AGV Wheels Explained: Types, Materials and How to Choose the Right One

The wheel is the most underestimated component on a mobile robot. Teams will spend weeks selecting motors and controllers, then bolt on whatever wheel the supplier throws in — and wonder why odometry drifts, floors get chewed up, or the drive unit fails early.

This guide covers the decisions that actually matter: drive wheels vs. load wheels, materials, the five specs to check, and how wheel choice interacts with the rest of your drivetrain.

1. Drive wheels vs. load (caster) wheels

Every AGV/AMR runs two kinds of wheels, and they fail in different ways:

• Drive wheels transmit torque. They need grip, wear resistance, and a hub/bearing assembly that survives the motor's output torque. This is where polyurethane dominates.
• Load wheels / casters carry weight and stabilise the vehicle. They see less torque but constant side load — hardness and bearing quality matter more than grip.

Spec'ing both from the same datasheet is the most common mistake we see. A wheel that works fine as a caster can be a poor drive wheel.

2. Wheel materials: the real trade-offs

Polyurethane (PU) — the default for drive wheels. Good grip on concrete and epoxy floors, excellent wear resistance, typically 85–95A Shore hardness. Downsides: it can chunk under shock loads if the formulation is wrong, and cheap PU debonds from the hub.

Rubber — quieter and more forgiving on rough floors, but wears faster and has higher rolling resistance. Fine for light-duty indoor robots.

Nylon / polyamide — very hard, very low rolling resistance, high load capacity. But grip is poor: on a dusty warehouse floor a nylon drive wheel will spin. Mostly a caster material.

Steel — only for rail-guided or extreme-temperature applications. It destroys floors.

For drive wheels on a typical warehouse AGV: start with PU at 90–95A and only deviate for a reason.

3. The five specs that matter

1. Diameter — larger rolls over obstacles more easily and lowers rolling resistance, but raises the centre of gravity and needs more torque for the same tractive force.
2. Width / contact patch — wider spreads the load (less floor pressure, less wear) but increases scrub torque when steering.
3. Load rating — rated per wheel, with a safety margin. Remember dynamic loads: braking and turning shift weight between wheels.
4. Shore hardness — softer grips better but wears faster and raises rolling resistance. 85A vs 95A is a real decision, not a rounding error.
5. Hub and bearing — keyway vs. press fit, bearing load rating, and critically the bond between tyre and hub on PU wheels. Most field failures we hear about are bond failures, not tread wear.

4. How wheel choice ripples through the vehicle

• Traction: your drive unit can only deliver the force the wheel–floor contact patch can hold. Run the numbers with our tractive force and wheel load calculation guide before finalising the wheel.
• Odometry: softer compounds compress and slip more, degrading dead-reckoning accuracy. If you navigate by wheel encoders, hardness is a navigation decision.
• Floor wear: hard wheels on soft floors (epoxy, tiles) leave marks and eventually damage the surface. Match the wheel to the floor, not just the robot.
• Noise: rubber and soft PU are noticeably quieter — relevant for robots working near people.

5. A practical selection sequence

1. Fix the load case: total mass and worst-case load transfer (braking, gradients).
2. Calculate required tractive force and per-wheel load (guide).
3. Pick material for your floor and duty cycle (default: PU 90–95A).
4. Size diameter and width against obstacle, envelope and torque constraints.
5. Check the hub interface against your drive unit's output shaft. Our horizontal drive-steering units, for example, ship with matched PU drive wheels, so this step disappears.

Bottom line

The wheel is a systems decision, not a commodity. Get the material, hardness and load rating right, and the rest of the drivetrain has a much easier life.

If you're matching wheels to a drive unit, message us on WhatsApp or email info@jy-robots.com — send your load case and floor type and we'll recommend a combination.