Misplaced Pages

#557442

40-497: Since mounting or dismounting a step-through does not require swinging one leg to hip-height, they are widely used as delivery bicycles, and for other purposes where the rider has to mount and dismount frequently. Traditionally, bicycles with a step-through frame were known as "ladies ' ", "women's" or "girls' bicycles", as they allow skirts or dresses to hang fairly normally. Bicycles with a high top tube (cross-bar), known as a, were known as "men's", "gents", or "boys' bicycles". Even in

80-458: A sport . Other named French styles of step-through frames, in addition to mixte and sport , include berceau , Anglais , jumele , col de cygne and double col de cygne . Another type of step-through frame is called a cross . The cross frame consists mainly of two tubes that form a cross : a seat tube from the bottom bracket to the saddle, and a backbone from the head tube to the rear hub. Bicycle frame#Top tube A bicycle frame

120-492: A utility bicycle emphasizes comfort and has higher handlebars resulting in an upright riding position. Frame geometry also affects handling characteristics. For more information, see the articles on bicycle and motorcycle geometry and bicycle and motorcycle dynamics . Frame size was traditionally measured along the seat tube from the center of the bottom bracket to the center of the top tube. Typical "medium" sizes are 54 or 56 cm (approximately 21.2 or 22 inches) for

160-415: A European men's racing bicycle or 46 cm (about 18.5 inches) for a men's mountain bike . The wider range of frame geometries that now exist has also led to other methods of measuring frame size. Touring frames tend to be longer, while racing frames are more compact. A road racing bicycle is designed for efficient power transfer at minimum weight and drag. Broadly speaking, the road bicycle geometry

200-443: A hollow shell with no internal structure. Folding bicycle frames are characterized by the ability to fold into a compact shape for transportation or storage. Penny-farthing frames are characterized by a large front wheel and a small rear wheel. Tandem and sociable frames support multiple riders. There are many variations on the basic diamond frame design. The cycle types article describes additional variations. It

240-446: A stronger stroking position. The trade-off is comfort. Touring and comfort bicycles tend to have more slack (less vertical) seat tube angle traditionally. This positions the rider more on the sit bones and takes weight off the wrists, arms and neck, and, for men, improves circulation to the urinary and reproductive areas. With a slacker angle, designers lengthen the chain stay so that the center of gravity (that would otherwise be farther to

280-402: A top tube that connected in the middle of the seat tube instead of the top, resulting in a lower standover height . This was to allow the rider to dismount while wearing a skirt or dress . The design has since been used in unisex utility bikes to facilitate easy mounting and dismounting, and is also known as a step-through frame or an open frame. Another style that accomplishes similar results

320-423: A top tube that slopes down steeply to allow the rider to mount and dismount the bicycle more easily. Alternative step-through designs may include leaving out the top tube out completely, as in monocoque mainframe designs using a separated or hinged seat tube, and twin top tubes that continue to the rear fork ends as with the mixte frame. These alternatives to the diamond frame provide greater versatility, though at

360-453: Is also possible to add couplers either during manufacturing or as a retrofit so that the frame can be disassembled into smaller pieces to facilitate packing and travel. The diamond frame consists of two triangles, a main triangle and a paired rear triangle. The main triangle consists of the head tube, top tube, down tube and seat tube. The rear triangle consists of the seat tube, and paired chain stays and seat stays. The head tube contains

400-474: Is also routed along the chain stay. Occasionally (principally on frames made since the late 1990s) mountings for disc brakes will be attached to the chain stays. There may be a small brace that connects the chain stays in front of the rear wheel and behind the bottom bracket shell, called a "chainstay bridge". Chain stays may be designed using tapered or untapered tubing. They may be relieved, ovalized, crimped, S-shaped, or elevated to allow additional clearance for

440-468: Is categorized as either a traditional geometry with a horizontal top tube, or a compact geometry with a sloping top tube. Traditional geometry road frames are often associated with more comfort and greater stability, and tend to have a longer wheelbase which contributes to these two aspects. Compact geometry allows the top of the head tube to be above the top of the seat tube, decreasing standover height, and thus increasing standover clearance and lowering

SECTION 10

#1732859401558

480-404: Is most appropriate when used as part of a rear triangle subframe on a bicycle with independent rear suspension. A dual seat stay refers to seat stays which meet the front triangle of the bicycle at two separate points, usually side-by-side. Fastback seat stays meet the seat tube at the back instead of the sides of the tube. On most seat stays, a bridge or brace is typically used to connect

520-423: Is replaced with a pair of smaller tubes ( lateral tubes , or lats ) running from the top of the head tube all the way back to the rear axle, connecting at the seat tube on the way. The normal seat stays and chain stays are retained. This provides the lower standover height of a step-through frame bicycle with a strong diamond-frame geometry. Mixte (pronounced [mikst] ) is a direct appropriation of

560-451: Is the mixte . In a cantilever bicycle frame the seat stays continue past the seat post and curve downwards to meet with the down tube. Cantilever frames are popular on the cruiser bicycle , the lowrider bicycle , and the wheelie bike . In many cantilever frames the only straight tubes are the seat tube and the head tube. The recumbent bicycle moves the cranks to a position forward of the rider instead of underneath, generally improving

600-445: Is the main component of a bicycle , onto which wheels and other components are fitted. The modern and most common frame design for an upright bicycle is based on the safety bicycle , and consists of two triangles : a main triangle and a paired rear triangle. This is known as the diamond frame . Frames are required to be strong, stiff and light, which they do by combining different materials and shapes. A frameset consists of

640-570: Is typically larger, unthreaded, and sometimes split. The chain stays, seat tube, and down tube all typically connect to the bottom bracket shell. There are a few traditional standard shell widths (68, 70 or 73 mm). Road bikes usually use 68 mm; Italian road bikes use 70 mm; Early model mountain bikes use 73 mm; later models (1995 and newer) use 68 mm more commonly. Some modern bicycles have shell widths of 83 or 100 mm and these are for specialised downhill mountain biking or snowbiking applications. The shell width influences

680-451: The Q factor or tread of the bike. There are a few standard shell diameters (34.798 – 36 mm) with associated thread pitches (24 - 28 tpi). On some gearbox bicycles , the bottom bracket shell may be replaced by an integrated gearbox or a mounting location for a detachable gearbox. The length of the tubes, and the angles at which they are attached define a frame geometry . In comparing different frame geometries, designers often compare

720-449: The seatpost of the bike, which connects to the saddle. The saddle height is adjustable by changing how far the seatpost is inserted into the seat tube. On some bikes, this is achieved using a quick release lever. The seatpost must be inserted at least a certain length; this is marked with a minimum insertion mark . The seat tube also may have braze-on mounts for a bottle cage or front derailleur . The chain stays run parallel to

760-408: The 1800s, women often rode "men's" bicycles and vice-versa; from the 1890s onwards, women commonly wore bloomers to cycle. Since the late 20th century, descriptions that describe the frame style, rather than the presumed gender of the rider, are becoming increasingly common. One particular type of step-through frame is called a mixte . In a mixte frame, the top tube of the traditional diamond frame

800-461: The French word meaning "mixed" or "unisex". The usual North American bicycle industry pronunciation of this loan word is / ˈ m ɪ k s t iː / . A variant on the mixte uses a single, full sized top tube running from the upper head tube to the seat tube, but retains the middle set of stays. The FNCRM (Fédération Nationale du Commerce et de la Réparation du Cycle et du Motocycle) calls this style

840-559: The back over the wheel) is more ideally repositioned over the middle of the bike frame. The longer wheelbase contributes to effective shock absorption. In modern mass-manufactured touring and comfort bikes, the seat-tube angle is negligibly slacker, perhaps in order to reduce manufacturing costs by avoiding the need to reset welding jigs in automated processes, and thus do not provide the comfort of traditionally made or custom-made frames which do have noticeably slacker seat-tube angles. Skirt Too Many Requests If you report this error to

SECTION 20

#1732859401558

880-408: The cables from damage and dirt, which can e.g. make gear shifting unreliable. The space between the top tube and the rider's groin while straddling the bike and standing on the ground is called clearance. The total height from the ground to this point is called the height lever. The down tube connects the head tube to the bottom bracket shell. On racing bicycles and some mountain and hybrid bikes,

920-404: The center of gravity. Opinion is divided on the riding merits of the compact frame, but several manufacturers claim that a reduced range of sizes can fit most riders, and that it is easier to build a frame without a perfectly level top tube. Road bicycles for racing tend to have a steeper seat tube angle , measured from the horizontal plane. This positions the rider aerodynamically and arguably in

960-413: The chain, connecting the bottom bracket shell (which holds the axis around which the pedals and cranks rotate) to the rear fork ends or dropouts. A shorter chain stay generally means that the bike will accelerate faster and be easier to ride uphill, at least while the rider can avoid the front wheel losing contact with the ground. When the rear derailleur cable is routed partially along the down tube, it

1000-420: The cranks to the rear of the rider, resulting in a head-forward, chest-down riding position. A cross frame consists mainly of two tubes that form a cross: a seat tube from the bottom bracket to the saddle, and a backbone from the head tube to the rear hub. A truss frame uses additional tubes to form a truss . Examples include Humbers , Pedersens , and the one pictured. A monocoque frame consists only of

1040-441: The derailleur cables run along the down tube, or inside the down tube. On older racing bicycles, the shift levers were mounted on the down tube. On newer ones, they are mounted with the brake levers on the handlebars. Bottle cage mounts are also on the down tube, usually on the top side, sometimes also on the bottom side. In addition to bottle cages, small air pumps may be fitted to these mounts as well. The seat tube contains

1080-411: The expense of added weight to achieve equivalent strength and rigidity. Control cables are routed along mounts on the top tube, or sometimes inside the top tube. Most commonly, this includes the cable for the rear brake, but some mountain bikes and hybrid bicycles also route the front and rear derailleur cables along the top tube. Inside routing, once only present in the highest price ranges, protects

1120-426: The frame and fork of a bicycle and sometimes includes the headset and seat post . Frame builders will often produce the frame and fork together as a paired set. Besides the ubiquitous diamond frame, many different frame types have been developed for the bicycle, several of which are still in common use today. In the diamond frame, the main "triangle" is not actually a triangle because it consists of four tubes:

1160-448: The head tube to the bottom bracket shell. The rear triangle connects to the rear fork ends , where the rear wheel is attached. It consists of the seat tube and paired chain stays and seat stays. The chain stays run connecting the bottom bracket to the rear fork ends. The seat stays connect the top of the seat tube (often at or near the same point as the top tube) to the rear fork ends. Historically, bicycle frames designed for women had

1200-452: The head tube, top tube, down tube and seat tube. The rear triangle consists of the seat tube joined by paired chain stays and seat stays. The head tube contains the headset , the interface with the fork . The top tube connects the head tube to the seat tube at the top. The top tube may be positioned horizontally (parallel to the ground), or it may slope downwards towards the seat tube for additional stand-over clearance. The down tube connects

1240-431: The headset, the bearings for the fork via its steerer tube . In an integrated headset, cartridge bearings interface directly with the surface on the inside of the head tube, on non-integrated headsets the bearings (in a cartridge or not) interface with "cups" pressed into the head tube. The top tube , or cross-bar , connects the top of the head tube to the top of the seat tube. In a traditional-geometry diamond frame,

Step-through frame - Misplaced Pages Continue

1280-412: The other tubes in the frame, that runs side to side and holds the bottom bracket . It is usually threaded, often left-hand threaded on the right (drive) side of the bike to prevent loosening by fretting induced precession , and right-hand threaded on the left (non-drive) side. There are many variations, such as an eccentric bottom bracket, which allows for adjustment in tension of the bicycle's chain. It

1320-430: The rear wheel, chain, crankarms, or the heel of the foot. The seat stays connect the top of the seat tube (often at or near the same point as the top tube) to the rear fork dropouts. A traditional frame uses a simple set of paralleled tubes connected by a bridge above the rear wheel. When the rear derailleur cable is routed partially along the top tube, it is also usually routed along the seat stay. Many alternatives to

1360-434: The seat tube angle, head tube angle, (virtual) top tube length, and seat tube length. To complete the specification of a bicycle for use, the rider adjusts the relative positions of the saddle, pedals and handlebars: The geometry of the frame depends on the intended use. For instance, a road bicycle will place the handlebars in a lower and further position relative to the saddle giving a more crouched riding position; whereas

1400-466: The slipstream around the rider without the characteristic sharp bend at the waist used by racers of diamond-frame bicycles. Banned from bicycle racing in France in 1934 to avoid rendering diamond-frame bicycles obsolete in racing, manufacturing of recumbent bicycles remained depressed for another half century, but many models from a range of manufacturers were available by 2000. The uncommon prone bike moves

1440-399: The stays above the rear wheel and below the connection with the seat tube. Besides providing lateral rigidity, this bridge provides a mounting point for rear brakes, fenders, and racks. The seat stays themselves may also be fitted with brake mounts. Brake mounts are often absent from fixed-gear or track bike seat stays. The bottom bracket shell is a short and large diameter tube, relative to

1480-599: The top tube is horizontal (parallel to the ground). In a compact-geometry frame, the top tube is normally sloped downward toward the seat tube for additional standover clearance. In a mountain bike frame, the top tube is almost always sloped downward toward the seat tube. Radically sloped top tubes that compromise the integrity of the traditional diamond frame may require additional gusseting tubes, alternative frame construction, or different materials for equivalent strength. ( See Road and triathlon bicycles for more information on geometries. ) Step-through frames usually have

1520-548: The top tube was patented by Volagi Cycles . This frame element added length to the traditional design of seat stays, making a softer ride at the sacrifice of frame stiffness. Another common seat stay variant is the wishbone , single seat stay , or mono stay , which joins the stays together just above the rear wheel into a monotube that is joined to the seat tube. A wishbone design adds vertical rigidity without increasing lateral stiffness, generally an undesirable trait for bicycles with unsuspended rear wheels. The wishbone design

1560-500: The traditional seat stay design have been introduced over the years. A style of seat stay that extends forward of the seat tube, below the rear end of the top tube and connects to the top tube in front of the seat tube, creating a small triangle, is called a Hellenic stay after the British frame builder Fred Hellens, who introduced them in 1923. Hellenic seat stays add aesthetic appeal at the expense of added weight. This style of seat stay

1600-435: Was popularized again in the late 20th century by GT Bicycles (under the moniker "triple triangle"), who had incorporated the design element into their BMX frames, as it also made for a much stiffer rear triangle (an advantage in races); this design element has also been used on their mountain bike frames for similar reasons. In 2012, a variation of the traditional seat stay that bypasses the seat tube and connects further into

#557442