Aluminum vs Steel RC Upgrade Parts: What's the Real Difference?
When it comes to RC car upgrades, one of the most common questions we hear is: should I go with aluminum or steel parts? Walk into any RC hobby shop or browse any upgrade parts catalog, and you'll find both materials side by side, often for the same components — shocks, driveshafts, suspension arms, hubs, and more. The price difference can be significant, and so can the performance impact.
This guide breaks down the real-world differences between aluminum and steel RC upgrade parts, covering everything from weight and durability to cost and application. Whether you're running an ARRMA basher, a crawler build, or a speed run machine, understanding these materials will help you make smarter upgrade decisions.
Weight: Why It Matters More Than You Think
The most obvious difference between aluminum and steel is weight. Aluminum is roughly one-third the density of steel, which means an aluminum shock tower or suspension arm can weigh dramatically less than the equivalent steel part.
For RC cars, unsprung weight — the weight of components not supported by the suspension (wheels, hubs, driveshafts) — has a direct impact on handling. Less unsprung weight means the suspension can react faster to bumps and terrain changes. This translates to better traction, more predictable handling, and less stress on the drivetrain.
For bashing and speed runs with ARRMA trucks, aluminum upgrades like CVD driveshafts and shock bodies reduce rotational mass, which can meaningfully improve acceleration and top-end speed. For crawlers, the weight difference matters less for speed, but lighter components can still help with power consumption and motor heat.
That said, weight isn't everything. A slightly heavier steel part that never breaks will outperform a lighter aluminum component that cracks on the first big hit.
Durability and Impact Resistance
Steel is significantly stronger and more impact-resistant than aluminum in most RC applications. Steel components can absorb more energy before bending or breaking, which is why factory stock parts — driveshafts, axles, and structural chassis components — are often made from hardened steel.
Aluminum, while lighter, is more brittle under sudden impact. A hard crash can crack or shatter an aluminum part, whereas a steel equivalent might only bend. However, this isn't a simple "steel always wins" equation. Bending can also be catastrophic if it affects geometry — a bent steel steering knuckle can make your car undriveable, while a cracked aluminum part is more obvious and predictable to replace.
Modern RC upgrade manufacturers have improved aluminum alloys significantly. High-quality 7075 aluminum alloy — the same grade used in aerospace applications — is much harder and more impact-resistant than the softer 6061 alloy found in cheaper parts. When you're shopping for aluminum upgrades, pay attention to the alloy specification. Quality matters more than the material label alone.
Corrosion Resistance: Aluminum Wins Here
If you run your RC car in wet conditions, mud, or near saltwater, corrosion resistance becomes a critical factor. Aluminum naturally forms a protective oxide layer that resists rust and corrosion. Steel, even treated steel, will eventually rust if the protective coating wears off.
For outdoor crawling, trail running, or beach bashing, aluminum shocks and suspension components hold up much better over time without the maintenance burden of keeping steel parts clean and protected. Anodized aluminum — which most quality upgrade parts use — adds another layer of corrosion resistance and surface hardness.
If you're a crawler builder who regularly washes your rig with water, aluminum is often the more practical long-term choice for exposed components.
Heat Dissipation
One underappreciated advantage of aluminum is its superior heat conductivity compared to steel. Aluminum dissipates heat roughly four times faster than steel. For components that generate friction heat — shock bodies, differentials, motor mounts — aluminum can help keep temperatures lower during extended run sessions.
This is particularly relevant for high-speed ARRMA builds where shock oil temperature can affect damping performance. Aluminum shock bodies act as small heat sinks, keeping shock oil viscosity more consistent throughout your run.
Cost and Value Considerations
Quality steel upgrade parts — particularly hardened steel CVD driveshafts and gear shafts — are often more expensive to manufacture than aluminum equivalents, despite steel being a cheaper raw material. The machining and heat treatment processes required for hardened steel parts drive up costs. For critical drivetrain components, this cost is usually worth it.
Aluminum parts vary widely in cost and quality. Budget aluminum parts machined from soft alloys may actually provide worse performance than quality stock plastic parts. The sweet spot is mid-to-high-end aluminum upgrades from reputable manufacturers — they offer the weight and corrosion benefits of aluminum without sacrificing structural integrity.
When to Choose Aluminum vs Steel
Choose aluminum for:
- Shock bodies and shock towers — weight savings + heat dissipation
- Suspension arms and links — reduce unsprung weight
- Steering components — precise, responsive steering feel
- Motor mounts — heat management
- Any component exposed to moisture and mud
Choose steel for:
- CVD driveshafts and axles — maximum torque handling
- Differential gears and output shafts — high stress, wear resistance
- Chassis braces on heavy bashers — impact absorption
- Any component subject to high sustained stress rather than just weight-saving
Top ARRMA Upgrade Parts to Consider
For ARRMA 4S trucks like the Kraton, Outcast, and Typhon, the most impactful aluminum and steel upgrades are shocks, CVD driveshafts, and suspension arms. Here are 8 top-selling upgrades from our ARRMA collection:
1/10 Arrma 4S Outcast Kraton CVD Driveshaft Set – Blue
$69.99 Shop Now
1/10 Arrma 4S Outcast Kraton CVD Driveshaft Set – Red
$69.99 Shop Now
1/10 Arrma Kraton Outcast 4S 120mm Shocks – Blue
$31.99 Shop Now
1/10 Arrma Kraton Outcast 4S 120mm Shocks – Purple
$31.99 Shop Now
1/10 Arrma Kraton Outcast 4S 120mm Shocks – Red
$31.99 Shop Now
1/10 Arrma Kraton Outcast 4S 120mm Shocks – Silver
$31.99 Shop Now
1/10 Arrma Kraton Outcast 4S Front Lower Suspension Arm
$28.99 Shop Now
1/10 ARRMA Outcast Kraton 4s 140mm RC Rear Shocks – Blue
$31.99 Shop NowFAQ: Aluminum vs Steel RC Parts
Q: Are aluminum RC upgrade parts always better than stock plastic?
Not necessarily. Quality aluminum parts from reputable manufacturers are generally stronger and more precise than stock plastic. However, cheap aluminum parts machined from soft alloys can actually be worse — they may crack or strip threads under stress. Stick with established upgrade brands and look for 7075 aluminum alloy when possible.
Q: Will aluminum shocks make my ARRMA noticeably faster?
Aluminum shock bodies improve heat dissipation and reduce weight, which can improve handling and consistency during extended runs. The difference in straight-line speed is marginal, but the improved shock performance and reduced unsprung weight contribute to better overall handling and traction.
Q: Can I mix aluminum and steel upgrades on the same RC car?
Absolutely. Most experienced RC builders use a strategic mix — steel for high-stress drivetrain components (CVD shafts, diff gears), aluminum for suspension and shock components. This combination gives you the best of both worlds: durability where it counts most, and weight savings where it matters most.
Q: How do I know if my ARRMA needs aluminum or steel upgrades first?
Start with whatever breaks first. If you're stripping driveshafts, upgrade to steel CVDs. If your stock plastic shocks are inconsistent or leaking, aluminum shocks are the next step. Let your driving style and failure points guide your upgrade priority rather than upgrading everything at once.
