Background: My first Vibrams (Classics) arrived yesterday, and I'm now wondering whether I may have ordered the wrong size. I've Googled for the specific fitting problem I'm having and I'm coming up a little short on answers.
My issue is while the toes feel like they are fitting well, the heel is a little bit loose. The tab is chaffing a little on one of my Achille's tendon. Now, as these aren't normal shoes, I'm conscious that what might feel odd to me is actually normal for VFF wear.
So the question is a multiparter:
For my specific loose-heel problem, I found the following advice:
And I should mention that when I was investigating buying the Vibrams initially, the Birthday Shoes: Five Fingers Sizing Guide was fantastic.
I own the KSO Trek. I would strongly recommend anyone trying VFF's for the first time to try them on in person. The sizing is the biggest hurdle to overcome in my opinion. Once you get the size right, order from the best dealer.
Mine did feel a bit odd - but who hasn't felt that way wearing a toe sock shoe? If you're feeling rubbing, etc. - try them with a pair of Injinji socks. This may reduce the wear and is preferred to keep the smell down to a minimum.
I wore mine around the house a few weeks before I started running in them, but I have had no major problems with mine. Very comfortable and they get the looks (which I enjoy and answering questions about them).
Sadly, the best advice I can give is to go to a retailer and try on the pairs. I had to go through 4 pairs before I got one that fit well and I still think it's a size too big after the fact.
Just like regular shoes, you need to break them in and your heel will probably chaff a bit. I got a blister under the ball of my foot as well on my right foot and my left heel when I first bought them. My feet and the shoes definitely did adjust about a month in but I was wearing them as my regular, everyday shoes. If you are only wearing them for running or gym use, I suspect that they will take longer to break in. Hope it works out for you.
FYI, to reduce the smell, I recommend baking soda every so often into the shoes. You CAN wash them, and should if you wear them regularly, but they can get beaten up pretty bad in the washer if you do it too often and wear them a lot. Soaking them in warm soapy water and using baking soda are your best bets.
I initially bought Sprints, and then purchases KSO Treks later. I actually ended up purchasing different sizes in both, so fit varies even by model. My best advice would be to get a pair that fits "tightly" in Injinji socks and they will then also fit perfectly without socks at all.
I initially bought a "perfectly" fitting pair based on my bare feet. They seemed perfect because each of my toes went right to the tips of each toe pocket, but when I ran in them I developed a lot of blisters because the perfect fit was too snug creating friction spots at the base of my toes. I then bumped it up one size and just used the straps to make sure they were tight and I haven't had any problems since. My feet stay in place with the straps, but the constant friction has been reduced significantly.
1) KSO Treks. Followed the sizing instructions on the Vibram website. Ordered them over the internet. Getting my toes in was difficult at first, but once I figured it out this ceased to be a problem. Am wearing them now; no pressure points, I have a millimeter or two of toe room, and they feel very comfortable.
2) Sprints. Tried them on in a store. At first got a bit of pressure on the achilles tendon and some contact on the toe ends. These issues alleviated as I learned to adjust the straps in the correct order; insert toes, slide foot hard back into the heel, adjust instep strap, barely tighten heel straps.
I'm very happy with both. The Sprints are lighter and I get better ground feel (walking on gravel is a nice foot massage), the Treks I can wear to the office on Casual Fridays :).