The size is the same as the Vega 11.5 x 6.5 - 6. I don't know the compound. I only had a choice of the one tire so couldn't be too fussy about compound. It is marked D20A if that helps. I did fit it with the specified rotation, seemed like the right choice. For anyone wanting to do the change themselves my experience was that removing the wheel assembly was the easy part. I couldn't even get the tire to budge so took it to my local tire guys who used a machine to break the bead then tire spoons to remove and refit the tire. They then used air pressure to reseal the bead. It seemed to take a lot of air pressure to snap the bead back into place so I don't think you could achieve that with a hand pump. It was a bit scary trusting my Onewheel to them but luckily it seems to have worked out well. Given I'm in Australia, sending it back to the US for servicing would have cost at least $500 in shipping and probably taken 3-4 weeks so doing it myself locally was the only real option.