the type of taper of the free- wheel. ... freewheel has an open type taper. .... file. This precision design is gua- ran
CHORUS®
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"CHO RU S" C a m p agn olo grou p
composed of: Cat. No . Description
71 511 00 Subgroup bra kes (front and rear brake, two brake levers, cables and casings) 265/C5 Subgroup SM gear and bra ze-on front changer "Friction" levers braze-on version (left and 542/5 right h a nd leve r, cables, stainless steel
722/101 706/101 703/10 1 705/ 000
outer casing) Subgroup small fla nge hubs, (front and rear quick release hub) Subgroup chainwheel (r.h . crank wit h two chainrings, l.h. crank) Bottom bracket Subgroup pedals (l.h . and r.h . pedals com p lete wi t h steel toe-clips a nd straps)
7041101 Head set Seat pi n 180 m m , w ith fixi n g seat pin 545 screw and nut 0 8
lft I Alternat ive subg rou ps and com pon e nt s
Cat. No . Description 280/CS Subgroup I.G gear and braze-on front changer 702/ 101 clip-on front changer "FRICTION" levers with cables and stainl ess steel outer casing, versions: 543/ST braze-on on top of tub e 544/ F clip-on "DO PPLER" levers with cables and stainless steel outer casing, versions: 325 braze-on 326 braze-on on top of tube 327 clip-on "$YN CRO" levers with microm e tnc inserts for A and B positions of "DUAL· MO D E" syste m, cables e stainless steel oute r casing, versions: 535/ 6AB braze-on for 6 speed 536/6AB braze-on on top of tube for 6 speed 537/ M B dip-on for 6 speed 53 8/7AB braze-on for 7 speed 539/7AB braze-on on top of tube for 7 speed 54 1/7AB clip-on fo r 7 speed ' 71 6/ 102 Seat pin 130 mm, with AXing seat pin screw and nut 0 8.
CHORUS.
REAR DERAILLEUR AND FRONT D ERAILLEUR VERSATILE CO MPO NENTS Versatility. especially for a bicycle whose specifications lend it toward a wide range of uses, is an indispensable cha racterist ic. A bicycle tor professional racing ca n in fa ct be used for competition, touring, triathlons and non-com pet itive cycling.
T H E DUAL·MODE SYSTEM On account of these requirem ents and in view of using the same components for all kinds of
route, Campagnolo designed th e CHO RUS gear, the fi rst gear with variable geometry, thanks to the exclusive patented DUALMODE system. The DUAL-MODE system allows the parallelogram to be rotated in two different working
positions at angles of 5° and 30°, while the jockey wheel cage can rotate as well to provide optimum chain alignment . Two Allen-head screws situated in the parallel ogram provide easy switching fro m one position to the other.
The CH O RUS gear is designed in two versions, SM and LG, with different shifting capacities and biggest utilizable sprockets (see table] .
CHOOS E THE BEST G EOME· TRY The geo metry of the CHO RUS gear must be arranged acco rdi ng to the used freewheel. There are two elemen ts that must be considered: - the number of teeth of the sprocket in the last position - the type of ta per of the freewh eel. To determine the taper of the freew heel, .one may use the fast and easy system of the differen ce between the number of teeth of the sprocket in the last position and the one of the sprocket in the first position .
COMPAT IBILITY WITH SYNCRO The C HORUS derailleur is adaptable to all Cam pagnolo's shift levers includi ng Syncro. With the Syncro kit for C HORUS w ill come two toothed inserts for 7 speed freewheels, one for each trim position of the derailleurs parallelogram . Appropriate inserts for 6 speed freewheels are also available. In order to regulate cable tension th e C HORUS derailleurs utilize a barrel adjuster incorporated into the upper body. With the experience gained from its co mmitments to the world's most fa mous racing teams Campagnolo was able to develop a new fro nt derailleur for the CH O RUS gro up. Computer desi gned and tested in our Research & Development Department , this derailleur accompanies the chain during t ransfer, then allows it to ru n free elim inating the need to constantly adjust the changer after each shift .
If this difference is less than or equal to I I teeth [Li. 12/ 2 1 or 15/26), the freewheel has an acute taper; if the difference between th e fi rst and th e last sprocket is more th an or equal to 12 te eth [Li . 13/ 25 or 15/ 28) , the freewheel has an open type taper. The position of the DUAL· MODE system m ust be chosen following three sim p le rules:
I) With the CIIO RUS SM gear, when th e largest sprocket has 28 or more teeth (3 1 with th e CH ORUS LG gear), posi tion B must
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PERFECT ALIGNMENT As well as d ual positions in
both parallelogram and cage plate, the CH O RUS rear derailleurs feature an adjustm ent screw to vary the inclination with respect to the chainstays. Thus the best working position of the derailleurs can be selected on the basis of th e biggest sprocket, and th e winding of th e chain onto the sprockets.
he used.
MAX IMUM COMFORT
2) Whe n the freewh eel has an acute taper (difference between the fi rst and the last sp rocket ::; I I teeth) , position A must be used. • 3) When the freewheel has an open type taper [difference hetween the fi rst ana th e last sproc ket ~ 12 teeth) , position B m ust
The mo....ement of the C HORUS derailleurs is made smoother with the application of an antifriction treatment to the stainless stell pin joints. This treatment along with the narro w profile of the rollers co nsiderably improves the silent operation of the gear.
be used.
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The stainless steel pivot p ins of the CHO RUS front derailleur receive the sam e antifriction
treatment as the rear derailleur to enhance shifting even under severe conditions.
The CHORUS front derailleur is available in both braze-on and d ip-on versions.
The derailleu r's inner and outer range adjustments 3 Te made with two stainless steel screws located on the upp er body. Coaxial keeper sp rings insu re adjust-
ment accuracy and the adjustments can be made with either a Phillips head or conventional screwd river.
CHO RUS SPROCKETS
C HAINRINGS
A
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D B -
CHORUS
G earch ange capacit y = (D + A) - (C Biggest sprocket u tilizable = A = Front changer capacit y = (D - C)
=
+ B) =
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CHORUS LG
POS.A
em. B
em. A
I'OS . II
31
33
35
37
27
32
30
34
18
18
18
18
* chainrings are made with a high resistance alloy used in aerospace applications and a geometrical arrangement that has proven su ccessful in the Record group used by professiona l cyclists. The teeth have the classic Campagnolo profile. This precision design is guaranteed consistent by computer controlled gear cut machining rather than by stamping, a process that compromises precision and consistency.
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C HAINWHEEL AND BOTTO M BRACKET MAXIMUM SAFETY The geomet rical pattern of
the spokes and arm of the CHORUS cha inwheel have been co mputer-designed using nu merical analysis of the distribution of forces. Th is analysis has established a special curved p rofile to achieve th e best transfer of working loads directly to the bottom bracket axle . •
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Th is geometrical arrangement also b rings the center of t he
crank closer to th e main body of the bottom bracket, thus reducing the loss of ener~ that occurs due to the flexure of the system . T o keep the distances between the cranks at an optimum posi-
tion (about 115 mm .) the two crankarms have a curvature that moves t hem outward from the frame. Cam pagnolo engineers h ave
studied in depth the behavior of the Avional aluminium alloy used . As a result of our research, the particular h ot moulding used respects the met al's fiber structure while increasing its resistance to stress, from all aspects a great improvement to the t raditional met hod. Tests used to m easure the resistance of the crankarms to stress indicates resist ance levels decidedly higher than those encountered in actua l use. This insures maximum reliability . The chai nrtngs supplied with the C HORUS crankset have a center span of 135 mm. These
MINIMUM FRICTION A ND WEAR
A further contribution to the silent and efficient operation of the CHORUS eq uipped bicycle is minimum chain friction . This is enhanced with the perfectly circular chainring. The bottom bracket has a case-hardened steel axle which tu rns on hardened chrome-steel balls of 1/ 4" diameter. Th e races of the axle, and cups are preci sion-ground to ensure maximum smoothness. Consistent with all Campagnolo bottom brackets, the balls are selected to a tolerance of I micron . To the user this mea ns minimum wear of the races and a longer bottom b racket life. C rankarm length s can he supplied from 167.5, 170, 172 .5 and 175 mm . Chainrings range from 39 to 57 teeth.
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EXTREME SAFETY Applying the experience gained in designing professional racing bicycles, Campagnolo has incorporated the quick release mechanism into the brake lever instead of the caliper. The advan tage of this system , which varies the position of the brake lever as a m eans to expand the caliper, is simple in design and safe to use. In fa ct, with one button locat ed under the brake lever the release can be activated with out removing the hands from the handlebars.
BRAKES
PARTI CU LA R COMFORT
For the brakes of the CH O RUS group Campagnolo engineers have chosen th e mechanical caliper system tested and proven in Record groups by world class professional bicycle racers in t heir fa cilities, th e road. The CHO RUS brake cali per
With this special structure it has been possib le to develop two particulary sturdy arms with a stream lined profile resulting in a very com pact brake. The front brake center bol t is made from a
also has its ow n d esign features that make it an ex t rem ely mo -
dern looking and reliable brake. The arms of the CHO RUS brake are not simply superim posed, b u t the arms that cat ch and pass the cable are inserted one in
the other.
special steel, selected and tested
to guarantee a resistance to solicitations higher than 80 Kg per sq uare millimeter. C am pagnolo's
precise machining guarantees th e perfect alignment of the bolt with the bearing surface of the levers to a tolerance of one millimeter. All this contributes to th e rigidity of the system du ring braking. avoiding dangerous vibrations especially in the front brake.
Safety is considerably higher than traditiona l systems in that if :.~e brake quic k release is left in :.~e off position, braking is still ro ssible in that th e brake lever h-7 i : s-op do es not vary during brakine. Under no circumstances "'ill the brake lever contact the :-..andlebar as in traditiona l systerns. The only difference between the on and the off position is the distance between the brake lever and the handlebar which in the off positi on is greater than 12
A BSOLUTE RELIABILITY
The CH O RUS brakes have been eq ui pped with C am pagnolo's fam ous brake pads. T he co mposition of these pads have long since been the favo rite of the wad 's best cyclists. The pads co m po und has been tested and perfected in such laboratories as The Tour de France, Paris Roubaix and G iro d'Italta and is second t o non e in stopping ab ility an d overall perfonnance. The design criteria are as follows> I) Friction coefficient not too high for dry roads so as to avoid lock up and overheating. 2) Frictio n coefficient as high as
-nm .
The increased distance does not inhibit the maneuverability of the lever. Furthermore this 12 mm . increase is o nly present dUT· ing extreme braking conditio ns.
For no n-traditional routing Cam pagnolo e ngineers have enhan ced the patented system iri use with the brake of th e Record group . W ith this syst em the cable rests o n a stainless steel plate that moves in unison with the lever and the cable itself. Cable travel avoids the cri tical conditions of curving and friction th at w ill eventually cause fraying and failuce . •
Fitting th e b rake lever is
convenient and accessible with the US~ of a 5 mm. Allen bolt to attach the lever d ip to th e hand lebar. The fixing holt is accessible b y holding the leve r in the braking position. With the CHO· RUS brake, cables m ay be routed traditionally , inside the handleb ar or under the handlebar tape.
possible for wet roads. 3J Extended wear characteristics. 4 Consisten t braking even as pad wear increase.
H EADSET AND HUBS
The headset in the CHORUS grou p has three basic characteristi cs: sm ooth o peration ,
long life and reduced weight. Smooth ness is achieved by Campagnolo's system of cones, balls and locknut. The system has been successfully used for over thirty years on bicycles ridden by professional athletes. LO NG D URATION The m ost sign ificant in nova-
tion for headsets is SELFO RM. This syste m effectively dampens the ball races of th e cones and allows optimum distribution of loads over the balls and th e races, avoiding areas of stress that may
cause friction and brinelling of the races.
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T he SELFO RM and a nylon seal, sit uated on the lower part
of the cone prevents wate r directed up by th e wheel from infiltrating the syste m. With th e CHO Rus headset one can expect to double the li fe of ordinary head sets. Hubs are available in 32 and 36 hole drtllings. The hubs can accorn odate either six or seven speed freewheels. The wellproven Campagnolo hubs have hardened chrome-steel ball bearings which rotate on ground steel races in cups that are fi tted into th e light alloy hub body. A hole in the hub's dust cover allows lubrication of the bearings. Campagnolo's new 02-Z PT
grease is excellent for this purp osc . The hub also features the world rene wed Campagnolo quick release skewer with its patented design .
PEDAL .-\..' 10 SEAT PINS After thoroughly studying the ergonom ic ba lance of the pedals. Campagnolo has develored pedals that are widely used [n the racing world by professional and amateur cyclists. As an evolution of this st udy the C HORUS pedals combine ergono mic con side rat ions with t he an atomi-
cal and functional needs of the athletes' pedal stroke.
CO MFO RT AND EFFICIENCY
The shape of CHORUS pedal consid ers the body' s anatom ical requirements by following the
outline of t he foot. The result is a pedal with a slim profi le that ensu re m aximum lightness witho ut com p rom ising strength. ,
The rear pedal plate, derived from the ergonomic pedal of the Record group, accompanies the o uter foot rest as far as the axle. Incorpo rated into this plate is a 4 m m . tah to prevent the foot from sliding outwards when pedaling. This tab is specially shaped to protect the shoe and to elim inate sha rp edges that exert pressure o n the side of the foot . The safetv of the pedal/crank system is further improved by the larger size of the pedal axle support collar on the crank, the diameter of which has been increased to 20 mm .
The seat post, is available in 130 mm . and 180 mm . legths. It has the same slim profile as the seat post used in the Record group. The seat post brackets have seat rail cradles with a radi us of 4 mm . and a center dist ance of 42,2 m m . This combinatio n allows saddles with 7 and 8 mm . diameter rails to be used and that includes practically all the saddles o n t he world market. So thanks to the precise adjustment of this seatpost (in 2 degree increments) the cyclist can fi nd the best saddle pos ition and avoid discomfort. Saddle trim can b e adj usted by varying the coup ling of the o pposed surfaces of the seat post and the lower face for fixing the saddle. The two surfaces are knurled vert ically to en sure locking with no risk of slippage. The system for adjusting the trim and fixing the saddle is anchored with a single 6 mm . Allen head screw of hardened and ternpered steel w hich allows adjust. rnent and fixing operations that are much faster tha n those possible with the two-screw system.
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