Motorcycle airbags: tethered or electronic, marking, budget and upkeep

In fifteen years or so, the motorcycle airbag has gone from a racetrack curiosity to ordinary kit. Vests have got lighter, jackets now build the system in, and prices have come down. The question is no longer whether it works, but what it protects, what it genuinely costs over time, and above all what you have to do to make sure the thing is still live on the day it matters.

What an airbag protects, and what it doesn't

A motorcycle airbag inflates around the chest, abdomen, lower back and, depending on the model, the neck and collarbones. Those are precisely the areas a back protector alone leaves uncovered, and they account for a large share of serious injuries when a rider is thrown off.

The principle works two ways: absorb the energy of the impact, and stiffen the torso-and-neck assembly so the cervical spine can't travel to extremes.

What it doesn't protect: your limbs. An airbag replaces neither shoulder and elbow armour, nor knee protection, nor boots and gloves. It sits on top of your gear, it doesn't stand in for it.

Tethered or electronic: two different logics

Mechanical (tethered) triggering. A lanyard links the vest to the bike. If you're thrown off, the pull on the cable rips out a pin and releases the gas cartridge.

• Upsides: no battery, no electronics, lower purchase price (£180 to £400), fundamental reliability, simple to re-arm.
• Downsides: you have to clip on every time you get on and unclip every time you stop. Forget once as you swing a leg off and the airbag fires for nothing. And the system only protects in cases where your body moves away from the bike — not in an impact where you stay on the machine.

Electronic triggering. Inertial sensors monitor accelerations and angular rates continuously, and an algorithm decides when to fire.

• Upsides: no physical link to the bike, detection of scenarios a tether can't cover (frontal impact without ejection, low-side), firing within a few tens of milliseconds, often before you touch the ground.
• Downsides: higher price (£350 to £1,050), a battery to charge, software updates on some models, and sometimes a subscription with the makers who handle cartridge recharging as a service.

For everyday road riding, electronic wins comfortably on the usability point alone: the gear you actually wear is the gear you don't have to plug in.

What the marking tells you

A motorcycle airbag sold in the UK is personal protective equipment. It has to carry conformity marking — UKCA marking, with CE marking also accepted on the British market — and reference the standard that applies to inflatable protectors for motorcyclists. The marking sits on an internal label, along with the performance level and the date of manufacture.

Two things worth checking before you buy:

• The protection level claimed and the areas covered — not every vest covers the neck.
• How it's meant to be worn: an airbag designed to go over your jacket doesn't protect the same way underneath it, and vice versa. The wearing position is part of the approval.

The real five-year cost

This is the sum the product pages never show you.

The line that swings the whole calculation is the subscription, where one exists. Some makers keep it optional against a higher outright purchase price; others make it compulsory for the recharging service. Check before you buy, not after.

The servicing almost nobody does

An airbag is a pyrotechnic or pneumatic system with dated consumables. Your bike gets an annual MOT once it's three years old; your airbag gets nothing — nobody inspects it but you. Left unserviced, it becomes a garment.

• The gas cartridge has an expiry date, usually several years out, stamped on the cartridge body. An out-of-date cartridge can slowly lose pressure and no longer deliver the gas volume needed.
• The battery in an electronic system needs charging and checking. A vest left in a cupboard for two months can be flat on the first ride of spring.
• The start-up self-test should be checked every time you use it: a light, a beep or a buzz depending on the brand. It's the only sign the system is armed.
• The lanyard and pin on a tethered system wear and corrode. Check the anchor point on the bike too: a fixing on a plastic fairing panel won't take the pull.
• The periodic check the manufacturer recommends, typically every two to five years, verifies the bladder's air-tightness and the state of the sensors.

After it has fired, the system must be put back into service following the manufacturer's procedure. A bladder that's been deployed and then folded away unchecked will not deploy properly again.

Common mistakes in use

• Wearing the vest too loose. An airbag that flaps around inflates into thin air. The fit has to be adjusted over the layer you're actually wearing — so re-checked between summer and winter.
• Wearing it under a jacket that's too tight, which stops the volume forming.
• Forgetting to clip back on after a stop, on a tethered system. It's the most common failure mode of the lot.
• Storing it folded in a top box exposed to temperature swings, with the cartridge screwed in.
• Lending it to another rider without resetting the adjustment.

Should a pillion have one?

Rarely discussed: the pillion takes the same loads, usually with less chance to see it coming. Tethered pillion vests exist, with their own anchor point. On electronic systems, each person needs their own vest — an airbag isn't shared.

How to think about buying one

An airbag replaces nothing: it completes a full set of gear. If the budget is tight, the order of priority is still a recent, well-fitted helmet, approved gloves, jacket and trousers with armour at the joints, boots — then the airbag.

Once that lot is in place, the airbag is the addition that buys you the most per pound spent, because it covers areas nothing else does.