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Step-through frame
open-in-new
<h2 id="advantages">Advantages</h2> <ul><li>less risk of stretching or ripping clothes when mounting the saddle</li> <li>the rider can wear a skirt (also requires a <a href="/facts/Skirt_guard/HGUrEtgV">skirt guard</a> and possibly a <a href="/facts/Chain_guard/IBtYfDnG">chain guard</a>)</li> <li>very quick to mount and dismount, so is suitable for <a href="/facts/Delivery_bicycle/eNUwCzsQ">delivery bicycles</a>, or any journey with many stops</li> <li>suitable for elderly and others with restricted agility</li> <li>potentially safer than a high top tube; a rider who loses balance can step through the bicycle without becoming entangled</li> <li>compactness provides a popular starting point for <a href="/facts/Folding_bicycle/JR9A9fhF">folding bicycles</a>.</li></ul> <h2 id="disadvantages">Disadvantages</h2> <ul><li>Heavier. Compared to a traditional diamond frame consisting of two near-triangles, open or step-through frame designs must be designed with thicker <a href="/facts/Sheet_metal/3yK7SwL4">gauge</a> tubing, the use of additional gusseting members, and/or <a href="/facts/Monocoque/JmP1Dltq">monocoque</a> frame construction. These structural elements may add weight or cost over a traditional diamond design.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a><a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a><a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a></li> <li>Inattention to structural design can lead to excessive flexing, resulting in lower pedaling efficiency and reduced frame life.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a><a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a></li> <li>Fewer places to mount accessories, e.g. an air pump or water-bottle.</li> <li>More difficult to carry around off the ground due to the sloping tube near the bicycle's center of gravity, e.g. carrying it up stairs, or lifting to hang it for maintenance.</li></ul> <h2 id="variations">Variations</h2> <h3>Mixte</h3> <p>One particular type of step-through frame is called a mixte. In a mixte frame, the <a href="/facts/Bicycle_frame/jnDRoA4z">top tube</a> of the traditional <a href="/facts/Diamond_frame/jnDRoA4z">diamond frame</a> is replaced with a pair of smaller tubes (<i>lateral tubes</i>, or <i>lats</i>) running from the top of the <a href="/facts/Head_tube/fNYVMdLo">head tube</a> all the way back to the rear axle, connecting at the <a href="/facts/Bicycle_frame/jnDRoA4z">seat tube</a> on the way. The normal seat stays and chain stays are retained. This provides the lower <a href="/facts/Bicycle_frame/jnDRoA4z">standover height</a> of a step-through frame bicycle with a strong diamond-frame geometry. </p><p><i>Mixte</i> (pronounced [mikst]) is a direct appropriation of the French word meaning "mixed" or "unisex". The usual North American <a href="/facts/Bicycle_industry/fLWPy4bR">bicycle industry</a> pronunciation of this <a href="/facts/Loan_word/PWGYczgY">loan word</a> is /ˈmɪkstiː/.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a> </p><p>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.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> The FNCRM (Fédération Nationale du Commerce et de la Réparation du Cycle et du Motocycle) calls this style a <i>sport</i>.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> </p><p>Other named French styles of step-through frames, in addition to <i>mixte</i> and <i>sport</i>, include <i>berceau</i>, <i>Anglais</i>, <i>jumele</i>, <i>col de cygne</i> and <i>double col de cygne</i>. </p> <h3>Cross</h3> <p>Another type of step-through frame is called a <i>cross</i>. The cross frame consists mainly of two tubes that form a <a href="/facts/Cross/a3W7gkFH">cross</a>: a seat tube from the bottom bracket to the saddle, and a backbone from the head tube to the rear hub.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> <a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> </p> <h2 id="gallery">Gallery</h2> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Bicycle_frame/jnDRoA4z">Bicycle frame</a></li> <li><a href="/facts/Bicycling_and_feminism/T4HzTU02">Bicycling and feminism</a></li></ul> <h2 id="external-links">External links</h2> <ul><li> Media related to Bicycles with a step-through frame at Wikimedia Commons</li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>"Top Tube". Sheldon Brown. Retrieved 2010-02-07. <a href="http://www.sheldonbrown.com/gloss_ta-o.html#toptube" target="_blank">http://www.sheldonbrown.com/gloss_ta-o.html#toptube</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Van Der Plas, Rob, Bicycle Technology, San Francisco: Bicycle Books (3rd ed.), ISBN 0-933201-30-3, ISBN 978-0-933201-30-9 (1995), pp. 60-2 <a href="/wiki/ISBN_(identifier)" target="_blank">/wiki/ISBN_(identifier)</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Peterson, Leisha A. and Londry, Kelly J., Finite-Element Structural Analysis: A New Tool for Bicycle Frame Design: The Strain Energy Design Method, Bike Tech, Bicycling Magazine, Vol. 5 No. 2 (1986) <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Wingerter, R., and Lebossiere, P., ME 354, Mechanics of Materials Laboratory: Structures, University of Washington (February 2004), p.1 <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Van Der Plas, Rob, Bicycle Technology, San Francisco: Bicycle Books (3rd ed.), ISBN 0-933201-30-3, ISBN 978-0-933201-30-9 (1995), pp. 60-2 <a href="/wiki/ISBN_(identifier)" target="_blank">/wiki/ISBN_(identifier)</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Peterson, Leisha A. and Londry, Kelly J., Finite-Element Structural Analysis: A New Tool for Bicycle Frame Design: The Strain Energy Design Method, Bike Tech, Bicycling Magazine, Vol. 5 No. 2 (1986) <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Brown, Sheldon (April 19, 2010). John Allen (ed.). "Mixte". Sheldon Brown's Bicycle Glossary. Harris Cyclery. Retrieved April 4, 2011. <a href="/wiki/Sheldon_Brown_(bicycle_mechanic)" target="_blank">/wiki/Sheldon_Brown_(bicycle_mechanic)</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Brown, Sheldon (April 19, 2010). John Allen (ed.). "Mixte". Sheldon Brown's Bicycle Glossary. Harris Cyclery. Retrieved April 4, 2011. <a href="/wiki/Sheldon_Brown_(bicycle_mechanic)" target="_blank">/wiki/Sheldon_Brown_(bicycle_mechanic)</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>"Hirose's Photo Gallery 9 - 216 Sport車 （製作過程）". <a href="https://sites.google.com/site/hirosemuseum9/216" target="_blank">https://sites.google.com/site/hirosemuseum9/216</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Brown, Sheldon. "Cross Frame". Sheldon Brown's Bicycle Glossary. Harris Cyclery. Retrieved 2011-05-04. <a href="/wiki/Sheldon_Brown_(bicycle_mechanic)" target="_blank">/wiki/Sheldon_Brown_(bicycle_mechanic)</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Cross Frames at rijwiel.net http://www.rijwiel.net/kruisfre.htm <a href="http://www.rijwiel.net/kruisfre.htm" target="_blank">http://www.rijwiel.net/kruisfre.htm</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> </ol>