My Toyo R888 track tires are getting worn on the edges, particularly on front tires. I have used them 3 track days and I'm almost worn to the bottom of the rain grooves on the outer edges. R888's are uni-directional but symetrical so it looks like these tires can be flipped, re-mounted and switched to opposite side of car. Has anyone done this or does anyone have recommendations for or against? I'm debating whether to flip and try to extend life or just run-em down to the cord as-is. Thanks.