Check Your Tyre Tread
There are two popular ways to check for signs of tyre tread wear.
One easy way is the coin test - Simply insert a coin into your tyre's tread groove. If you can see all of coin's face, it's time to replace your tyres.
Another way is to look at the tread wear indicator bar that's molded into your tyres. The bars are located at the bottoms of the tread grooves in several locations around the tyre. When a tyre is so worn that these bars become visibly flush with the adjacent tread ribs, it's time to replace the tyre.
Penfold suggests using the tyre tread using either method every 3,000 miles.