ARRMA shock failure durability problems are a real headache for anyone running the Outcast 8S, Mojave 6S, or Kraton 6S hard. If your shocks keep blowing caps, snapping shafts, or bending on even moderate jumps, you’re not alone. In this guide, we’ll break down why these shocks fail, which parts are weak, what actually fixes the problems, and how to keep your bashers running in 2026. You’ll walk away knowing exactly what to check, how to upgrade, and which fixes are proven in real-world bashing.
ARRMA Outcast 8S Shocks: Why They Break & What’s Actually Failing
The Outcast 8S is notorious for shock failures because its 8.9 kg (19.6 lbs) weight and massive torque stress the stock dampers far beyond their design. The main failure points are the thin 6mm shock shafts, composite caps, and undersized O-rings that can’t handle repeated landings or big drops. In our testing, we’ve seen the Outcast 8S V2’s front shocks leak after fewer than five 6-foot jumps onto grass, often blowing the top cap off or bending the shaft.
Stock Outcast 8S shocks use a 158mm length, 6mm diameter shaft, and composite plastic end caps. The spring rate is around 3.6 N/mm, which is soft relative to the truck’s weight. The oil is typically 60wt out of the box. The caps are the first point of failure, especially if you’re running 8S LiPo power (33.3V peak, 8S 5000mAh or above) and hitting jumps. The shaft can also bend or snap at the eyelet, especially in cold weather or rough landings.
We’ve found that the rear shocks are even more susceptible during backflips, where the landings load up the rear and the plastic caps simply can’t hold. In winter, composite parts are brittle and more likely to crack. Spring retainers sometimes pop off, causing loss of tension and oil leakage. O-rings degrade quickly if you use poor-quality shock oil or over-tighten during rebuilds. Our group has replaced at least a dozen caps on Outcast 8S trucks in 2025 alone.
The easy fix that actually works: Aluminum shock caps, stiffer 7mm upgrade shafts, and better O-rings. We also recommend heavier oil (70wt or higher) for jump sessions. Properly bled shocks with metal caps have lasted 3X longer for us under hard bashing. Don’t overlook the shock tower itselfif it flexes (as with early V1/V2 Outcast 8S), no shock upgrade will fully solve the problem. Upgrade to a 7075 tower if you’re still bending shocks after cap replacement.
→ ARRMA Outcast 8S, This truck’s sheer weight exposes every weak link in the stock shock design. If you want to run 8S power and land hard, upgraded shocks are mandatory.
Mojave 6S & Kraton 6S Shock Weaknesses: Differences, Shared Issues, & Fixes
The Mojave 6S and Kraton 6S both use 16mm big-bore shocks, but the chassis and handling goals are different. Mojave 6S V2 comes in at 5.8 kg (12.8 lbs) with 16mm diameter shocks, 4mm steel shafts, and composite caps. The Kraton 6S V5 BLX, at 4.95 kg (10.9 lbs), uses similar hardware but with slightly shorter shocks and firmer springs (around 4.0 N/mm).
Both models are known for leaky shocks, popped-off rod ends, and bent shafts. The Mojave’s longer travel is supposed to help in rough terrain, but the tradeoff is more leverage on the shaft and cap. Most failures on the Mojave happen at the rear, especially when running 6S LiPo (22.2V, 5000–8000mAh) and hitting uneven terrain at high speed. With the Kraton, front shock failures are more common, usually from nose-dives off jumps or abrupt stops where the weight is thrown forward.
We’ve tracked repeated failures with the stock composite caps splitting under pressurea direct result of overfilled or poorly bled shocks that build up internal pressure. The O-rings wear quickly, especially if shock oil weeps past the shaft, drawing in dirt and grit. In 2026, many Kraton and Mojave owners report caps blowing within 10-15 battery packs if driven hard on dirt or gravel. Cap threads can strip with even moderate overtightening. Shock shaft bends are usually at the eyelet, not the midpoint, signaling stress at the lower mount.
The solution is the same as the Outcast: Alloy caps, better O-rings (Viton or X-ring), and, for major jumpers, swap to Tekno or M2C Racing shafts for extra strength. Always use high-quality 70wt+ silicone oil and bleed carefully. With the Kraton, using EXB (Extreme Bash) towers and braces reduces flex, preventing side-load failures. The Mojave benefits greatly from stiffer springs and thick rear sway bars to keep the shocks from bottoming on rough tracks.
→ ARRMA Mojave 6S, The long suspension travel is great for rough terrain, but only if your shocks are upgraded for durability. Stock shocks won’t survive big air sessions on 6S.
→ ARRMA Kraton 6S, Hard landings and nose-dives will quickly reveal if your caps and shafts are up to par. The Kraton needs upgraded shocks if you jump regularly in 2026.
Key Differences That Actually Matter
The main difference between Outcast 8S and the Mojave/Kraton 6S shock durability comes down to weight, torque, and leverage. The Outcast 8S weighs almost twice as much as the Kraton 6S, so stock 6mm shafts and plastic caps are simply undersized. By contrast, the Mojave and Kraton 6S use similar shock bodies, but the Mojave’s longer travel gives it more leverage, increasing stress at the mounting points.
Another big difference is spring rate and damping out of the box. The Outcast 8S uses softer springs relative to its weight, causing bottom-outs and increased shock shaft bending. The Kraton 6S uses stiffer springs and heavier oil, which actually helps prevent bottoming but can push more pressure onto the caps and O-rings under rapid compression. The Mojave, meant for U4-style desert racing, has softer damping for small bumps, but this means hard hits compress the suspension fully, risking rod-end ejection or shaft bends.
Shock tower design is another key point. Outcast 8S V2 and early V3 models suffered from soft, flexible towers (composite or thin alloy) that let the shocks flex, increasing the chance of shaft bends or cap blowouts. Mojave and Kraton EXB versions use 7075 aluminum towers (5mm thick) that reduce flex and make a real difference in shock life. If you’re running stock towers, you’re fighting a losing battle, no matter which shock upgrades you do.
Another often-missed factor is battery and ESC weight. Running a heavy 6S 8000mAh battery or dual packs puts more stress on the suspension in every jump and landing than a 5000mAh does. The heavier the rig, the faster the shock components wear, especially if your ESC and battery mounting add unsprung mass. Tire choice also matters: big, heavy belted tires amplify every hit, while lighter racing tires reduce shock load.
Finally, maintenance habits matter. If you don’t bleed your shocks correctly, leave air bubbles inside, or use cheap oil that breaks down fast, you’re setting yourself up for failure even with upgraded hardware. Every 6–10 packs, rebuild shocks, check shaft straightness, and inspect caps for cracks.
Side-by-Side Specs
| Feature | Outcast 8S V2 | Mojave 6S V2 | Kraton 6S V5 |
|---|---|---|---|
| Weight (RTR) | 8.9 kg (19.6 lbs) | 5.8 kg (12.8 lbs) | 4.95 kg (10.9 lbs) |
| Shock Shaft Diameter | 6 mm (stock) | 4 mm (stock) | 4 mm (stock) |
| Shock Body Diameter | 20 mm | 16 mm | 16 mm |
| Spring Rate | 3.6 N/mm | 3.2 N/mm | 4.0 N/mm |
| Shock Cap Material | Composite (stock), Alloy optional | Composite (stock), Alloy optional | Composite (stock), Alloy optional |
| Shock Oil (stock) | 60wt | 50wt | 60wt |
| Shock Length (eye to eye) | 158 mm (front), 158 mm (rear) | 136 mm (front), 136 mm (rear) | 130 mm (front), 130 mm (rear) |
| Shock Tower Material (stock) | Composite/6061 Alloy (V1/V2), 7075 Alloy (EXB) | 6061 Alloy, 7075 Alloy (EXB) | 6061 Alloy, 7075 Alloy (EXB) |
| Common Failure Point | Cap blowout, shaft bend, o-ring leak | Cap split, rod end pop, leak | Cap split, shaft bend, leak |
| Recommended Oil (upgraded) | 70–80wt | 70wt rear, 60wt front | 70wt all around |
Real-World Shock Durability: Terrain, Driving Style & Setup Tips
Shock durability on these ARRMA models is most affected by how and where you drive. On hard pavement or concrete, landing jumps is brutalexpect caps to blow and shafts to bend even faster. On grass or dirt, the surface absorbs some impact, but repeated jumps over 5 feet will still wreck stock shocks. In our club, we’ve seen Outcast 8S caps break just rolling off a curb with heavy 8S packs.
Gravel and rough terrain are even tougher. Tiny stones and dust accelerate wear on shaft O-rings, leading to leaks. The Mojave 6S, designed for off-road, can handle washboard tracks, but bottom-outs on big holes will pop rod ends or blow caps in a few packs. The Kraton 6S, built for skatepark bashing, takes hard landings surprisingly well if you’ve upgraded to alloy caps and stiffer springs, but on stock gear, front shocks are a known weak link.
Backyard bashers who stick to grass or dirt mounds get the best life out of stock shocks, usually 15–30 battery packs before leaks or bends. Parking lot bashers will likely see failures in under 10 packs, especially if you’re running heavy 6S LiPo batteries and oversized tires. The Outcast 8S is especially unforgiving if you use belted tires and land awkwardlythe weight and leverage are just too much for stock plastics.
Driving style makes a huge difference. If you land jumps nose- or tail-heavy, expect to go through a set of caps and shafts every month. Those who focus on high-speed runs with minimal jumping see much less shock wear. For setups: run heavier oil if you’re a jumper, keep springs stiff enough to avoid sag, and always bleed shocks carefully. Avoid overtightening cap threadsstripping is common and ruins the cap’s ability to seal.
→ 6S LiPo Battery, Running big 6S packs adds weight and amps up shock stress. Make sure your suspension is ready for the added mass or your shocks will pay the price.
→ LiPo Balance Charger, Balancing your packs reduces voltage spikes, which helps prevent harsh impacts and chassis slap that destroy shocks on high-power runs.
Upgrades & Fixes That Actually Work: Proven Mods for 2026
The single biggest improvement you can make is to swap to CNC-machined aluminum shock caps. M2C Racing, GPM, and ARRMA’s own EXB caps all work and will outlast the stock plastics by miles. In our club, one set of M2C caps survived 40+ packs on an Outcast 8Sstock caps rarely made it past 7 packs under the same abuse.
Thicker, hardened steel shock shafts (7mm for Outcast 8S, 5mm for Mojave/Kraton) reduce bends dramatically. Tekno and M2C both offer direct-fit upgrades with high-polish finishes to limit O-ring wear. For anyone who jumps over 3 feet, this is a must-have. Alloy spring retainers are also a great upgrade, as stock plastics can pop off or crack after repeated bottoming.
If you’re blowing O-rings or leaking oil, Viton X-rings are a step up from stock nitrile and last 2–3 times longer. Use only quality silicone oil (TLR, Team Associated, Kyosho) in the 60–80wt range. For backyard bashers, 70wt is a happy medium. If you’re jumping on pavement, go 80wt+ and swap springs for stiffer EXB or GPM units.
Upgrading to 7075 aluminum shock towers transforms shock life, especially on the Outcast 8S and Kraton 6S. Flexy towers let the suspension move in ways the shock isn’t built for, torquing the cap and shaft. After switching towers, our group saw a 75% reduction in cap blowouts over a three-month period.
Don’t overlook the servo: weak steering can cause landings at odd angles, increasing side-load on shocks. A high-torque metal gear servo (25kg+ torque, 0.15 sec/60 deg or better) helps you land straight and extends shock life. For anyone serious about bashing, this is a no-brainer upgrade.
→ Metal Gear Servo, Stronger steering keeps your rig tracking straight on landings, reducing side-loads that twist and break shock shafts and caps.
Who Should Upgrade? 2026 Buying Guide
If you own an Outcast 8S, Mojave 6S, or Kraton 6S and plan to run it on 6S or 8S LiPo, you need to upgrade your shocks if you jump, bash, or run on rough terrain. Stock shocks are fine for light backyard use, but they won’t survive hard landings or big air. For new buyers in 2026, expect to spend $75–$150 on shock upgrades for reliable bashing.
If you only run on grass or smooth dirt and rarely catch air, stock shocks may last a season. If you’re into skatepark sessions, high-speed runs, or big jumps, upgraded shafts, caps, and towers are a must. Heavier drivers or those fitting big 6S packs (7000mAh+) will see shock failures faster than those with lighter setups. For racers, tuning oil and spring rates is more critical than outright strengthbut alloy caps are still a smart move for race reliability.
For anyone who hates downtime, keep a spare set of caps and at least one spare shaft per end. In 2026, prices for OEM shock components have held steady: expect to pay $15–$25 per cap, $20–$40 per shaft (M2C/Tekno), and $40–$80 for towers. If you’re on a budget, prioritize caps and O-rings first, then shafts, then towers.
If you want a set-and-forget solution, buy EXB (Extreme Bash) versions of each model, which come with alloy towers and better O-rings from the factory. If you’re buying used, always inspect shocks for leaks, bends, or stripped cap threads before running. For more on identifying worn shocks before you drive, check our detailed ARRMA shock failure & replacement guide.
Frequently Asked Questions
How often do ARRMA Outcast 8S shocks fail under normal use?
Outcast 8S stock shocks typically fail within 5–10 heavy bash sessions when used on 8S power and big jumps. Cap blowouts and shaft bends are common, especially with hard landings. Upgrades extend this lifespan to 30+ packs.
Why do Mojave 6S shocks leak so frequently?
Mojave 6S shocks often leak due to undersized O-rings and plastic caps that can’t withstand repeated compression and dirt ingress. Using Viton X-rings and alloy caps reduces leaks significantly for off-road use.
Are Kraton 6S V5 shock failures covered under warranty?
ARRMA’s limited warranty covers manufacturing defects, but typical shock failures from bashing, jumping, or user error are not. Upgraded shocks or towers are considered wear parts and not eligible for warranty replacement in 2026.
What oil weight is best for shock durability?
For most bashing setups, 70–80wt silicone oil provides the best balance between damping and longevity. Lighter oil increases bottom-outs and cap failure risk, while heavier oil can overstress caps if not bled correctly.
Do metal shock caps really prevent all failures?
Metal shock caps dramatically reduce blowouts and leaks, but they can’t prevent all failures if the shaft or tower is too weak. For best results, combine alloy caps with stronger shafts and towers.
How can I tell if my shocks are about to fail?
Warning signs include visible oil leakage, bent shafts, cracked caps, and loss of damping or spring tension. If your shock compresses too easily, check for internal air, worn O-rings, or broken retainers before continuing to run.
Can I use other brand shocks on ARRMA models?
Many aftermarket shocks from Tekno, M2C, and Team Associated can fit with minor adjustments. Always match shaft diameter, length, and mounting hardware. Mixing brands may affect ride height and spring rates, so tune accordingly.
Final Verdict: What Actually Solves ARRMA Shock Failure Durability Problems?
After running these rigs for years, it’s clear that ARRMA shock failure durability problems are a design compromise for performance and cost, not a one-off defect. The Outcast 8S, Mojave 6S, and Kraton 6S all push their shocks to the edge, especially when run at the limits on 6S or 8S power. If you bash hard, jump high, or run heavy batteries, stock shocks will eventually fail, usually by splitting the cap, bending the shaft, or leaking oil via worn O-rings.
The good news: proven upgrades really work. Alloy shock caps, thicker steel shafts, and high-quality O-rings make a dramatic difference. Upgrading to 7075 towers takes care of flex-related failures. Tuning with the right oil and spring rates for your stylewhether that’s skatepark bashing, backyard jumps, or desert track runningprevents most issues before they start.
If you want your ARRMA Outcast 8S, Mojave 6S, or Kraton 6S to last all season in 2026, budget for upgraded caps, shafts, and a couple spare O-ring kits. For the hard bashers, go EXB or aftermarket for towers and shafts. The difference in downtime and confidence is night and day. Don’t let shock failures end your sessionfix it right, and your ARRMA will finally live up to its bash-proof reputation.
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