142:(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
270:. 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
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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
81:
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
487:
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
265:
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,
359:
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
218:
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
371:
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.
664:
237:
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).
62:, 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
146:, 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.
450:
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:
386:, 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.
418:) 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
190:
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
126:
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
958:
705:
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There have been several attempts to implement front steering and suspension without using anything that could be described as a "fork". Examples include
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94:
A variety of fork arrangements have been tried during more than one hundred years of motorcycle development, several of which remain available today.
70:
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.
1334:
282:) used the Earles design on their roadsters or off-road machines. BMW used Earles forks on all their motorcycles between 1955 and 1968.
261:
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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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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194:, 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.
606:
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66:
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
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unit. This relieves the forks of any braking and suspension forces. With a Saxon-Motodd fork, the trail and
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919:"Lot 417: The ex-Mead & Tomkinson, 1976 Laverda 1,000cc 'Nessie' Endurance Racing Prototype - Bonhams"
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from 1948. Girdraulic forks featured hydraulic damping with forged alloy blades providing extra strength.
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especially against lateral deflection caused by hard cornering (as when racing), or when cornering with a
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While both may have an exposed spring near the triple clamp, a girder fork is distinguishable from a
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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
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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.
725:
662:, Earles, Ernest, "Motor cycle front wheel forks", published 1953-07-01
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442:) 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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702:"BMW Telelever and telescopic forks: which is better ?"
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competed in endurance racing in the 1970s with "Nessie," a
406:) has a wishbone that mounts to the frame and supports the
131:
a clean and simple appearance that bikers find attractive.
112:
BMW's version of oil-damped telescopic fork, on a 1939 R12
534:
A single-sided girder "fork" was used by the German firm
654:
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885:
Wilson, Hugo (1995). "The
Directory of Motorcycles".
781:(Third impression ed.). Hamlyn. pp. 30–32.
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548:-based racing motorcycle with hub-centre steering.
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739:"Coaxial steering and suspension for motorcycle"
402:The Saxon-Motodd fork (marketed as Telelever by
849:Wilson, Hugo (1995). "The A-Z of Motorcycles".
438:The Hossack/Fior fork (marketed as Duolever by
166:; it was also used by BMW for its early bikes.
46:Unusual "trailing bottom link" on a Honda Rune
952:
158:Trailing link fork on a 1928 Indian Big Chief
8:
1163:
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339:Learn how and when to remove this message
210:Early Harley-Davidson with springer fork
1335:Outline of motorcycles and motorcycling
594:
186:motorcycles used leading link forks on
178:Ural's variant of the leading link fork
893:. London: Dorling Kindersley. p.
857:. London: Dorling Kindersley. p.
777:Willoughby, Vic (1977) . "Ner-a-Car".
524:, and implemented in the 1990s on the
7:
635:. Dorling-Kindersley. p. 181.
27:Component of motorized two-wheelers
1190:Continuously variable transmission
889:The Encyclopedia of the Motorcycle
853:The Encyclopedia of the Motorcycle
25:
680:"A Brief History of Girder Forks"
479:Coaxial steering front suspension
278:, while other companies (such as
38:with conventional telescopic fork
1356:Motorcycle suspension technology
1012:
294:
708:from the original on 2010-05-16
563:Bicycle and motorcycle geometry
558:Bicycle and motorcycle dynamics
520:, used as early as 1920 on the
58:'s front wheel and axle to its
1174:Sequential manual transmission
678:Robert Smith (May–June 2011).
398:Telelever fork on a BMW R1150R
1:
368:
138:are at the top, secured by a
633:The Ultimate Motorcycle Book
446:and used by Claude Fior and
355:1934 Cotton with girder fork
223:, and is available today on
542:Mead & Tomkinson Racing
314:. The specific problem is:
234:
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921:. Bonhams. 20 October 2007
498:
310:to meet Knowledge (XXG)'s
101:
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134:Conventionally, the fork
1322:Anti-lock braking system
1195:Dual-clutch transmission
390:Saxon-Motodd (Telelever)
1317:Traction control system
578:Suspension (motorcycle)
538:between 1949 and 1951.
426:Hossack/Fior (Duolever)
825:"The Bike, Yamaha USA"
804:"STEER FOR THE FUTURE"
755:. 2006. Archived from
583:Suspension (mechanics)
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435:
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250:Earles fork on a 1952
211:
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1361:Motorcycle technology
968:Motorcycle components
682:. Motorcycle Classics
631:Wilson, Hugo (1993).
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111:
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33:
728:Retrieved 2014-03-16
660:GB patent 693646
321:improve this section
779:Classic Motorcycles
573:Hub-center steering
518:hub-center steering
501:Hub-center steering
434:Duolever front fork
362:Vincent motorcycles
84:hub-center steering
1145:Hydrogen fuel cell
759:on 1 December 2006
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280:Douglas motorcycle
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225:Harley-Davidson's
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1140:Gasoline (petrol)
1053:Flat twin (boxer)
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312:quality standards
303:This section may
252:Douglas Dragonfly
16:(Redirected from
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1031:Layouts (common)
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607:"TO DIVE OR ..."
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164:Indian Motocycle
144:upside-down fork
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18:Motorcycle forks
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1097:Layouts (other)
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726:Hossack Design
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530:Yamaha GTS1000
510:Yamaha GTS1000
499:Main article:
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444:Norman Hossack
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831:on 2007-05-28
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802:Foale, Tony.
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1078:Straight-six
993:
923:. Retrieved
913:
888:
852:
844:
833:. Retrieved
829:the original
818:
807:. Retrieved
797:
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761:. Retrieved
757:the original
747:
733:
721:
710:. Retrieved
695:
684:. Retrieved
673:
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615:. Retrieved
611:the original
597:
568:Bicycle fork
540:
533:
515:
490:
482:
448:John Britten
437:
412:caster angle
401:
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319:Please help
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170:Leading link
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51:
49:
1258:Accessories
1244:Shaft drive
1234:Chain drive
1227:Final drive
1063:Inline-four
753:"MotoCzysz"
603:Foale, Tony
420:BMW R nineT
379:, a modern
323:if you can.
259:Earles fork
235:girder fork
54:connects a
1350:Categories
1302:Drum brake
1297:Disc brake
1239:Belt drive
989:Suspension
925:3 February
835:2006-12-09
809:2006-12-09
763:2006-12-14
712:2012-04-07
686:2011-05-20
617:2006-12-08
589:References
512:suspension
384:motorcycle
329:March 2016
263:Englishman
136:stanchions
124:fork tubes
98:Telescopic
90:Variations
68:handlebars
64:suspension
56:motorcycle
1183:Automatic
1073:Flat-four
522:Ner-a-Car
495:Non-forks
485:MotoCzysz
408:monoshock
377:Ariel Ace
272:MV Agusta
36:BMW R60US
1135:Electric
1083:Flat-six
999:Swingarm
706:Archived
552:See also
305:require
221:choppers
202:Springer
82:such as
1281:Trailer
1276:Sidecar
1271:Pannier
1266:Fairing
1218:Slipper
1109:Turbine
976:Chassis
546:Laverda
473:K1300GT
469:K1200GT
307:cleanup
268:sidecar
188:sidecar
128:gaiters
1307:Saddle
1210:Clutch
1167:Manual
1130:Diesel
1058:Triple
1048:V-twin
1038:Single
1023:Engine
1004:Wheels
901:
865:
785:
666:
639:
526:Bimota
465:K1300S
461:K1200S
457:K1300R
453:K1200R
381:sports
286:Girder
242:Earles
192:trikes
1312:Tires
1290:Other
984:Frame
122:uses
79:dives
60:frame
34:1968
994:Fork
927:2014
899:ISBN
863:ISBN
783:ISBN
637:ISBN
536:Imme
471:and
416:rake
274:and
257:The
214:The
184:Ural
140:yoke
895:241
859:100
440:BMW
404:BMW
1352::
1088:V8
1068:V4
897:.
877:^
861:.
704:.
651:^
605:.
475:.
467:,
463:,
459:,
455:,
230:.
198:.
116:A
86:.
50:A
960:e
953:t
946:v
929:.
907:.
871:.
838:.
812:.
791:.
766:.
741:.
715:.
689:.
645:.
620:.
414:(
342:)
336:(
331:)
327:(
20:)
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