I bought this product in my normal shoe size (10 Wide) from a retail dealer, but I wore thin socks.  After my first run, I could tell these shoes weren't going to be big enough.  They crunched my toes, and any wear for more than 30 minutes made my feet go numb.  After reading other reviews, and realizing this shoe runs small, I went online and ordered a size up (11 wide).  I thought they might be a little big, but after an hour's workout, my feet swelled a little and they still fit fine without crunching my toes.  I did however, make sure I used a runner's lace (using the outside loop to make sure the ankle fits right).  The runner's lace kept my foot next to the cushioned ankle area and my high arch right over the arch support.  I love the get cumulus for the cushy ride.  I had a pair of gel-nimbus, but I didn't like the off-side lacing, and was super happy to finally get a pair gel-cumulus that fit, and at a great price too.  The online dealer had my shoes to the door in 3 days..awesome!