Sea to Summit Basecamp Down Sleeping Bag
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Basecamp Down Sleeping Bag
Sleep System · Comfort · Car Camping
The Basecamp takes vehicle-based camping to the next level. This version of the Free-Flow Zip system allows you to open either side of the bag or the footbox for the greatest ventilation possible. With a relaxed semi-rectangular fit, for even more space you can zip two Basecamp sleeping bags together as a double, or unzip the upper section for use as a quilt. RDS-certified, 650+ fillpower duck down with a non-PFAS Ultra-Dry Down treatment, a box baffle construction with vertical chest baffles in the torso for reduced down movement, and a hood large enough to accommodate your favourite pillow from home. If you're looking for one of the best, most comfortable vehicle-based sleeping bags available, look no further.
Car Camping Comfort
Semi-rectangular fit + oversized hood = more room to move, more comfort than backpacking mummy bags.
Zip-Together
Two Basecamp bags zip together as a double. Left/right zippers also pair with most STS Women's/Unisex bags.
Free-Flow+ Zip System
Upgraded version with zipper ploughs (covers over teeth) — prevents cold infiltration + zipper snags.
Pillow-Friendly Hood
Oversized hood with adjustment cords has space for your favourite pillow from home.
Multi-Mode
Open both sides for max ventilation. Open footbox only. Use as quilt by removing upper section.
Sustainably Sourced
RDS-certified duck down with non-PFAS Ultra-Dry Down treatment.
650+ Fillpower RDS Duck Down (NEW — FIRST DUCK DOWN)
The Basecamp uses 650+ fillpower duck down — the first STS sleeping bag I've built that uses duck rather than goose. Duck down is slightly less lofty per ounce than goose down (goose typically achieves higher fillpower for the same cluster size), but duck down is more affordable — explains the lower price point ($414 vs $449-$934 for the other STS bags). RDS-certified for ethical sourcing, treated with non-PFAS Ultra-Dry Down.
Free-Flow+ Zip System (NEW — UPGRADED VARIANT)
The Basecamp uses an upgraded Free-Flow+ Zip System with zipper ploughs — fabric flaps that cover the zipper teeth when closed. Zipper ploughs:
- Prevent cold air infiltration through the zipper teeth
- Prevent fabric from snagging in the zipper
- Add weather resistance in the zipper area
- Make the zipper quieter (less metal-on-metal clicking)
The "plus" version is an upgrade over the standard Free-Flow Zip System used in the Ascent and Alpine.
Two Full-Length Side Zippers + Footbox Zip (NEW — UNIQUE)
The Basecamp has two full-length YKK #5 side zippers — one on each side of the bag, each with two sliders. Plus a YKK #5 footbox zip. This combination enables:
- Open either side for ventilation (left only, right only, or both)
- Open footbox only for foot ventilation
- Open both sides + footbox = flat quilt mode
- Zip two Basecamp bags together as a double-wide sleeping bag
- Left/right zippers pair with STS Women's/Unisex bags for mixed pairs (e.g., Ascent Women's left + Basecamp right)
Relaxed Semi-Rectangular Fit (NEW — DIFFERENT FROM MUMMY)
The Basecamp uses a relaxed semi-rectangular fit — wider than a mummy bag but narrower than a full rectangular bag. Trades packability for comfort and room to move. Designed for car camping where pack size doesn't matter, but the user wants more comfort than a mummy provides.
Oversized Pillow-Friendly Hood
The hood is intentionally oversized — has space for your favourite pillow from home (e.g., a regular bed pillow) inside the hood, not just an inflatable camping pillow. A unique comfort feature for car campers who don't need to minimize pack size.
Box Baffle Construction
Box baffles throughout with vertical chest baffles in the torso — 3D fabric walls that prevent down from shifting. Vertical chest baffles specifically minimize vertical down shift in the critical chest area where body weight can compress down.
Lightweight 20D Recycled Polyester Shell
The shell is lightweight 20D recycled polyester with non-PFAS DWR finish. Note: this is recycled polyester, not the recycled nylon used in the Ascent and Alpine. Recycled polyester is slightly heavier than recycled nylon at the same denier but more affordable.
Use Cases (Car Camping Specific)
Not for Backpacking
Per STS FAQ: "The Basecamp is too heavy and too bulky for anything more than a hike-in to a campsite. For a comfort-oriented performance backpacking bag, check out the Ascent/Women's Ascent."
Explicit positioning: Basecamp is for car camping (drive to campsite) and short hike-ins only. NOT for backpackers who count every gram.
Zip-Together Couples/Family Camping (NEW — KEY FEATURE)
The Basecamp's left/right zippers allow it to be zipped to another Basecamp to form a double-wide sleeping bag. Per STS FAQ: "Yes! The left & right zippers can be zipped to another Basecamp or to most STS Women's and Unisex sleeping bags."
This means:
- Couples camping: Two Basecamps zip together for shared bed
- Parent-child camping: Adult Basecamp + kid's sleeping bag (if STS makes one with compatible zipper)
- Different temp ratings: Mix and match (e.g., 15°F Basecamp + 30°F Ascent Women's for partners with different cold tolerances)
For SpokeX: worth featuring prominently — couples/family camping is a major market segment.
Quilt Mode (NEW)
Per STS description: "for even more space you can zip two Basecamp sleeping bags together as a double, or unzip the upper section for use as a quilt." The Basecamp can be unzipped to function as a quilt for warm nights — versatile multi-mode usage.
Temperature Rating
15°F (Single Temperature Rating)
The Basecamp comes in one temperature rating (15°F / ISO Lower 16°F / Women's ISO Comfort 25°F) — designed for spring, summer, fall, and mild winter camping. For colder conditions, STS recommends the Ascent Women's (15°F) or Alpine Down (-20°F).
Temperature Rating
ISO Lower Limit
16°F / -9°C
ISO Comfort (Women)
25°F / -4°C
Climate Category
Comfort / Car Camping
Dimensions & Weight (by size)
| Measurement | Regular | Long |
|---|---|---|
| Total Weight | 64.3 oz / 1822 g | 71.7 oz / 2033 g |
| Fill Weight | 26.46 oz / 750 g | 30.34 oz / 860 g |
| Compressed Volume | 13.9 L | 15 L |
| Recommended User Height | 72.05 in / 183 cm | 77.95 in / 198 cm |
Materials & Construction
Shell
100% Recycled Polyester (Lightweight 20D, non-PFAS DWR finish)
Lining
100% Recycled Polyester (20D)
Down Fill
RDS-certified, 650+ fillpower duck down (90/10 ratio) with non-PFC Ultra-Dry Down treatment
Stuff Sack
100% Nylon (included, excluding trims)
Zippers
2× full-length YKK #5 side zippers (2 sliders each) + YKK #5 footbox zip
Zipper Ploughs
Yes (Free-Flow+ Zip System — fabric covers over zipper teeth)
Baffle Construction
Box baffles throughout + vertical chest baffles in torso
Fit
Relaxed semi-rectangular (wider than mummy, narrower than rectangular)
Zip Compatibility
Left/right zippers pair with another Basecamp OR most STS Women's/Unisex sleeping bags
Performance (STS scales)
Weight Class
Midweight (heaviest STS bag — designed for car camping, not packability)
Midweight
Compatibility
Use Cases
Car camping, drive-in campsites, short hike-ins, RV camping, cabin trips, festival camping (with car), basecamp camping
Not For
Backpacking, multi-day hikes, mountaineering (too heavy + bulky per STS FAQ)
Sleeping Pad Pairing
Pair with Comfort Deluxe SI pad ($265) for car camping comfort system
Sleeping Bag Liner Pairing
Compatible with STS Silk Blend, Reactor Lightweight, Reactor Midweight liners
Profile
Brand
Sea to Summit (Australian outdoor gear, founded 1994)
Category
Sleeping Bag / Down Sleeping Bag / Car Camping Sleeping Bag
Activity
Car camping, drive-in campsites, RV camping, festival camping (with car), cabin trips
Season
Spring, summer, fall, mild winter
Cleaning (Down Bag Specific)
Hand wash or machine wash (front-loading washer only, no top-loaders with agitators) in cold water with a down-specific technical wash like Nikwax Down Wash or Grangers Down Wash. Regular detergent strips natural oils from down and degrades the Ultra-Dry Down treatment. Wash infrequently — most down bags only need washing once every 5-10 trips. Spot clean between washes. Do not dry clean — solvents strip the down treatment and damage the shell DWR.
Drying (Down Bag Specific)
Tumble dry low with 3-4 clean tennis balls or dryer balls — the balls break up down clumps as the bag dries, restoring loft. Drying takes 2-4 hours minimum. Ensure the bag is completely dry before storage — any retained moisture causes mildew and down clumping. Can also air dry in sunlight on a dry day, but fluff by hand periodically.
Storage (Down Bag Specific)
Store UNCOMPRESSED in a large cotton storage sack — not the included compression stuff sack. Long-term compression damages down loft permanently. STS typically includes a large cotton storage sack with their down bags. Store in a cool, dry place away from direct sunlight.
Ultra-Dry Down Treatment Care
The Ultra-Dry Down treatment is durable but wears off with years of use and washing. Refresh with Nikwax Down Proof or similar down-specific water-resistant treatments after washing. Apply to clean, dry bag and tumble dry low with tennis balls to activate.
Shell DWR Refresh
The shell's non-PFAS DWR will wear off with use. Refresh with a PFC-free spray-on DWR (Nikwax TX.Direct Spray-On, Grangers Performance Repel, Gear Aid ReviveX). Apply to clean bag, let cure for 24 hours before use.
YKK Zipper Care
All zippers (2× full-length side zips, footbox zip) are YKK #5 — industry-leading brand. After exposure to sand, salt, or dirt, rinse with fresh water. If zippers stick, apply beeswax or a graphite pencil tip to the teeth — avoid silicone-based lubricants which attract dirt. Periodically check zipper ploughs (fabric covers) for proper alignment.
Box Baffle Maintenance
Box baffles can develop cold spots over years of use as down shifts between chambers. To re-distribute down: lay the bag flat, massage the chambers to push down back into even distribution. Do this periodically for optimal warmth.
Zip-Together Care
When zipping two Basecamp bags together (or a Basecamp with another STS bag), ensure both zippers are aligned correctly before zipping. Mismatched zipper alignment can damage the teeth. Practice zipping together at home before relying on it in the field. Periodically inspect the zipper alignment for any bent teeth.
Long-Term Loft Maintenance
Down bags lose some loft over years of use. To refresh loft: tumble dry low with tennis balls for 30 minutes every 6-12 months. Replace bags showing significant loft loss.
Repair
Small shell tears: STS repair patches or any silicone/PU repair tape. Large tears, baffle failures, or zipper failures: contact STS warranty service.
Car Camping Tip
The Basecamp's semi-rectangular fit makes it ideal for car camping comfort — much roomier than a mummy bag. The zip-together feature is great for couples: buy two Basecamps for a shared sleeping surface (still separate comfort zones). For best warmth, pair with the Comfort Deluxe SI sleeping pad ($265) which is similarly comfort-oriented. Use the Free-Flow+ Zip System to vent in warm weather — open both side zippers and the footbox for maximum airflow, or unzip the upper entirely to use as a quilt.
Shipping Policy
Components:
All component items (wheels, drivetrains, suspension, brakes, etc.) ship within 2-5 business days of purchase.
Bicycles:
Complete bikes typically ship within 2–3 weeks due to build, tuning, and inspection times. You will receive tracking information as soon as your order is ready to ship.
Riding Gear & Apparel:
Riding gear and apparel orders (helmets, jerseys, gloves, etc.) ship within 2-5 business days.
Returns & Exchanges:
If you received the wrong size or wish to exchange an item, it must be returned in original condition—unused, uninstalled, and with all packaging intact.
For full details, please see our Refund Policy before initiating a return.
