I enjoyed that last night. The 40mm tyres performed brilliantly on all 4 sections of COR that I ended up riding. The worst of them was the last bit between Tolleshunt Knights and Tudwick road with lots of nettles and brambles growing over the path and obvious signs of equine activity during muddier times! OD's piece of COR being the best as is was just a farm track although it was quite loose and I was glad I had the wide rubber on, I was able to stay at full power for the whole track with no real consequences....brilliant!