Pinging devices on different subnets

For some reason, I cannot ping devices on different subnets from the Pi. A Windows computer is able to ping across subnets just fine, so I must have missed a setting on the Pi somewhere. (e.g. pi is 192.168.0.X and different subnet is 10.8.0.X)

Rebooted router and suddenly it works, though I had already tried that…

Try setting a static route on the router (which is presumably your gateway)