I'm not an expert on this, but if you're just riding on pavement to work and back, I really dont see a problem. I've run mismatched tires many times. As long as the front tire isn't bald (preferably neither being bald, but especially the front), I'd say its just fine. Some guys I know feel that some tires are better as "drive tires" and others are better as "steering tires". I cant speak to that, but it seems to work for them.