Wear indicators on Continental road tyres.

When I first fitted the Conti Grandprix GTs, I spotted a couple of what I thought were minor manufacturing defects, like tiny bubble holes, in the rubber of the tread. I thought it was odd given the very Germanic quality one expects from Continental tyres but thought nothing more of it.

A few weeks ago I was bored at work and looking around the technologies section of the Continental road bike tyres website when I found that these holes are actually wear indicators! When the hole effectively disappears due to tread wear, replace the tyre - simple. They're not universal, I've just checked the GT 4 Seasons I have waiting to go on when the weather changes, but very useful if they are present.