By Claire WhitakerUpdated November 2026
A saddle bag for bikepacking is the simplest way to carry sleeping gear, clothing or spare parts without loading up your handlebars or frame. Under-seat bags sit behind the saddle, strap to the seatpost and rails, and leave the rest of the bike free for water bottles and steering. This list compares seven widely sold saddle bags on the factors that matter most on multi-day trips: capacity, water resistance, how the bag mounts, and how well it suits road, gravel and mountain bikes. Listings were reviewed through manufacturer specifications, brand reputation and common owner feedback patterns, not hands-on testing.
Our top picks at a glance
- 1
TOP CHOICEBest overallRhinowalk Waterproof Bike Saddle Bag 13LView on Amazon - 2
TOP CHOICEBest for larger loadsWaterproof Bike Saddle Bag Large Capacity 15LView on Amazon - 3
TOP CHOICEBest for expandable storageKEMIMOTO Bike Seat Bag 11L ExpandableView on Amazon - 4
Best for wet-weather tripsKEMIMOTO Bike Saddle Bag 13-15L Expandable WaterproofView on Amazon - 5
Best for roll-top sealingRhinowalk Waterproof Bike Saddle Bag 10L Roll-topView on Amazon - 6
Best for a established brand optionTopeak BackLoader Bike BagView on Amazon - 7
Best budget pickBike Saddle Bag Waterproof Expandable 13LView on Amazon
Our Top Picks
Each pick below is a saddle bag sold on Amazon US. The order reflects how well each bag fits the selection criteria: capacity range suited to bikepacking, water resistance claimed by the manufacturer, mounting compatibility with common seatposts and rails, and consistency of specifications across the listing.
Quick Comparison
| Product | Best for | Key feature |
|---|---|---|
| Rhinowalk Waterproof Bike Saddle Bag 13L | Everyday bikepacking overnights | Waterproof body in a 13L size |
| Waterproof Bike Saddle Bag Large Capacity 15L | Larger loads on longer trips | 15L main volume |
| KEMIMOTO Bike Seat Bag 11L Expandable | Riders who change load size | Expandable main compartment |
| KEMIMOTO Bike Saddle Bag 13-15L | Wet-weather touring | Air release valve for compression |
| Rhinowalk Waterproof Bike Saddle Bag 10L Roll-top | Compact, sealed packing | Roll-top closure and sealed seams |
| Topeak BackLoader Bike Bag | Riders who prefer a known brand | Established saddle bag design |
| Bike Saddle Bag Waterproof Expandable 13L | Budget-minded riders | Expandable 13L waterproof bag |
Rhinowalk Waterproof Bike Saddle Bag 13L
Rhinowalk Waterproof Bike Saddle Bag 13L – Under Seat Storage for Mountain Road Biking and Commuting Trips
Best for: Everyday bikepacking overnights with a light sleep kit and clothing
This bag suits riders carrying a sleeping bag, a spare layer and a few tools on road, gravel or mountain bikes. Its 13-liter capacity covers most overnight and weekend loads without making the bike unwieldy.
Key specs
- Listed capacity: 13 liters
- Marketed as waterproof, under-seat design
- Fits road and mountain bikes per listing
Pros
- Capacity suits overnight bikepacking
- Waterproof construction claimed by the manufacturer
- Under-seat placement keeps handlebars clear
Cons
- Limited room for bulky winter gear
- Strap fit depends on seatpost diameter
Bottom line: A strong first saddle bag for riders who want moderate capacity and a waterproof body without paying for extras.
Waterproof Bike Saddle Bag Large Capacity 15L
Waterproof Bike Saddle Bag Large Capacity 15L Bikepacking Bicycle Seat Bag for Road Mountain
Best for: Larger loads on longer trips
Riders who need more room than a 10 or 11-liter bag will appreciate the 15-liter volume. It works well for multi-day tours where food, layers and a sleeping system all compete for space.
Key specs
- Listed capacity: 15 liters
- Bikepacking-style under-seat bag
- Designed for road and mountain bikes
Pros
- Generous capacity for longer tours
- Stays out of the way of pedaling and steering
- Good match for packing a full sleep kit
Cons
- Larger volume can sway if overfilled
- May be too big for short rides
Bottom line: Best for riders who regularly pack for several nights and want the extra room.
KEMIMOTO Bike Seat Bag 11L Expandable
Bikepacking Road Bicycle Rear Pack Under Seat with PVC Reflective Panel & Four Bottom Hardboards KEMIMOTO Bike Seat Bag, Expandable 11L Water Resistant Saddle Pouch
Best for: Riders who change their load size from trip to trip
The expandable design lets you run a smaller footprint on day rides and open it up for overnights. It also includes a reflective panel and bottom hardboards to keep the shape stable.
Key specs
- Listed capacity: 11 liters, expandable
- PVC reflective panel
- Four bottom hardboards for shape retention
Pros
- Expandable volume suits varied trip lengths
- Hardboards help the bag keep its shape
- Reflective panel adds visibility
Cons
- Expanded capacity is less stable than a fixed-volume bag
- Owners sometimes mention strap adjustment takes patience
Bottom line: A flexible option for riders who alternate between commuting and short tours.
KEMIMOTO Bike Saddle Bag 13-15L Expandable Waterproof
Air Release Valve for Compression, PVC Reflective Panels, Fits Road, MTB, E-Bikes, Touring, Commuter & Gravel Bikes KEMIMOTO Bike Saddle Bag, 13-15L Expandable Waterproof Bikepacking Seat Bag
Best for: Wet-weather touring where compression matters
The air release valve lets you squeeze out trapped air when packing a sleeping bag or jacket, which reduces the bag’s volume and keeps contents compact. It is listed for a range of bike types including gravel and touring.
Key specs
- Listed capacity: 13 to 15 liters, expandable
- Air release valve for compression
- PVC reflective panels
Pros
- Air valve helps compress bulky loads
- Waterproof construction claimed
- Suits road, MTB, e-bike and gravel setups per listing
Cons
- Valve adds a small point to maintain
- Expanded size may interfere with long seatpost clearance
Bottom line: Good for touring riders who need dry storage and want to shrink their load when packing.
Rhinowalk Waterproof Bike Saddle Bag 10L Roll-top
10L Roll-top Bikepacking Saddle Bag, Waterproof Inner Bag, Sealed Seams, Anti-slip Pad, Tail Light Hook, Reflective Rhinowalk Waterproof Bike Saddle Bag 10L TPU Under Seat Bag for Road/MTB
Best for: Compact, sealed packing on fast trips
The roll-top closure is a common choice for riders who want a fully sealed bag that resists rain. The 10-liter size suits lightweight kits and riders who carry less.
Key specs
- Listed capacity: 10 liters
- Roll-top closure with sealed seams
- Includes an inner waterproof bag, anti-slip pad and tail light hook
Pros
- Roll-top closure seals against rain
- Tail light hook adds rear visibility
- Compact size keeps the bike handling light
Cons
- Smaller volume rules out heavy kits
- Roll-top needs to be rolled tightly each time
Bottom line: Ideal for riders who prioritize weather sealing and a lean setup.
Topeak BackLoader Bike Bag
Topeak BackLoader Bike Bag
Best for: Riders who prefer an established brand
Topeak is a long-established maker of bike accessories, and the BackLoader is one of its well-known under-seat bags. It suits riders who want a recognizable name and a straightforward design.
Key specs
- Under-seat bag from an established accessories brand
- Designed for quick attachment and removal
Pros
- Established brand with a long track record
- Simple, uncluttered design
- Easy to mount and remove
Cons
- Capacity is modest for full overnight kits
- Less feature-rich than newer bikepacking-specific bags
Bottom line: A dependable choice for riders who value brand reputation and a simple setup.
Bike Saddle Bag Waterproof Expandable 13L
Bike Saddle Bag Waterproof Bike Seat Bag Expandable Capacity Cycling Under Seat Pouch for Mountain Road Biking and Commuting Trips 13L
Best for: Budget-minded riders who want expandable storage
This is a practical option for riders testing bikepacking before committing to a premium setup. Its 13-liter expandable design covers the same range as higher-priced bags.
Key specs
- Listed capacity: 13 liters, expandable
- Waterproof under-seat pouch for mountain and road bikes
Pros
- Good capacity range for the category
- Expandable design adds flexibility
- Suits common road and mountain bike setups
Cons
- Brand-level support may be less established
- Owner feedback on long-term durability varies
Bottom line: A sensible starting point for riders who want to see whether under-seat bikepacking suits them.
Buying Guide
Capacity and trip length
Match volume to how many nights you plan to ride. A 10 to 13-liter bag typically handles a sleeping bag, a spare layer and tools for an overnight or weekend. Multi-day tours usually need 13 liters or more, or an expandable bag that grows with your load. Check the listed capacity, and remember that stuffed clothing takes more room than it looks.
Good picks for this: Waterproof Bike Saddle Bag Large Capacity 15L, KEMIMOTO Bike Seat Bag 11L Expandable
Water resistance and sealing
Look for a bag described as waterproof, sealed seams or a roll-top closure. A roll-top closure generally offers better protection than a zipper alone, because the fold creates a barrier. Zippers can still admit water over time, so consider an inner dry bag for sleeping gear.
Good picks for this: Rhinowalk Waterproof Bike Saddle Bag 10L Roll-top, KEMIMOTO Bike Saddle Bag 13-15L Expandable Waterproof
Mounting and bike fit
Under-seat bags attach with straps to the saddle rails and seatpost. Measure your seatpost diameter and check that the bag clears your tire, especially on mountain bikes with suspension or wide tires. Confirm that the bag will not rub against the rear tire at full compression.
Good picks for this: Rhinowalk Waterproof Bike Saddle Bag 13L, Topeak BackLoader Bike Bag
Expandable versus fixed volume
Expandable bags let you change capacity, which helps if your load varies. Fixed-volume bags usually hold their shape better and sway less at speed. Choose expandable if you ride both short and long trips; choose fixed if you always pack a similar kit.
Good picks for this: KEMIMOTO Bike Seat Bag 11L Expandable, Bike Saddle Bag Waterproof Expandable 13L
Air compression
Compression valves let you squeeze air out of a packed sleeping bag or jacket, which reduces the bag’s footprint. This matters most on longer tours where space is tight. A valve adds one more component to keep clean and check for leaks.
Good picks for this: KEMIMOTO Bike Saddle Bag 13-15L Expandable Waterproof
Visibility and safety
Reflective panels and a tail light attachment point improve visibility on roads and at dusk. Many riders add a rear light regardless, but a reflective bag adds a useful secondary cue. Check that any tail light hook fits your light’s mount.
Good picks for this: Rhinowalk Waterproof Bike Saddle Bag 10L Roll-top, Rhinowalk Waterproof Bike Saddle Bag 13L
Durability and care
Wipe down the bag after muddy or wet rides and let it dry fully before storing. Check the strap buckles and attachment points for wear every few rides. Overloading stresses the seams and rails, so stay within the listed capacity.
Good picks for this: Topeak BackLoader Bike Bag, Waterproof Bike Saddle Bag Large Capacity 15L
FAQ
What size saddle bag do I need for bikepacking?
For a single overnight, 10 to 13 liters is usually enough. For multi-day touring, plan on 13 liters or more, or choose an expandable bag. Pack a test load at home before your trip.
Are saddle bags waterproof?
Many are marketed as waterproof or water-resistant, but few are fully sealed. Roll-top closures and sealed seams offer better protection than zippers. Using an inner dry bag for sleeping gear adds another layer.
Will a saddle bag rub my tire?
It can, especially with wide tires, suspension or a loaded bag that sways. Check clearance before buying and adjust the mounting straps so the bag sits securely above the rear wheel.
Can I use a saddle bag on a road bike?
Yes. Most under-seat bags are listed for road, gravel and mountain bikes. Confirm your seatpost diameter and rail setup match the mounting system.
How much weight can a saddle bag carry?
Weight limits depend on the model and mounting. Stay within the manufacturer’s stated capacity and distribute heavy items close to the center of the bag to reduce sway. If you are unsure about load limits, consult the product documentation or a bike shop.
Should I choose a saddle bag or a seat post bag?
A saddle bag mounts to the rails and seatpost and sits behind the saddle. Seatpost bags are smaller and mount only to the post. Choose based on how much gear you carry.
Conclusion
For most riders starting out, a 13-liter waterproof saddle bag offers the best balance of capacity and handling. Riders who need extra room for longer tours should look at the 15-liter option, while those who value sealed storage will find the roll-top 10-liter bag a good fit. Expandable bags suit riders whose loads vary, and compression valves help on longer, wetter trips. Confirm seatpost and tire clearance before buying, and match the bag to the number of nights you plan to ride.
For more on setting up the rest of your bike, see 5 Best Saddle Bags Bikepackings for Every Rider (2026), Full Frame Bag Bikepacking: How to Choose and Pack One (2026) and Best Handlebar Bags Bikepacking: 6 Styles and Sizes Compared (2026).
Sources
- Consumer product safety guidance on bicycle equipment and reflective visibility (cpsc.gov)
- Trail and backcountry travel guidance for multi-day outdoor trips (nps.gov)
Related reading
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- 7 Best Fork Bags for Bikepacking: Our Picks Compared (2026)
About Claire Whitaker
Claire Whitaker is part of our editorial team and reviews and edits our bike touring & bikepacking guides, checking product details against manufacturer specifications and owner feedback.
