Measure these three things before you order
1. Rack tube diameter.Put a tape across the top rail and the lower stay where a hook or a lower anchor would sit. This is the measurement that decides whether the bag attaches at all, and it is the one no pannier listing publishes. Ortlieb’s QL system is the most adjustable hardware in this group, which is exactly why it is the safe answer on an unusual rack.
2. What else is on the rack.Look for a tail light bolted to the rear face, a wiring loom clipped under the deck, a rack-mounted battery, or a licence-plate-style reflector bracket. Any of those can sit precisely where a pannier’s upper hook wants to be, and pinching a light cable between a bag and a rail is how a tail light fails three months later. If there is wiring in the way, a rack-top bag is often the better answer than side bags — best bike trunk bags covers that route.
3. Heel clearance.E-bike chainstays are frequently longer than a road bike’s to make room for a hub motor and a battery, which usually helps. But fat-tire folders put the rack high and far back over a 20-inch wheel, which changes where the bag hangs. Sit on the bike with the bag fitted and pedal backwards before you commit to a mounting position.
The hardware, side by side
This is the table to read. Capacity is the easy number; the mount is what decides whether the purchase works.
| Bag | Mount (as listed) | Capacity | Water strategy | E-bike fitment claim |
|---|
| OutWurx Grocery Pannier | 3-point lock-down | 23 L (single) | Included rain cover | Yes, stated |
| Ortlieb Back-Roller Classic | QL2.1 quick-release hooks | 40 L (pair) | Fully welded roll-top | Not stated (most adjustable hardware here) |
| RockBros 30L pair | Generic hooks | Up to 30 L (pair) | Stitched roll-top | Not stated |
| Ibera PakRak Clip-On pair | Quick-release clip-on | Pair | Included rain cover | Not stated; best on Ibera PakRak racks |
| Rhinowalk 27L | Standard hooks | 27 L (single) | Waterproof body | Not stated |
Why we did not just rank by capacity
Because an e-bike removes the constraint that makes capacity interesting. On an unassisted bike, every extra kilo is yours to carry up the hill, so you buy the smallest bag that works. On an e-bike the motor absorbs the weight and the real limits move elsewhere: what the rack is rated to hold, whether the bag stays attached, and whether the loaded bike is still manageable when you park it. Rack load ratings are the number to respect here, and we go through them in how much can a rack hold. If your e-bike did not come with a rack at all, start at rear racks for e-bikes — fitment there is harder than the bag choice.
Load one side or both?
On an e-bike, one side is fine for a normal commute and better than most people assume. The bike is heavy enough that a single 8–10 kg bag is a smaller proportion of the total mass than the same bag on a 10 kg road bike, so the handling asymmetry you feel is less, not more. Two caveats: load the single bag on the side away from traffic so you are not reaching into the road to unclip it, and keep heavy items low and forward in the bag rather than high and back. We work through the physics and the which-side question in one pannier or two.
Security, which is a real e-bike problem
Two things are worth saying plainly. First, no pannier mount is a lock. Quick-release hardware is designed to release quickly, and that works for everybody. Take the bag with you; leave nothing in it when you cannot. Second, an e-bike is a higher-value theft target than a bicycle and the bags make it look worth checking. Pair the bags with a lock appropriate to what the bike is worth — best e-bike locks is the honest spend-tier argument, and anti-theft devices covers the tracker-and-alarm layer that sits on top of a lock rather than replacing one.
What we would skip
Open-top grocery panniers as a daily commuting bag. They are excellent at groceries and wrong for a laptop in the rain. That is a different page: best grocery panniers.
Bungee-and-hook bags on a fast, heavy bike. An elastic cord is not a retention system under motor torque and over kerbs.
Rail-system bags without checking the rail.Proprietary rail bags attach to that brand’s rack and nothing else.
Anything that needs to be bolted to a rack carrying the battery or wiring. Clamping a loom is a problem you will find in February, not in October.
