Yes absolutly they can handle it. I just got myself a fixie a few weeks ago, it's my first bike with 700cc wheels and I love it . I run 32mm tires and I never have a problem riding unpaved trails and paths. So far the wheels have stayed true but I don't do any crazy stuff with them.. I have a MTB with 26 inch wheels for doing really rough stuff . For long distance riding and fast commuting I prefer 700cc wheels. Much faster and less rolling resistence then my very heavy 26 inch wheels and 2.5 tires.