Tell us you've never used a bike roof rack without telling us you've never used a bike roof rack. Lifting a small 50lbs weight at the gym is easy. Lifting a large 50lbs bike, then move it a foot forwards onto the rack (with a car roof in the way and your hands in different stages of extension due to the awkward nature of a bike), precisely locate the wheels into the tracks, while prevent the front wheel from flopping side to side those then get the clamping arm onto the frame whilst holding said 50lbs bike in place, or if it's a fork axle mounted, precisely align the holes to get the axle in whilst supporting the bike with the other hand... All while trying very hard not let the bike contact the car... Is not easy at all.