Editing Recumbent bicycle (section)

==Description==
[[File:CNC Cruzbike 2007.jpg|thumb|260px|Woman riding a Cruzbike Sofrider (PBFWD recumbent) near the end of the {{convert|500|mi|km|-1|adj=on}} "Ride Across North Carolina" 2007]]
Recumbents can be categorized by their wheelbase, wheel sizes, steering system, faired or unfaired, and front-wheel or rear-wheel drive.

===Wheelbase===
[[File:LWB Lowrider Recumbent.jpg|thumb|240px|Long-wheel-base low-rider recumbent with steering u-joint (UA)]]
Long-wheelbase (LWB) models have the pedals located between the front and rear wheels; short-wheelbase (SWB) models have the pedals in front of the front wheel; compact long-wheelbase (CLWB) models have the pedals either very close to the front wheel or above it. Within these categories are variations, intermediate types, and even convertible designs (LWB to CLWB) {{Ndash}}there is no "standard" recumbent.

===Wheel sizes===
The rear wheel of a recumbent is usually behind the rider and may be any size, from around {{convert|16|in|mm}} to the 700c (or 27″ on some older models, as on upright road bikes of that time) of an upright racing cycle. The front wheel is commonly smaller than the rear, although a number of recumbents feature dual 26-inch (ISO 559), 650c (ISO 571), 700c (ISO 622), or even 29 × 4″ oversize all-terrain tires. Given the higher rolling resistance of the smaller front wheel, loss of steering and control are somewhat more likely attempting sharp or quick changes of direction while crossing over patches of loose dirt, sand or pebbles.<ref>{{cite news |url=https://pedallers.com/are-recumbent-bikes-any-good/ |title = Are Recumbent Bikes Any Good? |date=25 March 2020 |access-date=10 April 2020|work=Pedallers}}</ref> Larger diameter wheels generally have lower [[rolling resistance]] but a higher profile leading to higher air resistance. High-racer aficionados also claim that they are more stable, and although it is easier to balance a bicycle with a higher center of mass,<ref name=Fajans>{{cite web
 |title       = Email Questions and Answers: Robot Bicycles
 |last        = Fajans
 |first       = Joel
 |url         = http://socrates.berkeley.edu/~fajans/Teaching/MoreBikeFiles/BikeQuestions.htm#Robot_Bicycles
 |quote       = Likewise, a short bicycle falls over more quickly than a tall one. So a kid's bike is actually more difficult to balance than an adult bike.
 |access-date  = 4 October 2012
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20060901080953/http://socrates.berkeley.edu/~fajans/Teaching/MoreBikeFiles/BikeQuestions.htm#Robot_Bicycles
 |archive-date = 1 September 2006
 |df          = dmy-all
}}</ref> the wide variety of recumbent designs makes such generalizations unreliable. Another advantage of both wheels being the same size is that the bike requires only one size of inner tube.

One common arrangement is an ISO 559 (26-inch) rear wheel and an ISO 406 or ISO 451 (20-inch) front wheel. The small front wheel and large rear wheel combination is used to keep the pedals and front wheel clear of each other, avoiding the problem on a short wheelbase recumbent called "heel strike" (where the rider's heels catch the wheel in tight turns). A pivoting-boom front-wheel drive (PBFWD aka moving bottom bracket recumbent) configuration also overcomes heel strike since the pedals and front wheel turn together. PBFWD bikes may have dual {{convert|26|in|mm|adj=on}} wheels or larger.

[[File:Under seat steering.JPG|thumb|300px|Handlebar setup for under-seat steering (USS)]]

===Steering===<!-- This section is linked from [[Bicycle]] -->
[[File:0x-flevo-1.jpg|thumb|260px|right|A Flevobike showing pivot steering (and FWD)]]
Steering for recumbent bikes can be generally categorized as
* over-seat (OSS) or above seat steering (ASS);
* under-seat (USS); or
* center steering or pivot steering.
OSS/ASS is generally direct—the steerer acts on the front fork like a standard [[bicycle handlebar]]—but the bars themselves may extend well behind the front wheel (more like a [[tiller]]); alternatively the bars might have long rearward extensions (sometimes known as Superman or Kingcycle bars). Chopper-style bars are sometimes seen on LWB bikes.

USS is usually indirect—the bars link to the headset through a system of rods or cables and possibly a [[bell crank]].<ref>{{cite web
|url = http://hasbrouck.org/bike/Infinity-manual.pdf
|title = 1992 Infinity price list & user's manual
|access-date = 24 May 2011}}</ref> Most tadpole trikes are USS.

Center steered or pivot steered recumbents, such as Flevobikes and Pythons, may have no handlebars at all.<ref>{{cite web
|url = http://flevofanclub.ligfiets.net/?doc=ch4-02&lang=en
|title = The official Flevobike Fanclub Site: Photos: Lowracers
|access-date = 9 May 2009}}</ref><ref>{{cite web
|url = http://www.python-lowracer.de/pics/gallery/Jonkoping2006-25.jpg
|title = Python Gallery
|access-date = 9 May 2009}}</ref>

In addition, some trikes such as the Sidewinder have used rear-wheel steer, instead of the more common front-wheel steer.  They can provide good maneuverability at low speeds, but have been reported to be potentially unstable at speeds above {{convert|25|mph|abbr=on}}.<ref>{{cite web|title=Sidewinder trikes|url=http://www.sidewindercycle.com/|publisher=Sidewinder|access-date=28 October 2015}}</ref>

===Drive===
Most recumbents have the cranks attached to a boom fixed to the frame, with a long drive chain for rear wheel drive. However, due to the proximity of the crank to the front wheel, front wheel drive (FWD) can be an option, and it allows for a much shorter chain. One style requires the chain to twist slightly to allow for steering.<ref name="Toxy">{{cite web
| url = https://recumbentbikelab.com/
| title = Recumbent Exercise Bike Resources
| access-date = 24 July 2018}}</ref>

[[File:CruzbikeSilvio 2009.jpg|thumb|260px|Cruzbike Silvio (2009) A moving (pivoting) bottom bracket, front wheel-drive, 700C road bike (with rear rack).]]
Another style, pivoting-boom FWD (PBFWD), has the crankset connected to and moving with the front fork.<ref name="traylor">{{cite web
| url = http://traylorfwd.home.mindspring.com/fwd.html
 | title = Front Wheel Drive – Is it practical?
| access-date = 22 October 2006 |archive-url = https://web.archive.org/web/20061022094132/http://traylorfwd.home.mindspring.com/fwd.html |archive-date = 22 October 2006}}</ref> In addition to the much shorter chain, the advantages to PBFWD are use of a larger front wheel for lower rolling resistance without heel strike (you can pedal while turning) and use of the upper body when sprinting or climbing. The main disadvantage to all FWD designs is "wheelspin" when climbing steep hills covered with loose gravel, wet grass, etc. This mainly affects off-road riders, and can be ameliorated by shifting the weight forward, applying steady pressure to the pedals, and using [[Bicycle tire|tires]] with more aggressive tread. Another disadvantage of PBFWD for some riders is a slightly longer "learning curve" due to adaptation to the pedal-steer effect (forces applied to the pedal can actually steer the bike). Beginner riders tend to swerve along a serpentine path until they adapt a balanced pedal motion. After adaptation, a PBFWD recumbent can be ridden in as straight a line as any other bike, and can even be steered accurately with the feet only. [[Cruzbike]] is the only PBFWD recumbent currently in production, and features a traditional steering axis similar to most standard and recumbent bikes. Flevobike formerly produced a center-steered FWD bike similar to the [[Python Lowracer]].

Yet another drive-train variation is on [[rowing cycles]] where the rider rows using arms and legs.

===Fully suspended bikes===
Modern recumbent bikes are increasingly being fitted with front and rear suspension systems for increased comfort and traction on rough surfaces. Coil, elastomer, and air-sprung suspension systems have all been used on recumbent bikes, with oil or air-damping in the forks and rear shock absorbers. The maturation of fully suspended conventional mountain bikes has aided the development of these designs, which often use many of the same parts, suitably modified for recumbent use.

[[File:Nzleitras.jpg|thumbnail|Leitra Velomobiles]]

===Fairings===
{{Main|Bicycle fairing}}

Some riders fit their bikes with [[aerodynamic]] devices called [[Bicycle fairing|fairing]]s. These can reduce aerodynamic drag<ref>{{cite web
| url = http://www.hostelshoppe.com/atp_archives/mit_windtunnel.pdf
| title = Aerodynamic Performance of VISION recumbents
| author = Grant Bower
| publisher = Advanced Transportation Products
| year = 1999
| access-date = 1 October 2010}}</ref> and help keep the rider warmer and drier in cold and wet weather. Fairings are also available for upright bikes, but are much less common. Fully enclosed bikes and trikes are considered [[velomobile]]s.

===Seats===
{{Main|Bicycle seat}}
The seats themselves are either of mesh stretched tightly over a frame or foam cushions over hard shells like the Stinger pictured, which might be moulded or assembled from sheet materials. Hard-shell seats predominate in Europe, mesh seats in the USA.{{Citation needed|date=March 2025}}