If the sidecar is attached the pump, then no problems. This pump is compact in size, so it is possible to always carry with them. If you go down the wheel while walking, even mom will be able to pump it up and continue your walk or ride home.
If the pump is not included, you have to look for something to pump up the wheels. The best option is a Bicycle pump. It is almost all. If it is not you, then surely he is your friends, acquaintances, neighbors. With a Bicycle pump you will easily cope with this problem.
If near you there is a tire, a contact there. Most likely, you will not give up in the solution of this problem. Perhaps you don't even take money for it.
Wheel your stroller , you can try to pump motor the compressor. But you may have problems. The fact that the tip on the compressor hose may not fit between the rim and the hub of the wheel. So you need an adapter, which is not so easy to find.
To this question, as the pumping wheel in the stroller, serious as it concerns the safety and comfort of your baby.