I got my 26" mountain bike fit with 5 derailer type gears. Earlier it had a single freewheel. I need to know whether the chain too needs to be changed or the old (used over 200Km) will do? The length has been adjusted properly but does the pitch and width matter too?
'''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
The pitch most definitely matters but all bicycle chains are 1/2" pitch. The width matters depending on the cog spacing. Most single speed chains are too wide for derailleur gear use. A new set of cogs should have a new chain regardless but get the correct type.