Supair RADICAL 4

From £400.50 Excl. Tax: £333.75 Was £445.00
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1 in stock 1 in stock In stock and ready to ship. See our Shipping and Stock page for more info.

When in stock, UK approx 2-5 workdays, other countries see shipping page


The RADICAL 4 is a light and versatile mountain harness, designed with hike and fly in mind. It's suitable for a wide range of users, from leisure pilots to more experienced mountaineers. Building on the strengths of the RADICAL 3, the RADICAL 4 has been designed in order to offer a modern hike and fly harness with sleek lines. The comfort of the harness is optimized to be able to spend several hours soaring and thermaling.

It also offers the possibility to connect the optional extra RADICAL 4 Airbag-Backpack Module, sold separately, converting the RADICAL 4 into a light reversible harness with airbag protection and an integrated under seat reserve compartment.


Model Status: Current model



Standard UK delivery - £3.95 / FREE on orders over £100.

Outside the UK - delivery calculated at checkout (based on the total order value and your delivery address).

We use Royal Mail, Parcelforce Worldwide and other courier companies (e.g. DHL, DPD) depending on shipment value, weight, destination etc.

For more information, please view our order and delivery FAQs page.


If you are not 100% satisfied with your order, you have 14 days from the day of delivery to request a refund.

Delivery costs will not be refunded and ou will be responsible for the delivery cost to return the order.

For more information, please read our returns policy.

Technical data

Supair RADICAL 4 tech data key diagram

Size  S M L
Pilot size (cm) 160 – 175 170 – 185 180 – 205
Pilot weight (mini – maxi) (kg) 50 – 70 65 – 90 70 – 120 
Harness weight (as delivered) (g) 910 920 970
Harness weight (with Airbag module) (g) 2160 2190 2260
Maximum carrying volume(L) 62 62 67
Back height (cm) A 62 65 70
Back inclination length (cm) B 30 33 36
Seat length (cm) C 42 42 44
Carabiners height (cm) D 45 45 47
Carabiners distance (cm) E 33 – 44 33 – 44  34-48
Admissible reserve volume (L) 2.9 to 4.75 2.9 to 4.75 2.9 to 4.75

Sizing guide

Supair RADICAL 4 sizing guide table


  • Harness
  • Karabiners

Optional extras

RADICAL 4: light, simple, flexible. For hike & fly.

Thanks to its comfort, its lightness and its simplicity, the RADICAL 4 is suitable for both leisure pilots and more experienced mountaineers looking for a technical and accessorized product for the mountains. With its foam back and stiffened leg straps thanks to mylar, the comfort of the harness is optimized to be able to spend several hours in the air and fly in thermals or soaring.

Light and compact, easy to put on and use, the RADICAL 4 adapts to your movements to allow the pilot to play freely, to go fast, better, high and far. The RADICAL was the pioneer harness for hike and fly. In its fourth generation it still loves the mountains and vertical slopes.

Walk lightly, put into action easily, fly with confidence. The RADICAL 4 takes you up into the mountains, with a take-off from an incomparable viewpoint, at the time of the ascents, after a phase of skiing, fast-hiking or even climbing.

Its refined design embodies the spirit in which it was conceived: to keep only the essential to magnify the experience in flight. Its light weight does not reduce its comfort, thanks to its foamed back, neither its efficiency in turns: the support is precise, damped (the independent leg straps, stiffened with mylar, erase the irregularities of the air mass) and balanced (its structure erase the parasitic movements).

The RADICAL 4 gives "a feeling of smooth control, of controlled glide", describes Yoann Chavanne, its designer. This soft precision in piloting is explained by its capacity to deform itself to adapt to the body of the pilot.

Well accessorized (pole holder, removable chest strap) the RADICAL 4 reveals itself in its finishing details. We touch with our eyes: every useful detail, every worked finish, every material chosen for its nobility and durability. The structure of the strap and the frame, the subcutaneous airbag relocated in front of the harness and using a rush designed with a resistant material, have been thought to improve safety. The backpack and harness have been designed separately to push the technical and aesthetic solutions to their limits.

Freedom, lightness, simplicity, because when there is nothing left to remove, the important thing remains.

The RADICAL 4 can be transformed into a light reversible harness-backpack with the optional extra Airbag-Backpack Module fitted. More info below.



  • Sitting position
  • Mountain flights and progression
  • Tandem pilot or passenger
  • No seat plate, but leg straps to reduce weight


  • Opening of the harness by the carabiners
  • Self-stabilizing leg-strap system
  • Pre-equipment for parachute (shoulder rescue straps, reserve parachute riser in chest and subcutaneous position with Airbag module)

Gear / Comfort

  • Accelerator pulleys
  • Back with stiffening foam and comfort foam
  • Semi-rigid ergonomic leg straps


  • Dorsal pocket (approximately 10 L)
  • Hydration pipette hole at the top of the dorsal pocket
  • Micro vario fastener on right shoulder


  • Chest strap adjustment
  • Adjustable backrest support incline
  • Shoulder straps adjustments


  • Dyneema and polyester webbing
  • Nylon 210D Ripstop and Nylon 70D Diamond ripstop
  • Nylon Skytex

RADICAL 4 Airbag-Backpack Module (optional extra)

The RADICAL 4 offers the possibility to connect a removable airbag / reversible backpack module, which includes airbag protection and a reserve parachute compartment integrated under the seat.

Pre-shaped, the airbag has been reworked compared to the RADICAL 3 version. It comes further forward of the harness and uses a new, stronger material. Certification tests have confirmed it offers optimum safety.

The module is also reversible into a roll-top backpack, accessorized for the mountain (multiple easily accessible pockets, a baton holder, ice axe holder, hydration system pocket...). Its new ergonomic straps and removable belt allow a high carry with a light backpack or a classic portage when the backpack is heavier. The backpack is adapted to the pilot's morphology, with a larger backrest on size L than on sizes S and M. The volume of the carrying bag is larger than on the RADICAL 3. It has been designed to hold a LEAF 2 Light glider, a reserve parachute and a open face helmet.

Safety (with optional Airbag-Backpack Module)

With the optional extra Airbag-Backpack Module fitted, the RADICAL 4 offers the safety features shown below.

Supair RADICAL 4 safety with Airbag-Backpack Module fitted

A – Airbag
B – Integrated rescue parachute container
C – Storage pocket


The ready to fly harness in size M weighs 920 grams.

With the airbag module it weighs 2190 grams.

Flybubble review

“We tried Radical 4 harness with attached optinal extra Airbag-Backpack Module. Overall very nice harness. Very simple and comfortable."

– Nancy Elliott, Flybubble

“First impressions of Radical 4 Airbag-Backpack Module. Seems like it's a very clever design. It takes a little bit of getting used to because it's different from other things. You need to get your head around how it reverses, how it all goes in, and where the different bits are. But overall I think it's very nice. The Straps are well shaped and quite padded. Quite wide straps, wider than others. So, I found it really comfortable to walk with. Some bags really wobble about on your back and unbalance you, but this stayed nicely on my back. It's not an X-Alps racing rucksack but it's very comfortable to carry. Great for what it's designed for, for hike and fly."

– Carlo Borsattino, Flybubble

Watch the Flybubble First impression video review


More Information
Condition New
Shipping Details When in stock, UK approx 2-5 workdays, other countries see shipping page
Model Status Current model