Just a function of being bigger, out on the road when I ride with my wife I can loose her if I try hard though she gets a great draft off me, if we ride into a strong wind she can't pull away but neither can I. She isn't as strong but is half my mass and doesn't feel the wind for sure. on the trainer which doesn't account for wind I have no trouble dusting her on the same course, she started the last 13mi ride a min early and I finished 4 min before her, lack of wind/pushing into the air is nice.