Polar fit review - Zamberlan Polar Hunter GTX RR Boa Hiking Shoes - Men's

I spent the better part of 2 days looking into every review possible to find the correct fit for the Polar and no luck. I have always worn a size 10.5 US, I measured my foot and my left one was exactly 11inches. Fit guide from zamberlan suggested size 10US, I ordered a size 10.5 and it was WAY too tight. My foot even runs narrow to standard. With a thick wool sock this boot needs to be sized up. I reordered a size 11.5 and with a thick sock it fits much better, just a little loose. Boot is very stiff, fit is much more like a ski boot, alot of pressure in the anterior tibia and I leave the strap undone. I have mixed feelings, boot is very warm,boa works excellent, I wish it weren't so stiff and zipper is very tight to get done up, catches on strap. Size up at least 1/2 size or a full size if you plan on a thick wool sock. In a 10.5 when I first zipped it up the zipper split apart trying to zip it up.