Editing Bicycle (section)

===Dynamics===
{{Main|Bicycle and motorcycle dynamics}}
[[File:Jersey Town Criterium 2011 81.jpg|thumb|upright|A cyclist leaning in a turn]]

A bicycle stays upright while moving forward by being steered so as to keep its [[center of mass]] over the wheels.<ref name="NS2581">{{cite journal|last=Various|date=9 December 2006|title=Like falling off|url=https://www.newscientist.com/article/mg19225812.400|url-status=dead|journal=New Scientist|issue=2581|page=93|archive-url=https://web.archive.org/web/20081204070845/https://www.newscientist.com/article/mg19225812.400|archive-date=4 December 2008|access-date=27 January 2009}}</ref> This steering is usually provided by the rider, but under certain conditions may be provided by the bicycle itself.<ref name=MPRS>{{cite journal
| journal = [[Proceedings of the Royal Society A]]
| volume = 463
| issue = 2084
| year = 2007
| pages = 1955–82
| title = Linearized dynamics equations for the balance and steer of a bicycle: a benchmark and review
| last1 = Meijaard
| doi = 10.1098/rspa.2007.1857
| first1 = J.P.
| last2 = Papadopoulos
| first2 = Jim M.
| last3 = Ruina
| first3 = Andy
| last4 = Schwab
| first4 = A.L.
| bibcode=2007RSPSA.463.1955M
| s2cid = 18309860
 | issn=1364-5021 }}</ref>

The combined center of mass of a bicycle and its rider must lean into a turn to successfully navigate it. This lean is induced by a method known as [[countersteering]], which can be performed by the rider turning the handlebars directly with the hands<ref name="Wilson">{{cite book
| title = Bicycling Science
|url=https://archive.org/details/isbn_9780262731546
| url-access = registration
| edition = Third
| last = Wilson
| first = David Gordon
|author2=Jim Papadopoulos
| year = 2004
| publisher = The MIT Press
| isbn = 978-0-262-73154-6
| pages = [https://archive.org/details/isbn_9780262731546/page/270 270–72]}}</ref> or indirectly by leaning the bicycle.<ref name="fajans">{{cite journal|last=Fajans|first=Joel|date=July 1738|title=Steering in bicycles and motorcycles|url=http://socrates.berkeley.edu/~fajans/pub/pdffiles/SteerBikeAJP.PDF|url-status=dead|journal=American Journal of Physics|volume=68|issue=7|pages=654–59|bibcode=2000AmJPh..68..654F|doi=10.1119/1.19504|archive-url=https://web.archive.org/web/20060901081011/http://socrates.berkeley.edu/~fajans/pub/pdffiles/SteerBikeAJP.PDF|archive-date=1 September 2006|access-date=4 August 2006}}</ref>

Short-wheelbase or tall bicycles, when braking, can generate enough stopping force at the front wheel to flip longitudinally.<ref>{{cite book
| title = Motorcycle Dynamics
| edition = Second
| last = Cossalter
| first = Vittore
| year = 2006
| publisher = [[Lulu (company)|Lulu]]
| isbn = 978-1-4303-0861-4
| pages = 241–342}}</ref> The act of purposefully using this force to lift the rear wheel and balance on the front without tipping over is a trick known as a [[stoppie]], endo, or front wheelie.