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Colin FosterBy Colin Foster

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A sleeping bag on a bike tour has to fit in a pannier or bag and still keep you warm on the coldest night of the trip. Packed size and weight matter as much as the temperature rating, so the list below starts with those numbers wherever a listing gives them.

Each product text comes from the maker’s own listing, so the claims are the brand’s, not independent findings. Where a listing does not give a weight, temperature rating or fill type, the table says Not stated rather than filling the gap.

Every specification on this page comes from each product’s Amazon listing, checked on 14 November 2026. We have not used these products ourselves, so the picks are based on published specifications only.

Quick picks

How we chose these

  • Pack weight. Listed weight decides how much a bag adds to the load, and several listings in this group give it directly.
  • Temperature rating. Check the rating against the coldest night you expect, since many bags here are listed for mild or warm nights.
  • Insulation type. Down and synthetic fills are described differently by each maker, so compare the fill named in each listing.
  • Size and fit. Height limits and length vary, and some makers list a maximum height for the bag.

These criteria follow the details that the makers list in their own product text, so a Not stated cell means that listing did not give that detail.

Comparison table

Product Weight Temperature rating Insulation Best for
1. Sea to Summit Traveller Down Blanket 1.29 pounds 45°F (7°C) 650+ fill power down Warm-weather blanket use
2. Sea to Summit Spark 45°F 13.6 ounces 45°F (7°C) 850+ fill power down Warm-weather touring
3. Sea to Summit Spark 0°F 2.6 lb 0°F (-18°C) 850+ fill power down Colder nights
4. Kelty Cosmic 20 2.6 lb Not stated 550 fill power down Campsite comfort
5. Naturehike 40-12℉ 2 lbs (910 g) Comfort 40.4°F (4.7°C) 650 fill power down Small packed size
6. Kelty Cosmic Synthetic 40 2 lb. 8 oz. 40°F Recycled CirroLoft ECO synthetic Mild-weather nights
7. NewDoar Ultralight 1.5lbs 1.5 lbs 50°F-70°F (10°C-21°C) Polyester fill Warm summer nights
8. BORULL Lightweight Compact 1.5 lb Comfort 50°F-77°F Not stated Lightest pack weight
9. Naturehike 41/28℉ 1.63 lb (medium) 41/28℉ (in name) Polyester fill Side-zip access
10. Wind Tour 3 Season 2.2 lb (1.0 kg) 43°F-59°F (6°C-15°C) Cotton fill (listed) Quilt mode
11. Nature Link Mummy 2.87 lbs 42°F-55°F 300g/m² imitation silk cotton Roomy, longer fit
12. Big Agnes Anthracite Long 3 lb 2 oz Not stated FireLine Pro Eco synthetic Riders up to 6 ft 6 in

Not stated means the listing does not give that value. Weights and temperatures are the makers’ own listed figures.

Down bags that pack small

Down-filled bags that the makers describe as compact or ultralight.

1. Sea to Summit Traveller Down Blanket: Warm-weather nights and blanket use

Sea to Summit positions this as a light down option for mild-weather trips, including bike touring, hut stays and travel.

Once unpacked, it opens into a rectangular bag and can zip out flat as a blanket. Shoulder and foot drawcords let you adjust warmth or ventilation, according to the maker.

  • Weighs 1.29 pounds (Sea to Summit)
  • Includes an Ultra-Sil compression sack (Sea to Summit)

2. Sea to Summit Spark Ultralight Down Bag: Warm-weather touring

Sea to Summit markets this lighter down bag for warm-weather use on backpacking, bike packing and touring trips.

The maker says the 850+ fill power down has a treatment to hold loft when damp, and the hood and footbox have a water-resistant shell.

  • Maximum height recommendation of 6 feet (Sea to Summit)
  • Closure is a zipper with YKK #5 zippers (Sea to Summit)

3. Sea to Summit Spark 0-Degree Regular: Colder nights on a tour

Sea to Summit lists this zero-degree Fahrenheit version as a three-season option for backpacking and touring.

The maker says full box baffles add warmth, and the bag uses the same 850+ fill power down described for the lighter version.

  • Temperature rating of 0°F (-18°C) (Sea to Summit)
  • Maximum height recommendation of 6 feet (Sea to Summit)

4. Kelty Cosmic 20 Down Mummy Sleeping Bag: Campsite comfort with recycled fabrics

Kelty says the Cosmic 20 has long been part of its backpacking lineup and uses compressible 550 fill power down.

The shell and liner are recycled nylon and polyester taffeta with a durable water repellent finish, and Kelty says its down is traceable through RDS.

  • Dual-direction zippers (Kelty)
  • Down traceable batch by batch through RDS (Kelty)

5. Naturehike 40-12℉ Ultralight Down Bag: Small packed size for 3-season trips

Naturehike says this bag has a mummy upper body with a rectangular lower body, so the feet can move or stay exposed.

The package includes a storage bag plus a compression sack, and the maker says each RDS label traces where the down came from.

  • Weighs 2 lbs (910 g) (Naturehike)
  • Packed size 13.8 x 7.1 inches (Naturehike)

Synthetic and mild-weather bags

Synthetic or polyester-filled bags, many listed for mild or warm nights.

6. Kelty Cosmic Synthetic Fill 40 Degree Bag: Mild-weather nights

Kelty says this bag uses recycled CirroLoft ECO insulation for 40-degree warmth on lighter-weather trips and summer camps.

The updated mummy shape adds room, and dual locking sliders help with venting.

  • Weighs 2 lb. 8 oz. (Kelty)
  • Fits sleepers up to 6 ft. 6 in. (Kelty)

7. NewDoar Ultralight 1.5lbs Sleeping Bag: Warm summer nights

NewDoar describes this 1.5 lb bag for warm weather, with a three-season comfort range of 50°F to 70°F.

The maker says the 20D 380T nylon shell is waterproof and that two-way zippers can link two bags or open into a blanket.

  • Packs to 11.8 x 6.5 inches (NewDoar)
  • Medium fits 5 ft 7 in and under; Large fits 6 ft 3 in and under (NewDoar)

8. BORULL Lightweight Compact Bag: Lightest pack weight

BORULL says this bag weighs 1.5 lb and packs to 7.9 inches, a size it compares to a soccer ball.

The maker lists the bag at 79 inches long and 30 inches wide, and gives a comfort range of 50°F to 77°F.

  • Packs to 7.9 inches (BORULL)
  • Recommended for users under 165 lbs (BORULL)

9. Naturehike 41/28℉ Lightweight Sleeping Bag: Light mummy bag with side zippers

Naturehike says this mummy-style bag is about 30% lighter than other mummy bags with the same temperature rating.

The maker says its polyester fill gives warmth comparable to 550 fill power down, and zippers on both sides let you reach inside.

  • Medium weighs 1.63 lb; large weighs 1.81 lb (Naturehike)
  • Medium packs to 12.6 x 7.5 inches (Naturehike)

10. Wind Tour 3 Season Lightweight Bag: Quilt or sleep mode use

Wind Tour describes a dual-size design with a sleep mode that includes an 11.8-inch hood extension and a quilt mode for other use.

The maker gives a temperature range of 43°F to 59°F (6°C to 15°C) for spring, fall and cool summer use.

  • Total weight 2.2 lb (1.0 kg) (Wind Tour)
  • Storage sack 12 x 8 inches (Wind Tour)

Longer and roomier bags

Bags that makers describe with extra length, width or room for taller sleepers.

11. Nature Link Mummy Sleeping Bag 2.87lbs: Roomy fit for taller sleepers

Nature Link lists dimensions of 86.6 x 29.5 x 22.8 inches and says the foot area has extra insulation.

The maker says the shell and lining are 20D nylon, with a water-repellent shell, and that the bag is machine washable.

  • Weighs 2.87 lbs (Nature Link)
  • Packs down to 13 inches in height (Nature Link)

12. Big Agnes Anthracite Sleeping Bag: Taller riders

Big Agnes lists the Long size for riders up to 6 ft 6 in (198 cm), at 3 lb 2 oz.

The maker describes a comfort-fit hood, an anti-draft collar and FireLine Pro Eco synthetic insulation that it says stays efficient in damp camping conditions.

  • Compresses to 10 x 9 inches (Big Agnes)
  • Two-way anti-snag zipper that can be joined with women’s bags (Big Agnes)

Which one fits you

Your situation Look at Why
You ride in warm weather and want a light bag Sea to Summit Traveller Down Blanket Sea to Summit lists it at 1.29 pounds with a 45°F (7°C) rating and a blanket mode.
Colder nights are possible on the route Sea to Summit Spark 0-Degree Regular Its listed 0°F (-18°C) rating covers colder nights than the 45°F version.
You want the smallest pack weight BORULL Lightweight Compact Bag BORULL lists 1.5 lb and a packed size of 7.9 inches.
You are tall or want extra length Big Agnes Anthracite Sleeping Bag Big Agnes says the Long model fits up to 6 ft 6 in.

Practical tips

  • Check the temperature rating against the coldest night you expect on the route, since several bags here are listed only for mild or warm nights.
  • Compare listed weight and packed size, because several listings in this group do not give a weight.
  • Confirm any maximum height limit before buying, since several makers list one.

FAQ

Which bag is lightest in this list?

BORULL and NewDoar both list 1.5 lb. Several other listings leave weight out, so check each one before you decide.

Is a 45°F bag enough for cold nights?

Sea to Summit lists its 45°F versions at 45°F (7°C). For colder nights, the 0°F version from the same maker is the one to compare.

Does Sea to Summit say its blanket suits bike touring?

Yes. Sea to Summit lists bike touring among the uses for its Traveller Down Sleeping Bag Blanket.

Sources

Specifications from each product’s Amazon listing, checked 14 November 2026: Sea to Summit Traveller Down Blanket, Sea to Summit Spark Ultralight Down Bag, Sea to Summit Spark 0-Degree Regular, Kelty Cosmic 20 Down Mummy Sleeping Bag, Naturehike 40-12℉ Ultralight Down Bag, Kelty Cosmic Synthetic Fill 40 Degree Bag, NewDoar Ultralight 1.5lbs Sleeping Bag, BORULL Lightweight Compact Bag, Naturehike 41/28℉ Lightweight Sleeping Bag, Wind Tour 3 Season Lightweight Bag, Nature Link Mummy Sleeping Bag 2.87lbs, Big Agnes Anthracite Sleeping Bag. Makers can change specifications; check the product page before you buy.

Colin Foster

About Colin Foster

Colin Foster is part of our editorial team and reviews and edits our bike touring & bikepacking guides, checking product details against manufacturer specifications and owner feedback.