I am a huge fan of the Continental GP4000s tyres on my road bike and earlier this year I went onto my third set- this time in 25mm width. I love the tyres they are fast – quick rolling and pretty tough.
Yesterday I was reconsidering after a ride out involved a moment with a loud BANG. I stopped and was amused – this was the first puncture i have had on the road bike in 3000+miles (I am not counting the two punctures on the turbo when the inner overheated)
I changed tube and pumped when I saw the inner tube starting to bulge out of the seam on the tyre – I managed to deflate just in time – inspected and realised the seam had given way.
I reinflated the tyre but this time to only around 30psi (as above – the seam bulged and stayed put) and then limped home at 20kmh.
Have emailed Conti UK to see what they have to say – it must have been a bad batch – the previous 4 have all been good.