\n | 110 rpm<\/td>\n | 25.5<\/td>\n <\/tr>\n <\/tbody>\n <\/table>\n <\/div>\n\n The circumference is worked out from the ISO size printed on the tire wall: \u03c0 \u00d7 (rim diameter + twice the tire width). That runs about one percent above the tables built into bike computers, because a loaded tire is not a circle. For an exact figure, mark the valve, roll the bike forward one full turn with your weight on it, and measure the distance.<\/p>\n<\/div>\n K\u0101 notiek apr\u0113\u0137ins<\/h2>\nVelosip\u0113dam nav p\u0101rnesumk\u0101rbas automa\u0161\u012bnas izpratn\u0113. Tas, ko j\u016bs main\u0101t, p\u0101rsl\u0113dzot p\u0101rnesumu, ir attiec\u012bba starp diviem zobratiem, un viss p\u0101r\u0113jais no t\u0101s izriet aritm\u0113tiski. Nav neviena sl\u0113pta koeficienta un nekas nepaz\u016bd: viss ietilpst vien\u0101 rind\u0101.<\/p>\n J\u016bsu p\u0101rnesums ir vienk\u0101r\u0161i priek\u0161\u0113jais zobrats, dal\u012bts ar aizmugur\u0113jo. Piecdesmit zobu priek\u0161\u0113jais zobrats pret septi\u0146padsmit zobu aizmugur\u0113jo dod 2,94, kas noz\u012bm\u0113, ka aizmugur\u0113jais ritenis apgrie\u017eas 2,94 reizes uz katru klo\u0137a apgriezienu. Sareiziniet to ar ce\u013cu, ko ritenis veic vien\u0101 apgriezien\u0101, un ar klo\u0137a apgriezieniem min\u016bt\u0113, un jums ir \u0101trums.<\/p>\n \u0101trums = kadence \u00d7 (priek\u0161\u0113jais zobrats \u00f7 aizmugur\u0113jais) \u00d7 rites apk\u0101rtm\u0113rs<\/strong><\/p>\nVien\u012bgais lielums, kas uz velosip\u0113da nav uzrakst\u012bts, ir p\u0113d\u0113jais, un to kalkulators j\u016bsu viet\u0101 atvasina no riepas izm\u0113ra.<\/p>\n P\u0101rnesuma collas un ce\u013c\u0161 uz vienu klo\u0137a apgriezienu<\/h2>\nKaila attiec\u012bba 2,94 pati par sevi neko nepasaka, jo ne\u0146em v\u0113r\u0101 riteni. T\u0101 pati attiec\u012bba kalnu velosip\u0113dam ar 26 collu loka un \u0161osejas velosip\u0113dam ar 700C dod divus j\u016btami at\u0161\u0137ir\u012bgus p\u0101rnesumus. T\u0101p\u0113c rite\u0146brauc\u0113ji sal\u012bdzina p\u0101rnesumus vien\u012bb\u0101s, kur\u0101s ritenis jau ir iek\u013cauts.<\/p>\n P\u0101rnesuma collas ir vec\u0101k\u0101 no ab\u0101m: diametrs, k\u0101ds b\u016btu vajadz\u012bgs tie\u0161i piedzenamam augstajam velosip\u0113dam, lai uz vienu ped\u0101\u013ca spiedienu aizrit\u0113tu tikpat t\u0101lu. No pirm\u0101 acu uzmetiena muzeja ekspon\u0101ts un tom\u0113r joproj\u0101m tas skaitlis, ko visi min, jo tas padara divus velosip\u0113dus ar da\u017e\u0101diem rite\u0146iem tie\u0161i sal\u012bdzin\u0101mus. Ce\u013c\u0161 uz klo\u0137a apgriezienu saka to pa\u0161u metros un ir viegl\u0101k izt\u0113lojams: 78 collu p\u0101rnesums p\u0101rvieto j\u016bs par aptuveni 6,2 metriem katr\u0101 piln\u0101 klo\u0137a apgriezien\u0101.<\/p>\n K\u0101 prec\u012bzi izm\u0113r\u012bt rites apk\u0101rtm\u0113ru<\/h2>\nKalkulators atvasina apk\u0101rtm\u0113ru no riepas s\u0101n\u0101 iespiest\u0101 ISO izm\u0113ra: \u03c0 \u00d7 (loka diametrs + divas riepas platuma reizes). Riepa 700 \u00d7 25C ir ISO 25-622, t\u0101tad \u03c0 \u00d7 (622 + 50) dod 2111 mm. Tas ir caurskat\u0101mi un p\u0101rbaud\u0101mi, ko nevar teikt par vairum\u0101 velodatoru ieb\u016bv\u0113taj\u0101m tabul\u0101m: t\u0101s savstarp\u0113ji at\u0161\u0137iras un nenor\u0101da nevienu avotu.<\/p>\n Tas ar\u012b ir aptuveni par procentu par augstu, jo riepa ar brauc\u0113ju virs\u016b nav aplis. Ja v\u0113laties \u012bsto skaitli, veiciet rites m\u0113r\u012bjumu: atz\u012bm\u0113jiet ventili apak\u0161\u0101, aps\u0113dieties uz velosip\u0113da, aizritiniet uz priek\u0161u, l\u012bdz ventilis atkal ir apak\u0161\u0101, un izm\u0113riet att\u0101lumu starp ab\u0101m atz\u012bm\u0113m. Atk\u0101rtojiet tr\u012bs reizes un apr\u0113\u0137iniet vid\u0113jo. \u0160is viens m\u0113r\u012bjums p\u0101rsp\u0113j jebkuru tabulu, un tas ir ar\u012b skaitlis, ko v\u0113rts ievad\u012bt velodator\u0101, lai t\u0101 att\u0101lumi b\u016btu pareizi.<\/p>\n Se\u0161i p\u0101rnesumi, izr\u0113\u0137in\u0101ti<\/h2>\nVisi se\u0161i ar riepu 700 \u00d7 25C, t\u0101tad ar 2111 mm apk\u0101rtm\u0113ru. \u0100trumi r\u0113\u0137in\u0101ti pie 90 rpm, kadences, ko vair\u0101kums notur l\u012bdzenum\u0101.<\/p>\n \n\n\n| P\u0101rnesums<\/th>\n | Kam dom\u0101ts<\/th>\n | P\u0101rnesuma collas<\/th>\n | Ce\u013c\u0161 uz klo\u0137a apgriezienu<\/th>\n | km\/h pie 90 rpm<\/th>\n<\/tr>\n<\/thead>\n | \n\n| 34 \/ 28<\/td>\n | St\u0101vs k\u0101pums<\/td>\n | 32,1<\/td>\n | 2,6 m<\/td>\n | 13,8<\/td>\n<\/tr>\n | \n| 34 \/ 21<\/td>\n | Vi\u013c\u0146ains reljefs<\/td>\n | 42,8<\/td>\n | 3,4 m<\/td>\n | 18,5<\/td>\n<\/tr>\n | \n| 50 \/ 17<\/td>\n | Brauk\u0161ana pa l\u012bdzenumu<\/td>\n | 77,8<\/td>\n | 6,2 m<\/td>\n | 33,5<\/td>\n<\/tr>\n | \n| 50 \/ 14<\/td>\n | \u0100trs grupas brauciens<\/td>\n | 94,5<\/td>\n | 7,5 m<\/td>\n | 40,7<\/td>\n<\/tr>\n | \n| 50 \/ 11<\/td>\n | Sprints<\/td>\n | 120,2<\/td>\n | 9,6 m<\/td>\n | 51,8<\/td>\n<\/tr>\n | \n| 42 \/ 16<\/td>\n | Tipisks viena p\u0101rnesuma<\/td>\n | 69,4<\/td>\n | 5,5 m<\/td>\n | 29,9<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\nK\u0101da kadence k\u0101dam p\u0101rnesumam<\/h2>\nKalkulators labpr\u0101t pateiks, ka 50 \u00d7 11 pie 110 rpm ir 63 km\/h. Tas nepateiks, ka to gandr\u012bz neviens nenotur, un tie\u0161i te p\u0101rnesumu kalkulators beidz b\u016bt pietiekams. To, k\u0101du p\u0101rnesumu sp\u0113jat griezt, ierobe\u017eo j\u016bsu jauda, bet kadence iz\u0161\u0137ir, vai \u0161\u012b jauda n\u0101k no musku\u013cu sp\u0113ka vai no sirds un plau\u0161\u0101m.<\/p>\n \u012asi: vair\u0101kumam noder\u012bgais diapazons ir no 70 l\u012bdz 100 rpm, un pareizais p\u0101rnesums ir tas, kas notur j\u016bs taj\u0101 uz reljefa, pa kuru braucat. Ja k\u0101pum\u0101 non\u0101kat zem 70 rpm, atbilde ir viegl\u0101ks p\u0101rnesums, nevis liel\u0101ka piep\u016ble. Kadences ce\u013cvedis<\/a> apskata \u0161os diapazonus, to, ko p\u0113t\u012bjumi patie\u0161\u0101m izm\u0113r\u012bja, un tr\u012bs treni\u0146us to papla\u0161in\u0101\u0161anai.<\/p>\nBie\u017e\u0101k uzdotie jaut\u0101jumi<\/h2>\nK\u0101ds p\u0101rnesums ir labs \u0161osejas velosip\u0113dam?<\/strong> Visp\u0101r\u0113jai brauk\u0161anai 50\/34 klo\u0137i ar 11-32 kaseti nosedz gandr\u012bz visu: apak\u0161\u0101 ap 28 coll\u0101m st\u0101viem k\u0101pumiem un aug\u0161\u0101 ap 120 nobraucieniem.<\/p>\nKas ir p\u0101rnesuma collas?<\/strong> Rite\u0146a diametrs, k\u0101ds b\u016btu vajadz\u012bgs tie\u0161i piedzenamam velosip\u0113dam, lai uz vienu ped\u0101\u013ca spiedienu veiktu t\u0101du pa\u0161u att\u0101lumu. Veids, k\u0101 sal\u012bdzin\u0101t p\u0101rnesumus starp velosip\u0113diem ar da\u017e\u0101da izm\u0113ra rite\u0146iem.<\/p>\nK\u0101 apr\u0113\u0137in\u0101t \u0101trumu no kadences un p\u0101rnesuma?<\/strong> Sareiziniet kadenci ar p\u0101rnesuma attiec\u012bbu un rites apk\u0101rtm\u0113ru. Pie 90 rpm ar 50\/17 un 2111 mm riteni izn\u0101k 33,5 km\/h.<\/p>\nVai riepas platums maina manu p\u0101rnesumu?<\/strong> Nedaudz. P\u0101reja no 25 mm uz 32 mm pievieno aptuveni 44 mm apk\u0101rtm\u0113ra, kas pie t\u0101s pa\u0161as kadences un t\u0101 pa\u0161a p\u0101rnesuma ir apm\u0113ram divi procenti liel\u0101ks \u0101trums.<\/p>\nK\u0101du apk\u0101rtm\u0113ru ievad\u012bt velodator\u0101?<\/strong> To, ko izm\u0113r\u0101t, ritinot velosip\u0113du ar savu svaru virs\u016b. Tabulas v\u0113rt\u012bbas parasti ir par procentu optimistiskas, kas 40 km braucien\u0101 ir aptuveni 400 metru.<\/p>\nVai liel\u0101ks p\u0101rnesums vienm\u0113r ir \u0101tr\u0101ks?<\/strong> Tikai tad, ja to v\u0113l sp\u0113jat griezt sapr\u0101t\u012bg\u0101 kadenc\u0113. P\u0101rnesums, ko ma\u013cat pie 55 rpm, ilgtermi\u0146\u0101 dod maz\u0101k jaudas nek\u0101 viegl\u0101ks, ko grie\u017eat pie 90.<\/p>\nUz k\u0101du kadenci tiekties?<\/strong> Vair\u0101kumam vislab\u0101k der no 70 l\u012bdz 100 rpm, turkl\u0101t ap 90 rpm ir visbie\u017e\u0101k min\u0113t\u0101 atskaites v\u0113rt\u012bba.<\/p>\n | |