57.1mm (2.25") x 20mm Treaded Low Bounce Polyurethane Wheels for 4mm Axle (2 Pack) by Du-Bro - 225T
Du-Bro's Low Bounce class of wheels have been on more RC aircraft over the decades than any other wheel on the market.  Consistent wall thickness provides a well-balanced tire.  Works great on both grass and paved runways.
Features:
\nShock Absorbing
Fits inside most Wheels Pants and Retracts
Grey Eight Spoke Hub Design
\nIncludes:
\nTwo Wheels
\n
 
  WARNING: This product can expose you to Diisononyl phthalate (DINP), which is known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov.