The RadWagon rims fit standard 26" by 2.3" tires. You can purchase replacement tires directly from the Rad Power Bikes website on the page linked HERE and replacement inner tubes HERE, which are both located on the Replacement parts page.
Since the tires and tubes are a standard size, all reputable bike shops should carry compatible replacement tires.
Ensure replacement tires have reflective striping or other reflectors, such as spoke mounted reflectors, are installed on your bike so the bike is adequately visible in low-light conditions.
NOTICE: If you do not have the experience, skill, and tools to maintain the wheels and tires, Rad Power Bikes highly recommends having a certified, reputable bike mechanic complete these procedures as well as any future maintenance, adjustments, or tuning.
Low pressure may result in loss of control, and overinflated tires may burst. Failure to always maintain the air pressure rating indicated on pneumatic tires may result in tire and/or wheel failure. Do not overinflate or underinflate tires. Inflate your tires from a regulated air source with an available pressure gauge. Inflating your tires from an unregulated air source could overinflate them, resulting in a burst tire.