• Beginning September 2014, the setscrew will be changed from 4-40 to 6-32. They will use a 1/16" hex wrench.
• For the remainder of the year you can still ask for 4-40 if you prefer, just write it into the Additional Comments section during checkout.
• To differentiate, the 6-32 wheels will have a mark inside the hub.
Cobra Minisumo Wheels are top-quality competition wheels. Supplied in packs of 2.
- The fiberglass-infused nylon hubs are designed with a ring of captive holes for locking the tire in place.
- Tire tread composed of Shore A20 polyurethane makes these the highest traction wheels you can buy.
- The wheel is designed to envelop a 16mm gearbox.  Perfect where length is a concern.  (Two Gold Spark motors with these wheels will fit into the 10cm width limit of minisumo events.)
- An extra-long setscrew allows you to easily tighten the wheels onto a 3mm motor shaft.
- Setscrew is accessed through tyre. (Don't forget your hex wrench)

Specifications:
Hub material: Fiberglass-reinforced nylon
Tire material: Shore A20 polyurethane, professionally vacuum-degassed
Coefficient of Friction (against smooth unpainted MDF wood): μ=1.75 (Silicone μ=1.30, Rubber μ=1.05)
Diameter: 2.86cm (1.125")
Width: 2.16cm (0.85")
Inner diameter: 1.76cm (0.688")
Shaft bore: 3mm (0.118")
Weight: 12.6grams each (0.44oz)

Tip: Clean the tires with isopropyl alcohol wipes before each match for optimal traction.