[thstone]

In regards to the replacement of a single tire (per axle), the best recommendation is to replace the used tire if it has less than 70% tread remaining.

Tread remaining is a much better criteria than how many miles might be on a tire because different tires and how they were driven can result in a huge difference in tire wear.

With only 1,500 miles on the tires, the remaining tire probably has more than 70% of its tread left, but its best to check it just to be sure.