Hi Eileen;

What is your budget? Are you interested in new or used?

This is a good starter: http://www.trekbikes.com/us/en/bikes...n/tandem/t_900#

Make sure that you and your husband read: http://www.gtgtandems.com/tech/propmethod.html

We are in our 50's also. My wife cannot ride a single due to balance and vision issues. We purchased our Trek T50 used three years ago, and I modified it to suit us.