A Guide for Cargo Bike Panniers

by North St Bags

We love our hook attachment system—it's strong, durable, and easy to service after whatever years on the road have in store. The simplicity of this system also means that there's no room for planned obsolescence, but plenty of room to adjust it to fit your bike perfectly.

When you order your new bike pannier or convertible backpack pannier you’ll need to select the hook size that best fits your bike’s cargo rack. These hooks—two near the top of the pannier—slot over the horizontal tube(s) of the cargo rack and then a bottom hook on a bungee holds tension for a secure fit.

While it’s a simple system, one of the most common questions we get is: what’s the right hook size for my bike?

So here’s how to choose the right fit for your rack:


1. Confirm Cargo Rack and Hook Spacing

North St Bags Pannier Hook Spacing

 The distance between these hooks is fixed (distance B in the diagram below), and while this works for most racks, in some rare instances the hooks will fall over a welded cross tube or the top deck, if your rack has one.

Measure your cargo rack to make sure our pannier hook spacing (see specs below) aligns with the rack structure and the deck cutouts.


North St Bags Pannier Hook Sizing

2. Measure the Diameter of Your Rack
North St Bags Measure rack rail diameter

We sell our panniers with one of three hook size options: 3/8" (9mm), 1/2" (12mm), and 3/4" (16mm).

The main consideration between these sizes is the diameter of the top bar of your rack. The most common top bar measurement for road bike racks is ~9mm, or 3/8 inch. Many cargo and e-bikes have thicker-than-usual rack bars to support additional riders, kids' seats, and bigger, heavier loads in general. You can order our hooks up to 3/4 inch to make our panniers compatible with many of these custom built-in cargo and e-bike racks.

Not every rack falls perfectly into the 3/8" (9mm), 1/2" (12mm), 3/4" (16mm) measurements that we offer. Fortunately, our stainless steel hooks are prime for some adjustment without compromising hold or quality. For most average users, the hooks can be bent outward up to around 1/2" over their standard size. So if your rack measures 10 or 11mm, you can simply adapt the standard 9mm hooks to fit. The exception to this is heavy use. If you are regularly carrying 20+ pounds in your bag, we recommend you spring for the larger hooks and tighten them down to fit to ensure longevity of the hook system.

Also note, it’s the bungee tension that does most of the work in keeping a pannier secure. So if your tubes are in between our hook sizes and behind the wiggle room mentioned above, we recommend sizing up. Larger hooks still work well on smaller bars as long as the bungee is well secured (although there might be a little more rattling).

Before ordering a pannier, measure the diameter of your rack’s top tubes (or main attachment site) and then select the best-fitting option.

3. Select the Corresponding Hook Size

Once you pick your new bike pannier or convertible backpack pannier

If you’re ordering online, on the product page, select the color option you’d like and then the hook size that works best for your setup. Finally, click “Add to Cart”, go through the checkout process, and keep your eye out for delivery!

If you’re in Portland and want to swing by the North St. HQ (2134 N. Flint Ave.) in person, bring your rig with you and we’d be happy to help you find the right hook size—and we’ll even give you a demo on how to mount the pannier.

Rad Power Racks (and other Super Oversized Racks)

Our current pannier hook sizes max out at 3/4 inch, but we've tested these on racks up to 1-inch in diameter and found they still keep a solid hold.

For tubes over 1 inch in diameter, found on some Rad Power bikes or other custom cargo carriers, we have not fit or strength-tested our hooks against this size. 

The only exception is with our Adventure Micro Pannier, which features a hook-and-loop attachment system that is large and flexible enough to attach to oversized cargo racks for a semi-permanent pannier option.

North St. Bags