Amazon.com: MroMax 1Pc Stroller Wheel Set, 130mm x 33mm Swivel Wheel, Plastic Swivel Wheel Replacement for Stroller and Pet Stroller Black : Pet Supplies
Source 5 inch 6 inch 7 inch small plastic doll pram wheels on m.alibaba.com
1-Wheel Stroller Kit for Burley Bike Trailers - Burley
Vintage French Doll Pram Doucet Metal W/ Rubber Wheels Carriage Buggy - Ruby Lane