Ortlieb bags are famous for their durable, waterproof construction. The German-made seat bags and panniers are a favorite with all-weather riders who want their gear to remain dry in adverse conditions. And now, Ortlieb broadens their product range with the introduction of the company’s Seatpost Bags.
Unlike their original seat bags, Ortlieb’s Seatpost Bags attach directly to the seatpost. The integrated mount fits ‘posts from 25.4mm to 34.9mm diameter. A quick-release strap allows easy installation and removal. Ortlieb offers the Seatpost Bag in two sizes: small (1.5kg max load, 1.5 litre capacity), and medium (2.5kg max load, 4 litre capacity). Both bags feature high-frequency welded seams, waterproof fabrics, hi-viz reflective accents, and tabs for attaching blinky-style lights.
The Seatpost Bags utilize a ratchet-type design that’s similar to the closures found on many cycling shoes. This tool-free system allows quick-and-easy installation and removal, while still providing a secure interface with the seatpost (Ortlieb does not recommend using the Seatpost Bags with carbon or aero seatposts). The mounting bracket features a soft rubber insert which helps reduce slippage, as well as protecting the seatpost’s finish. During our testing, we had no difficulty swapping the bags between 27.2mm and 31.6mm seatposts.
Even when loaded to their respective max capacities, both bags remained securely attached and noise-free. The packs themselves did exhibit some minor flex, but it wasn’t noticeable during actual riding (even on bumpy dirt roads/trails). The dry bag-style rolled closures did an outstanding job of keeping the bags’ contents dry, and unlike zippers, didn’t become jammed when exposed to grit and grime (of which there was no shortage).
For day rides, centuries, and light commuting, the medium Seatpost Bag would be an excellent choice. The pack’s internal mesh pockets help keep items organized, and the elastic cord can easily accommodate a light jacket or other clothing. At 442g, it’s lighter than a dedicated rack-top bag, and can be easily removed when not needed. While the smaller Ortlieb Seatpost Bag is heavier (243g) than a conventional seat pack of comparable capacity, the former’s mounting system makes it compatible with hard-to-fit saddles such as those with springs or I-beam designs.
Disclosure: Ortlieb USA provided review samples for this article, but offered no other form of compensation for this review.