Check out any of the seven Wheels/tires components enlisted.
On this parts fiche the Washer,10.5x25x1.6 is the most specified component.
A sample from the products for the Wheels/tires include: Tire,rr,at20x10r9,kt3, Valve, Rim,fr,10x5.5at, Washer,10.5x25x1.6.