Left foot goes numb :(

It could be something more up in your leg or lower back...pinched nerve? A chiro could help that.

If it's just since having these shoes and you've had no problem running in other shoes, then get new ones. Something about the shoe just isn't right for you.

sounds like your shoe is too narrow for your foot regardless of how tight you lace them. I did some significant research on this subject for school last semester. the following is some info I found from a Doctor Sam Schimelpfenig:

"your history is consistant with a neuroma, or a thickening of the nerve tissue which can occur in various parts of the body. the most common neuroma in the foot is called a Morton's neuroma. sometimes the interdigital nerves, nerves that run between or around the metatarsal bones, get compressed or imflamed, or swelling of the connective tissue around the nerves can cause symptoms.

neuroma's are often associated with wearing narrow shoes, or with toe dorsiflexion that can occur with uphill or downhill running. common symptoms include tingling, or a burning type pain that radiates to the toes and is relieved with rest or removing the shoe. only 40% of people with have numbness in the toes"

I had switched to the Nike Triax running shoe and got the same symptoms you are having. the shoe store let me return them for a shoe with a wider toe box...a pair of Asics GT-2140's...never had that problem again.

hope this helps
Angelo

You can't necessarily judge the fit of the shoe by the fact that your other foot doesn't bother you.

My left foot is all of a 1/2 size larger than my right.

yeah, its quite odd that my right foot is completely fine.  I have noticed that it gets worse when i'm running hills.... Unfortunately, hills are the only thing around my house. I'd have to run 5 miles out from my house just to escape the hills.

Mine too

I have some numbness/tingling in my left foot, also, although I wear Adidas Supernova Sequences.  It's on the top of my foot a couple of inches or so below my middle toes and I'm pretty sure it's a neuroma like a pp said.  It started after I added elastic laces to my shoes.  I love my elasties and have tried loosening them but it hasn't helped much. I am thinking of using regular laces during training and only breaking elastics out for races.  I imagine allowing this to go on long-term is not ideal.

If you find out what it is PLEASE share.  I have encountered this same problem...same foot, but not when just running.  Only have encountered it in a race.  Almost exactly 2 miles into run portion of a tri.  I have gone through every scenerio (shoes, laces, etc).  Even thought maybe something was going on during the bike that was causing it.  My ex boyfriend is a podiatrist, and even he can't figure it out.

After speaking with my dad  (4th place in 1976 olympic qualifiers)  He told me its a back issue manifesting itself in my foot.  He told me to make sure and stretch/massage my legs to ensure good circulation before my workouts.  Also to throw my shoulders back and arch my back to kind of stretch it. Since this issue was mainly on hilly courses, he advised me to lean forward a little when i attack hills, and move my shoulders back and let your foot fall lightly while decending hills.   These tips also helped a lot. 

so yes, massage those muscles to help circulation.

I switched out my laces this weekend and it seems to help.  Doesn't cure it but definitely an improvement.  I will try to work on circulation, etc.  Thanks for the tips!