as they dont last much longer than about 300- 400 miles on hard surface

couldn’t tell although on wearing them I do notice a kind of spring in my stride, it could be down to a substance they use called Substance 257 which rebounds more quickly than standard midsole EVAs. Apparently this Substance 257 means your 400th mile

like they are near to needing replacing at around 300 miles as the midsole doesn`t seem to have the cushioning that it had initially. Mind you, I have just ordered another pair anyway! Gareth Purdy: GREAT SHOE, V COMFY Strengths: Lightweight, very comfy