The Helion Criterion is a popular 1/10 scale RC truck known for its durability and off-road capability. Like any RC vehicle, the rear suspension takes a beating, especially if you run on rough terrain or bash hard. Whether you're looking to replace a broken part or upgrade for better handling, understanding the available rear suspension parts is key. This guide covers everything from stock replacements to aftermarket upgrades, helping you make the right choice for your driving style and budget.
Understanding the Helion Criterion Rear Suspension Layout
The Helion Criterion uses a solid rear axle setup with four-link suspension geometry. This design provides excellent traction and stability over uneven ground. The main components of the rear suspension include:
Key Components: A-Arms, Shocks, Hinge Pins, and More
- Rear A-Arms (Lower and Upper): These connect the axle to the chassis and allow vertical wheel travel. Stock arms are made from composite plastic. They are lightweight and flexible but can snap on hard impacts.
- Shocks (Dampers): The Criterion comes with oil-filled shocks that offer adjustable damping. They contain springs, shock oil, and seals. Over time, seals can leak, and oil viscosity changes.
- Hinge Pins: These are the metal pins that attach the A-arms to the chassis and axle. They wear out and bend, causing slop in the suspension.
- Pivot Balls and Ball Joints: Found at the ends of links and shocks. They allow smooth articulation but can loosen or pop out.
- Sway Bar (Anti-Roll Bar): Some versions include a rear sway bar to reduce body roll. Not all models have it, but it can be added as an upgrade.
- Links: The four links (two upper, two lower) connect the axle to the chassis. They often come with plastic rod ends that can strip.
Common Rear Suspension Problems and When to Replace
Knowing the weak points helps you plan for maintenance. Here are the most frequent issues:
Bent or Broken A-Arms
If you land a jump wrong or hit a curb, the rear A-arms often break first. Stock composite arms are inexpensive but can crack. Check for visible cracks or if the arm has excessive play. Replacing them with upgraded aluminum arms prevents future breakage but transfers more stress to other parts.
Leaking or Weak Shocks
Oil-filled shocks eventually leak from the seal, especially after hard use. You'll notice oil on the shock body or reduced damping. If the shocks still work but feel weak, you may just need fresh oil. If they are leaking badly, replace the shock bodies or get complete aftermarket shocks with better seals.
Worn Hinge Pins and Bushings
The steel hinge pins wear grooves over time, especially if dirt gets in. This causes slop and imprecise handling. Replace pins when you see wear. Upgrade to stainless steel or titanium pins for longer life.
Upgrading Your Helion Criterion Rear Suspension
Upgrading can improve durability and handling. Here are the most effective upgrades:
Aluminum vs. Composite A-Arms
Aluminum A-arms are stronger and won't break, but they are heavier and can bend instead of flexing. If you bash hard and break arms often, aluminum is a good investment. However, they may transfer impact to the chassis or axle housing. Composite arms (like RPM brand) are a middle ground—they are more flexible than stock but much tougher than stock plastic. For most drivers, upgraded composite arms offer a great balance.
Oil-Filled vs. Friction Shocks
Stock shocks are oil-filled, which is good. Some budget upgrades offer friction shocks (no oil), but these provide poor damping and should be avoided. Instead, look for shocks with threaded bodies for preload adjustment and better seal design. Brands like Hot Racing or Integy offer direct-fit aluminum shocks for the Criterion. They come with different spring rates and allow you to tune for your terrain.
Upgraded Hinge Pins and Bushings
Stainless steel hinge pins resist wear better than stock steel. Also consider installing bushing sleeves or replacing plastic bushings with brass or aluminum ones. This reduces slop and keeps the suspension tight. Many aftermarket kits include shims to adjust play.
Sway Bar Install
If your Criterion didn't come with a rear sway bar, adding one reduces body roll and improves cornering stability. It's an easy upgrade that makes a noticeable difference on track or hard-packed surfaces. You'll need the sway bar kit, which includes the bar, links, and mounting hardware.
How to Choose the Right Parts
With multiple brands and options, selecting parts can be overwhelming. Focus on these factors:
Genuine Helion vs. Aftermarket
Genuine Helion parts are readily available and guarantee fit. They are usually cheaper but may not be as durable as aftermarket. For critical components like A-arms, aftermarket options (RPM, Hot Racing, Treal) offer improved materials and design. For shocks, aftermarket often provides better sealing and adjustability. Always check compatibility: some parts from other models (like Traxxas Slash or Arrma Senton) might fit with modifications, but it's safer to stick with Criterion-specific parts.
Compatibility with Other Models
Helion parts share some dimensions with other brands. For example, the Criterion rear shock length is similar to many 1/10 scale trucks. However, mounting points differ. If you want to use a shock from another vehicle, measure the eye-to-eye length and compare to stock. Online forums can help, but your best bet is to search for "Helion Criterion [part name] upgrade" to see verified options.
Budget Considerations
- Stock replacement: Least expensive. Buy a set of plastic arms and basic shocks. Plan for frequent replacements if you drive hard.
- Mid-range: Upgraded composite arms (e.g., RPM) and decent oil-filled shocks from a known brand. This is the sweet spot for most bashers.
- High-end: Aluminum arms, premium shocks with threaded bodies, titanium hinge pins, and sway bar. Great for competitive racing or extreme bashing.
Installation Tips
Replacing rear suspension parts is straightforward with basic tools: hex wrenches, screwdrivers, and pliers. Here are a few pointers:
- When removing A-arms, note the orientation of washers and clips. Use a magnetic tray to avoid losing small parts.
- Apply threadlocker to hinge pin set screws to prevent them from backing out.
- For shocks, bleed them properly to remove air bubbles. Fill with oil to the top, then slowly cycle the shaft to expel air.
- After installation, check for binding. The suspension should move freely without friction. Add shims if there is side-to-side play.
- Test drive on a flat surface to verify handling. Adjust shock preload and oil weight as needed.
Final Recommendation
For a Helion Criterion owner who wants reliable performance without breaking the bank, start with upgraded composite A-arms (RPM or equivalent) and a set of mid-range oil-filled shocks from Hot Racing. Replace hinge pins with stainless steel ones and add a rear sway bar if your truck didn't come with one. This combination will dramatically improve durability and handling while keeping costs under control. If you're on a tight budget, stick with stock replacements but inspect frequently. If you're a serious racer or extreme basher, invest in aluminum arms and premium threaded shocks. Whatever path you choose, maintaining the rear suspension properly will keep your Criterion running strong for years.