RideFast JUNE 2021

This USD arrangement has two advantages: It decreases the unsprung
weight of the motorcycle; and it increases torsional stiffness, which can
improve handling. Two disadvantages of USD forks are they are more
expensive than conventional telescopic forks; and they are liable to lose
all their damping oil should an oil seal fail. USD forks are typically found
on sport bikes and dirt bikes, though the Honda Valkyrie featured USD
forks.
TECH FEATURE
SUSPENSION
• Gas-charged cartridge forks, which became available in
2007,consist of gas-charged cartridges fitted within standard forks.
This kit is suitable for super sport and dirt bike classes of racing, where
regulations prohibit a complete fork replacement but allow modification of
the original forks
• Other fork designs are girder forks, suspended on sprung
parallel links, (not common since the 1940s)
• and bottom leading link designs, not common since the 1960s.
• Vincent Black Lightning with Girdraulic front suspension was a
telescopic fork with a trailing linkage at the bottom attached to a form of
shock absorber behind the fork and then attached to the bottom of the
steering neck, early BMw’s used a similar system as well.
• Some manufacturers (e.g. Greeves) used a version of the
swinging arm for front suspension on their motocross designs. A singlesided
version of the idea is also used in motor scooters such as the
Vespa.
• The hub-center steering as developed by Ascanio Rodorigo, on
a concept associated to Massimo Tamburini is a complex front swingarm
alternative system that entails suspension and steering, as seen in
projects such as Bimota Tesi and Vyrus motorcycles.
• Scott produced a motorcycle with telescopic forks in 1908 and
would continue to use them until 1931
• In 1935 BMW became the first manufacturer to produce a
motorcycle with hydraulically damped telescopic forks
• Most motorcycles today use telescopic forks for the front
suspension.
• A lot of high end modern motorcycle these days have electronic,
reactive suspensions with factory pre set adjustments which are
accessed and set by scrolling and selecting through the menu on the
digital and/or TFT displays.
• A lot of the heavier BMW models use a tele-lever system upfront
• Dirt bikes use a range of either linkage or PDS systems, which
we will look at the difference a little bit later.
A NEW STANDARD OF
SUSPENSION TECH
WP SEMI-ACTIVE SUSPENSION (SAT): KTM and WP Suspension again set the bar in the motorcycle mar
up-to-minute generation of the WP ‘SAT’. The result? More sensitivity, feedback and possibilities for persona
on-the-go. Reach a new standard of comfort and improve the overall riding experience thanks to the updated
Control Unit (SCU) that adjusts the damping rates with magnetic valves in real-time to react to surfaces and
Stroke sensors form the basis of this advanced kit that is fully tunable from the comfort of the TFT display a
switches where the rider can make adjustments for both the front and rear units individually (optional Techn
Accessory). There are three different damping modes: COMFORT, STREET and SPORT as well as OFFROAD
as optional extras; all using the copious data provided by the 6-axis lean angle sensor and the riding style.
The KTM 1290 SUPER ADVENTURE S uses a 48 mm (200 mm of travel) WP APEX SAT fork that features a
engageable (optional) anti-dive function, thus keeping the front from diving under hard braking. One innovat
highlight of the SAT technology is the automatic damping mode, which adapts the damping according to the
style and conditions. The electronically controlled, automatic damping option is an innovative feature develo
by KTM and WP.
The rear end uses the WP APEX SAT shock absorber (200 mm of wheel travel) with a completely new hydrau
pre-load adjuster that is also manipulated electronically. The shock profits from a sensor delivering informat
the SCU for automatic preload adjustment of the spring to achieve the ideal balance (sag) of the bike, indep
weight. The preload can be adjusted by 20 mm on the 2021 KTM 1290 SUPER ADVENTURE S, which is a
10 mm over its predecessor.
In addition, the spring preload of the rear suspension can be set via the menu in 10 steps according to the r
of the rider or in three automatic modes called auto leveling (optional TA) in low, standard high. The setting
performed on the fly or while riding.
RIDEFAST MAGAZINE JUNE 2021 27