I think that the biggest advantage of the tandem is in wind resistance. Essentially, the stoker is always drafting the captain, therefore you have half the frontal area and half the wind restistance that 2 singles would have. This becomes an advantage with speed; wind resistance increases exponentially with speed. At 10 mph, this is minimal. Be patient and enjoy the experience...you will learn to work together in time and there is great satisfaction in that. As far as stregnth, you are bringing more to the table and you need to make sure that you are not going to overpower your stoker. Make sure that she gradually puts in more work and you will see the speeds increase. Once you start to go faster, you will see the advantage of the lesser wind resistance. On my single, I can average 18 mph over long stretches with a fair amount of work. My wife can do about 14. On the tandem, we can cruise at 20 all day on the flats and rolling terrain. We have also gotten to the point where we can climb short stretches with all but the strongest of our single riding friends. Of course, it is much easier to ride with fellow tandems, rather than singles. This is because I find that I am always out of sink with the singles when climbing or accelerating. This is where the added mass of the tandem puts us at a dissadvantage.