In reply to tony:
> I hope you're planning to actually try them on before you buy. Trail shoes do come in lots of different shapes, even from the same manufacturers, and sizing does appear to be a bit random. Buying without trying could be a really bad idea.
Yes, what I meant to say above was I buy the same fit for any trainer, i.e. I don't make a difference for trail, road, ultra, etc. Sizes, as in numbers are relative.
The point about width is important though. Many people buy shoes to short, in order not to slide around, but what they really need is a better fit for their foot in terms of width.