103:. The technology of the high wheeler imposed a natural limit—a 60-inch wheel was about the maximum size that could be straddled by ordinary sized legs. When "safeties" replaced "ordinaries", chains and sprockets allowed small wheels to be turned faster than the pedal cranks. As result, a 28-inch wheel could be made to move a bicycle at the same speed as a 60-inch wheel. Such a bicycle was then said to be geared at 60 gear inches and pedalled similar to an ordinary with a 60-inch wheel. Thus on a bicycle geared at 72 gear inches one revolution of the pedals advances the bicycle the distance that a 72-inch wheel would in one revolution.
17:
309:
195:" (ETRTO 630). Strictly speaking, the rolling diameter of a 700c wheel may be significantly higher or lower than 27", depending on the tire size, e.g. nearly 27.5" for a 700x38 tire, or just over 26" for a 700x20 tire. This can be the source of some confusion when comparing gears unless it is clear whether gear inches have been calculated using the actual wheel size or a conventionalised 27".
216:
167:
wheel is said to be "26 gear inches." If the front chainring has 48 teeth and the rear sprocket has 24 teeth, then each turn of the pedals produces two turns of the rear wheel. This is equivalent to doubling the size of the drive wheel; that is, it is like a directly driven bicycle with a 52-inch wheel. That gear is said to be "52 gear inches."
532:
477:
155:
1197:
For example, a common junior gearing until 2023 was 52 teeth on the largest ring at the crank, and 14 as the heaviest gear available in the rear wheel. Coupled with a 700c wheel (622 mm diameter) and a 23 mm tire size (which approximately adds 2×23 mm to the wheel diameter), this gives
166:
For example, suppose the drive wheel is actually 26 inches in diameter. If the front chainring and rear sprocket have equal numbers of teeth, one turn of the pedals produces exactly one turn of the drive wheel, just as if the pedals were directly driving the drive wheel. That combination of gears and
1220:
of the drivetrain, but neither of them take into account the length of the crankarm, which can vary from bike to bike. The crankarm is a lever arm. If two bicycles have different crank lengths but are otherwise identical, a longer lever arm gives a greater mechanical advantage. To take this into
206:
which is equal to 26.3 inches (rounded to 1 decimal place). 26 inch mountain bicycle wheels have a rim diameter of 559 mm. This ignores factors that contribute to the actual rolling radius of the tyre and rim together: the vertical deflection of the tire above the contact patch and the
85:
Typical gear ratios on bicycles range from very low or light gearing around 20 gear inches (1.6 metres per revolution), via medium gearing around 70 gear inches (5.6 m), to very high or heavy gearing around 125 gear inches (10 m). As in a car, low gearing is for going up hills and high
304:{\displaystyle {\text{speed in mph}}=({\text{gear inches}}\times {\text{π}}){\frac {\text{inches}}{\text{revolution}}}\times {\text{cadence}}{\frac {\text{revolutions}}{\text{minute}}}\times {\frac {\text{1 mile}}{\text{63,360 inches}}}\times {\frac {\text{60 minutes}}{\text{1 hour}}}}
415:
361:
488:
439:
117:
549:
The following theoretical table indicates the metres traveled per pedal revolution for a typical combination of a 622 mm (700C) rim with a 23 mm tire. In practice, the result will vary with the profile of the tire and other factors.
98:
was the "ordinary" bicycle form, the comparative diameter in inches of the driven wheel was an indication of relative speed and effort. A 60-inch wheel propelled a bicycle faster than a 50-inch wheel when both were cranked at the same
367:
1229:, which is calculated by the distance travelled by the bike divided by the distance of revolution of the pedal axle during one turn of the crank. He argued that it also has the advantage of being
315:
1307:
527:{\displaystyle {\text{rollout distance}}=\pi \cdot {\text{drive wheel diameter in metres}}\times {\frac {\text{number of teeth in front chainring}}{\text{number of teeth in rear sprocket}}}}
160:
This formula assumes that any hub gear is in direct drive. A further factor is needed for other gears (many online gear calculators have these factors built in for common hub gears).
472:{\displaystyle {\text{development}}={\text{drive wheel circumference in metres}}\times {\frac {\text{number of teeth in front chainring}}{\text{number of teeth in rear sprocket}}}}
150:{\displaystyle {\text{gear inches}}={\text{drive wheel diameter in inches}}\times {\frac {\text{number of teeth in front chainring}}{\text{number of teeth in rear sprocket}}}}
1198:
an approximate diameter of 0.645 metres (depending on various factors such as air pressure, tire and rim), resulting in an estimated rollout distance of: π ⋅ 0.668 m ⋅
181:
For bicycles with 700c wheels, some cyclists quote gear inches based on a nominal wheel diameter of 27 inches, corresponding to the old
British tire size of 27 x
1216:
Both "gear inches" and "metres of development" are concerned with the distance travelled per turn of the pedals, and are ultimately ways of indicating the
1314:
1283:
20:
Simplified diagram of gear inches: As the rear sprocket is halfed in size, the distance traveled by the rear wheel doubles, at half the torque.
1452:
A drivetrain analyzer and gear calculator for HPV's (Human
Powered Vehicles) that will handle compound drives and geared cranks and hubs.
541:
times imperial-to-metric conversion. To convert from gear inches to metres of development, multiply by 0.08 (more precisely: 0.0254π).
433:, is a measurement which specifies how many metres a bicycle travels per revolution of the crank. It can be calculated by the formula:
202:
tire, which has a nominal cross-section of 23 mm. 700c wheels have a rim diameter of 622 mm. Hence the wheel diameter is
1222:
170:
A bicycle with a 26-inch wheel, a 48-tooth chainring, and a cassette with gears ranging from 11 to 34 teeth has a lowest gear of
1439:
198:
One way to estimate wheel diameter is to add twice the nominal tyre cross-section to the rim diameter. For example, consider a
111:
Gear inches express gear ratios in terms of the diameter of an equivalent directly driven wheel, and is calculated as follows:
1188:
410:{\displaystyle {\text{speed in mph}}{\text{ ≈ }}{\text{gear inches}}\times {\text{cadence in rpm}}\times {\frac {1}{336}}}
48:
356:{\displaystyle {\text{speed in mph}}={\text{gear inches}}\times {\text{cadence in rpm}}\times {\frac {\text{π}}{1056}}}
1338:
16:
1352:
1373:
1465:
1230:
44:
207:
difference between the manufacturer's stated size and the actual tire radius when mounted and inflated.
74:
of different gears, which combined with the wheel diameter determines how far the bicycle advances per
1217:
71:
1247:
1431:
1262:
100:
1252:
1443:
1242:
67:
95:
40:
28:
1436:
1459:
75:
1284:"The end of junior gearing? UCI gets rid of rule restricting ratios for under 18s"
612:
36:
1411:
1191:
limited junior riders to a rollout distance of 7.93 metres (~99 gear inches).
163:
For simplicity, 'gear inches' is normally rounded to the nearest whole number.
1194:
Some national cycling federations limit rollout distances for younger riders.
554:
622/23 (700/23), combinations of number of teeth at the cassette and crank
1257:
79:
1426:
1396:
1313:. Union Cycliste Internationale. 2023-01-01. p. 20. Archived from
210:
Gear inches, along with cadence, can be converted to speed as follows:
1421:
1414:
Online calculator for gear inches, metres development, and gain ratio
1446:
Online calculator for derailleur gears, with useful graphic displays
60:
15:
1449:
32:
1386:(in Austrian German). Cycling Austria. 2023-06-06. p. 2.
538:
1397:
Satisfy Junior
Gearing Restrictions with Superior Shifting
66:
In contrast to gear ratio which is a relative measure of
1417:
537:
Thus gear inches and development differ by a factor of
1427:
Gain Ratios—A New Way to
Designate Bicycle Gears
491:
442:
370:
318:
219:
120:
1380:ÖRV Competition Regulations - Chapter 20 - Appendix
526:
471:
409:
355:
303:
149:
1420:has a graphical means of displaying gear inches
63:a bicycle travels per revolution of the crank.
1375:ÖRV-Wettfahrbestimmungen - Kapitel 20 - Anhang
1340:Wettkampfbestimmungen für den Straßenrennsport
1308:"UCI Cycling Regulations - Part 2 Road Races"
8:
1225:proposed a gear measurement system called
514:
506:
492:
490:
459:
451:
443:
441:
397:
389:
381:
376:
371:
369:
343:
335:
327:
319:
317:
291:
278:
265:
260:
247:
239:
231:
220:
218:
137:
129:
121:
119:
31:measure corresponding to the diameter in
552:
1345:Competition Regulations for Road Racing
1274:
421:Relationship to metres of development
7:
453:drive wheel circumference in metres
517:number of teeth in front chainring
462:number of teeth in front chainring
174:gear inches and a highest gear of
140:number of teeth in front chainring
14:
520:number of teeth in rear sprocket
465:number of teeth in rear sprocket
143:number of teeth in rear sprocket
1412:Sheldon Brown's gear calculator
1437:Mike Sherman's gear calculator
508:drive wheel diameter in metres
244:
228:
131:drive wheel diameter in inches
90:Origin of the term gear inches
1:
545:Examples of rollout distances
204:(2 × 23 mm) + 622 mm = 668 mm
70:giving an indication of the
86:gearing is for going fast.
59:, which specifies how many
47:) gearing. A commonly used
1482:
1282:Adam Becket (2022-06-23).
1212:Relationship to gain ratio
1432:Gain and Watts Calculator
1353:German Cycling Federation
94:When the high wheeler or
43:bicycle with equivalent (
1355:. 2023-04-01. p. 21
51:alternative is known as
1450:HPV Drivetrain Analyzer
107:Calculating gear inches
528:
473:
411:
357:
305:
151:
21:
529:
474:
431:metres of development
412:
358:
306:
152:
53:metres of development
19:
1218:mechanical advantage
489:
440:
378: ≈
368:
316:
217:
118:
72:mechanical advantage
1248:Bicycle performance
1187:Up until 2023, the
555:
1442:2011-03-10 at the
1263:Outline of cycling
553:
524:
469:
407:
353:
301:
176:26 × 48 / 11 = 113
147:
22:
1422:as described here
1288:cyclingweekly.com
1180:
1179:
522:
521:
518:
509:
495:
482:or equivalently:
467:
466:
463:
454:
446:
405:
392:
384:
379:
374:
351:
347:
338:
330:
322:
299:
298:
295:
286:
285:
282:
273:
272:
269:
263:
255:
254:
251:
242:
234:
223:
172:26 × 48 / 34 = 37
145:
144:
141:
132:
124:
1473:
1399:
1394:
1388:
1387:
1385:
1370:
1364:
1363:
1361:
1360:
1350:
1335:
1329:
1328:
1326:
1325:
1319:
1312:
1304:
1298:
1297:
1295:
1294:
1279:
1253:Derailleur gears
1207:
1206:
1202:
556:
533:
531:
530:
525:
523:
519:
516:
515:
510:
507:
496:
494:rollout distance
493:
478:
476:
475:
470:
468:
464:
461:
460:
455:
452:
447:
444:
429:, also known as
427:rollout distance
416:
414:
413:
408:
406:
398:
393:
390:
385:
382:
380:
377:
375:
372:
362:
360:
359:
354:
352:
345:
344:
339:
336:
331:
328:
323:
320:
310:
308:
307:
302:
300:
296:
293:
292:
287:
283:
280:
279:
274:
270:
267:
266:
264:
261:
256:
252:
249:
248:
243:
240:
235:
232:
224:
221:
205:
201:
194:
193:
189:
186:
177:
173:
156:
154:
153:
148:
146:
142:
139:
138:
133:
130:
125:
122:
57:rollout distance
1481:
1480:
1476:
1475:
1474:
1472:
1471:
1470:
1456:
1455:
1444:Wayback Machine
1408:
1403:
1402:
1395:
1391:
1383:
1372:
1371:
1367:
1358:
1356:
1348:
1337:
1336:
1332:
1323:
1321:
1317:
1310:
1306:
1305:
1301:
1292:
1290:
1281:
1280:
1276:
1271:
1243:Bicycle gearing
1239:
1214:
1204:
1200:
1199:
1185:
564:
561:
547:
487:
486:
438:
437:
423:
366:
365:
314:
313:
215:
214:
203:
199:
191:
187:
184:
182:
175:
171:
116:
115:
109:
92:
68:bicycle gearing
12:
11:
5:
1479:
1477:
1469:
1468:
1458:
1457:
1454:
1453:
1447:
1434:
1429:
1424:
1415:
1407:
1406:External links
1404:
1401:
1400:
1389:
1365:
1330:
1299:
1273:
1272:
1270:
1267:
1266:
1265:
1260:
1255:
1250:
1245:
1238:
1235:
1213:
1210:
1208:~ 7.53 m
1184:
1181:
1178:
1177:
1174:
1171:
1168:
1165:
1162:
1159:
1156:
1153:
1150:
1147:
1144:
1141:
1138:
1135:
1131:
1130:
1127:
1124:
1121:
1118:
1115:
1112:
1109:
1106:
1103:
1100:
1097:
1094:
1091:
1088:
1084:
1083:
1080:
1077:
1074:
1071:
1068:
1065:
1062:
1059:
1056:
1053:
1050:
1047:
1044:
1041:
1037:
1036:
1033:
1030:
1027:
1024:
1021:
1018:
1015:
1012:
1009:
1006:
1003:
1000:
997:
994:
990:
989:
986:
983:
980:
977:
974:
971:
968:
965:
962:
959:
956:
953:
950:
947:
943:
942:
939:
936:
933:
930:
927:
924:
921:
918:
915:
912:
909:
906:
903:
900:
896:
895:
892:
889:
886:
883:
880:
877:
874:
871:
868:
865:
862:
859:
856:
853:
849:
848:
845:
840:
837:
834:
831:
828:
825:
822:
819:
816:
813:
810:
807:
804:
800:
799:
796:
793:
790:
787:
784:
781:
778:
775:
772:
769:
766:
763:
760:
757:
753:
752:
749:
746:
743:
740:
737:
734:
731:
728:
725:
722:
719:
716:
713:
710:
706:
705:
702:
699:
696:
693:
690:
687:
684:
681:
678:
675:
672:
669:
666:
663:
659:
658:
655:
652:
649:
646:
643:
640:
637:
634:
631:
628:
625:
622:
619:
616:
608:
607:
604:
601:
598:
595:
592:
589:
586:
583:
580:
577:
574:
571:
568:
565:
562:
559:
546:
543:
535:
534:
513:
505:
502:
499:
480:
479:
458:
450:
422:
419:
418:
417:
404:
401:
396:
391:cadence in rpm
388:
363:
350:
342:
337:cadence in rpm
334:
326:
311:
290:
277:
259:
246:
238:
230:
227:
158:
157:
136:
128:
108:
105:
96:penny-farthing
91:
88:
41:penny-farthing
13:
10:
9:
6:
4:
3:
2:
1478:
1467:
1466:Bicycle gears
1464:
1463:
1461:
1451:
1448:
1445:
1441:
1438:
1435:
1433:
1430:
1428:
1425:
1423:
1419:
1416:
1413:
1410:
1409:
1405:
1398:
1393:
1390:
1381:
1377:
1376:
1369:
1366:
1354:
1351:(in German).
1346:
1342:
1341:
1334:
1331:
1320:on 2023-02-20
1316:
1309:
1303:
1300:
1289:
1285:
1278:
1275:
1268:
1264:
1261:
1259:
1256:
1254:
1251:
1249:
1246:
1244:
1241:
1240:
1236:
1234:
1232:
1231:dimensionless
1228:
1224:
1223:Sheldon Brown
1219:
1211:
1209:
1195:
1192:
1190:
1182:
1175:
1172:
1169:
1166:
1163:
1160:
1157:
1154:
1151:
1148:
1145:
1142:
1139:
1136:
1133:
1132:
1128:
1125:
1122:
1119:
1116:
1113:
1110:
1107:
1104:
1101:
1098:
1095:
1092:
1089:
1086:
1085:
1081:
1078:
1075:
1072:
1069:
1066:
1063:
1060:
1057:
1054:
1051:
1048:
1045:
1042:
1039:
1038:
1034:
1031:
1028:
1025:
1022:
1019:
1016:
1013:
1010:
1007:
1004:
1001:
998:
995:
992:
991:
987:
984:
981:
978:
975:
972:
969:
966:
963:
960:
957:
954:
951:
948:
945:
944:
940:
937:
934:
931:
928:
925:
922:
919:
916:
913:
910:
907:
904:
901:
898:
897:
893:
890:
887:
884:
881:
878:
875:
872:
869:
866:
863:
860:
857:
854:
851:
850:
846:
844:
841:
838:
835:
832:
829:
826:
823:
820:
817:
814:
811:
808:
805:
802:
801:
797:
794:
791:
788:
785:
782:
779:
776:
773:
770:
767:
764:
761:
758:
755:
754:
750:
747:
744:
741:
738:
735:
732:
729:
726:
723:
720:
717:
714:
711:
708:
707:
703:
700:
697:
694:
691:
688:
685:
682:
679:
676:
673:
670:
667:
664:
661:
660:
656:
653:
650:
647:
644:
641:
638:
635:
632:
629:
626:
623:
620:
617:
614:
610:
609:
605:
602:
599:
596:
593:
590:
587:
584:
581:
578:
575:
572:
569:
566:
558:
557:
551:
544:
542:
540:
511:
503:
500:
497:
485:
484:
483:
456:
448:
436:
435:
434:
432:
428:
420:
402:
399:
394:
386:
364:
348:
340:
332:
324:
312:
288:
284:63,360 inches
275:
257:
236:
225:
213:
212:
211:
208:
196:
179:
178:gear inches.
168:
164:
161:
134:
126:
114:
113:
112:
106:
104:
102:
97:
89:
87:
83:
81:
77:
73:
69:
64:
62:
58:
54:
50:
46:
42:
38:
34:
30:
26:
18:
1392:
1379:
1374:
1368:
1357:. Retrieved
1344:
1339:
1333:
1322:. Retrieved
1315:the original
1302:
1291:. Retrieved
1287:
1277:
1226:
1215:
1196:
1193:
1186:
842:
548:
536:
481:
430:
426:
424:
373:speed in mph
321:speed in mph
222:speed in mph
209:
200:700c × 23 mm
197:
180:
169:
165:
162:
159:
110:
93:
84:
82:revolution.
65:
56:
52:
45:direct-drive
24:
23:
1183:Regulations
445:development
383:gear inches
329:gear inches
268:revolutions
233:gear inches
123:gear inches
37:drive wheel
25:Gear inches
1359:2023-10-16
1324:2023-02-20
1293:2023-02-20
1269:References
1227:gain ratio
294:60 minutes
253:revolution
1221:account,
512:×
504:⋅
501:π
457:×
395:×
387:×
341:×
333:×
289:×
276:×
258:×
237:×
135:×
1460:Category
1440:Archived
1258:Hub gear
1237:See also
563:Cassette
29:imperial
1418:BikeCAD
1203:⁄
346:π
262:cadence
241:π
190:⁄
101:cadence
35:of the
1382:]
1347:]
704:10.12
657:11.12
654:10.91
651:10.70
648:10.49
645:10.28
642:10.07
297:1 hour
281:1 mile
271:minute
250:inches
61:metres
49:metric
33:inches
27:is an
1384:(PDF)
1378:[
1349:(PDF)
1343:[
1318:(PDF)
1311:(PDF)
1176:5.29
1173:5.20
1170:5.10
1167:4.99
1164:4.89
1161:4.81
1158:4.70
1155:4.60
1152:4.49
1149:4.41
1146:4.30
1143:4.20
1140:4.09
1137:3.99
1129:5.56
1126:5.46
1123:5.35
1120:5.25
1117:5.14
1114:5.04
1111:4.93
1108:4.83
1105:4.72
1102:4.62
1099:4.51
1096:4.41
1093:4.30
1090:4.20
1082:5.86
1079:5.75
1076:5.62
1073:5.52
1070:5.41
1067:5.31
1064:5.18
1061:5.08
1058:4.97
1055:4.87
1052:4.74
1049:4.64
1046:4.53
1043:4.43
1035:6.17
1032:6.06
1029:5.94
1026:5.83
1023:5.71
1020:5.60
1017:5.48
1014:5.37
1011:5.25
1008:5.12
1005:5.02
1002:4.89
999:4.78
996:4.66
988:6.55
985:6.42
982:6.30
979:6.17
976:6.04
973:5.92
970:5.79
967:5.69
964:5.56
961:5.44
958:5.31
955:5.18
952:5.06
949:4.93
941:6.95
938:6.82
935:6.69
932:6.57
929:6.42
926:6.30
923:6.17
920:6.04
917:5.90
914:5.77
911:5.65
908:5.52
905:5.37
902:5.25
894:7.41
891:7.28
888:7.14
885:6.99
882:6.86
879:6.72
876:6.57
873:6.44
870:6.30
867:6.15
864:6.02
861:5.88
858:5.73
855:5.60
847:7.95
839:7.64
836:7.49
833:7.35
830:7.20
827:7.05
824:6.90
821:6.74
818:6.59
815:6.44
812:6.30
809:6.15
806:6.00
798:8.56
795:8.39
792:8.23
789:8.08
786:7.91
783:7.74
780:7.60
777:7.43
774:7.26
771:7.09
768:6.95
765:6.78
762:6.61
759:6.46
751:9.28
748:9.09
745:8.92
742:8.75
739:8.56
736:8.39
733:8.23
730:8.04
727:7.87
724:7.70
721:7.51
718:7.35
715:7.18
712:6.99
701:9.93
698:9.74
695:9.55
692:9.34
689:9.15
686:8.96
683:8.77
680:8.58
677:8.39
674:8.21
671:8.02
668:7.83
665:7.64
639:9.86
636:9.65
633:9.44
630:9.23
627:9.02
624:8.81
621:8.60
618:8.39
613:micro
560:Crank
80:crank
76:pedal
39:of a
843:7.79
611:10 (
425:The
349:1056
1189:UCI
1134:21
1087:20
1040:19
993:18
946:17
899:16
852:15
803:14
756:13
709:12
662:11
606:53
603:52
600:51
597:50
594:49
591:48
588:47
585:46
582:45
579:44
576:43
573:42
570:41
567:40
403:336
78:or
55:or
1462::
1286:.
1233:.
1205:14
1201:52
615:)
1362:.
1327:.
1296:.
539:π
498:=
449:=
400:1
325:=
245:)
229:(
226:=
192:4
188:1
185:+
183:1
127:=
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
