The Tesi 3D E looks bizarre, but how does that hub centre steering

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TEST MARK McVEIGH
PHOTOGRAPHY 404SHOTS
The Tesi 3D E looks bizarre, but how does that hub centre
steering technology actually work? Here’s a layman’s guide
I
magine for a moment, you are lying in
hospital, all busted up from crashing your
bike on the racetrack. Leathers ripped,
ride trashed and your new Arai now only
good enough for the bin. Most normal
people would be resting up, feeling sorry
for themselves. Not Massimo Tamburini.
In September, 1972 the now famous
designer crashed his Honda 750 Four at the
Misano racetrack in Italy – the stack left him
with three broken ribs. While recovering,
Signore Tamburini constructed a tubular
steel frame to handle the power then being
produced by the Japanese bikes. It was called
the HB1 and that’s when Bimota was born.
Born from a young university graduate’s
mind, it was engineer Pierluigi Marconi’s
university thesis (“tesi” in Italian) that directly
led to the first Bimota Tesi 1D hub centre
steered motorcycle in 1990. The later, Andrea
Acquaviva designed, iteration of this ground
breaking bike, the 3D, looks quite similar to its
predecessor the 2D. However, Andrea started
with a relatively empty CAD computer screen
to produce a bike that corrected the 2D’s
drawbacks of limited steering lock – improved
from 18° to 23° – a repositioned front shock to
clear the rider’s knees, a narrower build and a
simpler steering system to improve feel.
The new-for-2012 Tesi 3D E is an evolution
of the 3D which includes a further revised front
shock position. The 3D pull-rod mechanism
hydraulic suspension which was located low
beside the engine has been replaced on this
Evo version with a more traditional spring over
damper shock directly mounted on the front
swingarm translating into more responsive
damping of the front end. The Evo version also
has heaps more carbon fibre and a very handy
STM slipper clutch.
The 3D Tesi’s Desmo donk is sandwiched
between a pair of beautifully machined
aluminium billets serving as the main chassis
to which the front and rear swingarms are
mounted, while the steering head is attached
to a tubular-steel subframe coming off the
front of the billet chassis. Thanks to hub
centre design fundamentals, the 3D Tesi’s
steering head does not see the mega load path
inherent on a traditional forked machine and
is ultra lightweight as a result. The rear end
is exquisitely detailed carbon-fibre complete
with its tidy solo seat, and the exhaust,
headlight and dash come from the Delirio.
The 3D Tesi E uses Ducati’s 1079cc dualspark engine producing 100hp (75kW) with
100Nm of torque. The placid nature of this
1
2
Main: There’s no doubt it’s a unique-looking bike
1. Front end trellis swingarm and steering linkage
2. Rear shock settings are easily adjusted
amcn /52
53/ amcn
1
hub centre
science
Rake: 21°
2
Rake: 26°
3
Trail: 115mm
Trail: 105mm
Hub centre steering has the potential to improve the
performance and safety of motorcycles because
it separates the steering, braking, and suspension
forces compared to the typical standard fork-equipped
motorcycle. The front suspension on a motorcycle
equipped with a conventional fork is compressed under
braking forces. This also has the effect of reducing
the trail (see steering geometry) increasing the
motorcycle’s roll rate or ability to turn, which reduces
the motorcycle’s stability, compared to a hub centre
steering system.
Typical standard motorcycle forks also lack
stiffness in comparison to hub centre steering, as they
act as a long lever to the headstock. This long lever
design also transfers large braking forces through
the frame headstock which subsequently is required
to be very robust, adding to the bike’s weight and high
centre of mass.
Hub centre steering is a triangulated design that,
by nature, transfers loads directly to the chassis away
from the headstock, resulting in a lighter headstock
design. This design also has the benefit of reduced
steering flex under heavy braking.
Also, hub centre steering systems typically use a
linkage which maintains steering geometry – namely
trail – with front wheel travel, negating the adverse
steering geometry change experienced when braking
on a typical standard fork-equipped motorcycle. The
king pin centreline defines the steering axis compared
to a conventional forked motorcycle where the steering
axis is generally through the headstock centreline.
The 3D Tesi hub centre design has lots of positive
handling benefits including low unsprung mass, high
rigidity, low steering inertia plus easy rake and trail
adjustment.
Hub centre steering motorcycles have been around
for a while now and have been relatively unsuccessful
commercially for a number of reasons – for instance,
some aesthetically unattractive designs have had a
negative effect on the motorcycling public’s perception.
Technically, hub centre steering systems’ Achilles
heel is the lack of front-end feel. This is mainly due
to the extra elements between the tyre contact patch
and the handlebars. If you think about a standard fork,
there is a very direct connection to the rider’s hands,
which gives good tyre contact patch feedback. Hub
centre steering bikes however have extra parts, or
elements, each with a certain amount of friction and
movement which reduces the sensitivity and feel to the
contact patch. Recently manufacturers such as Bimota
and Vyrus have been creating some very cool highspec bikes. With continual development and modern
technology, we may see resurgence in hub centre
steering motorcycles.
amcn /54
BIO
Mark McVeigh is a
freelance technical moto
journalist, road-race
coach and development
rider. Mark owns motoDNA, an Australianbased consultancy which provides high
performance road race coaching plus
design, prototyping and testing services
to motorcycle manufacturers and race
teams around the world.
older motor doesn’t really fit with the 3D Tesi’s
high-tech mega-detailed chassis, however it
makes the bike very easy to ride and it gets along
quite nicely if you keep the motor on the boil. The
power delivery is reasonably linear and smooth
although a little soft, so you definitely have to
keep the revs up to maintain a decent pace.
A set of open pipes and some engine
re-mapping would certainly add to the ponies
and sharpen up the power delivery. The motor
is pretty quiet, too, and by the day’s end I was
hanging for some Desmo tones. The electronics
are from Bimota and the motor redlines at
9000rpm which I bounced off a few times before
getting used to the relatively low rev ceiling.
The Ducati gearbox is reasonable, too –
but it’s a little notchy especially noticeable
on multiple downshifts where I can’t bang
down several gears at once, separating each
downshift instead to keep everything smooth.
Saying that, the well-spaced gears make
the best of the motor and engine braking is
excellent with no rear wheel lock ups, the
STM dry slipper clutch working very well.
This Bimota has extra connotations
best described as a 3D feast of motorcycle
engineering jewellery. Every time I looked at
this smorgasbord of aluminium, chromalloy
and carbon fibre, I’d spot some new intricate
detail. The bike is one of only a handful in the
country and the others are in living rooms
like art pieces. The fact I was allowed to fang
this $50,000-plus bike around Queensland’s
Lakeside racetrack is testament to the
motorcycling spirit of its owner, Mark Grant.
After testing all nine of the latest superbikes
at AMCN’s AUSTest in June, I had a fresh feel for
the latest motorcycling technology – and the 3D
Tesi E was a big surprise. Mark is a solid 100kg
and it’s his weight that Bimota used to set the
bike up at the factory. I spent the morning tuning
the spring preload and damping rates to suit
my Leprechaun-esque 75kg. The Extreme Tech
suspension has a good range of spring preload,
compression and rebound adjustability, although
I found the clickers a little insensitive to change
compared to the latest European superbikes.
This bike is a lot of fun. While I was getting
caned down Lakeside Raceway’s straight by the
more powerful machines sharing the track on
this rideday, the Tesi’s strengths – stability, agility
and powerful, progressive brakes – meant I could
make up heaps of time, especially through the
high-speed turns, chicanes and by trail braking
deep into the corners with the Brembo four-pot
radial calipers on 320mm discs.
Normally, motorcycle stability and agility are
trade-offs, as front-end geometry with a larger,
stable trail effectively reduces the bike’s roll
rate, making it harder to turn. The 3D Tesi is very
stable yet also very manoeuvrable; not quite the
Panigale’s level of agility, but very respectable
a 20-year-old design. The 3D is very narrow
and reasonably light, with a 167kg dry weight.
Lightweight Oz wheels and a centralised mass
combine to deliver excellent handling.
The fact I was allowed to fang this $50,000-plus bike
around a racetrack is a testament to its owner
1. Dry slipper clutch works
a treat while the cover is
carbon and billet art
2. Brembo brakes are
powerful and progressive
3. Dash from a Delirio
IN THE REAL WORLD
If you’re riding a Bimota Tesi 3D, you’ll definitely
stand out from the crowd. The day after our track
test we rode to the popular motorcyclist’s haven of
Canungra in the Gold Coast hinterland.
According to bike owner Mark Grant, the biggest
issue in the real world is the crowd control required
when you park up at the café with your mates.
People swarm around the Tesi and just stare
in awe at this amazing machine with questions
aplenty; the most common query simply being,
“How does it work?”
Mark rode the bike as I had set it up at the
track the previous day and reported a much more
compliant and smooth ride, deciding to leave the 3D
Tesi as set up for a smaller 75kg pilot on the track,
maybe a reflection of the Queensland road surface.
There is no doubt this is a dream bike. As a
teenager, I drooled over the Bimota Tesi posters on
my bedroom wall and to get the chance to test this
cool machine on a rideday at Lakeside Raceway in
Queensland was fantastic fun.
55/ amcn
CHAMPION’S RIDE DAYS
Many thanks to Champion’s Ride Days for accommodating
the AMCN crew for this test. The safety, professionalism
and friendly team at Champions ensured we had a fun and
fast time on the racetrack!
Champions host over 120 events per year with over
16,000 customers in most states of Australia.
Offering a fleet of brand new Honda CBR600RR hire
bikes, the company also supplies a complete range of
safety apparel including leathers, boots, gloves and
helmets, a frequent rider program, trackday tuition, text
messages and e-newsletters plus freight services for
customers so they can ride different tracks in different
states. Champion’s Ride Days also give back to the sport by
supporting talented local riders with their well-respected
At the handlebars, the 3D Tesi E generally feels
similar to a conventional forked machine. Under
acceleration and through high-speed turns the
bike is impressively balanced and planted. Through
Lakeside’s high-speed turn one there was some
headshake but nothing to ever get concerned about
as you can feel the lightweight Oz wheels low mass
would never let this translate into anything serious.
Impressively, no steering damper was fitted or needed.
The differences between the Tesi and bikes with
regular forks become apparent when you begin
braking. There is no noticeable front-end dive and
also minimal pitching, the bike remaining relatively
flat, minimising weight transfer to the front tyre. The
Tesi feels more stable under heavy braking than a
conventional machine which inspired confidence,
encouraging serious trail braking. Turn-in stability is
great, the Tesi holding its line beautifully.
Then approaching the middle of low- and mediumspeed corners, a certain vagueness and reduced
feeling with the front tyre is apparent. My apex speed
would certainly have been slower on the Tesi E
compared to the latest European superbikes. This is
probably due to the friction in the multiple elements
of the hub centre steering system and lack of weight
transfer to the front tyre. The 3D was so good overall
I reckon some detail design changes to low friction
privateer race team, winning the Australian Superstock
1000 Championship.
Champion’s Ride Days holds events at the following
racetracks.
A. QLD Raceway (Qld)
B. Lakeside Raceway (Qld)
C. Winton Raceway (Vic)
D. Broadford Raceway (Vic)
G
E. Mallala Raceway (SA)
F. Mac Park Raceway (SA)
G. Barbagallo Raceway (WA)
B
A
E
F DC
Check them out at www.championsridedays.com.au.
bearings and higher quality Öhlins suspension would
be a good step forward. A dynamic trail system
that optimises the steering geometry at this point
would also be a tidy evolution to hub centre steering
technology that could possibly see it overtaking
current conventional superbikes.
Hard braking over bumps is one of this bike’s
strengths as the suspension deals with bumps
separately to the braking forces. There’s heaps of
ground clearance with only the Michelin Pilot road
tyres and the threat of a $50,000-plus repair bill
limiting my bravery.
A bump on the exit of Lakeside’s bus stop chicane
created some unusual vibration through the front
trellis swingarm which was a bit disconcerting
considering my brief was not to scratch this superexpensive piece of motorcycling exotica, but as I
got used to the Tesi’s idiosyncrasies I became more
comfortable in the twilight of the assessment.
It’s great to see smaller niche companies like
Bimota successfully manufacturing motorcycling
exotica and overall I love this bike – it’s a lot of fun,
looks very cool and handles superbly. I’m sure Bimota
is looking at a more recent donk for the next version, to
bring the power delivery up to spec on this expensive
and exotic machine. Perhaps a 4D Tesi with a Panigale
motor is on the cards… I sure hope so!
It's great to see smaller niche companies
like Bimota making bike exotica
1. Seat is narrow and short, which
is just great for the track
2. The front shock position is the
main evolution on this year’s Tesi
Engine
Configuration Ducati L4, twin-cylinder
Cylinder head SOHC, four valves per cylinder
Capacity 1078cc
Bore/stroke 98 x 71.5mm
Compression ratio 10.7:1
Cooling Air
Fueling EFI, 2 x 45mm Magneti Marelli throttle
bodies
Power 73kW @ 7500rpm (claimed)
Torque 105Nm @ 5500rpm (claimed)
TRANSMISSION
Type Six-speed
Clutch Dry
Final drive Chain
CHASSIS
Frame material Light alloy
Frame layout Twin Omega
Rake 21˚
Trail Not given
suspension
Extreme Tech
Front: Monoshock, hub centre steering,
fully adjustable, 115mm travel
Rear: Monoshock, fully adjustable,
120mm travel
wheels/tyres
Wheels Forged aluminium
Front: 17 x 3.5 Rear: 17 x 5.5
Tyres Michelin Power Pure
Front: 120/70ZR17
Rear: 180/55ZR17
brakes
Brembo/Bimota
Front: Twin 320mm discs, four-piston calipers
Rear: 220mm disc, single-piston caliper
DIMENSIONS
Weight 167kg (dry, claimed)
Seat height 800mm
Max width 720mm
Max height 1120mm
Wheelbase 1390mm
Fuel capacity 16L
Performance
Fuel consumption Not given
Top speed 237km/h (claimed)
Contact & sale info
Testbike Bimota Australia
Contact www.bimotaaustralia.com.au
(03) 9387 8827
Colour options Red and White or Carbon Black
Warranty 24 months, unlimited km
Price $54,990
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amcn /56