it wont matter front or back, besides SOLD IN PAIRS were them in same time one of front one on back, if you worry just ROTATE THE THINGS, As PROTO Had wrote in past, you DONT NEED TO wear them in from testing there done its NOT NEEDED but recommended, but the Wheels are Fresh you shouldnt ride them till late DEC, other wise they will wear, chunk quick due not 100% set
as for wearing them in as they stated u Dont need to, the Design basicly from what i seen, is great, that wheel cant seperate from the alloy core, its virtualy IMPOSSIBLE,