Sheldon Brown's

Cyclecomputer Calibration Chart

Tire Size	Group A	Group B	Group C	Group D	Group E	Group F
700 X 56	91.53	249	232	370	1444	2325
700 X 50	90.29	246	229	365	1424	2293
700 X 44	87.55	236	222	354	1382	2224
700 X 38	85.82	231	218	347	1355	2180
700 X 35	84.21	230	217	345	1347	2168
700 X 32	83.22	227	216	342	1339	2155
700 X 28	82.55	225	214	336	1327	2136
700 X 25	82.12	223	211	335	1308	2105
700 X 23	81.56	222	210	333	1302	2097
700 X 20	81.02	221	209	332	1296	2086
27 X 1 3/8	85.08	232	217	345	1349	2169
27 X 1 1/4	84.33	230	216	343	1343	2161
27 X 1 1/8	83.58	228	216	342	1339	2155
27 X 1	82.91	226	215	340	1333	2145
26 X 2.125	82.12	225	207	330	1286	2070
26 X 1.9	80.63	220	206	324	1276	2055
26 X 1.5	77.71	212	199	312	1234	1985
26 X 1.25	77.44	206	195	311	1213	1953
26 X 1.0 (559 mm)	75.31	205	191	305	1189	1913
26 x 1 (650C)	76.85	206	195	311	1213	1952
Wide Tubular	83.34	224	212	338	1316	2117
Narrow Tubular	82.12	223	210	335	1308	2105
26 X 1 3/8	81.41	222	207	330	1288	2068
24	75.43	205	192	305	1191	1916
24 x 1	69.01	188	175	279	1089	1753
20 X 1.75 (406)	60.15	158	150	254	927	1491
20 X 1 1/4 (451)	63.70	173	162	257	1005	1618
17 x 1 1/4	52.17	142	133	211	838	1325
16 x 1 3/8	50.47	137	128	204	797	1282

Links:

Cyclecomputers and GPS, table of contents

Riding with RidewithGPS

GPS problems and solutions with old smartphones

Database of cyclecomputer and GPS instruction manuals

Installing cyclecomputers

Calibrating cyclecomputer wheel sensors

Printer-friendly cyclecomputer calibration chart

Troubleshooting cyclecomputers

Errors due to incorrect wheel magnet orientation

Accuracy limitations of cyclecomputers and GPS

Discrepancies due to the internal math of cyclecomputers

Copyright © 1996 Sheldon Brown

Harris Cyclery Home Page

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Last Updated: by Harriet Fell