Editing Recumbent bicycle (section)

===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)]]