Tyre Damage : Doh!

Okay ... so I am stupid. Yes, I do cherish my bikes ... yes I know them intimately ... Of course I do!!!!

This afternoon I showed the very helpful Jason up at Halter's Cycles and it turns out these are wear indicators; ie: they show how much the tread is worn. Clever, huh?

So thanks Jason. I will buy something worthwhile from your really rather good bike shop some time soon.

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* see my Bike Index here

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Tyre Damage : Continental GP4000

Can anyone identify this tyre damage or possible flaw?

This Continental GP4000 tyre has done about 200 road miles at 120psi on the rear of my bike. I weigh about 190lb.

I noticed this after climbing a local hill which has been recently relaid. At the time I noted to myself that the blacktop seemed to incorporate a lot of what appeared to be glass granules, about the same sort of size / appearance as glass from a broken windscreen. The glass definitely appears to be a part of the surface, not just pressed in by traffic.

I don't normally ruminate about the composition of road surfaces, but in the last couple of days I had been listening to an article on NPR which stated that low grade glass is recycled for road surfaces ...
So anyway, at a coffee stop, not a mile from the hill, I happened to notice these rather odd pock-marks, rather as if a miniature ice-cream scoop had gouged out the tyre compound. The cut seems very clean.

Now I can't say for certain that this had only just happened, but I had just checked / adjusted my spoke tension / wheel trueness just a couple of days before and hadn't noticed any damage.

Does anyone have a clue what's happened?

Otherwise, I love these Contis. And yes, I can spell tyre ;-)