So I was checking out my tires during lunch on the bike and see that my rear is getting close to the wear bars. I have about 4k on the rear. I check the front and it to is getting close to being worn to the bar. I dont drag knees but do like to lean the bike over. I though you usually go thru 2 back tires to 1 front. is that the not the case or is something wrong with my bike?