For reference

I wear 43.0 in my Sidi Wire Vents. I really like them, but they feel a bit narrow to me and on longer rides, the sides of my feet start to ache, which is why I bought the Sphyres in the first place. (I don't think it would have been good for me to try 43.5 in the Sidis as they were already long enough.)

I have two different pairs of Shimano mountain-cleat shoes, summer shoes and winter boots, both in 43.0. They fit just right.

Also for reference, I still have an older pair of high-end Mavic road shoes in 43.5 and they were just a bit too big. I can still wear them with a couple pairs of socks but I wished I'd bought 43.0. Mostly these sit in my closet for "just in case"

All of which is to say, my size seems to be 43.0, regardless of brand

So I bought 43.0 in Shimano RC-9 Sphyre. They were the right size. They are very comfortable. Far more comfortable than the Sidis. I am very happy I bought them.

Same as joe...I am 43.5 in Shimano shoes, bontrager, PI. I went with the 43 in sphyre. Great shoes, nice and stiff and the boas do allow for my non narrow forefoot. You won't be disappointed

Thanks good info.

I forgot to add I did try a set of Bontrager XXX at a local shop and the 43 seemed to be a good fit. All in all sounds like 43.5 would be the way to go for the Shimano. The shop was really pushing the Bontrager's and also allows you to exchange them after riding in them for another size if needed which is nice, but I just like the Shimano's better.

I am looking at these shoes now. What size shoes do you wear normally in US sizing?

Generally size 10

I normally am between a 9.5-10. Running in the Kinvara right now in a 10. Thinking that a 43.5 would be best in the Shimano which it sounds like what you went with.