FlexCore RC: Experimental Parametric TPU Tire Inserts

🏁 Experimental Parametric TPU Tire Inserts – The Future of RC Traction

Tired of foam inserts getting soaked, rotting, or developing flat spots? This experimental project brings a 3D-printed solution for the entire RC community. Whether you race 1/10 on-road, crawl over rocks, or jump with a buggy, these TPU inserts offer a durable and consistent alternative to traditional foam.

Note: The included model fits the rim I created for the Alfa Romeo 75. Since there are countless rims and tires, it is necessary to create your own version of the insert.

The heart of this project is the included OpenSCAD parametric file. You can easily customize the inner/outer diameter, width, and stiffness to fit any rim or tire size.

🌟 Key Benefits

• 🌊 Zero Water Absorption: Perfect for wet conditions, mud, and snow. No more unbalanced wheels due to water weight!

• 🛡 Indestructible: Unlike foam which degrades, TPU survives the life of the car.

• 🚫 No Flat Spots: Maintains roundness even after long storage periods.

• 🔧 Fully Customizable: Use the provided .scad file to match your specific RC scale (1/10, 1/8, etc.) and tire type.

•  📊 Smart Analysis: Built-in physics engine calculates weight and stiffness indices in real-time.

📊 Physics Analysis & Simulation

The script now includes a real-time analysis module. Check the Echo/Console window in OpenSCAD to see calculated properties of your design:

• *   Radial Stiffness Index: Measures vertical hardness (bumps/jumps).

• *   Lateral Stiffness Index: Measures side-to-side stability (cornering).

• *   Void Ratio (%): Percentage of air vs. material.

  • > 90% = Soft (Crawlers)

  • < 85% = Hard (Racers)

• Est. Weight: Approximate weight in grams to help with wheel balancing.

• Effective Density: Comparison to foam density (g/cm³).

⚙ How to Adjust Stiffness (Soft / Medium / Hard)

You can tune the insert's performance to match your driving style by modifying the parameters in the .scad file or changing your slicer settings.

• SOFT (Crawler / High Grip):

  • SCAD: Decrease lamella_count (e.g., 10-14).

  • SCAD: Decrease lamella_thickness (e.g., 0.4mm).

  • Material: Use softer TPU (Shore 85A or 90A).

• MEDIUM (General Bashing / All-Round):

  • SCAD: Default settings (approx. 18 lamellas, 0.5mm thickness).

  • Material: Standard TPU 95A.

• HARD (On-Road / High Speed / Heavy Trucks):

  • SCAD: Increase lamella_count (e.g., 24+).

  • SCAD: Increase lamella_thickness (e.g., 0.6mm - 0.8mm).

  • Slicer: Add more perimeters (walls) to the print.

🧪 Experimental Status

This is an active prototype. I primarily test on 1/10 On-Road chassis using TPU 95A. I encourage the community to test, remix, and share feedback on different pattern parameters and materials!

Requirements:

• BOSL2 Library for OpenSCAD is required to render the file.

Updates:

🆕 New Features (v1.02)

• Tread Generator: You can now generate tread patterns directly on the insert enable_tread), allowing it to function as a standalone airless tire for light robots.

• Mounting System: Support for custom 2-part rims using protrusions or holes enable_mounting_system).

• 📊 Smart Analysis: Built-in physics engine calculates weight and stiffness indices in real-time.

🆕 New Features (v1.01)

Advanced Tuning Options:

• Lamella Profiles lamella_profile_type):** Choose between "S-Curve" (standard), "Straight" (linear), or "Curved" (progressive arc).

• Progressive Stiffness: Enable add_staggered_lamellas to add a second, shorter set of lamellas that engage only under heavier compression. Adjust their length with staggered_lamella_length_ratio.

• Variable Thickness: Fine-tune flex by setting different thicknesses for the start and end of the lamellas lamella_thickness vs lamella_thickness_outer).

• Mirrored Layout: Use add_mirrored_lamellas to create a cross-hatch pattern for unique structural properties.