We did a 4.5 hour guided "Panoramic" tour of Rome by bike with a company called "Top Bike Rentals". I used to ride a bike but have not done so for some years and had no trouble keeping up. This was a great way to see Rome from a different angle (having already done walking tours). Travelling by bike means you can cover a lot more ground. We had a great guide called Emanuelle, but all the staff there seemed good. He took us to some amazing spots. And gave a very entertaining series of mini lectures on the city and its architecture, about both of which he was very knowledgable and passionate. Ride 5 - 10 mins, stop and talk 5 - 10 mins. He was good at noticing when we had tuned out of the lectures. It is a good buzz cruising through streets and lanes like you are a local. I felt very safe throughout. Definitely recommended.