I had to go up a full uk size with AM 40s. With 5 10s they were normal. Much to be said for both shoes. Am40s are lighter, and dry out quicker, but are more fragile and not as grippy. Less than 6 months in, the soles started to come off mine and all the outer coating meaning they let lots of water in. 5 10s are much more durable, (one pair lasted me 3 years) much grippier but take an age to dry out and are quite heavy.
I liked inner ankle protection and very stiff sole on the am40s too. Currently trying out the new Vans Gravel bike shoe – so far they seem to be the best yet, time will tell if they can stand up to much abuse.