Build Essentials

Efficiency Guidelines: Weight & Friction

Your V5RC robot is limited to 88W of power and two air tanks. More weight or friction strains mechanisms, reducing speed and torque. In a timed game, speed is essential to outscore opponents.

Goal: Reduce weight and friction without compromising structural integrity. Avoid designs that are light but fragile.

Friction reductions: Use proper spacing, materials, tightness, angles, and ensure connections are square. Builds should be self-correcting and structurally stable.

Tournaments: Consider modular components with pre-assembled backups to justify lightweight designs even if damage is possible.

IMPORTANT
Below are some important concepts to follow to help improve your build quality

Screw Joints

Prefer screw joints over shafts wherever possible (especially chassis wheel connections).

➔  Stronger, more reliable, and easier to control friction than shafts.

Boxing

Use spacers or standoffs to fill the gap between C channels to increase strength of connections

➔  Increases connection strength, reduces bending, minimizes wasted metal.

Squaring

Use bearings/Retainers/shoulder screws/custom plastic to center connections

➔  Maintains low friction and aligns geometry with CAD plans.

Bearings: are a MUST for Shaft connections

  • Always use 2 bearings per shaft (motor counts as one).
  • Fewer than 2: Not enough support.
  • More than 2: Adds friction.

➔  Ensures proper support and minimal friction.

Old Vs New Wheels: Why new wheels are optimal

New wheels are narrower, lighter, and have multiple mounting holes.

➔  They work well with screw joints (older wheels often only fit LS shafts and don’t allow for circular inserts)
➔  Narrow wheels allow closer drive channels → stronger joints, lighter robot, smaller chassis → better maneuverability.

Thin Nylocks & Torx Screws

Use thin nylocks instead of thick: lighter, easier to fit, no structural compromise.

Use Torx T15 screws to prevent stripping.

NOTE
The thin Nylocks and Torques T15 Screws can be ordered on ROBOSOURCE (where our club usually orders all of our screws and nuts)

Blue cartridges: Have less friction

  • VEX motors without a cartridge spin at 3600 RPM. Cartridges gear this down.
  • Lower-speed cartridges (green, red) use more internal gears → more friction and less efficiency.

Rule of thumb:

  • Use blue (fastest) cartridge and gear down to target speed.
  • Only use green/red if mechanism speed ≤ 200 RPM.
➔  Avoid gearing up from low-speed cartridges to reduce friction

Use Appropriate screw lengths

Screws should be only as long as needed.

Excess screw length will add to the robots weight
The content for this page was provided by Zane Radawiec.