131:(also called a triple tree or a triple clamp), and the sliders are at the bottom, attached to the front wheel spindle. On some modern sport bikes and most off-road bikes, this system is inverted, with "sliders" (complete with the spring/damper unit) at the top, clamped to the yoke, while the stanchions are at the bottom. This is done (i) to reduce unsprung weight by having the heavier components suspended, and (ii) to improve the strength and rigidity of the assembly by having the strong large-diameter "sliders" clamped in the yokes. The inverted system is referred to as an
144:
495:
384:
196:
236:
259:. This triangulated fork causes the front end of a motorcycle to rise slightly when braking hard, as the mechanical braking forces rotate 'downward' relative to the fork's pivot point. This action can be disconcerting to riders used to telescopic forks, which have the opposite reaction to braking forces ('brake dive'). Several motorcycle manufacturers licensed the Earles patent forks for racing motorcycles in 1953, such as
20:
420:
341:
32:
285:
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119:
for protection against abrasive elements on the suspension cylinders. The main advantages of the telescopic fork are that (i) it is simple in design and relatively cheap to manufacture and assemble; (ii) it is lighter than older designs using external components and linkage systems; and (iii) it has
70:
during braking. While the standard telescopic fork arrangement is found with few major differences among mainstream street motorcycles since the 1970s, historically there have been many variations, including trailing or leading link, springer, Earles, girder, and others, as well as non-fork steering
476:
for their C1 and awarded United States Patent 7111700 on
September 26, 2006. Defined as a motorcycle or bicycle front end having coaxial steering and suspension components, and having telescopic forks. Swing weight of the forks is dramatically reduced by removing their suspension components to the
254:
Ernest Earles in 1953, the design is constructed of light tubing, with conventional 'shock absorbers' mounted near the front axle. The Earles fork has a very small wheelbase change under braking or under compression, unlike telescopic forks. Their construction is much stronger than teleforks,
348:
One of the earliest types of motorcycle front suspension, the girder fork consists of a pair of uprights attached to the triple clamp by linkages with a spring usually between the top and bottom triple clamps. The design reached a peak in the "Girdraulics" used on
207:
is an early type of leading link fork. A springer fork does not have the suspension built into the fork tubes, but instead has it mounted externally, where it may be integrated into the triple clamp. This style of fork may be found on antique motorcycles or
360:
by the wheel being fixed firmly to the (usually a long diamond shape) upright. The pivot points are short links mounted to the top and bottom triple clamps. The spring is usually mounted to the girder and compressed against the upper triple clamp.
653:
226:
by its two parallel sets of legs. The rear is firmly fixed to the bottom triple clamp (usually brazed or welded). A short leading link holds the wheel and the forward leg which actuates the springs (usually mounted on the triple clamp).
51:, typically via a yoke, also known as a triple clamp, which consists of an upper yoke joined to a lower yoke via a steering stem, a shaft that runs through the steering head, creating the steering axis. Most forks incorporate the front
135:, or "USD" for short. A disadvantage of this USD design is that the entire reservoir of damping oil is above the slider seal so that, if the slider seal were to leak, the oil could drain out, rendering any damping ineffective.
439:
on racebikes, Hossack described the system as a 'steered upright'. In 2004 BMW announced the K1200S with a new front suspension that appears to be based upon the design. As of 2006, the
Duolever is on the BMW K models:
375:, has an alloy space frame and a matching girder fork. This Ariel girder fork is just as prone to brake dive as any telescopic fork, but is claimed to be more resistant to torsional twisting.
407:) increases during braking instead of decreasing as with traditional telescopic forks. BMW's boxer twins have been equipped with Telelever forks since 1994, but some newer boxers like the
179:
equipped motorcycles, and aftermarket leading link forks are often installed today on motorcycles when they are outfitted with sidecars. They are also very popular with
115:
which contain the suspension components (coil springs and damper) internally. This is the most common form of fork commercially available. It may or may not include
694:
505:
There have been several attempts to implement front steering and suspension without using anything that could be described as a "fork". Examples include
83:
A variety of fork arrangements have been tried during more than one hundred years of motorcycle development, several of which remain available today.
59:
attach to the top clamp in various ways, while clip-on handlebars clamp to the fork tubes, either just above or just below the upper triple clamp.
947:
591:
271:) used the Earles design on their roadsters or off-road machines. BMW used Earles forks on all their motorcycles between 1955 and 1968.
250:
is a variety of leading link fork where the pivot point is behind the front wheel, which is the basis of the Earles' patent. Patented by
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404:
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central location, coaxially within the steering tube. Ride height can be adjusted without loosening the forks in the triple clamps.
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A trailing link fork suspends the wheel on a link (or links) with a pivot point forward of the wheel axle. Most famously used by
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813:
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183:, improving the handling while steering or braking. The most common example of a leading link fork is that found on the
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This particular fork, as implemented on the MotoCzysz C1, also has adjustable trail, from 89 mm to 101 mm.
327:
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55:
and front brake, and allow the front wheel to rotate about the steering axis so that the bike may be steered. Most
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A leading link fork suspends the wheel on a link (or links) with a pivot point aft of the wheel axle. Russian
399:
unit. This relieves the forks of any braking and suspension forces. With a Saxon-Motodd fork, the trail and
1133:
67:
908:"Lot 417: The ex-Mead & Tomkinson, 1976 Laverda 1,000cc 'Nessie' Endurance Racing Prototype - Bonhams"
353:
from 1948. Girdraulic forks featured hydraulic damping with forged alloy blades providing extra strength.
255:
especially against lateral deflection caused by hard cornering (as when racing), or when cornering with a
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648:
356:
While both may have an exposed spring near the triple clamp, a girder fork is distinguishable from a
300:
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While it may have an exposed spring near the triple clamp, a springer fork is distinguishable from a
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The fork and its attachment points on the frame establish the critical geometric parameters of
305:
incorrect use of (American jargon) telescopic fork terminology not applicable to Girder forks.
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have reverted to conventional telescopic forks for aesthetic and packaging reasons.
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651:, Earles, Ernest, "Motor cycle front wheel forks", published 1953-07-01
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431:) completely separates the suspension from steering forces. Developed by
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Although girder forks are associated with early motorcycles, the
British
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66:, which play a major role in defining how a motorcycle handles and
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31:
1002:
691:"BMW Telelever and telescopic forks: which is better ?"
163:
533:
competed in endurance racing in the 1970s with "Nessie," a
395:) has a wishbone that mounts to the frame and supports the
128:
120:
a clean and simple appearance that bikers find attractive.
97:
101:
BMW's version of oil-damped telescopic fork, on a 1939 R12
523:
A single-sided girder "fork" was used by the German firm
264:
643:
641:
874:
Wilson, Hugo (1995). "The
Directory of Motorcycles".
770:(Third impression ed.). Hamlyn. pp. 30–32.
638:
467:
537:-based racing motorcycle with hub-centre steering.
875:
839:
869:
867:
759:
1336:
728:"Coaxial steering and suspension for motorcycle"
391:The Saxon-Motodd fork (marketed as Telelever by
1019:
838:Wilson, Hugo (1995). "The A-Z of Motorcycles".
427:The Hossack/Fior fork (marketed as Duolever by
155:; it was also used by BMW for its early bikes.
864:
831:
647:
35:Unusual "trailing bottom link" on a Honda Rune
941:
147:Trailing link fork on a 1928 Indian Big Chief
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328:Learn how and when to remove this message
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199:Early Harley-Davidson with springer fork
194:
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142:
96:
30:
18:
1324:Outline of motorcycles and motorcycling
175:motorcycles used leading link forks on
167:Ural's variant of the leading link fork
1337:
882:. London: Dorling Kindersley. p.
873:
846:. London: Dorling Kindersley. p.
837:
784:
766:Willoughby, Vic (1977) . "Ner-a-Car".
619:
513:, and implemented in the 1990s on the
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624:. Dorling-Kindersley. p. 181.
16:Component of motorized two-wheelers
13:
1179:Continuously variable transmission
878:The Encyclopedia of the Motorcycle
842:The Encyclopedia of the Motorcycle
14:
1361:
790:
669:"A Brief History of Girder Forks"
590:
468:Coaxial steering front suspension
267:, while other companies (such as
27:with conventional telescopic fork
1345:Motorcycle suspension technology
1001:
283:
138:
900:
697:from the original on 2010-05-16
552:Bicycle and motorcycle geometry
547:Bicycle and motorcycle dynamics
509:, used as early as 1920 on the
158:
47:'s front wheel and axle to its
1163:Sequential manual transmission
708:
667:Robert Smith (May–June 2011).
660:
387:Telelever fork on a BMW R1150R
1:
577:
357:
127:are at the top, secured by a
86:
78:
622:The Ultimate Motorcycle Book
483:
435:and used by Claude Fior and
344:1934 Cotton with girder fork
212:, and is available today on
7:
540:
531:Mead & Tomkinson Racing
303:. The specific problem is:
223:
190:
10:
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910:. Bonhams. 20 October 2007
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123:Conventionally, the fork
1311:Anti-lock braking system
1184:Dual-clutch transmission
379:Saxon-Motodd (Telelever)
1306:Traction control system
567:Suspension (motorcycle)
527:between 1949 and 1951.
415:Hossack/Fior (Duolever)
814:"The Bike, Yamaha USA"
793:"STEER FOR THE FUTURE"
744:. 2006. Archived from
572:Suspension (mechanics)
502:
424:
388:
345:
243:
239:Earles fork on a 1952
200:
168:
148:
102:
36:
28:
1350:Motorcycle technology
957:Motorcycle components
671:. Motorcycle Classics
620:Wilson, Hugo (1993).
497:
422:
386:
343:
238:
198:
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146:
100:
34:
22:
717:Retrieved 2014-03-16
649:GB patent 693646
310:improve this section
299:to meet Knowledge's
768:Classic Motorcycles
562:Hub-center steering
507:hub-center steering
490:Hub-center steering
423:Duolever front fork
351:Vincent motorcycles
73:hub-center steering
1134:Hydrogen fuel cell
748:on 1 December 2006
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269:Douglas motorcycle
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214:Harley-Davidson's
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1129:Gasoline (petrol)
1042:Flat twin (boxer)
338:
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301:quality standards
292:This section may
241:Douglas Dragonfly
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1020:Layouts (common)
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816:. Archived from
812:McClellan, Don.
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596:"TO DIVE OR ..."
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216:Softail Springer
153:Indian Motocycle
133:upside-down fork
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1103:Wankel (rotary)
1086:Layouts (other)
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185:Honda Super Cub
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108:telescopic fork
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93:Telescopic fork
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41:motorcycle fork
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715:Hossack Design
707:
689:Cossalter, V.
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598:Archived from
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519:Yamaha GTS1000
499:Yamaha GTS1000
488:Main article:
485:
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433:Norman Hossack
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265:BMW Motorcycle
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91:Main article:
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64:rake and trail
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1032:Parallel twin
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893:0-7513-0206-6
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857:0-7513-0206-6
853:
849:
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820:on 2007-05-28
819:
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794:
791:Foale, Tony.
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779:
777:0-600-31870-2
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631:0-7513-0043-8
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602:on 2013-02-04
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517:Tesi and the
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472:Developed by
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358:springer fork
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205:springer fork
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139:Trailing link
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1148:Transmission
1067:Straight-six
982:
912:. Retrieved
902:
877:
841:
833:
822:. Retrieved
818:the original
807:
796:. Retrieved
786:
767:
761:
750:. Retrieved
746:the original
736:
722:
710:
699:. Retrieved
684:
673:. Retrieved
662:
621:
615:
604:. Retrieved
600:the original
586:
557:Bicycle fork
529:
522:
504:
479:
471:
437:John Britten
426:
401:caster angle
390:
363:
355:
347:
324:
315:
308:Please help
304:
293:
247:
245:
221:
215:
204:
202:
170:
159:Leading link
150:
132:
122:
106:
104:
82:
61:
40:
38:
1247:Accessories
1233:Shaft drive
1223:Chain drive
1216:Final drive
1052:Inline-four
742:"MotoCzysz"
592:Foale, Tony
409:BMW R nineT
368:, a modern
312:if you can.
248:Earles fork
224:girder fork
43:connects a
1339:Categories
1291:Drum brake
1286:Disc brake
1228:Belt drive
978:Suspension
914:3 February
824:2006-12-09
798:2006-12-09
752:2006-12-14
701:2012-04-07
675:2011-05-20
606:2006-12-08
578:References
501:suspension
373:motorcycle
318:March 2016
252:Englishman
125:stanchions
113:fork tubes
87:Telescopic
79:Variations
57:handlebars
53:suspension
45:motorcycle
1172:Automatic
1062:Flat-four
511:Ner-a-Car
484:Non-forks
474:MotoCzysz
397:monoshock
366:Ariel Ace
261:MV Agusta
25:BMW R60US
1124:Electric
1072:Flat-six
988:Swingarm
695:Archived
541:See also
294:require
210:choppers
191:Springer
71:such as
1270:Trailer
1265:Sidecar
1260:Pannier
1255:Fairing
1207:Slipper
1098:Turbine
965:Chassis
535:Laverda
462:K1300GT
458:K1200GT
296:cleanup
257:sidecar
177:sidecar
117:gaiters
1296:Saddle
1199:Clutch
1156:Manual
1119:Diesel
1047:Triple
1037:V-twin
1027:Single
1012:Engine
993:Wheels
890:
854:
774:
655:
628:
515:Bimota
454:K1300S
450:K1200S
446:K1300R
442:K1200R
370:sports
275:Girder
231:Earles
181:trikes
1301:Tires
1279:Other
973:Frame
111:uses
68:dives
49:frame
23:1968
983:Fork
916:2014
888:ISBN
852:ISBN
772:ISBN
626:ISBN
525:Imme
460:and
405:rake
263:and
246:The
203:The
173:Ural
129:yoke
884:241
848:100
429:BMW
393:BMW
1341::
1077:V8
1057:V4
886:.
866:^
850:.
693:.
640:^
594:.
464:.
456:,
452:,
448:,
444:,
219:.
187:.
105:A
75:.
39:A
949:e
942:t
935:v
918:.
896:.
860:.
827:.
801:.
780:.
755:.
730:.
704:.
678:.
634:.
609:.
403:(
331:)
325:(
320:)
316:(
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