I am looking for new bike shoes (for IM distance+) and have aero performance as priority number one.
I would guess that the fastest shoes are either the Bont Crono MK2 or the Velovetta´s. I know Velovetta has done wind tunnel testing, but thats the only one I have seen. https://bontcycling.com/products/crono-mk2 and https://www.velovetta.com/
I currently have the laced Giro Empire ACC which are aero but slightly tight for the loooong rides. I am also tempted to get a pair of Specialized Exos Road as they are super light weight but uncertain if the single boa dial on top are screwing things up aerodynamically (I can hide it with a an aero shoe cover).
Any thoughts?
Old blog post from back in 2016 regarding testing my Giro Empire SLX shoes from the Wind Tunnel. Sample size very small obviously. What I realized about this test (later), and extensively testing clothing in the water and in the wind tunnel is that used equipment is slow. If I was going to buy a pair of shoes I would just do a visual eyeball test. Are they bulky with straps and buckles, or slim. Go with the slim. Also go with the smallest size that you can reasonably fit your feet in, adjusted for fluid pooling in feet during hot conditions.