Alternative odometry pod designs beyond the standard swing-arm. Each has different fabrication requirements and tradeoffs. Build the swing-arm first — these are for teams ready to go further.
Prerequisite: Complete the swing-arm guide first. The designs on this page require laser-cutting, custom polycarbonate or Delrin parts, and more precise fabrication. Do not start here.
Static / Hard-Mount Pod
🛠 Static Mount — Jaime Rebollar · Perrybotics
Low Profile Screw Joint Pod
A hard-mounted (non-pivoting) screw joint pod. No rubber band, no pivot hinge — the pod mounts rigidly to the chassis. Simpler to build but only works on flat surfaces where the robot chassis does not flex. Best for lightweight robots with stiff frames.
⚙️ Assembly detail — how the insert stack works
One bronze insert spans both the wheel and the rotation sensor, sitting halfway between them — this is why the wheel and sensor sit directly adjacent in the assembly, otherwise the insert would not be long enough to reach across. One green insert goes on each outer side to fill the remaining space and prevent wobble.
Parts: rotation sensor · 2″ omni wheel · high-strength shaft adapter (round piece from the High Strength Shaft Insert Kit) · high-strength spacers · 2-wide C-channel · nylock nuts · screws (length depends on your stack-up — measure before you cut).
Summarized from community discussion on VEX Forum.
Requirement: Rigid chassis — any flex lifts the wheel and breaks tracking
Pros: Simple build, no tensioning, no pivot alignment
Cons: Loses contact on uneven surfaces or over game elements
Uses a polycarbonate flexure piece (the "leaf spring") instead of a rigid pivot and rubber band. The poly piece flexes naturally to keep the wheel pressed against the floor. More consistent floor contact than a rigid mount, and more compact than a swing arm.
Requirement: Laser cutter — the polycarb flexure piece must be precisely cut
The most accurate design covered here. The wheel is supported on both sides and has a very strong mounting point, so it cannot bend. Uses a doubled axle through a custom laser-cut polycarbonate piece with round inserts. Requires sanding a 1.25" screw to fit the pod correctly on some drivetrains. Recommended by EthanMik for teams with laser-cutting access who want the most accurate odometry.
EthanMik's tutorial covers all five tracking wheel designs in one video — screw pod, upgraded screw joint, doubled 2" omnis, leafspring, and pivoting pod. Onshape conversions of the Fusion 360 files by Jaime Rebollar.
2:48 Screw Pod · 3:43 Upgraded Screw Joint · 4:08 Doubled 2" Omnis · 5:00 Leafspring · 5:27 Pivoting Pod · 8:53 Inertial Mount
Credit: Tutorial by EthanMik · Onshape conversions by Jaime Rebollar · Leafspring design by 2654E Echo · Original CAD credits to 1095R, 2654E, and the VEX CAD community.