You should e-mail Roger Berg, who manufacture the stroller, and he can help you out. runabout@teleport.co m

This is straight from his 2011 price list...I don't know what the different parts mean but Roger will be helpful, I'm sure.

16” or 18” Wheel /Tire Complete: $75
16” or 18” Wheel, Axle, Discs: $50
Axle & Bolt /Washers with Loctite: $13
Bearings with Loctite: $13/set
16” Front Wheel Rim: $25
Front Axle with Nuts/Washers: $13
Wheel Discs: $10 ea
Airless Tires / 16”&18”/Black: $25ea