I think a 36mm socket is unnecessary for the track. Unless you plan on changing the oil there.
But if you DO get a 36mm socket...I think most rear axle nuts are 12pt 36mm...might want to get one that will remove the spindle nut whenever you need to do rear axle/wheel bearing work.
2015 F34 328iX GT Glacier Silver
2011 E90 M3 Monte Carlo Blue
2004 E46 M3 Imola Red