Over the years Alan Locke and I have had problems with Schwalbe tyres - usually on the rear wheel. This mostly manifests itself as a weakening of the tyre wall so that the tyre wont stay on the rim but this year two of my Big Apple tyres have split along the tread. The photo attached shows the split I noticed (quite by chance) after our signing ride on 15th November. It is 55mm end to end. There is plenty of tread left - as there should be with a tyre which has done about 2500km. The first such problem I had was whilst in France earlier in the year when it was the front tyre which split. This is a pity because we dont have a huge choice of tyres and the Big Apple rides well.