I use Looks on my road bikes, and performance brand spds on my fixie and my mountain bike. That way I can walk without problems when I get to work (fixie is my main commuter). When I do use the Looks, I have the 'kool' covers so the cleats don't wear out as fast. You might try putting new cleats on before you do anything else... maybe they're just worn and don't clip in well...

train safe-