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Calculate bicycle gear ratios, gear inches, and development for any chainring and cassette cog combination on your bike.
Find the correct bicycle frame size from inseam, height, and riding style for road, mountain, hybrid, and gravel bicycles.
Calculate bicycle spoke length from hub flange diameter, rim ERD, lacing pattern, and number of crosses for wheel building.
Industry method wraps chain around big-big without derailleur, adds links for cage path.
links = L/2 + (T_big + T_cog)/4 + 1 (round to even whole links)Measure center of bottom bracket to rear axle along chain line. Longer stays need slightly more chain.
Modern chains join with pin or master link pairs. Total link count must be even.
Updated: July 2026
Size chain for 42T ring and 42T cassette on a 430 mm chainstay.
Confirm link count matches prior chain if cassette and range are unchanged.
Verify big-big wrap capacity when using 50T+ cogs.
Derailleur chains are sized so the largest ring and largest cog engage safely with tension.
Odd link counts cannot accept standard connecting links. Remove one link to make the count even.
Cut a new chain once, correctly. Enter largest chainring and cog, chainstay length, and derailleur type to get recommended link count.