thats proabably because you are leaning more left than staying toward the center.
if you are leaning more toward the left it may be because you are pressing on the left peg harder than the right or because of the raod.

 

I find that a bit awkward lol. I do take lefts way better than rights, no chicken strip on the left, and maybe an 1/8 inch on the right. But looking at the wear pattern down the center I can see that it's wearing towards the left center more. And I doubt it's because I'm slightly leaned left 80% of the time lol. I think my chain adjusters have to do with it wearing funny.