Front loading vs. top loading
A quick description
Front loading, also called side loading or panel loading, bags are panniers that are accessed with zippers, opening them a bit like a suitcase. Usually these are squarer in shape and have multiple pockets.
Conversely, top loading bags are panniers that aren't using zippers but a system of skirt and hood closed with straps and buckles. Usually these are taller in shape and have fewer pockets.
Front loading panniers
GT-54 and GT-18
T-42 and T-28
B-26 and B-40
Top loading panniers
Dolphins 32, 40 and 48
XM-45 and XM-28
Akin to many expedition backpacks, top loaders trade easy access in favor an expendable main compartment. Effectively, front loaders are limited to the size they are designed with while top loaders can usually expand upward thanks to the skirt and adjustable straps. Yet, livability greatly suffers. In the Arkel panniers we added a no-stress side zipper to slice the bag in two in the search for a better access in a top loading pannier.
Winner in the opening category: Front loading panniers.
We can't dismiss modern zippers that easily though. We've seen panniers nearly 15 years old with their original zippers, just as we've seen 6 months old ones with R.I.P. zippers. We use the best, state-of-the-art zippers so we know they won't fail anytime soon. We have enough confidence in them that we are making our best, toughest panniers with zippers.
Yet whatever we say, one thing is for sure: if there is no zipper, it cannot break! Because of that, the top loading panniers win the durability category.
Winner of the durability category: Top loading panniers
Winner of the volume category: Draw
Word of wisdom
Here at Arkel we use both, depending on the whimsy and preference of each of us. Sometimes in innovative ways too. In the end both systems have their merit. Your choice will ultimately be the best one for you.