We have two very high quality spare wheel options. We offer pneumatic wheels in a few different quantities as well as replacement stair climber tri-wheels. The pneumatic wheel replacements are a very good idea to have at hand. Due to them being air filled they are susceptible to puncture if they hit something sharp, though they are still extremely sturdy something like a large nail would puncture the wheel. The spare tri-wheels though they are solid wheels and won't puncture after heavy use wear and teat will become a factor, so these cheap replacements are great to have at hand.