BK

SIZING
BACKLASH FREE, TORSIONALLY STIFF
METAL BELLOWS COUPLINGS

INSTALLATION
2 - 10,000 Nm

COUPLINGS BK
BELLOWS
COUPLINGS MK
MINIATURE
COUPLINGS EK | TX
ELASTOMER
SAFETY COUPLINGS
Optional:

SK | ES | SL
GENERAL INFORMATION ABOUT R+W BELLOWS COUPLINGS:

SERVICE LIFE TEMPERATURE RANGE

R+W bellows couplings are fatigue resistant and wear -30 to +100° C
free for an infinite service life, as long as the technical
limits are not exceeded.
LINE SHAFTS

SPECIAL SOLUTIONS
ZA | EZ

Various materials, tolerances, dimensions and

FIT CLEARANCE performance ratings available for custom applications
Overall shaft / hub clearance of 0.01 - 0.05 mm on request.

ROTATIONAL SPEED ATEX (Optional)

Standard up to 10,000 rpm. For use in hazardous zones 1/21 and 2/22, the metal
ATEX CERTIFIED

Over 10,000 rpm in finely balanced version; up to grade bellows has been authorized under directive 94/9/EG
COUPLINGS

ISO G=2.5 is available. and is available with certification.

RW-COUPLINGS.COM 29
 BK

TORSIONALLY STIFF BELLOWS COUPLINGS

2 - 10,000 Nm
MODEL FEATURES

with simple flange mounting Page 33

BK1 from 15 - 10,000 Nm
for adapting the metal bellows to
custom drive components
custom flange patterns available

with clamping hub Page 34

BK2 from 15 - 10,000 Nm
easy to mount
availalbe in multiple lengths
low moment of inertia

with split clamping hub Page 35

BKH from 15 - 4,000 Nm
radial mounting possible
easy to install onto pre-aligned
shafts
low moment of inertia

economy class with clamping hub Page 36

BKL from 2 - 500 Nm
easy to mount
optional self-opening clamp system
low moment of inertia

compact version with clamping hub Page 37

BKC from 15 - 500 Nm
low moment of inertia
compact design
optional self-opening clamp system

30
 SIZING
INSTALLATION
MODEL FEATURES

COUPLINGS BK
BELLOWS
torsional stiff with clamping hub Page 38
BKM from 20 - 1,000 Nm
high torque density
ultra compact
lowest moment of inertia of all
clamping hub designs

COUPLINGS MK
MINIATURE
welded with clamping hub Page 39
BKS from 15 – 500 Nm
all stainless steel construction
temperatures up to 300˚C
easy to mount

COUPLINGS EK | TX
ELASTOMER
with conical clamping hub Page 40
BK3 from 15 - 10,000 Nm
high clamping pressure
modern design for removal
system
highly reliable

SAFETY COUPLINGS
SK | ES | SL
with external clamping ring Page 41
SP3 from 15 – 500 Nm
highly concentric symmetrical design
very true running to the shaft axis
for high speed applications
LINE SHAFTS

Page 42
ZA | EZ

for tapered shafts

BK4 from 15 - 150 Nm
standard 1:10 taper with
feather keyway
special designs on request
ATEX CERTIFIED
COUPLINGS

RW-COUPLINGS.COM 31
 BK

TORSIONALLY STIFF BELLOWS COUPLINGS

SIZES FROM 2 - 10,000 Nm
MODEL FEATURES

with clamping hub and Page 43

BK5 blind mate connection
from 15 - 1,500 Nm
backlash free with two piece design
easy installation and removal
available as separate components

with conical clamping ring and Page 44

BK6 blind mate connection
from 15 - 1,500 Nm
eliminates need for screw access holes
self centering hubs for highly concentric mounting
easy installation and removal

with expanding shaft Page 45

BK7 from 15 - 300 Nm
for hollow shaft mounting
save space and cost
solution for mismatched
shaft/bore diameters

with ISO flange mounting Page 46

BK8 from 50 - 2,600 Nm
for flange output gearboxes
allows for continuous hollow
through axis with some right angle
gearbox designs
compact layout

32
 WITH FLANGE MOUNTING
BK1 15 - 10,000 Nm

SIZING
PROPERTIES
FEATURES Hubs: steel
For simple flange mounting to special
drive components DESIGN

INSTALLATION
custom flange patterns available Two mounting flanges concentrically
assembled to the flexible bellows.
MATERIAL Brief overloads of up to 1.5x the rated
Bellows: high grade stainless steel torque are acceptable.

A-2 Ø F ±0,2

C C E E 6

COUPLINGS BK
x6
0˚

BELLOWS
Ø DH7
Ø DH7

Ø Gf7
Ø Gf7
ØB

COUPLINGS MK
MINIATURE
MODEL BK1
SIZE 15 30 60 150 200 300 500 800 1500 4000 6000 10000

COUPLINGS EK | TX
Rated torque (Nm) TKN 15 30 60 150 200 300 500 800 1500 4000 6000 10000

ELASTOMER
Overall length (mm) A-2 30 37 36 44 43 53 50 62 53 65 56 70 64 77 81 100 145 138 150

Outside diameter of bellows (mm) B 49 55 66 81 90 110 124 133 157 200 253 303

Fit length/thread depth (mm) C 7.5 10 11 13 14.5 15 16 18 22 30 30 36

Inside diameter H7 (mm) D 25 28 38 50 58 65 70 75 85 100 145 190

Fastening threads E 6 x M5 6 x M5 6 x M6 6 x M6 6 x M6 6 x M8 6 x M8 6 x M10 6 x M16 6 x M20 8 x M20 8 x M24

Bolt circle diameter ± 0.2 (mm) F 35 37 46 62 70 80 94 90 110 140 190 234

SAFETY COUPLINGS
Outside diameter f7 (mm) G 49 55 66 81 90 110 122 116 140 182 235 295

SK | ES | SL
Moment of inertia (10 ³ kgm²)
-
Jges 0.07 0.08 0.14 0.15 0.30 0.32 0.90 0.95 1.30 1.40 1.95 2.10 3.0 3.4 4.3 10.6 46 132 350

Approximate weight (kg) 0.15 0.2 0.3 0.6 0.8 1.35 1.8 1.9 3.3 8.9 13.9 23.7

Torsional stiffness (10³ Nm/rad) CT 20 15 39 28 76 55 175 110 191 140 450 350 510 500 780 1304 3400 5700 10950

Axial ± (mm) 1 2 1 2 1.5 2 2 3 2 3 2.5 3.5 2.5 3.5 3.5 3.5 3.5 3 3
Max.
Lateral ± (mm) 0.15 0.2 0.2 0.25 0.2 0.25 0.2 0.25 0.25 0.3 0.25 0.3 0.3 0.35 0.35 0.35 0.4 0.4 0.4
values
Angular ± (degree) 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1.5 1.5 1.5 1.5 1.5

Axial spring stiffness (N/mm) Ca 25 15 50 30 72 48 82 52 90 60 105 71 70 48 100 320 565 1030 985

Lateral spring stiffness (N/mm) Cr 475 137 900 270 1200 420 1550 435 2040 610 3750 1050 2500 840 2000 3600 6070 19200 21800
LINE SHAFTS
ZA | EZ

ORDERING EXAMPLE BK1 150 62 XX

Model
Special designation only
Size
(e.g. high speed balancing).
Overall length mm
For custom features place an XX at the end of the part number and describe the special requirements (e.g. BK1 / 150 / 62 / XX; XX=finely balanced for 25,000 rpm)
ATEX CERTIFIED
COUPLINGS

RW-COUPLINGS.COM 33
 WITH CLAMPING HUB
BK2 15 - 10,000 Nm

PROPERTIES
FEATURES DESIGN
easy to mount Two clamping hubs concentrically
Optional: bolt tensioning system in mounted to flexible bellows.
size 800 and up Brief overloads of up to 1.5x the rated
light weight and low moment of torque are acceptable.
inertia

MATERIAL
Bellows: high grade stainless steel
Hubs: see table

A-2 F
NEW F
G
bolt tensioning C E ISO 4762
system

Advantage:
reduce screw
tightening torques
by up to 90% by
Ø D 1H7

Ø D 2H7
ØB

using multiple
smaller screws to
create the same
tension.
DIN or ANSI DIN or ANSI
keyway available keyway available

MODEL BK2
SIZE 15 30 60 80 150 200 300 500 800 1500 4000 6000 10000
Rated torque (Nm) TKN 15 30 60 80 150 200 300 500 800 1500 4000 6000 10000

Overall length (mm) A -2

59 66 99 69 77 113 83 93 130 94 106 143 95 107 144 105 117 163 111 125 200 133 146 169 140 179 166 230 225 252 288

Outside diameter (mm) B 49 55 66 81 81 90 110 124 134 157 200 253 303

Fit length (mm) C 22 27 31 36 36 41 43 51 45 55 85 107 129

Inside diameter possible D1/

8-28 10-30 12-35 14-42 19-42 22-45 24-60 35-60 40-75 50-80 50-90 60-140 70-180
from Ø to Ø H7 (mm) D2
Fastening screw 2x 2x 2x 2x 2x
M5 M6 M8 M10 M10 M12 M12 M16
ISO 4762 M16* M20* M24* M24* M30*
E
Tightening torque of the
8 15 40 50 70 120 130 200 250 470 1200 1200 2400
fastening screw (Nm)
Distance between
F 17 19 23 27 27 31 39 41 2x48 2x55 2x65 2x90 2x117
centerlines (mm)

Distance (mm) G 6.5 7.5 9.5 11 11 12.5 13 16.5 18 22.5 28 35 42

Moment of
Jges 0.06 0.07 0.08 0.12 0.13 0.14 0.32 0.35 0.4 0.8 0.85 0.9 1.9 2 2.1 3.2 3.4 3.6 7.6 7.9 8.3 14.3 14.6 14.8 16.2 17 43 45 165 495 1214
inertia (10-³ kgm²)
Al Al Al Al steel steel steel steel
Hub material optional optional optional optional optional optional optional optional steel steel steel steel steel
steel steel steel steel AL AL AL AL
Approximate
0.16 0.26 0.48 0.8 1.85 2.65 4 6.3 5.7 11.5 28.8 49.4 80.9
weight (kg)
Torsional
CT 20 15 14 39 28 27 76 55 54 129 85 84 175 110 97 191 140 135 450 350 340 510 500 400 780 711 1304 1180 3400 5700 10950
stiffness (10 ³ Nm/rad)

Axial ± (mm) 1 2 3 1 2 3 1.5 2 3 2 3 4 2 3 4 2 3 4 2.5 3.5 4.5 2.5 3.5 4.5 3.5 4.5 3.5 4.5 3.5 3 3
Max.
Lateral ± (mm) values 0.15 0.2 1 0.2 0.25 1 0.2 0.25 1 0.2 0.25 1 0.2 0.25 1 0.25 0.3 1 0.25 0.3 1 0.3 0.35 1 0.35 1 0.35 1 0.4 0.4 0.4

Angular ± (degree) 1 1.5 2 1 1.5 2 1 1.5 2 1 1.5 2 1 1.5 2 1 1.5 2 1 1.5 2 1 1.5 2 1.5 2 1.5 2 1.5 1.5 1.5

Axial spring Ca 25 15 84 50 30 118 72 48 165 48 32 144 82 52 130 90 60 280 105 71 605 70 48 85 100 285 320 440 565 1030 985
stiffness (N/mm)
Lateral spring Cr 475 137 140 900 270 224 1200 420 337 920 290 401 1550 435 500 2040 610 750 3750 1050 1200 2500 840 614 2000 1490 3600 1700 6070 19200 21800
stiffness (N/mm)

* 180˚ opposed in each clamping hub.

34
 WITH SPLIT CLAMPING HUB
BKH 15 - 4,000 Nm

SIZING
PROPERTIES
FEATURES DESIGN
radial mounting possible Two split clamping hubs with two
easy installation onto pre-aligned screws in each. Brief overloads of up to

INSTALLATION
shafts 1.5x the rated torque are acceptable.
low moment of inertia

MATERIAL
Bellows: high grade stainless steel
Hubs: see table

COUPLINGS BK
A-2 F F

BELLOWS
G C DIN or ANSI keyway
available
Ø D 1H7

Ø D 2H7

COUPLINGS MK
ØB

MINIATURE
E ISO 4762

H -2

COUPLINGS EK | TX
MODEL BKH

ELASTOMER
SIZE 15 30 60 80 150 200 300 500 800 1500 4000
Rated torque (Nm) TKN 15 30 60 80 150 200 300 500 800 1500 4000
Overall length (mm) A-2 59 66 69 77 83 93 94 106 95 107 105 117 111 125 133 146 140 166 225
Outside diameter (mm) B 49 55 66 81 81 90 110 124 134 157 200
Fit length (mm) C 22 27 31 36 36 41 43 51 45 55 85
Inside diameter possible
D1/D2 8-28 10-30 12-35 14-42 19-42 22-45 24-60 35-60 40-75 50-80 50-90

SAFETY COUPLINGS
from Ø to Ø H7 (mm)
Fastening screw ISO 4762 M5 M6 M8 M10 M10 M12 M12 M16 M16 M20 M24

SK | ES | SL
Tightening torque of the E
8 15 40 50 70 120 130 200 250 470 1200
fastening screw (Nm)
Distance between
F 17.5 19 23 27 27 31 39 41 48 55 65
centerlines (mm)
Distance (mm) G 7 7.5 9.5 12 12 12.5 14 16.5 18 22.5 28
Distance (mm) H-2 29 36 35 43 41 51 47 59 48 60 50 62 55 69 61 75 65.5 71 109
Moment of inertia (10-³ kgm²) Jges 0.07 0.08 0.14 0.15 0.23 0.26 0.65 0.67 2.5 3.2 4.5 5.4 8.5 10.5 17.3 19.6 24.3 49.2 165
Al Al Al Al steel steel steel steel
Hub material optional optional optional optional optional optional optional optional steel steel steel
steel steel steel steel AL AL AL AL
Approximate weight (kg) 0.15 0.3 0.4 0.8 1.7 2.5 4 7.5 7 12 28
LINE SHAFTS

Torsional stiffness (10 ³ Nm/rad) CT 20 15 39 28 76 55 129 85 175 110 191 140 450 350 510 500 780 1304 3400
ZA | EZ

Axial ± (mm) 1 2 1 2 1.5 2 2 3 2 3 2 3 2.5 3.5 2.5 3.5 3.5 3.5 3.5
Max.
Lateral ± (mm) 0.15 0.2 0.2 0.25 0.2 0.25 0.2 0.25 0.2 0.25 0.25 0.3 0.25 0.3 0.3 0.35 0.35 0.35 0.4
values
Angular ± (degree) 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1.5 1.5 1.5
Axial spring stiffness (N/mm) Ca 25 15 50 30 72 48 48 32 82 52 90 60 105 71 70 48 100 320 565
Lateral spring stiffness (N/mm) Cr 475 137 900 270 1200 420 920 290 1550 435 2040 610 3750 1050 2500 840 2000 3600 6070

ORDERING EXAMPLE BK2 / BKH 80 94 20 22.23 XX

ATEX CERTIFIED

Model
COUPLINGS

Size
Special designation only
Overall length mm
(e.g. anodized hubs).
Bore D1 H7
Bore D2 H7
For custom features place an XX at the end of the part number and describe the special requirements (e.g. BKH / 80 / 94 / 20 / 22.23 / XX; XX=finely balanced for 25,000 rpm)

RW-COUPLINGS.COM 35
 WITH CLAMPING HUB
BKL 2 - 500 Nm

PROPERTIES
FEATURES Two clamping hubs concentrically
easy to mount mounted to flexible bellows.
light weight and low moment of Brief overloads of up to 1.5x the rated
inertia torque are acceptable.

MATERIAL
Bellows: high grade stainless steel
Hubs: see table
DESIGN

C C optional self-opening F
clamp system
G G

E ISO 4762
Optional:
self-opening clamp
system to open the bore
during installation and

Ø D 2H7
Ø D 1H7

removal by backing out

Ø B

the clamping screw.

A-2 DIN or ANSI keyway

available

MODEL BKL
SIZE 2 4.5 10 15 30 60 80 150 300 500
Rated torque (Nm) TKN 2 4.5 10 15 30 60 80 150 300 500
Overall length (mm) A-2 30 40 44 58 68 79 92 92 109 114
Outside diameter (mm) B 25 32 40 49 56 66 82 82 110 123
Fit length (mm) C 10 13 13 21.5 26 28 32.5 32.5 41 42.5
Inside diameter possible
D1/2 4-12.7 6-16 6-24 8-28 10-32 14-35 16-42 19-42 24-60 35-62
from Ø to Ø H7 (mm)
Fastening screw ISO 4762 M3 M4 M4 M5 M6 M8 M10 M10 M12 M16
Tightening torque of E
2.3 4 4.5 8 15 40 70 85 120 200
the fastening screw (Nm)
Distance between centerlines (mm) F 8 11 14 17 20 23 27 27 39 41
Distance (mm) G 4 5 5 6.5 7.5 9.5 11 11 13 17
Moment of inertia (10¯³ kgm²) Jges. 0.002 0.007 0.016 0.065 0.12 0.3 0.75 1.8 0.8 7.5 3.1 11.7 4.9
AL AL AL AL AL AL AL steel steel steel
Hub material
optional steel optional steel optional steel optional steel optional steel optional steel optional steel optional AL optional AL optional AL
Approximate weight (kg) 0.02 0.05 0.06 0.16 0.25 0.4 0.7 1.7 0.75 3.8 1.6 4.9 2.1
Torsional stiffness (10³ Nm/rad) CT 1.5 7 9 23 31 72 80 141 157 290
Axial ± (mm) 0.5 1 1 1 1 1.5 2 2 2 2.5
Max.
Lateral ± (mm) 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
values
Angular ± (degree) 1 1 1 1 1 1 1 1 1 1
Axial spring stiffness (N/mm) Ca 8 35 30 30 50 67 44 77 112 72
Lateral spring stiffness (N/mm) Cr 50 350 320 315 366 679 590 960 2940 1450

ORDERING EXAMPLE BKL 80 26 22.23 XX

Model
Size Special designation only
Bore D1 H7 (e.g. anodized hubs).

Bore D2 H7
For custom features place an XX at the end of the part number and describe the special requirements (e.g. BKL / 80 / 26 / 22.23 / XX; XX=finely balanced for 25,000 rpm)

36
 COMPACT DESIGN WITH CLAMPING HUB
BKC 15 - 500 Nm

SIZING
PROPERTIES
FEATURES DESIGN
for space restricted installations Two clamping hubs concentrically
light weight and low moment of mounted to flexible bellows.

INSTALLATION
inertia Brief overloads of up to 1.5x the rated
easy to mount torque are acceptable.

MATERIAL
Bellows: high grade stainless steel
Hubs: see table

COUPLINGS BK
C C self-opening clamp system F

BELLOWS
optional
G G
E ISO 4762
Optional:
self-opening clamp
system to open the bore
during installation and

Ø D 2H7
Ø D 1H7

removal by backing out

Ø B

COUPLINGS MK
the clamping screw.

MINIATURE
A-2 DIN or ANSI keyway
available

COUPLINGS EK | TX
MODEL BKC

ELASTOMER
SIZE 15 30 60 150 300 500
Rated torque (Nm) TKN 15 30 60 150 300 500
Overall length (mm) A-2 48 58 67 78 94 100
Outside diameter (mm) B 49 56 66 82 110 123
Fit length (mm) C 16.5 21 23 27.5 34 34
Inside diameter possible

SAFETY COUPLINGS
D1/D2 8-28 12-32 14-35 19-42 24-60 32-75
from Ø to Ø H7 (mm)

SK | ES | SL
Fastening screw ISO 4762 M5 M6 M8 M10 M12 M12
Tightening torque of E
8 15 40 75 120 125
the fastening screw (Nm)
Distance between centerlines (mm) F 17.5 20 23 27 39 45
Distance (mm) G 6.5 7.5 9.5 11 13 13
Moment of inertia (10¯³ kgm²) Jges. 0.05 0.1 0.26 0.65 6.3 9
Hub material AL AL AL AL steel steel
Approximate weight (kg) 0.13 0.21 0.37 0.72 3.26 3.52
Torsional stiffness (10³ Nm/rad) CT 23 31 72 141 157 290
Axial ± (mm) 1 1 1.5 2 2 2.5
LINE SHAFTS

Max.
ZA | EZ

Lateral ± (mm) 0.2 0.2 0.2 0.2 0.2 0.2

values
Angular ± (degree) 1 1 1 1 1 1
Axial spring stiffness (N/mm) Ca 30 50 67 77 112 72
Lateral spring stiffness (N/mm) Cr 315 366 679 960 2940 2200
Speed max. with
80,000 70,000 60,000 50,000 40,000 30,000
G = 2.5 balancing (min-1)

ORDERING EXAMPLE BKC 60 26 22.23 XX

ATEX CERTIFIED
COUPLINGS

Model
Size Special designation only
(e.g. special bore
Bore D1 H7 tolerance).
Bore D2 H7
For custom features place an XX at the end of the part number and describe the special requirements (e.g. BKC / 60 / 26 / 22.23 / XX; XX=finely balanced for 25,000 rpm)

RW-COUPLINGS.COM 37
 TORSIONAL STIFF WITH CLAMPING HUB
BKM 20 - 1,000 NM

PROPERTIES
FEATURES DESIGN
extremely compact Two clamping hubs concentrically
high torque density mounted to flexible bellows.
high torsional stiffness Brief overloads of up to 1.5x the rated
torque are acceptable.
MATERIAL
Bellows: high grade stainless steel
Hubs: see table

C C F
self-opening clamp
Key application: system optional
For mounting on a G G
torque transducer. E ISO 4762
Ø D 1H7

Ø D 2H7
Ø B

torque
transducer

A-2 DIN or ANSI kewyay optional

MODEL BKM
SIZE 20 200 400 1000
Rated torque (Nm) TKN 20 200 400 1000
Overall length (mm) A-2 40 59 75 89
Outside diameter (mm) B 49 66 82 110
Fit length (mm) C 16.5 23 27.5 34
Inside diameter possible
D1/2 15-28 24-35 32-42 40-60
from Ø to Ø H7 (mm)
Fastening screw ISO 4762 M5 M8 M10 M12
Tightening torque of E
8 40 60 130
the fastening screw (Nm)
Distance between centerlines (mm) F 17 23 27 39
Distance (mm) G 6 9.5 11 13
Moment of inertia (10¯³ kgm²) Jges. 0.05 0.18 0.62 7.2
Hub material AL AL AL steel
Approximate weight (kg) 0.13 0.4 0.7 3.5
Torsional stiffness (10³ Nm/rad) CT 41.9 138 170 570
Axial ± (mm) 1 1.5 1 2
Max.
Lateral ± (mm) 0.06 0.08 0.1 0.1
values
Angular ± (degree) 0.5 0.5 0.5 0.5
Axial spring stiffness (N/mm) Ca 55.8 153 114 148
Lateral spring stiffness (N/mm) Cr 3,710 11,000 6,058 9,010
Speed max. with
80,000 60,000 50,000 40,000
G = 2.5 balancing min-1

ORDERING EXAMPLE BKM 20 20 19.05 XX

Model
Size Special designation only
(e.g. special bore
Bore D1 H7 tolerance).
Bore D2 H7
For custom features place an XX at the end of the part number and describe the special requirements (e.g. BKM / 20 / 20 / 19.05 / XX; XX=finely balanced for 25,000 rpm)

38
 WELDED WITH CLAMPING HUB
BKS 15 - 500 Nm

SIZING
PROPERTIES
FEATURES Screws: Grade 12.9 Geomet coated
for high temperatures and aggressive (alternate materials on request)
media

INSTALLATION
compact design DESIGN
welded version Two clamping hubs concentrically
mounted to flexible bellows.
MATERIAL Brief overloads of up to 1.5x the rated
Bellows: high grade stainless steel torque are acceptable.
Hubs: high grade stainless steel From -40˚ to +300˚C operating
temperature.

COUPLINGS BK
C C self-opening clamp F

BELLOWS
Optional: system optional
self-opening clamp G G
system to open the bore E ISO 4762
during installation and
removal by backing out
the clamping screw.
Ø D 1H7

Ø D 2H7

COUPLINGS MK
ØB

MINIATURE
A-2 DIN or ANSI keyway
available

COUPLINGS EK | TX
MODEL BKS

ELASTOMER
SIZE 15 30 60 150 300 500
Rated torque (Nm) TKN 15 30 60 150 300 500
Overall length (mm) A-2 45 52 66 76 89 95
Outside diameter (mm) B 49 56 66 82 110 123
Fit length (mm) C 17 20 24 30 34 35
Inside diameter*

SAFETY COUPLINGS
D1/D2 12-28 14-32 16-35 19-42 24-60 32-75
possible from Ø to Ø H7 (mm)

SK | ES | SL
Fastening screw ISO 4762 M5 M6 M8 M10 M12 M12
Tightening torque of E
8 15 40 75 120 125
the fastening screw (Nm)
Distance between centerlines (mm) F 17.5 20 23 27 39 45
Distance (mm) G 6 7.5 9.5 11 13 13
Moment of inertia (10¯³ kgm²) Jges. 0.1 0.2 0.53 1.5 5.5 8.1
Approximate weight (kg) 0.27 0.42 0.78 1.5 2.9 3.5
Torsional stiffness (10³ Nm/rad) CT 23 31 72 141 157 290
Axial ± (mm) 1 1 1.5 2 2 2.5
LINE SHAFTS

Max.
Lateral ± (mm) 0.2 0.2 0.2 0.2 0.2 0.2
values
ZA | EZ

Angular ± (degree) 1 1 1 1 1 1
Axial spring stiffness (N/mm) Ca 30 50 67 77 112 72
Lateral spring stiffness (N/mm) Cr 315 366 679 960 2940 2200
Speed max. with
60,000 50,500 50,000 40,500 40,000 30,000
G = 2.5 balancing (min-1)

* Smaller bore diameter available at reduced torque capacity

ATEX CERTIFIED

ORDERING EXAMPLE BKS 15 20 19.05 XX

COUPLINGS

Model
Size Special designation only
(e.g. special bore
Bore D1 H7 tolerance).
Bore D2 H7
For custom features place an XX at the end of the part number and describe the special requirements (e.g. BKS / 15 / 20 / 19.05 / XX; XX=finely balanced for 25,000 rpm)

RW-COUPLINGS.COM 39
 WITH CONICAL CLAMPING SYSTEM
BK3 15 - 10,000 Nm

PROPERTIES
FEATURES DESIGN
high clamping pressure Two conical clamping hubs concentri-
high torque version cally mounted to flexible bellows.
compact design Brief overloads of up to 1.5x the rated
torque are acceptable.
MATERIAL
Bellows: high grade stainless steel
Hubs: steel

A-2 ØB

C C E ISO 4017

Ø D 2H7
Ø D 1H7
ØG

F ISO 4017

MODEL BK3
SIZE 15 30 60 150 200 300 500 800 1500 4000 6000 10000
Rated torque (Nm) TKN 15 30 60 150 200 300 500 800 1500 4000 6000 10000

Overall length (mm) A -2

48 55 55 65 66 76 75 87 78 90 89 103 97 110 114 141 195 210 217

Outside diameter (mm) B 49 57 66 81 90 110 124 133 157 200 253 303

Fit length (mm) C 19 22 27 32 32 41 41 50 61 80 85 92

Inside diameter possible

D1/2 10-22 12-23 12-29 15-38 15-44 24-56 24-60 30-60 35-70 50-100 60-140 70-180
from Ø to Ø H7 (mm)

Fastening screw ISO 4017 6 x M4 6 x M5 6 x M5 6 x M6 6 x M6 6 x M8 6 x M8 6 x M10 6 x M12 6 x M16 6 x M16 8 x M16

E
Tightening torque of
4 6 8 12 14 18 25 40 70 120 150 160
the fastening screw (Nm)

Jack screw ISO 4017 F 3 x M4 3 x M4 3 x M5 3 x M5 3 x M6 3 x M6 3 x M6 3 x M8 6 x M8 6 x M10 6 x M10 4 x M10

Outside diameter of hub (mm) G 49 55 66 81 90 110 122 116 135 180 246 295

Moment of inertia (10 ³ kgm²)

-
Jges 0.07 0.08 0.15 0.16 0.39 0.41 1.2 1.6 1.7 2.5 5.1 5.9 9.1 9.9 13.2 34.9 85.5 254 629

Approximate weight (kg) 0.25 0.4 0.8 1.2 1.8 3 4.2 5.6 8.2 23 32.6 45.5

Torsional stiffness (10 ³ Nm/rad) CT 20 15 39 28 76 55 175 110 191 140 450 350 510 500 780 1304 3400 5700 10950

Axial ± (mm) 1 2 1 2 1.5 2 2 3 2 3 2.5 3.5 2.5 3.5 3.5 3.5 3.5 3 3
Max.
Lateral ± (mm) 0.15 0.2 0.2 0.25 0.2 0.25 0.2 0.25 0.25 0.3 0.25 0.3 0.3 0.35 0.35 0.35 0.4 0.4 0.4
values
Angular ± (degree) 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1.5 1.5 1.5 1.5 1.5

Axial spring stiffness (N/mm) Ca 25 15 50 30 72 48 82 52 90 60 105 71 70 48 100 320 565 1030 985

Lateral spring stiffness (N/mm) Cr 475 137 900 270 1200 420 1500 435 2040 610 3750 1050 2500 840 2000 3600 6070 19200 21800

ORDERING EXAMPLE BK3 60 76 20 22.23 XX

Model
Size
Special designation only
Overall length mm (e.g. non-standard bore
tolerance)
Bore D1 H7
Bore D2 H7
For custom features place an XX at the end of the part number and describe the special requirements (e.g. BK3 / 60 / 76 / 20 / 22.23 / XX; XX=K6 bore tolerance on D1)

40
 WITH EXTERNAL CLAMPING RING
SP3 60 - 500 Nm

SIZING
NEW
PROPERTIES
FEATURES DESIGN
very high balancing quality due to Two precision machined clamping ring
symmetrical design hubs mounted concentrically to a flex-

INSTALLATION
high operating speeds ible bellows. Brief overloads of up to
extremely smooth running 1.5x the rated torque are acceptable.

MATERIAL FIT CLEARANCE

Bellows: high grade stainless steel Overall shaft / hub tolerance
High speed Hubs and clamping ring: steel 0.01 - 0.025 mm

A-2

COUPLINGS BK
BELLOWS
E ISO 4017
C C
Ø D1

Ø D2
Ø B

COUPLINGS MK
MINIATURE
F ISO 4029

MODEL SP3

COUPLINGS EK | TX
SIZE 60 150 200 300 500

ELASTOMER
Rated torque (Nm) TKN 60 150 200 300 500

Overall length (mm) A -2

66 76 75 87 76 88 89 103 97 110

Outside diameter (mm) B 66 81 90 110 124

Fit length (mm) C 25 30 32 36 40

Inside diameter possible

D1/D2 14-32 18-35 20-42 25-55 30-60
from Ø to Ø H7 (mm)

Fastening screw ISO 4017 6 x M5 6 x M6 6 x M6 6 x M8 6 x M8

SAFETY COUPLINGS
Tightening torque of E
8.5 14 14 30 35
the fastening screw (Nm)

SK | ES | SL
Jack screw ISO 4017 F 3 x M5 3 x M6 3 x M6 3 x M8 3 x M8

Outside diameter of hub (mm) G 66 81 90 110 122

Moment of inertia (10 ³ kgm²)

-
Jges 0.58 0.60 1.6 1.62 2.42 2.52 6.38 6.56 10.35 10.67

Approximate weight (kg) 0.9 0.92 1.7 1.8 2.1 2.2 3.52 3.6 4.73 4.83

Torsional stiffness (10 ³ Nm/rad) CT 76 55 175 110 191 140 450 350 510 500

Axial ± (mm) 1.5 2 2 3 2 3 2.5 3.5 2.5 3.5

max.
Lateral ± (mm) 0.2 0.25 0.2 0.25 0.25 0.3 0.25 0.3 0.3 0.35
values
LINE SHAFTS

Angular ± (degree) 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5

ZA | EZ

Axial spring stiffness (N/mm) Ca 72 48 82 52 90 60 105 71 70 48

Lateral spring stiffness (N/mm) Cl 1200 420 1500 435 2040 610 3750 1050 2500 840

Speed standard (min -1) n 22500 16500 16500 13500 12500

* Recommended fit pairing H7 / k6; H6 / j5 (short spindle); starting at Ø55 G7 / m6

ORDERING EXAMPLE SP3 150 87 20 32 XX

ATEX CERTIFIED

Model
COUPLINGS

Size Special designation only

(e.g. non-standard bore
Overall length mm tolerance)
Bore D1 H7
Bore D2 H7
For custom features place an XX at the end of the part number and describe the special requirements (e.g. SP3 / 150 / 87 / 20 / 32 / XX)

RW-COUPLINGS.COM 41
 FOR TAPERED SHAFTS
BK4 15 - 150 Nm

PROPERTIES
FEATURES DESIGN
for tapered shafts Conical clamping system opposite 1:10
easy to mount and dismount tapered bore with feather keyway.
high installed concentricity Brief overloads of up to 1.5x the rated
torque acceptable.
MATERIAL
Bellows: high grade stainless steel
Hubs: steel

A-2 ØB

E ISO 4017 C H
E ISO 4017

Fanuc
Ø DH7
ØB

Motor
ØG

ØI

F ISO 4017 F ISO 4017

MODEL BK4
SIZE 15 30 60 150
Rated torque (Nm) TKN 15 30 60 150
Overall length (mm) A-2 47 54 68 76 72 82 82 94
Outside diameter (mm) B 49 55 66 81
Fit length (mm) C 19 22 27 32
Inside diameter possible
D 10-22 12-23 12-29 15-37
from Ø to Ø H7 (mm)
Fastening screw ISO 4017 6 x M4 6 x M5 6 x M5 6 x M6
Tightening torque of E
4 6 8 12
the fastening screw (Nm)
Jack screw ISO 4017 F 3 x M4 3 x M4 3 x M5 3 x M5
Outside diameter of hub (mm) G 20 27 30 30
Hub length (mm) H 8.5 22 18 20
Moment of inertia (10-³ kgm²) Jges 0.10 0.12 0.22 0.27 0.58 0.61 1.1 1.4
Approximate weight (kg) 0.25 0.4 0.8 1.35
Torsional stiffness (10 ³ Nm/rad) CT 20 15 39 28 76 55 175 110
Axial ± (mm) 1 2 1 2 1.5 2 2 3
Max.
Lateral ± (mm) 0.15 0.2 0.2 0.25 0.2 0.25 0.2 0.25
values
Angular ± (degree) 1 1.5 1 1.5 1 1.5 1 1.5
Axial spring stiffness (N/mm) Ca 25 15 50 30 72 48 82 52
Lateral spring stiffness (N/mm) Cr 475 137 900 270 1200 420 1500 435
Cone Ø (Fanuc-Motor) (mm) I 11 16 16 16
Key width (mm) K 4 5 5 5

ORDERING EXAMPLE BK4 150 82 20 XX

Model
Size Special designation only
(e.g. non-standard bore
Overall length mm tolerance)
Bore D1 H7
For custom features place an XX at the end of the part number and describe the special requirements (e.g. BK4 / 150 / 82 / 20 / XX; XX=finely balanced for 25,000 rpm)

42
 BLIND MATE WITH CLAMPING HUB
BK5 15 - 1,500 Nm

SIZING
PROPERTIES
FEATURES Tapered male segment: high strength
easy installation and removal plastic
electrically and thermally isolating

INSTALLATION
absolutely backlash free assembly DESIGN
Two clamping hubs, one of which has a
MATERIAL tapered male projection for bind mate
Bellows: high grade stainless steel connection. Brief overloads of up to
Hubs: up through size 80 Aluminum, 1.5x the rated torque are acceptable.
size 150 and up steel

bellows body

COUPLINGS BK
BELLOWS
C1 C2
tapered segment
G E ISO 4762 G
F

Ø D2H7
Ø D1H7

COUPLINGS MK
ØB

MINIATURE
F
multi-position single position
(standard) with one larger drive
lug (optional)
A +0.5 (assembled length)
preload
compression H

MODEL BK5

COUPLINGS EK | TX
ELASTOMER
SIZE 15 30 60 80 150 300 500 800 1500
Rated torque (Nm) TKN 15 30 60 80 150 300 500 800 1500
Overall length (inserted) (mm) A+0,5 60 67 71 79 85 95 94 106 95 107 114 128 136 149 150 172
Outside diameter (mm) B 49 55 66 81 81 110 124 133 157
Fit length (mm) C1 22 27 31 36 36 43 51 45 55
Fit length (mm) C2 28 33 39 43 43 52 61 74 94
Inside diameter possible
D1 8-28 10-30 12-35 14-42 14-42 24-60 35-60 40-75 50-80

SAFETY COUPLINGS
from Ø to Ø H7 (mm)
Inside diameter possible

SK | ES | SL
D2 8-22 10-25 12-32 14-38 14-38 24-58 35-60 40-62 50-75
from Ø to Ø H7 (mm)
Fastening screw ISO 4762 M5 M6 M8 M10 M10 M12 M16 2 x M16** 2 x M20**
Tightening torque of E
8 15 40 50 70 130 200 250 470
the fastening screw (Nm)
Distance between centerlines (mm) F 17 19 23 27 27 39 41 2 x 48** 2 x 55**
Distance (mm) G 6.5 7.5 9.5 11 11 13 16.5 18 22.5
Preload compression (mm) 0.2 - 1.0 0.5 - 1.0 0.5 - 1.5 0.5 - 1.5 0.5 - 1.5 0.5 - 1.5 1.0 - 2.0 1.0 - 2.5 0.5 - 1.5
Axial recovery force at H
20 12 50 30 70 45 48 32 82 52 157 106 140 96 200 650
maximum pretensioning (N)
Moment of inertia (10-³ kgm²) Jges 0.07 0.08 0.14 0.15 0.23 0.26 0.65 0.67 2.2 2.4 7.4 7.9 13.7 14.4 21.5 51.4
LINE SHAFTS

Approximate weight (kg) 0.1 0.1 0.3 0.3 0.4 0.4 0.9 0.9 1.8 1.8 4 4 6.5 6.7 9 15.3
ZA | EZ

Torsional stiffness (10 ³ Nm/rad) CT 10 8 20 14 38 28 65 43 88 55 225 175 255 245 400 650
Axial* ± (mm) 0.5 1 0.5 1 0.5 1 1 2 1 2 1.5 2 2.5 3.5 3 2
Max.
Lateral ± (mm) 0.15 0.2 0.2 0.25 0.2 0.25 0.2 0.25 0.2 0.25 0.25 0.3 0.3 0.35 0.35 0.35
values
Angular ± (degree) 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1.5 1.5
Lateral spring stiffness (N/mm) Cr 475 137 900 270 1200 420 920 290 1550 435 3750 1050 2500 840 2000 3600

*in addition to maximum allowable pretension **180˚ opposed in each clamping hub.

ORDERING EXAMPLE BK5 30 71 18 19 XX

ATEX CERTIFIED

Model
COUPLINGS

Size
Special designation only
Overall length mm (e.g. special
bore tolerance).
Bore D1 H7
Bore D2 H7
For custom features place an XX at the end of the part number and describe the special requirements (e.g. BK5 / 30 / 71 / 18 / 19 / XX; XX=finely balanced for 25,000 rpm)

RW-COUPLINGS.COM 43
 BLIND MATE WITH CONICAL CLAMPING RING
BK6 15 - 1,500 Nm

PROPERTIES
FEATURES Tapered male segment: high strength
axial mounting possible plastic
easy installation and removal
naturally very well balanced due to DESIGN
self centering clamping ring system Two conical clamping ring hubs, one of
absolutely backlash free assembly which has a tapered male projection for
bind mate connection.
MATERIAL Brief overloads of up to 1.5x the rated
Bellows: high grade stainless steel torque are acceptable.
Hubs: steel

bellows body

C1 C2
tapered segment
G 6xE G
ISO 4762
Ø D1H7

Ø D2H7
ØB

ØF

multi-position single position

(standard) with one larger drive
A +0.5 (assembled length) lug (optional)

preload
compression H

MODEL BK6
SIZE 15 30 60 150 300 500 800 1500
Rated torque (Nm) TKN 15 30 60 150 300 500 800 1500
Overall length (gesteckt) (mm) A+0,5 58 65 68 76 79 89 97 109 113 127 132 145 140 158
Outside diameter (mm) B 49 55 66 81 110 124 133 157
Fit length (mm) C1 13.5 21.5 18 23.5 27 32 42 53
Fit length (mm) C2 29 34 39 49.5 59 68 74 90.5
Inside diameter possible
D1 10-22 12-24 12-32 15-40 24-56 30-60 40-62 50-75
from Ø to Ø H7 (mm)
Inside diameter possible
D2 10-22 12-24 12-32 15-40 24-56 30-60 40-62 50-75
from Ø to Ø H7 (mm)
Fastening screw ISO 4762 M4 M5 M5 M6 M8 M8 M10 M12
Tightening torque of the E
3.5 6.5 8 12 30 32 55 110
fastening screw (Nm)
Diameter of clamping ring (mm) F 46.5 51 60 74 102 114 126 146
Clamping ring length (mm) G 9.5 10.5 11.5 17.5 20 23 27 32
Preload compression (mm) 0.2 - 1.0 0.5 - 1.0 0.5 - 1.5 0.5 - 1.5 0.5 - 1.5 1.0 - 2.0 1.0 - 2.0 0.5 - 1.5
Axial recovery force at H
20 12 50 30 70 45 82 52 157 106 140 96 400 650
maximum pretensioning (N)
Moment of inertia (10-³ kgm²) Jges 0.1 0.12 0.2 0.25 0.4 0.45 2.0 2.5 5.4 6.1 8.4 9.1 17.5 44
Approximate weight (kg) 0.3 0.32 0.5 0.52 0.82 0.84 1.6 1.7 4.1 4.2 6.0 6.3 8.1 16.2
Torsional stiffness (10 ³ Nm/rad) CT 10 8 20 14 38 28 88 55 225 175 255 245 400 660
Axial* ± (mm) 0.5 1 0.5 1 0.5 1 1 2 1.5 2 2.5 3.5 3 2
Max.
Lateral ± (mm) 0.15 0.2 0.2 0.25 0.2 0.25 0.2 0.25 0.25 0.3 0.3 0.35 0.35 0.35
values
Angular ± (degree) 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5 1.5 1.5
Lateral spring stiffness (N/mm) Cr 475 137 900 270 1200 420 1550 435 3750 1050 2500 840 2000 3600
* in addition to maximum allowable pretension Higher torques upon request

ORDERING EXAMPLE BK6 30 76 18 19 XX

Model
Size
Special designation only
Overall length mm (e.g. special bore
tolerance).
Bore D1 H7
Bore D2 H7
For custom features place an XX at the end of the part number and describe the special requirements (e.g. BK6 / 30 / 76 / 18 / 19 / XX; XX=finely balanced for 25,000 rpm)

44
 WITH EXPANDING SHAFT
BK7 15 - 300 Nm

SIZING
PROPERTIES
FEATURES DESIGN
for hollow shaft mounting One clamping hub on one end with an
short design saves installation space expanding shaft on the other end.

INSTALLATION
solution for mismatched shaft / bore Brief overloads of up to 1.5x the rated
torque are acceptable.
MATERIAL
Bellows: high grade stainless steel
Hubs: see table
Expanding mandrel system: steel

COUPLINGS BK
A-2 E1 ISO 4762 F

BELLOWS
G C2 E2 ISO 4762

Ø D2h7 max.
Ø D2h7 min.
Ø D1H7
ØB

COUPLINGS MK
MINIATURE
C1 DIN or ANSI keyway
available

MODEL BK7

COUPLINGS EK | TX
ELASTOMER
SIZE 15 30 60 150 300
Rated torque (Nm) TKN 15 30 60 150 300
Overall length (mm) A-2 45 52 53 61 62 72 71 83 84 98
Outside diameter (mm) B 49 55 66 81 110
Fit length (mm) C1 22 27 31 36 43
Fit length (mm) C2 20 25 27 32 45
Inside diameter possible

SAFETY COUPLINGS
D1 8-28 10-30 12-35 19-42 30-60
from Ø to Ø H7 (mm)

SK | ES | SL
Shaft diameter from Ø to Ø h7 (mm) D2 13-25 14-30 23-38 26-42 38-60
Fastening screw ISO 4762 E1/2 M5 M6 M8 M10 M12
Tightening torque of E1/2 8 14 38 65 120
the fastening screw (Nm)
Distance between centerlines (mm) F 17 19 23 27 39
Distance (mm) G 6.5 7.5 9.5 11 13
Moment of inertia (10-³ kgm²) Jges 0.07 0.08 0.14 0.15 0.23 0.26 2.2 2.4 6.5 8.9
Hub material Al Al Al steel steel
Approximate weight (kg) 0.15 0.3 0.4 1.7 4
LINE SHAFTS

Torsional stiffness (10³ Nm/rad) CT 20 15 39 28 76 55 175 110 450 350

ZA | EZ

Axial ± (mm) 1 2 1 2 1.5 2 2 3 2.5 3.5

Max.
Lateral ± (mm) 0.15 0.2 0.2 0.25 0.2 0.25 0.2 0.25 0.25 0.3
values
Angular ± (degree) 1 1.5 1 1.5 1 1.5 1 1.5 1 1.5
Axial spring stiffness (N/mm) Ca 20 12 50 30 72 48 82 52 105 71
Lateral spring stiffness (N/mm) Cr 315 108 730 230 1200 380 1550 435 3750 1050

ORDERING EXAMPLE BK7 150 71 32 22.23 XX

ATEX CERTIFIED

Model
COUPLINGS

Size
Special designation only
Overall length mm (e.g. special bore
tolerance).
Bore D1 H7
Shaft D2 f7
For custom features place an XX at the end of the part number and describe the special requirements (e.g. BK7 / 150 / 71 / 32 / 22.23 / XX; XX=finely balanced for 25,000 rpm)

RW-COUPLINGS.COM 45
 WITH ISO FLANGE CONNECTION
BK8 50 - 2,600 Nm

PROPERTIES
FEATURES Hubs: up through size 300 aluminum,
for ISO flange output gearboxes size 1500 and up steel
allows for continuous hollow through Adapter flange: steel
axis with some right angle gearbox
designs DESIGN
compact design One clamping hub on one end with an
integral flange and adapter flange on
MATERIAL the other end. Maximum transmittable
Bellows: high grade stainless steel torque depends on the bore diameter.

Ø B2

A1-2 Ø DL
servo gearbox with
C1 ISO 4762 ISO flange output F

G ISO 4017

Centering diameter
Ø D1H7

Ø LK
Ø B1

bellows coupling intermediate flange

with mounting flange for gearbox
DIN or ANSI E ISO 4762
A2-2 keyway optional

MODEL BK8
SIZE 15 60 150 300 1500
Flange centering diameter (mm) 40 h7 63 h7 80 h7 100 h7 160 h7
Flange bolt circle / thread Ø (mm) 31.5 / 8 x M5 50 / 8 x M6 63 / 12 x M6 80 / 12 x M8 125 / 12 x M10
Maximum torque* (Nm) 50 210 380 750 2600
Length -2 (mm) A1 48.5 67 72 90 140
Length -2 (mm) A2 68 97 101 128 190
Outside diameter of hub (mm) B1 49 66 82 110 157
Flange diameter (mm) B2 63.5 86 108 132 188
Fit length (mm) C1 16.5 23 27.5 34 55
Inside diameter possible
D1 12-28 14-35 19-42 24-60 50-80
from Ø to Ø H7 (mm)
Hub bolt circle (mm) 56.5 76 97 120 170
DL
Fastening threads (mm) 10 x M4 10 x M5 10 x M6 12 x M6 16 x M8
Fastening screws ISO 4762 1 x M5 1 x M8 1 x M10 1 x M12 2 x M20
Tightening torque of the E1
8 45 80 120 470
fastening screw (Nm)
Distance between centerlines (mm) F 1 x 17.5 1 x 23 1 x 27 1 x 39 2 x 55
Distance (mm) G 6.5 9.5 11 13 22.5
Approximate weight (kg) 0.3 0.7 1 2.8 10
Moment of inertia (10-3 kgm2) Jges 0.15 0.65 1.3 5.5 45
Lateral ± (mm) 0.25 0.25 0.25 0.25 0.25
Max.
Angular ± (degree) 1 1 1 1 1
values
Axial ± (mm) 1 1.5 2 2.5 3
* maximum torque transmittable only for brief periods and requires maximum bore for clamping strength

ORDERING EXAMPLE BK8 60 22.23 67 XX

Model
Size Special designation only
(e.g. special bore
Bore D1 H7 tolerance).
Overall length mm
For custom features place an XX at the end of the part number and describe the special requirements (e.g. BK8 / 60 / 22.23 / 67 / XX; XX=anodized hubs)

46