There are a few ways to tell if your tire is backwards. One way is to look at the tread pattern. If the tread is running in the opposite direction of what it should be, then the tire is probably mounted backwards. Another way to tell is by looking at the sidewall of the tire. The manufacturer's information should be facing out, and if it's not, then the tire is likely mounted backwards. Finally, you can try spinning the wheel and see which way the tire rotates. If it rotates in the wrong direction, then the tire is most likely mounted backwards.