i just bought it about 4 months ago... so i dont know the history of the tires... but im about 90% sure two of the tires were replaced much more recently than the other two (they might even still be from the factory?) because the treads on the front and the tread on the back are very different, which is a pain, cause i dont want to replace just two tires... and i also dont want to toss two perfectly good tires.. hopefully ill be able to find someone willing to buy the two in good shape when the time comes to replace (which doesnt seem too far off)