A decaleur is a quick release for a handlebar bag. It attaches the bag securely while keeping it offset from the bars so there’s room for your hands on the handlebars. (The French “decaler” means “to offset” or “to move out of the way”.) It also allows easy removal when you want to take the bag with you after parking the bike. A decaleur really optimizes the benefits of a handlebar bag.
The bag does not hang from the decaleur. Its weight is supported by a small front rack. Traditionally, decaleurs were custom-made for each bike. Many constructeurs used a system of two tubes that attach to the stem. A bar with two pins is attached to the bag. The pins slide into the tubes to connect the bag to the stem. The key to this design is getting the friction fit between the male and female pieces just right. The bag must not jump out of the decaleur when you go over a bump, yet you want to insert and remove it with ease.
This perfect fit is difficult to achieve, especially in a production setting. All pieces have tolerances, and then there is the chrome-plating that adds varying thickness… The Grand Bois decaleurs we sell are made by Nitto. Their fit is better than most, but even with these decaleurs, the bag could jump out and fall off the bike. Grand Bois recommends attaching the bag to the rack with a strap, but that defeats the “quick release” function of the decaleur.
We looked at the problem and figured out a way to make the decaleurs more secure by tightening the tolerances at the pin connection, so that no additional straps are needed. We’ve tested this on some very rough roads, with the bag held in place only by the decaleur. The bag remained securely inserted in the decaleur.
All decaleurs sold by Compass Bicycles since April 2013 already feature this upgrade. If you bought your decaleur from us before that date, and if you experience problems with the decaleur’s pins moving out of the stem-mounted tubes, we will retrofit the decaleurs free of charge until December 31, 2013. Just mail both the bag-mounted piece with the prongs and the stem-mounted part with the tubes back to us, together with a copy of the receipt. (Our address is here.) Include a $ 10 check for return shipping (U.S. customers; $ 20 international). Allow 5 weeks for the upgrade.
Please note that this upgrade is made by Compass Bicycles, not Grand Bois. It is available only on decaleurs sold through us, either directly or via one of our retail partners.
One problem with traditional decaleurs is that their height is not adjustable. For that reason, we offer Gilles Berthoud handlebar bags in three sizes, so you can pick a bag that fits into the space between your handlebars and your rack. However, even the largest bag is not tall enough for very large frames.
Based on the idea of a Bicycle Quarterly reader, we now offer a drop kit that moves the decaleur downward (above). This is available with a drop of either 10, 20 or 30 mm. It is compatible only with Grand Bois decaleurs for Grand Bois stems.
Compass Bicycles also offers Grand Bois decaleurs for Nitto Pearl stems, as well as a generic model for aluminum stems with a horizontal handlebar clamp bolt (above). These decaleurs also feature our upgrade to hold the bag securely. They do not work with the drop kit, since their attachment bolts are horizontal, not vertical.
We believe that these decaleurs now offer the best solution for mounting a handlebar bag on your bike. For liability reasons, we cannot guarantee that your bag never will come off, but in normal riding, you should not worry about your handlebar bag flying off or rattling. It should not take more than a quick upward lift to remove the bag and take it with you.
Achieving tight tolerances is labor-intensive, and most makers don’t bother. But when I ride my bike on challenging terrain, the last thing I want to worry about is my handlebar bag!