What’s the springiest material out there? Well (sometimes) it’s the very air we breathe itself! This means it is a useful shock absorbing aid and this fact has been utilised by many engineers in the past.
We know that air suspension has been used on many vehicles but what about bikes? Well, Suzuki aimed to sort out their GP bikes in the 1970s with air suspension thanks to issues with excessive weight and ‘chatter’.
Chatter with the bikes back in the day was thanks to the cross-ply tyres of the time in 500cc Grand Prix racing – we’re talking of the mid-1970s. Apparently, if the tyre moved in frequency with the springs you would have chatter and it could be very bad indeed.
So, what could be done? It was found that air being introduced in the forks could help handle the heavier tyres. Apparently something like 1.2psi would make the feel from the tyres better: and – as racing improves the breed – this went from Suzuki Grand Prix bikes to their own road bikes… It made sense: if their race bikes were heavy and their road bikes were getting heavier, why not sort both?
We know now that air forks/suspension was a thing that worked at the time: even Barry Sheene went from adopting-to-hating-to-adopting the system… When people were running into chatter from the weight of cross-ply tyres in the 1970s/1980s it seemed that this was the way to go to eliminate it.
Suzuki led the field with air suspension on road bikes: the 1978 GS1000 – which was Suzuki’s first litre-class superbike – would debut Kayaba’s air suspenders at both ends: eventually. Why? Because big four-stroke bikes at the time wallowed like a hippopotamus in muddy water. This meant that – in the 1970s – if you wanted a bike that handled or you wanted a Jap bike to handle, you either bought a European bike (and would suffer from other reliability issues) or you got a Jap bike which was wrapped up in a European frame…
Some say the Suzuki GS1000 was when the Japanese began to turn this all around. The GS had a heavily braced frame and beefy 37mm forks, which featured dual-rate coil springs and air and oil damping, as well as conventional spring-laden rear shocks which were actually adjustable.
Suzuki even later went one better, when – in the 1978 model year – the rear spring dampers would be replaced by springless gas/air shocks. The sturdy chassis and suspension meant that the GS was a winner in the handling, ride and comfort stakes. Suzuki were pre-empting 1990s designs by two decades by looking at ‘less’ not ‘more’ weight and advanced chassis components to build a better bike.
So how did the ‘air’ in ‘air forks’ help? Well, this was an addition to contemporary spring and oil-filled forks… this meant the owner could release or add air as required to the top of the forks. Mainly, this added more pre-load to the forks and not much else, but in the 1980s, this was a big thing.
As time went on, other manufacturers followed suit, with differing results. The big thing – like forks and suspension in general – was that, when things didn’t receive TLC, they went to pot or seals could go pop if too much air was added.
So it was that air-assisted forks for the majority of road bikes disappeared in the 1990s. Tyres became radial (and lighter) while suspension became more adjustable and more advanced, again thanks to racing, but air forks had their place and pointed the way forward to a time when riders wanted more adjustability out of their machines…so don’t knock them!