12
OP
I
S
T
EM
T
he
fo
ll
owing
procedure
shou
l
d
on
l
y
be
comp
l
e
t
ed
by
a
professiona
l
bike
mechanic.
Before
insta
ll
ation,
make
sure
a
ll
part
surfaces
are
c
l
ean.
App
l
y
a
high-
q
ua
l
ity
bicyc
l
e
bearing
grease
to
the
surfaces
indicated.
See
shaded
areas
in
i
ll
ustration,
next
page.
M
ake
sure
both
upper
and
l
ower
head
tube
bearings
are
fu
ll
y
seated
in
the
headtube.
F
o
ll
ow
t
hese
s
t
eps
carefu
ll
y:
1.
I
nsta
ll
the
upper
bearing
sea
l
onto
the
upper
headtube
bearing.
T
he
open
side
of
the
sea
l
faces
the
bearing.
2.
Position
the
Lefty
onto
the
headtube
by
s
l
iding
the
Lefty
c
l
amps
over
the
head
tube
and
sea
l
.
3
.
S
l
ide
the
ny
l
on
washer
onto
the
OP
I
stem
with
rounded
side
facing
the
shou
l
der
of
the
stem.
4
.
App
l
y
grease
to
fu
ll
y
cover
stem
bearing
surface
and
the
interna
l
steerer
threads.
A
l
so
app
l
y
grease
to
the
inner
race
of
the
upper
and
l
ower
headtube
bearings.
S
l
ide
the
desired
number
of
spacers
onto
the
stem.
Y
ou
may
use
0
-
3
spacers
onto
the
OP
I
stem.
Use
on
l
y
OP
I
spacers.
See
the
warning
be
l
ow.
5
.
M
ake
sure
the
Lefty
is
a
l
igned
over
the
head
tube
bearings,
insert
stem
(with
ny
l
on
washer,
and
desired
spacers)
through
upper
c
l
amp/sea
l
and
onto
the
bearing.
With
a
soft
ma
ll
et,
carefu
ll
y
drive
stem
straight
down
unti
l
fu
ll
y
seated.
6
.
Next,
insta
ll
the
ny
l
on
washer
onto
steerer
with
the
rounded
side
of
the
washer
facing
the
steerer
bottom
fl
ange.
G
rease
entire
steerer
l
ower
bearing
surface
and
the
steerer
threads.
7
.
I
nsert
steerer
into
bearing
and
carefu
ll
y
hand
thread
into
stem.
Do
not
use
a
too
l
.
Continue
hand
threading
unti
l
the
steerer
contacts
the
l
ower
c
l
amp
surface.
8
.
T
ighten
the
steerer
to
12
Nm
using
the
Shimano
T
L-
F
C
33
bottom
bracket
too
l
and
a
tor
q
ue
wrench.
T
his
step
draws
the
stem
and
spacer
stack
to
the
upper
c
l
amp.
When
tightened,
a
l
ign
the
stem
and
on
l
y
hand
tighten
the
upper
c
l
amp
bo
l
t.
9
.
Re-tighten
the
steerer
to
12
Nm,
ensuring
the
stem
and
Lefty
do
not
move
re
l
ative
to
each
other.
T
hen,
hand
tighten
the
l
ower
c
l
amp
bo
l
t.
1
0
.
F
inish
by
tightening
both
the
upper
and
l
ower
Lefty
c
l
amp
bo
l
ts
to
the
fina
l
tor
q
ue
of
7
-
9
Nm.
11.
App
l
y
Loctite
2
4
2
and
tighten
the
hand
l
ebar
c
l
amp
bo
l
ts
even
l
y
and
e
q
ua
ll
y
in
a
cross
pattern
to
6
Nm.
WARN
I
NG
USE
ONL
Y 0-3
OP
I
SPACERS.
DO
NO
T
USE
O
TH
ER
SPACERS.
I
nsta
ll
ing
extra
or
di
ff
erent
spacers
wi
ll
resu
l
t
in
inade
q
uate
thread
engagement
between
the
stem
and
steerer
resu
l
ting
in
serious
damage.
A
damaged
stem/
steerer
can
break
without
warning
and
you
cou
l
d
l
ose
contro
l
of
your
bicyc
l
e.
NO
TI
CE
USE
A
T
OR
Q
UE
WRENC
H
.
T
he
recommended
t
igh
t
ening
t
or
q
ue
for
Lef
t
y
c
l
amp
bo
lt
s
wi
t
h
t
he
OP
I
s
t
em
sys
t
em
is
7
Nm.
Do
no
t
e
x
ceed
9
Nm.
Over-tightening
can
damage
the
OP
I
steerer
parts
.
