So im upgrading to a nice road shoe with a carbon sole and Ive narrowed it down to the Sidi Genius 5.5 HT carbon, but i have a slight sizing issue.

I currently own a pair of sidi mtn shoes in a 45 which are pretty snug on me but still good that i use on my road bike now. I measure exactly on the 45 line for a sidi on the size chart so the question is do i go to 46 for the road shoe? (i cant seem to find them in a 45.5) Are cycling shoes supposed to be snug or is it better to have a lil extra room? Would a snug shoe cause more numbness? (seems to come and go on rides over 2 hrs in my current pair)

Thanks for the help, and if anyone has these sidis already Id love some feedback on them.

I was in between sizes too and thinking along your same lines, originally bought the larger size. I road on my trainer for a bit when I got home and my foot felt like it was rattlin' around inside the shoe. I returned them and got the snug size and am realy glad. They fit like socks now because shoes tend to stretch out a little bit after some use.

Here is a good aritcle on shoe fitting. https://www.bikesportmichigan.com/features/shoes.shtml

BTW: Sidi MTB & Road shoes fit exactly the same. Only you know how snug your mtb shoes are.

Cycling shoes should fit like a glove from the moment you put them on. Since Sidis run a bit small, I would go with the 46.

Agree on fit like glove. But if I have just a smidge too much room anywhere (except length), I don't mind -- I know I can replace the stock insole with one just slightly thicker and that will take care of the extra room.

Competitive cyclist have Sidi's in the 45.5 size.

https://www.competitivecyclist.com/za...MODE=&TFC=TRUE

https://rbikes.com/itemdetails.cfm?id=3845&affiliate=2

great article, thanks for the help. i think im gonna go with the 45's for the snugger fit.

Careful what socks you are wearing when you size your new bike shoes. I bought a pair of PI shoes. Now, most socks I wear make the shoes too snug. Particularily since the souls seem too rigid or something. I'd prefer putting inserts in them, but can't . Too tight. So they get worn infrequently and I ride mostly in my TIme's.

I was gonna get a pair of Sidi's but they felt too small so I got Diadoras instead. After riding for awhile I realized why the Sidi's were small, shoes stretch! The Diadoras still fit but I coulda definately gone with a msaller shoe. I'm guessing that's typical for all bike shoes since Joe mentioned this too.