Two very different commuter-cargo approaches: Ortlieb's waterproof rear pannier versus Topeak's rack-top trunk bag with fold-out panniers. Payload, weather-proofing, and how you lock up decide which one you want.
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| Aspect | Back Roller Pro Classic | TrunkBag DXP | Winner |
|---|---|---|---|
| Total capacity | 40 L (pair) | 22.6 L (expanded) | Pro Classic |
| Waterproofing | IP64 roll-top (welded seams) | Weather-resistant + rain cover | Pro Classic |
| Mount system | QL2.1 pannier hook | Topeak MTX QuickTrack | Tie |
| Rack compatibility | Any tubular rack | MTX rack only | Pro Classic |
| Off-bike carry | Shoulder strap | Shoulder strap + handle | TrunkBag DXP |
| Weight (empty) | ~1.9 kg (pair) | ~1.3 kg | TrunkBag DXP |
| Laptop sleeve | Optional insert | No | Pro Classic |
| Street price | ~$200 (pair) | ~$95 | TrunkBag DXP |
Pick the Ortlieb Back-Roller Classic (pair: 40 L) if you commute in real weather or tour — the roll-top seal is still the gold standard for keeping a laptop dry. Pick the Topeak TrunkBag DXP if you want one bag that lives on the bike, locks onto an MTX rack in a second, and expands into side panniers only when you grocery-shop.
Topeak TrunkBag DXP — one bag replaces trunk + pannier and it's under $100.
Ortlieb Back-Roller Classic — genuinely waterproof roll-top, higher payload, tour-proven.
Our sizing guides and category pages help you narrow the field.