Mill Supply carries a variety of replacement Lawn Mower Wheels including Plastic Wheels and many other mower parts.

6" x 1-1/2" Plastic wheel, 1-3/8" offset hub, 1/2" center hole, diamond tread

7" x 1-1/2" Plastic wheel, 1-3/8" offset hub, 1/2" center hole, diamond tread

7" x 1-3/4" Plastic wheel, 1-3/8" offset hub, 1/2" center hole, lug tread

7" X 1-3/4" Plastic wheel, 1-1/2" offset hub, 1/2" center hole, brick tread, gray

8" x 1-3/4" Plastic wheel, 1-1/2" offset hub, 1/2" center hole, brick tread, gray

8" x 1-3/4" Plastic wheel, 1-3/8" offset hub, 1/2" center hole, lug tread

8" x 1-1/2" Plastic wheel, 1-3/8" offset hub, 1/2" center hole, diamond tread
Mower-parts.net carries replacement Lawn Mower Plastic Wheels as well as other mower parts & accessories.