Electronic suspension
Like traction control, electronic suspension systems come in a couple of flavours – one for convenience, and one for performance. The most basic type merely tweaks the suspension damping and preload adjusters according to a pre-set programme. So early BMW versions of ESA (electronic suspension adjustment) would have an electric motor that turned the preload adjuster, for rider, rider and pillion, rider and luggage, or rider, pillion and luggage. It was just a fancy version of a C-spanner and screwdriver really – but the ease of use appealed to many less tech-minded riders.
The other type is called semi-active suspension, and this is much more advanced. Here, the suspension adjusters are constantly being trimmed by an ECU, according to a pre-set programme – but the ECU also takes into account what the bike is doing. So when you hit the brakes, the ECU knows, and can fettle the fork compression damping to control dive. Then on the gas back out of a bend, it will have a look at the rear shock and tweak the damping there for the best grip. Add in an IMU unit, and it knows how far you’re leant over, and that, plus speed, gear position, throttle opening and much more can all be used by the computer to constantly optimise the damping settings. Even more advanced set-ups are possible if the shock and forks have position sensors fitted too – so the ECU knows whereabouts in the stroke the damper is.
PROS – easier set-up, optimised damping for each situation (with semi-active)
CONS – a bit more weight and cost. Something else to go wrong…
THE RECKONING?
GOOD AIDS – the best systems are like having a superbike crew chief under the seat hump