I'm new to riding (started in September). In the fall I got a hybrid bike with slick, fairly narrow tires. I worked up from 3.5 miles per ride to about 15-ish miles per ride. When I rode 15 miles even on a slight (1% or 2%) uphill grade back home I was DYING and really couldn't get over 10 mph on the way home. Then I started riding a tandem with the DH who is a strong rider and immediately noticed that 30-40 miles was no problem, even on the same "hills". I wasn't tired when I got home either. Now I KNOW I was putting in effort and pedaling on that tandem. I was not "soft pedaling". Now about 4 or 5 months later I have not ridden my single bike and easily did a metric century on the tandem with no leg soreness or weakness at all. I am definitely putting in effort pedaling and climbing, etc. I know the tandem is supposed to be easier for those with different abilities, but what can I expect now that I've ridden the tandem 64 miles ? Does that mean I could do 30 on my single bike without dying? How does tandem effort and success translate to single bike effort and success? I don't really understand the physics that make the tandem easier for the stoker, but apparently more work for the captain even when both are putting forth effort pedaling.