I have an extremely narrow foot. My street shoe size is 10.5 (42.5-43), I wear a size 41 katana and the velcro straps hang way over the sides of the shoe, they work, but barley. I tried going 40.5 in the katana but they were too painful in the toes while still being nearly as narrow as you could strap them width wise. How does the width of this shoe compare to the katana? Would these shoes work for me?

Well first of all, since you have a very narrow foot, you should be looking a different shoe than the katana. You should be looking at the Testarossa or possibly the Miura VS, with the Testarossa being the smallest, tightest fitting, most narrow fitting shoe between Sportiva shoes. They are extremely tight and narrow in the toe box, and the fact that they have laces means you can get them super tight and tiny if you need to, which would be good in your situation with your narrow foot. Also, the heel fits amazing, almost as amazing as the solution. The Miura VS though are a little more of a mid sized toe box shoe. With the velcro though, they have the ability to get pretty narrow and tight. So first look at the Testarossa's, then the Miura VS. Either way, your getting the best shoe in the world. As for sizing, I don't know how the Katana's fit in length, but I can give you some comparison fits so that you can make an educated decision. So I wear a size 14 in athletic shoes, 13-14 in dress shoes, 13 in Fiveten Anasazi's, 45.5 in Solutions, 45 in Testarossa's, and 45 in Miura VS's. So in Miura and Testarossa's, I wear about 2-2.5 down from my street shoe if that helps. Also, I fit my climbing shoes tight with my toes scrunched, but not ridiculous painful like some people. Hope that helps.

I wear between a 10.5 and an 11 street shoe, and I just tried on a pair of these today. I fit in the 39.5, but I like a tight fit. I'd say 40-40.5 would be perfect.

I dont know if someone answered your question already, but I have actually worn both shoes, both size 41. It would be hard for me to say, but if you are looking for a snug fitting, aggressive shoe, I would size down the Muira VSs to a 40.5 I feel like you could fit these smaller than the same size in the Katana. Feel free to drop me any more questions.