{"id":1841,"date":"2011-01-09T18:25:22","date_gmt":"2011-01-09T17:25:22","guid":{"rendered":"https:\/\/medianbox.fr\/wordpress\/?p=1841"},"modified":"2014-08-13T22:50:47","modified_gmt":"2014-08-13T20:50:47","slug":"cyclisme-la-resistance-au-roulement-du-velo","status":"publish","type":"post","link":"https:\/\/medianbox.fr\/wordpress\/?p=1841","title":{"rendered":"MeDiaN@Sports &#8211; \u00ab La R\u00e9sistance au Roulement \u00e0 v\u00e9lo \u00bb"},"content":{"rendered":"<h3>Pr\u00e9sentation g\u00e9n\u00e9rale<\/h3>\n<p>Dans ce pr\u00e9c\u00e9dent <a title=\"Cyclisme : &quot;L'a\u00e9rodynamisme \u00e0 v\u00e9lo&quot;\" href=\"https:\/\/medianbox.fr\/wordpress\/?p=1561\" target=\"_blank\">article<\/a>, nous avons vu que l&rsquo;\u00e9quation g\u00e9rant le mouvement d&rsquo;un cycliste peut s&rsquo;\u00e9crire sous la forme suivante :<\/p>\n<p style=\"text-align: center;\"><img src='https:\/\/s0.wp.com\/latex.php?latex=C_%7Bm%7D+%3D+K%5Cddot%7B%5Ctheta_%7Bp%7D+%7D+%2B+%5Cleft+%28+%5Clambda_%7B1%7D%2B2.+%5Clambda_%7B2%7Dt+%5Cright+%29+%5Cdot%7B%5Ctheta_%7Bp%7D%7D+%2B+%5Cleft+%28M_%7Btot%7D+%5Cright+%29+.g.a.t.sin%28%5Calpha%29+%2B+k_%7Bcorr%7D.C_%7Baero_%7Bp%7D%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='C_{m} = K\\ddot{\\theta_{p} } + \\left ( \\lambda_{1}+2. \\lambda_{2}t \\right ) \\dot{\\theta_{p}} + \\left (M_{tot} \\right ) .g.a.t.sin(\\alpha) + k_{corr}.C_{aero_{p}}' title='C_{m} = K\\ddot{\\theta_{p} } + \\left ( \\lambda_{1}+2. \\lambda_{2}t \\right ) \\dot{\\theta_{p}} + \\left (M_{tot} \\right ) .g.a.t.sin(\\alpha) + k_{corr}.C_{aero_{p}}' class='latex' \/><br \/>\nAvec <img src='https:\/\/s0.wp.com\/latex.php?latex=K%3Da%5E%7B2%7D.t%5E%7B2%7D+%5Cleft+%28+M%2B2.+%5Cleft+%28M_%7B1%7D%2BM_%7B2%7D+%5Cright%29+%2B+m_%7BP%7D+%2B+2.+m_%7Bp%7D%2BM_%7BCycliste%7D+%5Cright%29%2B0%2C13%5E%7B2%7D+%5Cleft+%28m_%7BP%7D+%2B+2.+m_%7Bp%7D+%5Cright%29+&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='K=a^{2}.t^{2} \\left ( M+2. \\left (M_{1}+M_{2} \\right) + m_{P} + 2. m_{p}+M_{Cycliste} \\right)+0,13^{2} \\left (m_{P} + 2. m_{p} \\right) ' title='K=a^{2}.t^{2} \\left ( M+2. \\left (M_{1}+M_{2} \\right) + m_{P} + 2. m_{p}+M_{Cycliste} \\right)+0,13^{2} \\left (m_{P} + 2. m_{p} \\right) ' class='latex' \/><br \/>\n<img src='https:\/\/s0.wp.com\/latex.php?latex=M_%7Btot%7D+%3D+%5Cleft+%28M%2BM_%7B1%7D%2BM_%7B2%7D%2Bm_%7BP%7D%2B2m_%7Bp%7D%2BM_%7BCycliste%7D+%5Cright+%29+&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='M_{tot} = \\left (M+M_{1}+M_{2}+m_{P}+2m_{p}+M_{Cycliste} \\right ) ' title='M_{tot} = \\left (M+M_{1}+M_{2}+m_{P}+2m_{p}+M_{Cycliste} \\right ) ' class='latex' \/><br \/>\n<img src='https:\/\/s0.wp.com\/latex.php?latex=%5Calpha+%3D+Arctan+%28%5Cfrac%7BDenivele%7D%7B100%7D%29&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='\\alpha = Arctan (\\frac{Denivele}{100})' title='\\alpha = Arctan (\\frac{Denivele}{100})' class='latex' \/> ou <img src='https:\/\/s0.wp.com\/latex.php?latex=sin%28%5Calpha%29+%3D+%5Cfrac%7BDenivele_%7Btot%7D%7D%7BDistance_%7Btot%7D%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='sin(\\alpha) = \\frac{Denivele_{tot}}{Distance_{tot}}' title='sin(\\alpha) = \\frac{Denivele_{tot}}{Distance_{tot}}' class='latex' \/><br \/>\n<img src='https:\/\/s0.wp.com\/latex.php?latex=t%3D%5Cfrac%7BNdents_%7Bplateau%7D+%7D%7BNdents_%7Bpignon%7D%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='t=\\frac{Ndents_{plateau} }{Ndents_{pignon}}' title='t=\\frac{Ndents_{plateau} }{Ndents_{pignon}}' class='latex' \/><br \/>\n<img src='https:\/\/s0.wp.com\/latex.php?latex=k_%7Bcorr%7D+%3D+1-%5Cfrac%7Bt_%7Babrite%7D%7D%7B100%7D%2A0.3&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='k_{corr} = 1-\\frac{t_{abrite}}{100}*0.3' title='k_{corr} = 1-\\frac{t_{abrite}}{100}*0.3' class='latex' \/><br \/>\n<img src='https:\/\/s0.wp.com\/latex.php?latex=C_%7Baero_%7Bp%7D%7D%3Dt.C_%7Baero_%7Broues%7D%7D%3Da.t.R_%7Baero%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='C_{aero_{p}}=t.C_{aero_{roues}}=a.t.R_{aero}' title='C_{aero_{p}}=t.C_{aero_{roues}}=a.t.R_{aero}' class='latex' \/><br \/>\n<img src='https:\/\/s0.wp.com\/latex.php?latex=R_%7Baero%7D%3DR_%7BC_%7Bx%7D%7D%2BR_%7Bfriction_%7Bair%7D%7D%3D%28%5Cfrac%7B1%7D%7B2%7D%5Crho.S.C_%7Bx%7D%2BC_%7Bf%7D%29.%28V_%7BVent%7D.cos%28i%29%2Ba.t.%5Cdot%7B%5Ctheta_%7Bp%7D%7D%29%5E%7B2%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='R_{aero}=R_{C_{x}}+R_{friction_{air}}=(\\frac{1}{2}\\rho.S.C_{x}+C_{f}).(V_{Vent}.cos(i)+a.t.\\dot{\\theta_{p}})^{2}' title='R_{aero}=R_{C_{x}}+R_{friction_{air}}=(\\frac{1}{2}\\rho.S.C_{x}+C_{f}).(V_{Vent}.cos(i)+a.t.\\dot{\\theta_{p}})^{2}' class='latex' \/><\/p>\n<p style=\"text-align: left;\">Cette \u00e9quation nous donne la valeur du couple que le cycliste doit fournir\u00a0 pour rouler \u00e0 une vitesse donn\u00e9, et ce en prenant en compte les diff\u00e9rentes masses en mouvement, les pertes dans les liaisons, le profil de la route ainsi que l&rsquo;a\u00e9rodynamisme globale du syst\u00e8me. Pour tous ceux qui ont d\u00e9j\u00e0 roul\u00e9 \u00e0 v\u00e9lo, il existe un dernier aspect\u00a0 non moins fondamental \u00e0 consid\u00e9rer : la r\u00e9sistance au roulement.<\/p>\n<h2>R\u00e9sistance au roulement<\/h2>\n<p>De nombreuses relations ont successivement \u00e9t\u00e9 formul\u00e9es pour d\u00e9crire au mieux la r\u00e9sistance au roulement. Bien que les plus compl\u00e8tes fassent intervenir la vitesse dans le calcul, nous nous contenterons dans notre cas de la forme sa plus simple.<\/p>\n<p><a href=\"https:\/\/medianbox.fr\/wordpress\/?attachment_id=1925\" rel=\"attachment wp-att-1925\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-1925\" title=\"Rrr1\" src=\"https:\/\/medianbox.fr\/wordpress\/wp-content\/uploads\/2011\/01\/Rrr1.jpg\" alt=\"\" width=\"245\" height=\"193\" \/><\/a><\/p>\n<p>L&rsquo;adh\u00e9rence n\u00e9cessaire au roulement d&rsquo;un pneumatique sur le sol g\u00e9n\u00e8re une force oppos\u00e9e au mouvement qui est proportionnelle au\u00a0 poids du syst\u00e8me (v\u00e9lo + cycliste) selon un coefficient Crr. Ce coefficient d\u00e9pend :<\/p>\n<h4 style=\"padding-left: 60px;\">Des pneumatiques utilis\u00e9s<\/h4>\n<p style=\"padding-left: 90px;\">Tous les pneumatiques ne sont pas comparables du point de vue de leur r\u00e9sistance au roulement. Le tableau ci-dessous donne la valeur du Crr \u00e0 7bars pour diff\u00e9rents mod\u00e8les de pneus, dont celui des \u00ab\u00a0Michelin Carbon\u00a0\u00bb.<\/p>\n<p style=\"padding-left: 60px;\"><a href=\"https:\/\/medianbox.fr\/wordpress\/?attachment_id=1856\" rel=\"attachment wp-att-1856\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-1856\" title=\"Crr1\" src=\"https:\/\/medianbox.fr\/wordpress\/wp-content\/uploads\/2011\/01\/Crr1.jpg\" alt=\"\" width=\"498\" height=\"540\" srcset=\"https:\/\/medianbox.fr\/wordpress\/wp-content\/uploads\/2011\/01\/Crr1.jpg 498w, https:\/\/medianbox.fr\/wordpress\/wp-content\/uploads\/2011\/01\/Crr1-276x300.jpg 276w\" sizes=\"auto, (max-width: 498px) 100vw, 498px\" \/><\/a><\/p>\n<h4 style=\"padding-left: 60px;\">De la pression de gonflage<\/h4>\n<p style=\"padding-left: 90px;\">La r\u00e9sistance au roulement \u00e9volue \u00e9galement en fonction de la pression de gonflage. On retrouve souvent cette \u00e9volution caract\u00e9ris\u00e9e par la fonction suivante : <img src='https:\/\/s0.wp.com\/latex.php?latex=Crr+%3D+Coef_%7Bpneu%7D%2Ap%5E%7B-0.426%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='Crr = Coef_{pneu}*p^{-0.426}' title='Crr = Coef_{pneu}*p^{-0.426}' class='latex' \/> ou <img src='https:\/\/s0.wp.com\/latex.php?latex=Coef_%7Bpneu%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='Coef_{pneu}' title='Coef_{pneu}' class='latex' \/> d\u00e9pend du pneu et p est la pression de gonflage.<\/p>\n<p style=\"padding-left: 90px;\">Si l&rsquo;on consid\u00e8re un pneu Michelin Krylion Carbon 700&#215;23 par exemple, on a Crr \u00e0 7bars = 0.005. On en d\u00e9duit que\u00a0 <img src='https:\/\/s0.wp.com\/latex.php?latex=Coef_%7BKrylion%7D+%3D+%5Cfrac%7BCrr%7D%7Bp%5E%7B-0.426%7D%7D%3D%5Cfrac%7B0.005%7D%7B7%5E%7B-0.426%7D%7D%3D0%2C011454649&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='Coef_{Krylion} = \\frac{Crr}{p^{-0.426}}=\\frac{0.005}{7^{-0.426}}=0,011454649' title='Coef_{Krylion} = \\frac{Crr}{p^{-0.426}}=\\frac{0.005}{7^{-0.426}}=0,011454649' class='latex' \/><\/p>\n<p style=\"padding-left: 90px;\">Pour ces pneus, on peut donc donc \u00e9crire Crr comme ceci : <img src='https:\/\/s0.wp.com\/latex.php?latex=Crr_%7BKrylion%7D+%3D+0.011454649%2Ap%5E%7B-0.426%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='Crr_{Krylion} = 0.011454649*p^{-0.426}' title='Crr_{Krylion} = 0.011454649*p^{-0.426}' class='latex' \/><\/p>\n<h4 style=\"padding-left: 60px;\">De l&rsquo;\u00e9tat de la chauss\u00e9e<\/h4>\n<p style=\"padding-left: 90px;\">L&rsquo;\u00e9tat de la chauss\u00e9e joue \u00e9galement un grand r\u00f4le sur la mesure du coefficient de roulement. Les valeurs trouv\u00e9es dans la litt\u00e9rature vont ainsi de 0,004 pour la piste \u00e0 0,010 pour une route en asphalte en mauvais \u00e9tat. Pour un route en asphalte tr\u00e8s lisse &#8211; que l&rsquo;on peut consid\u00e9rer comme le cas retenu par les fabricants lorsqu&rsquo;ils nous donnent les caract\u00e9ristiques de leur pneus &#8211; la valeur du Crr est de 0,006.<\/p>\n<p style=\"padding-left: 90px;\">On peut donc consid\u00e9rer que le Crr varie entre 1*Crr (bonne route) et 1.65*Crr (route d\u00e9grad\u00e9e) suivant l&rsquo;\u00e9tat du rev\u00eatement.<\/p>\n<p style=\"padding-left: 90px; text-align: center;\"><img src='https:\/\/s0.wp.com\/latex.php?latex=Crr+%3D+Coeff_%7Broute%7D%2ACoef_%7Bpneu%7D%2Ap%5E%7B-0.426%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='Crr = Coeff_{route}*Coef_{pneu}*p^{-0.426}' title='Crr = Coeff_{route}*Coef_{pneu}*p^{-0.426}' class='latex' \/> avec <img src='https:\/\/s0.wp.com\/latex.php?latex=1%3CCoeff_%7Broute%7D%3C1.65&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='1&lt;Coeff_{route}&lt;1.65' title='1&lt;Coeff_{route}&lt;1.65' class='latex' \/><\/p>\n<p style=\"padding-left: 90px;\">En consid\u00e9rant que l&rsquo;on roule les 2\/3 du temps sur des routes correctes, la formule retenue pour les Krylion Carbon sera finalement la suivante :<\/p>\n<p style=\"padding-left: 60px; text-align: center;\"><img src='https:\/\/s0.wp.com\/latex.php?latex=Crr_%7BKrylion%7D+%3D+1.20%2A0.011454649%2Ap%5E%7B-0.426%7D%3D0%2C013745579%2Ap%5E%7B-0.426%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='Crr_{Krylion} = 1.20*0.011454649*p^{-0.426}=0,013745579*p^{-0.426}' title='Crr_{Krylion} = 1.20*0.011454649*p^{-0.426}=0,013745579*p^{-0.426}' class='latex' \/><\/p>\n<h3 style=\"padding-left: 30px; text-align: left;\">Bilan<\/h3>\n<p style=\"padding-left: 60px;\">La r\u00e9sistance au roulement est finalement donn\u00e9e par la relation<\/p>\n<p style=\"padding-left: 60px; text-align: center;\"><img src='https:\/\/s0.wp.com\/latex.php?latex=Rr%3DCrr.M_%7Btot%7D.g.cos%28%5Calpha%29&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='Rr=Crr.M_{tot}.g.cos(\\alpha)' title='Rr=Crr.M_{tot}.g.cos(\\alpha)' class='latex' \/> avec <img src='https:\/\/s0.wp.com\/latex.php?latex=%5Calpha%3DArctan%28%5Cfrac%7BDenivele%7D%7B100%7D%29&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='\\alpha=Arctan(\\frac{Denivele}{100})' title='\\alpha=Arctan(\\frac{Denivele}{100})' class='latex' \/><\/p>\n<h2>Conclusion<\/h2>\n<p>L&rsquo;\u00e9quation du mouvement qui tient compte de la r\u00e9sistance au roulement est donc :<\/p>\n<p style=\"text-align: center;\"><img src='https:\/\/s0.wp.com\/latex.php?latex=C_%7Bm%7D+%3D+K%5Cddot%7B%5Ctheta_%7Bp%7D+%7D+%2B+%5Cleft+%28+%5Clambda_%7B1%7D%2B2.+%5Clambda_%7B2%7Dt+%5Cright+%29+%5Cdot%7B%5Ctheta_%7Bp%7D%7D+%2B+%5Cleft+%28M_%7Btot%7D+%5Cright+%29+.g.a.t.sin%28%5Calpha%29+%2B+k_%7Bcorr%7D.C_%7Baero_%7Bp%7D%7D+%2B+C_%7Br_%7Bp%7D%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='C_{m} = K\\ddot{\\theta_{p} } + \\left ( \\lambda_{1}+2. \\lambda_{2}t \\right ) \\dot{\\theta_{p}} + \\left (M_{tot} \\right ) .g.a.t.sin(\\alpha) + k_{corr}.C_{aero_{p}} + C_{r_{p}}' title='C_{m} = K\\ddot{\\theta_{p} } + \\left ( \\lambda_{1}+2. \\lambda_{2}t \\right ) \\dot{\\theta_{p}} + \\left (M_{tot} \\right ) .g.a.t.sin(\\alpha) + k_{corr}.C_{aero_{p}} + C_{r_{p}}' class='latex' \/><\/p>\n<p style=\"text-align: left;\">Avec <img src='https:\/\/s0.wp.com\/latex.php?latex=K%3Da%5E%7B2%7D.t%5E%7B2%7D+%5Cleft+%28+M%2B2.+%5Cleft+%28M_%7B1%7D%2BM_%7B2%7D+%5Cright%29+%2B+m_%7BP%7D+%2B+2.+m_%7Bp%7D%2BM_%7BCycliste%7D+%5Cright%29%2B0%2C13%5E%7B2%7D+%5Cleft+%28m_%7BP%7D+%2B+2.+m_%7Bp%7D+%5Cright%29+&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='K=a^{2}.t^{2} \\left ( M+2. \\left (M_{1}+M_{2} \\right) + m_{P} + 2. m_{p}+M_{Cycliste} \\right)+0,13^{2} \\left (m_{P} + 2. m_{p} \\right) ' title='K=a^{2}.t^{2} \\left ( M+2. \\left (M_{1}+M_{2} \\right) + m_{P} + 2. m_{p}+M_{Cycliste} \\right)+0,13^{2} \\left (m_{P} + 2. m_{p} \\right) ' class='latex' \/><br \/>\n<img src='https:\/\/s0.wp.com\/latex.php?latex=M_%7Btot%7D+%3D+%5Cleft+%28M%2BM_%7B1%7D%2BM_%7B2%7D%2Bm_%7BP%7D%2B2m_%7Bp%7D%2BM_%7BCycliste%7D+%5Cright+%29+&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='M_{tot} = \\left (M+M_{1}+M_{2}+m_{P}+2m_{p}+M_{Cycliste} \\right ) ' title='M_{tot} = \\left (M+M_{1}+M_{2}+m_{P}+2m_{p}+M_{Cycliste} \\right ) ' class='latex' \/><\/p>\n<p><img src='https:\/\/s0.wp.com\/latex.php?latex=%5Calpha+%3D+Arctan+%28%5Cfrac%7BDenivele%7D%7B100%7D%29&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='\\alpha = Arctan (\\frac{Denivele}{100})' title='\\alpha = Arctan (\\frac{Denivele}{100})' class='latex' \/> ou <img src='https:\/\/s0.wp.com\/latex.php?latex=sin%28%5Calpha%29+%3D+%5Cfrac%7BDenivele_%7Btot%7D%7D%7BDistance_%7Btot%7D%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='sin(\\alpha) = \\frac{Denivele_{tot}}{Distance_{tot}}' title='sin(\\alpha) = \\frac{Denivele_{tot}}{Distance_{tot}}' class='latex' \/><br \/>\n<img src='https:\/\/s0.wp.com\/latex.php?latex=t%3D%5Cfrac%7BNdents_%7Bplateau%7D+%7D%7BNdents_%7Bpignon%7D%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='t=\\frac{Ndents_{plateau} }{Ndents_{pignon}}' title='t=\\frac{Ndents_{plateau} }{Ndents_{pignon}}' class='latex' \/><\/p>\n<p><img src='https:\/\/s0.wp.com\/latex.php?latex=k_%7Bcorr%7D+%3D+1-%5Cfrac%7Bt_%7Babrite%7D%7D%7B100%7D%2A0.3&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='k_{corr} = 1-\\frac{t_{abrite}}{100}*0.3' title='k_{corr} = 1-\\frac{t_{abrite}}{100}*0.3' class='latex' \/><br \/>\n<img src='https:\/\/s0.wp.com\/latex.php?latex=C_%7Baero_%7Bp%7D%7D%3Dt.C_%7Baero_%7Broues%7D%7D%3Da.t.R_%7Baero%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='C_{aero_{p}}=t.C_{aero_{roues}}=a.t.R_{aero}' title='C_{aero_{p}}=t.C_{aero_{roues}}=a.t.R_{aero}' class='latex' \/><br \/>\n<img src='https:\/\/s0.wp.com\/latex.php?latex=R_%7Baero%7D%3DR_%7BC_%7Bx%7D%7D%2BR_%7Bfriction_%7Bair%7D%7D%3D%28%5Cfrac%7B1%7D%7B2%7D%5Crho.S.C_%7Bx%7D%2BC_%7Bf%7D%29.%28V_%7BVent%7D.cos%28i%29%2Ba.t.%5Cdot%7B%5Ctheta_%7Bp%7D%7D%29%5E%7B2%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='R_{aero}=R_{C_{x}}+R_{friction_{air}}=(\\frac{1}{2}\\rho.S.C_{x}+C_{f}).(V_{Vent}.cos(i)+a.t.\\dot{\\theta_{p}})^{2}' title='R_{aero}=R_{C_{x}}+R_{friction_{air}}=(\\frac{1}{2}\\rho.S.C_{x}+C_{f}).(V_{Vent}.cos(i)+a.t.\\dot{\\theta_{p}})^{2}' class='latex' \/><\/p>\n<p><img src='https:\/\/s0.wp.com\/latex.php?latex=C_%7Br_%7Bp%7D%7D%3Dt.C_%7Br_%7Broues%7D%7D%3Da.t.R_%7Br%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='C_{r_{p}}=t.C_{r_{roues}}=a.t.R_{r}' title='C_{r_{p}}=t.C_{r_{roues}}=a.t.R_{r}' class='latex' \/><br \/>\n<img src='https:\/\/s0.wp.com\/latex.php?latex=R_%7Br%7D%3DCrr.M_%7Btot%7D.g.cos%28%5Calpha%29&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='R_{r}=Crr.M_{tot}.g.cos(\\alpha)' title='R_{r}=Crr.M_{tot}.g.cos(\\alpha)' class='latex' \/> Avec <img src='https:\/\/s0.wp.com\/latex.php?latex=Crr+%3D+Coeff_%7Broute%7D%2ACoef_%7Bpneu%7D%2Ap%5E%7B-0.426%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='Crr = Coeff_{route}*Coef_{pneu}*p^{-0.426}' title='Crr = Coeff_{route}*Coef_{pneu}*p^{-0.426}' class='latex' \/><br \/>\navec <img src='https:\/\/s0.wp.com\/latex.php?latex=cos%28%5Calpha%29%5E%7B2%7D%2Bsin%28%5Calpha%29%5E%7B2%7D%3D1&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='cos(\\alpha)^{2}+sin(\\alpha)^{2}=1' title='cos(\\alpha)^{2}+sin(\\alpha)^{2}=1' class='latex' \/> d&rsquo;o\u00f9 <img src='https:\/\/s0.wp.com\/latex.php?latex=cos%28%5Calpha%29%3D%5Csqrt%7B1-sin%28%5Calpha%29%5E%7B2%7D%7D&#038;bg=121315&#038;fg=ffffff&#038;s=0' alt='cos(\\alpha)=\\sqrt{1-sin(\\alpha)^{2}}' title='cos(\\alpha)=\\sqrt{1-sin(\\alpha)^{2}}' class='latex' \/><\/p>\n<p style=\"text-align: left;\">Ceci nous permet quelques remarques int\u00e9ressantes:<\/p>\n<p style=\"text-align: left;\">La r\u00e9sistance au roulement est bien \u00e9videmment directement li\u00e9e \u00e0 la qualit\u00e9 du pneumatique utilis\u00e9 et \u00e0 l&rsquo;\u00e9tat de la route sur laquelle le cycliste circule.<\/p>\n<p style=\"text-align: left;\">D&rsquo;apr\u00e8s l&rsquo;expression du coefficient de r\u00e9sistance au roulement, il est tr\u00e8s important de gonfl\u00e9 correctement ses pneus avant chaque sortie. Pour des Krylion Carbon par exemple, le passage de 5 (Crr=0.00692) \u00e0 7bars (Crr=0.006) se traduit par une r\u00e9sistance \u00e0 l&rsquo;avancement diminu\u00e9e d&rsquo;environ 13%.<\/p>\n<p style=\"text-align: left;\">La surface du pneu en contact avec le sol n&rsquo;intervient paradoxalement pas dans la relation.<\/p>\n<p style=\"text-align: left;\">Celle ci d\u00e9pend en fait de la masse cumul\u00e9e du cycliste et de son v\u00e9lo.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Equation du mouvement d&rsquo;un v\u00e9lo compl\u00e9t\u00e9 par l&rsquo;influence de la r\u00e9sistance au roulement.<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"ngg_post_thumbnail":0,"footnotes":""},"categories":[60],"tags":[],"class_list":["post-1841","post","type-post","status-publish","format-standard","hentry","category-mediansports"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.7 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>MeDiaN@Sports - \u00ab La R\u00e9sistance au Roulement \u00e0 v\u00e9lo \u00bb - MeDiaN@Tour<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/medianbox.fr\/wordpress\/?p=1841\" \/>\n<meta property=\"og:locale\" content=\"fr_FR\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"MeDiaN@Sports - \u00ab La R\u00e9sistance au Roulement \u00e0 v\u00e9lo \u00bb - MeDiaN@Tour\" \/>\n<meta property=\"og:description\" content=\"Equation du mouvement d&#039;un v\u00e9lo compl\u00e9t\u00e9 par l&#039;influence de la r\u00e9sistance au roulement.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/medianbox.fr\/wordpress\/?p=1841\" \/>\n<meta property=\"og:site_name\" content=\"MeDiaN@Tour\" \/>\n<meta property=\"article:published_time\" content=\"2011-01-09T17:25:22+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2014-08-13T20:50:47+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/medianbox.fr\/wordpress\/wp-content\/uploads\/2011\/01\/Rrr1.jpg\" \/>\n<meta name=\"author\" content=\"MeDiaN\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u00c9crit par\" \/>\n\t<meta name=\"twitter:data1\" content=\"MeDiaN\" \/>\n\t<meta name=\"twitter:label2\" content=\"Dur\u00e9e de lecture estim\u00e9e\" \/>\n\t<meta name=\"twitter:data2\" content=\"5 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/medianbox.fr\\\/wordpress\\\/?p=1841#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/medianbox.fr\\\/wordpress\\\/?p=1841\"},\"author\":{\"name\":\"MeDiaN\",\"@id\":\"https:\\\/\\\/medianbox.fr\\\/wordpress\\\/#\\\/schema\\\/person\\\/e1cba8e776ddbc5e91ef69e134732c6d\"},\"headline\":\"MeDiaN@Sports &#8211; 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