase. The Mojave Grom stretches to 220mm. The Mini Kraton sits at 215mm with taller suspension.
Stock, these trucks run on the included 2S 350mAh LiPo pack. It’s adequate for about 8-10 minutes of runtime, but the low capacity means you’re constantly swapping batteries. The included charger works, but it’s painfully slow at around 0.5A charge rate.
The ESC handles 2S LiPo input and includes a built-in receiver for the included SLT3 radio. This integrated design keeps weight down but limits your upgrade options for the radio system. The motor itself is surprisingly capable, though it runs hot during aggressive sessions.
Weak points on the stock platform include the plastic servo gears, the small stock battery, plastic shock caps that crack under impact, and the spur gear mesh that tends to strip if you land hard on the throttle. These are the areas where upgrades make the biggest difference.
→ ARRMA Grom, The standard Grom buggy is the lightest of the three variants at 340g, making it the best choice for pure speed runs on smooth surfaces.
Essential Electronics Upgrades: Power and Control
Better batteries deliver the single biggest improvement to Grom platform performance. The stock 350mAh pack limits both runtime and punch. Moving to a quality 2S LiPo in the 450-650mAh range transforms the driving experience.
We’ve tested packs from Gens Ace, Tattu, and CNHL in these trucks. The sweet spot is a 2S 550mAh pack with at least 50C discharge rating. This gives you 12-15 minutes of runtime while maintaining full power throughout the session. Packs over 650mAh start adding noticeable weight that affects handling.
Physical fit matters here. The Grom battery tray measures approximately 55mm x 30mm x 20mm. Stick to packs within those dimensions or be prepared to modify the tray. Some 650mAh packs require removing the foam battery spacer entirely.
For charging, the stock wall charger takes over an hour to fill the included pack. A proper balance charger lets you charge at 1C or higher, cutting that time dramatically. If you’re running multiple packs per session, a quality charger pays for itself in convenience.
→ LiPo Balance Charger, A good balance charger handles everything from micro Grom packs to full 6S batteries for your larger ARRMA trucks, making it a worthwhile investment.
The stock servo is the platform’s most notorious weak point. It uses plastic gears that strip within a few hard crashes. Replacing it with a metal gear micro servo is essentially mandatory if you bash with any intensity.
Look for servos in the 9g weight class with metal gears and at least 2kg-cm of torque. The Emax ES09MD and similar units work well. Installation requires removing the receiver box lid, unplugging the stock servo, and routing the new servo’s wire to the ESC’s servo port.
→ Metal Gear Servo, A quality metal gear micro servo eliminates the most common failure point on the Grom platform and costs under $15.
Motor upgrades exist but aren’t necessary for most users. The stock 8500Kv motor has plenty of power for the platform’s weight. If you want more speed, a 10000Kv motor swap is possible, but heat management becomes critical. Running a higher Kv motor on 2S generates significant heat in the small chassis with limited airflow.
ESC upgrades are complicated by the integrated receiver design. Swapping to a standalone ESC means also adding a separate receiver, which adds weight and complexity. For most bashers, the stock ESC handles everything the platform can dish out. The exception is if you’re running a brushless system swap in a Mini Kraton for serious monster truck stunts.
Drivetrain Hardening: Making It Last
The stock drivetrain uses a mix of metal and composite components that work fine for casual running but fail under aggressive use. Hardening the drivetrain extends part life dramatically and reduces mid-session breakdowns.
Start with the spur gear. The stock 45T spur is made from a composite material that can strip if you land hard while on throttle. Aftermarket steel spur gears eliminate this failure mode entirely. They’re slightly heavier but worth it for the peace of mind.
The pinion gear comes stock at 15T, giving a gear ratio around 3:1 for the final drive. This is well-balanced for mixed use. Going to a 17T pinion increases top speed but reduces acceleration and increases heat. A 13T pinion does the opposite. For bashing, stick with 15T or go down to 13T for better punch on rough terrain.
Differential gears see significant stress in the Grom platform. The stock internal gears are metal but can wear over time. Replacement diff gear sets are available and worth keeping in your parts bin. The front diff tends to wear faster due to the weight transfer under braking.
Bearings make a noticeable difference in how the truck rolls and how long components last. The stock bearings are adequate but benefit from replacement with quality sealed bearings. A full bearing kit for the Grom platform runs about $12-15 and includes all the wheel, diff, and transmission bearings.
Drive shafts on the Grom are surprisingly robust for the scale. The stock plastic CVDs handle most abuse. If you’re breaking them regularly, the issue is usually worn diff gears or a bent chassis rather than the shafts themselves. Metal CVD upgrades exist but add rotating mass that can stress other components.
The slipper clutch assembly rarely needs attention unless you’ve been running with incorrect mesh or a worn spur gear. If it starts slipping under normal load, check the spur gear teeth first. A new slipper pad costs a few dollars and takes five minutes to install.
Suspension Upgrades: Handling and Durability
Aluminum shock caps solve the most common suspension failure on the Grom platform. The stock plastic caps crack on hard landings, leaking oil and killing damping performance. Aftermarket aluminum caps from Hot Racing and similar brands fit all three Grom variants.
The shocks themselves are oil-filled coilovers with adjustable preload via threaded collars. Stock oil weight is around 30wt, which works well for most conditions. Going heavier to 40wt or 50wt slows the suspension response, useful for high-speed running on rough surfaces. Lighter oil improves small bump compliance but can cause bottoming on big hits.
Shock springs vary by model. The Mini Kraton runs stiffer springs to handle its higher ride height and monster truck body weight. The Grom buggy uses softer springs for better traction. Swapping springs between models lets you tune handling characteristics. Stiffer springs reduce body roll but can make the truck bouncy on rough terrain.
A-arms on the Grom platform are injection-molded nylon that flexes before breaking. This is actually good design for a micro basher. Rigid aluminum arms would transfer more impact force to the chassis and bulkhead. Keep spare stock arms on hand rather than upgrading to metal.
Steering components benefit from inspection after hard crashes. The stock plastic steering rack can crack at the pivot points. Aftermarket aluminum steering racks provide more precise response and better durability. The tradeoff is they don’t flex, so impacts go straight to the servo and chassis.
Ride height adjustment comes from the threaded shock collars. For parking lot running, drop the ride height to lower the center of gravity. For backyard dirt and grass, raise it to prevent the chassis from dragging. The Mojave Grom benefits from slightly higher front ride height to prevent nose-diving on rough terrain.
→ ARRMA Mojave Grom, The Mojave Grom’s desert truck suspension geometry handles rough terrain better than the standard buggy, making it the best choice for dirt and gravel bashing.
Chassis Protection and Body Upgrades
The Grom chassis is a molded composite tub that handles impacts well but can crack at stress points over time. Adding protection to high-wear areas extends chassis life significantly.
Skid plates aren’t strictly necessary on the Grom due to its light weight, but they help on rocky terrain. Thin HDPE or polycarbonate sheets cut to shape and attached with double-sided tape work better than heavy aluminum plates that would affect handling.
Body clips are the bane of micro RC existence. The stock clips are tiny and easy to lose. Aftermarket body clip sets with larger pull tabs make removing bodies much easier. Some users switch to magnetic body mounts, though these add weight and can come loose on hard landings.
Bumper upgrades vary by model. The Mini Kraton’s front bumper takes the most abuse due to its wheelie-prone nature. Reinforced bumpers or 3D-printed alternatives provide better protection. The Mojave Grom benefits from a front skid plate extension to protect the front diff housing.
Wheel hex upgrades improve durability if you’re breaking stock hexes. The stock plastic hexes can strip or crack. Aluminum hexes distribute load better and last longer. Make sure to use thread locker on the wheel nuts with aluminum hexes since they don’t flex to grip the nut like plastic does.
Tires are consumable items that significantly affect performance. Stock tires work well on hard surfaces but lack traction on loose dirt. Aftermarket tire options include softer compounds for better grip and different tread patterns for specific terrain. The Mini Kraton’s taller tires give it better obstacle clearance but raise the center of gravity.
→ ARRMA Mini Kraton, The Mini Kraton’s monster truck stance and tall tires make it the most capable Grom variant for backyard bashing over grass and obstacles.
Key Differences Between Grom Variants That Affect Upgrades
The standard Grom buggy prioritizes low weight and nimble handling. At 340g ready to run, it’s the lightest of the three. This makes it most sensitive to added weight from upgrades. Heavy aluminum parts affect the Grom buggy more than the other variants.
The Mojave Grom adds desert truck styling with a longer 220mm wheelbase. The extra length improves stability at speed but reduces turning agility. Its suspension geometry handles rough terrain better, making it the best choice for dirt and gravel running.
The Mini Kraton runs the tallest suspension with monster truck proportions. It weighs slightly more than the buggy due to larger tires and taller shocks. This variant handles backyard obstacles best but rolls over more easily due to its high center of gravity.
All three share the same electronics, motor, and core drivetrain. This means battery upgrades, servo swaps, and drivetrain hardening apply equally to all variants. Suspension components are model-specific due to different shock lengths and spring rates.
For detailed compatibility information on batteries across the Grom platform and larger ARRMA trucks, check our ARRMA battery compatibility guide which covers specs for the Typhon, Granite, Grom, and Mojave.
If you’re considering a more extensive electronics swap between Grom variants, our Mojave Grom vs Mini Kraton electronics comparison breaks down exactly what transfers and what doesn’t.
Side-by-Side Specs: Grom Platform Variants
| Feature | Grom Buggy | Mojave Grom | Mini Kraton |
|---|---|---|---|
| Scale | 1/18 | 1/18 | 1/18 |
| Weight (RTR) | 340g | 360g | 355g |
| Wheelbase | 200mm | 220mm | 215mm |
| Motor | 180 size 8500Kv | 180 size 8500Kv | 180 size 8500Kv |
| ESC | 2S integrated | 2S integrated | 2S integrated |
| Stock Battery | 2S 350mAh | 2S 350mAh | 2S 350mAh |
| Top Speed (stock) | 25+ mph | 23+ mph | 22+ mph |
| Ground Clearance | 18mm | 22mm | 28mm |
| Shock Type | Oil-filled coilover | Oil-filled coilover | Oil-filled coilover |
| Best Terrain | Pavement, smooth dirt | Dirt, gravel, mixed | Grass, backyard, obstacles |
Upgrade Priority Order: Where to Spend First
Metal gear servo should be your first upgrade regardless of which Grom variant you own. The stock servo’s plastic gears will strip eventually, and it’s better to replace it before failure leaves you stranded mid-session. Budget $12-18 for a quality micro metal gear servo.
Battery upgrade comes second. A 550mAh 2S LiPo with 50C or higher discharge rating costs around $15-20 and transforms the driving experience. Longer runtime and consistent power delivery make the truck more fun to drive.
Aluminum shock caps rank third. At $8-12 for a set, they eliminate the most common suspension failure. Install them before the stock caps crack rather than waiting for a failure.
Full bearing kit comes fourth. Quality sealed bearings reduce friction and last longer than stock bearings. A complete kit runs $12-15 and takes about 30 minutes to install throughout the truck.
Steel spur gear rounds out the essential upgrades. At $6-10, it prevents the frustrating stripped spur gear failure that can end a session instantly. Combined with proper gear mesh adjustment, it makes the drivetrain nearly bulletproof.
After these five essentials, additional upgrades depend on your specific use case. High-speed runners benefit from lower suspension and a pinion gear change. Backyard bashers should prioritize bumper protection and higher ride height. Dirt runners need better tires and possibly heavier shock oil.
Common Mistakes to Avoid When Upgrading
Over-upgrading with heavy aluminum parts kills the Grom’s performance advantage. The platform works because it’s light. Adding 50 grams of aluminum parts might sound minor, but it’s a 15% weight increase that affects acceleration, handling, and jump performance.
Ignoring gear mesh causes more stripped gears than any other factor. After any drivetrain work, check that the spur and pinion have proper mesh. There should be slight play but no binding. Too tight causes excessive wear. Too loose causes skipping and stripped teeth.
Running oversized batteries creates problems beyond just fit. Heavier batteries shift the weight balance and can stress the battery tray mounting points. Stick to packs under 700mAh for best results.
Skipping thread locker on critical fasteners leads to parts working loose during runs. The Grom’s vibrations are significant relative to its fastener sizes. Use blue thread locker on motor mount screws, shock tower bolts, and wheel nuts with aluminum hexes.
Neglecting maintenance between upgrades causes premature failures. Clean the truck after dusty sessions. Check for loose screws weekly if you run frequently. Inspect the spur gear and pinion for wear every few battery packs. Small issues caught early prevent bigger failures.
Real-World Performance After Upgrades
With the five essential upgrades installed, the Grom platform transforms from a fun toy to a legitimate micro basher. The metal servo provides consistent steering response without the anxiety of wondering when it will strip. Better batteries deliver 12-15 minutes of full-power runtime.
On pavement, the upgraded Grom buggy reaches speeds over 25 mph and handles with precision. The low center of gravity and light weight make it incredibly agile through tight corners. Aluminum shock caps survive curb hits that would crack stock caps.
On dirt and gravel, the Mojave Grom variant shines with its longer wheelbase providing stability over rough terrain. The hardened drivetrain handles the increased load from loose surface running without complaint. Better bearings keep rolling resistance low even after exposure to dust.
In the backyard, the Mini Kraton climbs over obstacles that would stop the other variants. Its tall suspension soaks up impacts from roots, rocks, and uneven ground. The monster truck proportions make it the most versatile of the three for mixed terrain sessions.
Jump performance improves across all variants with proper suspension setup. Stiffer springs and heavier shock oil prevent bottoming on big landings. The hardened drivetrain survives the throttle inputs needed for controlled air maneuvers.
Frequently Asked Questions
What is the best first upgrade for an ARRMA Grom?
A metal gear micro servo should be your first upgrade for any Grom variant. The stock servo uses plastic gears that strip easily during crashes. A quality metal gear servo costs $12-18 and eliminates the platform’s most common failure point, keeping you running longer between repairs.
Can I use the same upgrades on all three Grom variants?
Electronics, drivetrain, and bearing upgrades work across all three Grom variants since they share the same core platform. Suspension components are model-specific due to different shock lengths and spring rates. Always verify part compatibility before purchasing suspension upgrades.
What battery size works best for the Grom platform?
A 2S 550mAh LiPo with 50C discharge rating offers the best balance of runtime and performance. This size fits the stock battery tray without modification and provides 12-15 minutes of runtime. Packs over 650mAh add weight that affects handling.
Are aluminum A-arms worth it on the Grom?
Aluminum A-arms are generally not recommended for the Grom platform. Stock nylon arms flex before breaking, which protects other components from impact damage. Rigid aluminum arms transfer more force to the chassis and bulkhead, potentially causing more expensive failures.
How do I prevent stripped spur gears on my Grom?
Install a steel spur gear and maintain proper gear mesh with slight play between teeth. Avoid landing jumps while on full throttle, as this shock loads the drivetrain. Check mesh after any drivetrain work and adjust if binding or excessive play exists.
Which Grom variant is best for backyard bashing?
The Mini Kraton is the best Grom variant for backyard bashing due to its 28mm ground clearance and monster truck suspension geometry. It handles grass, roots, and small obstacles better than the lower Grom buggy or Mojave Grom variants.
Do I need a new charger for upgraded Grom batteries?
A quality balance charger is highly recommended when upgrading to larger capacity batteries. The stock wall charger works but charges slowly at around 0.5A. A proper balance charger lets you charge at 1C or higher, reducing charge times from over an hour to 30-40 minutes.
Final Verdict: Building Your Upgraded Grom
The best ARRMA Mojave Grom upgrades address real weak points rather than adding unnecessary bling. Start with the five essentials: metal gear servo, quality 2S LiPo battery, aluminum shock caps, full bearing kit, and steel spur gear. This combination costs under $150 total and transforms any Grom variant into a reliable micro basher.
For the standard Grom buggy, prioritize keeping weight down. This variant performs best when you resist the urge to add heavy aluminum parts everywhere. Focus on reliability upgrades and let the light weight do its job.
The Mojave Grom deserves slightly more attention to suspension tuning for rough terrain use. Its longer wheelbase handles dirt and gravel exceptionally well with the right shock oil weight and spring preload settings.
The Mini Kraton benefits most from chassis protection upgrades given its tendency to land hard from stunts and wheelies. A reinforced front bumper and proper skid protection extend chassis life significantly.
In 2026, aftermarket support for the Grom platform has matured considerably. Quality upgrade parts are readily available from multiple manufacturers at competitive prices. The platform has proven itself as a legitimate entry point to the ARRMA ecosystem, sharing design philosophy with larger trucks like the Typhon and Kraton while being accessible enough for new hobbyists.
Whether you’re running a Grom as your primary basher or keeping one around as a backyard fun machine alongside larger trucks, these upgrades make the experience significantly better. The platform rewards thoughtful modification rather than throwing money at every available upgrade. Choose your upgrades based on how you actually run the truck, and you’ll build something that handles your specific abuse without breaking the bank.
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