"The American College of Sports Medicine recommends 30-60 grams of carbohydrate per hour of exercise"
So about a bottle per hour seems good -- if a bottle contains 34 grams of carbs.
I think that if you are out for 1 hour, you won't notice a difference. If you spend the first hour of your cycling trip drinking one bottle of gatorade, I think by the middle to end of the second hour, you'll probably notice that you feel less-diminished than if you didn't intake any carbs at all. I'm more a fan of carbs in the form of a solid food and drinking water, I would have definitely asked my doctor about that option...like if you started with a snack with jelly, then every hour at that same snack with jelly, and just drank water when you were thirsty. For me anything 1.5 hours to 2 I have no problem just filling one bottle with gatorade though.