Alpinestars' Tech-Air MX airbag stayed folded through a Whistler drop, then inflated as the rider fell

At a glance

Best for: downhill mountain-bike riders.

Skip it if: you live outside Austria, France, Germany, Italy, Spain and the Netherlands, where the UK store delivers.

Reviewers agree: racers speak well of it, though the up-to-82% impact cut is Alpinestars' own claim.

Price: £569.99 on Alpinestars' UK store, checked 2 November 2026.

At the first UCI downhill World Cup held in Whistler, in late September 2026, Henri Kiefer reached the finish-line drop with his chain gone, both feet off the pedals and an Alpinestars Tech-Air MX airbag under his jersey. He landed still on the bike, then fell and slid. Brujula Bike reads the footage as showing the airbag staying folded through the jump and first landing, then inflating when the system identified the fall, before his body hit the ground. The Loam Wolf's Ethan Revitch reported seeing it inflate firsthand, and Kiefer said afterwards he was grateful to have worn it.[1] [2]

At the end of August 2026 Alpinestars gave Tech-Air MX, an existing motocross product, a downhill mountain-bike mode, delivered as an algorithm through the Tech-Air app. The system is a chest-and-back protector with an airbag and electronics built in. Six sensors, including a three-axis accelerometer and gyroscope, are read hundreds of times a second, and Alpinestars says the airbag deploys in roughly 32 to 45 milliseconds, covering shoulders, chest, back and upper arms. BikeRadar's Tom Marvin adds that the tuning drew on mountain-biker crash data since 2022, including manikins loaded with sensors to simulate over-the-bars falls, loss of control and failed jumps.[3] [2] [4]

Racers supply most of the hands-on evidence, and they speak well of it. BikeRadar's launch report quotes Jordan Williams saying he'll never race without it. Loïc Bruni, sceptical at first, said a first proper crash in it left him with no damage, and that it almost saved him in a later big World Cup crash. Canadian Cycling Magazine's Colin Field counted two deployments caught on World Cup cameras in consecutive weeks this summer: Williams's armour inflating as he fell while celebrating at La Thuile, and a different sponsor's vest appearing to inflate on Amaury Pierron at Pal Arinsal. Revitch adds that many Whistler riders were opting for the Tech-Air MX.[3] [5] [1]

Alpinestars' own claim is up to an 82% cut in transmitted impact energy against passive chest protectors. The independent numbers come from simulation: researchers from Autoliv and Chalmers, in the IRCOBI 2026 proceedings, found a conceptual cyclist airbag vest cut shoulder contact force by up to 60% in single-bicycle crashes, with mixed results against cars. That concept ran on simulations with a car model not validated against physical tests, so it speaks to the principle and says nothing about Alpinestars' figures. Brujula adds that nobody can say which injuries Kiefer's airbag spared him, only that it detected the fall and inflated before impact.[4] [6] [2]

Alpinestars' UK store lists Tech-Air MX with Downhill Algorithm at £569.99 (checked 2 November 2026) and delivers only to Austria, France, Germany, Italy, Spain and the Netherlands; BikeRadar says North America should follow later this year. The weight figures differ, so ask the seller: BikeRadar gives 1.6kg, while Alpinestars' MX product page lists about 3.1kg for the system. Before buying, look for owner reports from outside the race circuit, especially on unwanted inflations during ordinary rides.[3] [4] [7]