What size handlebar bag is best for you and your bike? Basically, the bag should fill the space between the front rack and the stem. To optimize the bike’s handling, the bag should be as low as possible, and well-supported on a rack just above the front wheel/fender. At the top, the bag attaches to the handlebars or stem to prevent the bag from swaying. When the bag’s top flap is level with the top of the handlebars, the bag contents are easily accessible while riding.
More space between the wheel and stem means that taller riders use bigger bags. Unfair? Maybe, but a taller rider’s clothes also take up more space. What if you don’t need that much luggage space? Then think of the bag as a fairing; it makes sense to size it so that the bag shields your chest cavity when you are in the drops or the aero tuck.
On some rides, my handlebar bag contains only a spare tube, tire levers and some money. I could just wrap those in a piece of cloth and strap them to the rack, but I don’t bother with that, just like I don’t take off the second bottle cage when I go for a ride that requires only a single waterbottle. In my car, I also don’t fill up the trunk on every trip. I think of the bag as an integral part of the bike.
If you look at the slightly bulging flap of my bag shown in the photo above, you’ll see that I often fill it to capacity and beyond. Sometimes it’s a day that starts chilly and warms up, and I need a place to stuff my extra clothes. Other days, I pass by the Farmers’ Market on the way home from a ride, and I am glad to have a place to put some vegetables and flowers. The photo above was taken after last year’s Paris-Brest-Paris ride, during a three-day trip across France to visit friends. The large bag meant that I didn’t need to bring the bolt-on rack flanges and panniers.
The largest Gilles Berthoud bag has 42% more capacity in the main compartment than the smallest bag shown above, yet it weighs only 11% more (not counting the superfluous stiffener). The weight of the bag comes from the leather reinforcements, pockets, straps and buckles, while the fabric is very lightweight. The larger bags just have a little extra fabric. The weight difference between the largest and smallest bags is 61 g, which is about the same as an empty bottle cage. As mentioned above, I don’t worry about riding with an empty bottle cage on my bike, either.
Gilles Berthoud makes their classic handlebar bags in three sizes. This range fits most bikes. If you need something significantly different, Phil Woosley of Loyal Designs, Guu Watanabe in Japan and others can make custom bags to your requirements. Click here for more information on the Gilles Berthoud bags, including dimensions and weights.