I've had two other pairs of Adidas trail running shoes of different models, both in size 6.5 which fit me perfectly.  I know shoe size can vary between companies, but it is ridiculous when the same company can't consistently size its own shoes!  I couldn't even get these on my feet they were so small. (And lest any reader think I am in some sort of crazy denial about my foot size, I was wearing one of my older pairs of size 6.5 Adidas trail running shoes when I tried these on and the size difference was profound.  I got the older pair at a brick and mortar shoe store and as soon as I put them on I knew they were a perfect fit -- with these, not so much.)

I've read some other reviews that recommend ordering up a half size, but I think the 6.5 size is really a full size smaller than that -- if not more.  It's really annoying to have to return them because the shipping comes out of my refund on the grounds that Amazon considers the size being too small as not their fault.  I agree that it isn't Amazon's fault, but I do consider it Adidas's fault because these shoes should fit.  The labeled size is not correct and it is verging on deceptive to claim they are 6.5, when they absolutely are not.

The lesson I take from this is not to buy shoes online unless I've already tried the exact model on and have confirmed what size will fit me.  Now I know that just because I've bought shoes from a company before and consistently worn the same size with that company, doesn't mean a different model of their shoe will fit remotely correctly even if it is the same size I've always worn.