On some parts of the course were crushed stones. Thus many riders decided to use 1.9 or even 2 bar pressure. Some of these stones had sharp edged that destroyed the side walls which was even more pronounced with this high pressure. Several riders of the Stevens Junior time really had problems with that and missed the first places since they get flats in the first round. Later, when it was not so crowded any more it was easier to find the best line and avoid the stones.