I visited Montreal for work and had just two days to be a tourist. To cover as much of the city as possible, I booked a bike tour with Cycle Tours. Shea was very responsive over email and went out of his way to make sure I could get on a tour, even though I was flying in that same day!
My tour group was roughly 10-ish people and was hosted by David (who, by now, is off to Germany to be a pilot). He knew everything there was to know about the city, both from the view of a tourist and as a local.
Even if you're not an experienced biker, you'll do just fine on this tour. You'll generally go 5-10 minutes, stop for an explanation, and then move on. It's a nice leisurely pace, especially when the weather is nice.
Definitely worth doing again!