Roadracing World – July 2019

Kalex: “You can see they’ve
added sections to the top of the
beams for more longitudinal rigid-
ity. The engine hangers are much
deeper with this bike; maybe that
was due to the engine shape, but
the engine mounts are kinked out
of the stress line, so they’ve creat-
ed a flex-control area. When you
have longer engine hangers, you
have a lever with which you can
do something. When the hangers
are short, it’s too sensitive, but if
they’re longer you have more con-
trol over the flex. The geometry
looks steep.”

Öhlins: “None of today’s rid-
ers would like this frame! They
would say it’s too stiff. I think ev-
eryone at this time had the philos-
ophy of building more stiffness.
We had our first upside-down
forks in 1988 and these are
Showa’s first upside-downs. They
affected the dynamic behavior of
the whole bike, so the factories
increased stiffness in other areas,
because everything must work in
symbiosis.”

` 1996 Honda NSR500
The 1989 input of Erv
Kanemoto and Eddie Lawson
helped Honda engineers find the
right direction in chassis design.
By 1996 the NSR500 was a fine-
ly honed weapon that won 13 of
15 races and took Mick Doohan to
the third of his five World Champi-
onships. Between 1984 and 2001
the various NSR iterations took
132 Grand Prix wins, making it
the most successful premier-class
motorcycle.

Kalex: “Now we are in our
age! The engine mounts are near-
er the front and although the 1989
NSR had three mounting bolts,
while this has only two, there’s
still enough space between them
to take longitudinal forces. The
swingarm pivot section is super
big and the pivot is higher, so the
anti-squat angle is greater. They
needed this because they had
more power, and aggressive pow-
er, which would otherwise com-
press the rear shock too much
and the front would be in the air
all the time. The higher section
of the swingarm shows that the
swingarm has really become part
of chassis design. But the pivot
isn’t adjustable, which I think is
absolutely wrong. The shock is
now easier to get at—so they were
realizing that if you can change
settings and springs quicker you
get more track time.”

Öhlins: “By this time chas-
sis engineers had realized that the
stiffer the frame, the more work
that gives the suspension. The
rider wants to feel confident in the

front when he goes into corners,

but he doesn’t want to feel every

seam and every ripple—because

it’s too much information. The

turning point was 1993. Yamaha

made a super-stiff frame. First

time he rode it, Wayne Rainey said

it felt so nice, but when he tried

to lay down lap times he looked

worried. So we drilled two holes

on the inside of each of the beams

and connected them with a hack-

saw, to give some chassis flex,

so the rider didn’t feel he was on

the razor’s edge. The NSR hardly

changed during this time. It’s got

45mm forks, with magnesium fork

bottoms. They used some Showa

forks that everyone called ‘Sholins’

—after they bought some 46mm

Superbike forks from our Japa-

nese importer.”

` 2002 Honda RC211V

Honda destroyed its rivals

with its first MotoGP bike, which

became the blueprint for MotoGP

design. Longer front engine hang-

ers—for more lateral flex—and

mass-centralization were the big

deal. The RC211V won 14 of 16

races during MotoGP’s inaugural

season.

Kalex: “Wonderful! And not

far from where we are now. The

engine hangers are long, so you’ve

got flex over quite a long distance,

so you can play with flex. The

whole design is so much cleaner:

everything is arranged where it

needs to be and the fuel is much

lower. The swingarm pivot section

is machined from solid, but they

were still pressing the main sec-

tions of the frame. The geometry

and squat hadn’t changed much

from the NSR, because they al-

ready had an understanding of

that. CAD [computer-aided design]

was a big thing by then, so they

were using computer simulations

to help design. Also, CAM (com-

puter-aided manufacturing) was

coming in, so machining was done

via your computer model, so free-

form shapes started appearing.”

Öhlins: “Compare the steer-

ing head area to the 0W76; it’s not

as stiff, to help the bike turn into

corners. People are starting to de-

sign things to work in harmony. I

know they were doing a lot of ex-

periments with engine-mount and

swingarm-pivot torque around

this time. Because you can make

a frame that’s 60% stiffer, but

when you bolt in the engine the

difference may only be 10%; so

you try to spread the load differ-

ently by torqueing the engine bolts

or swingarm pivot; maybe you try

40Nm, then 80Nm, then 160Nm.

The shock link is a typical SW

link. We call them SW, for Swin-

don, because they were designed

by Mick Mills, when he worked on

CCM Armstrong motocross bikes,

before he came to work for us.”

` 2007 Ducati Desmosedici GP07

Ducati’s Desmosedici used

the engine as a stressed part of the

chassis from 2003 to 2011 (steel,

then carbon-fiber], after which

they used aluminum beams, like

everyone else. This is the bike with

which Casey Stoner won the 2007

MotoGP crown.

Kalex: “I don’t think the

stressed engine was the problem,

but maybe the fact that the frame

section is very short, which makes

it difficult to control flex. Also, it’s

very difficult to get a full simula-

tion of engine flex with the engine

(Top) The 2002 Honda RC211V V5 ruled when the premier class went from 500cc two-strokes to 990cc four-

strokes, winning 14 of 16 races. (Above) The 2007 Ducati Desmosedici GP07 had steel-tube front frame and swing

arm pivot sections bolted to the V4 engine. Casey Stoner won the MotoGP World Championship on this bike.

24—Roadracing World, August 2019