chian sizes
 

could some help me
what chain should i get
and how do i kno wht size to get
does the size have to do with how many teeth the chainwheel has or freewheel

Chain for what? Bicycle? Dog? Chaingang?

Assuming it's for a bicycle, if you have more than one but less than 9 rear cogs, then you need a 3/32", or 8-speed chain. If you have 9 cogs, you need a 9-speed chain. If you have 10 cogs you need a 10-speed chain. If you have one cog, you need a 1/8" or singlespeed chain.

All chains are longer than you need unless you ride a recimbent bike. Take the old chain off and stretch it out next to the new chain. Remove any extra links so the new chain is the same size as the old one. If you ride a recumbent, you will probably need to buy more than one chain and put them together. If you have a tandem, you will also need to buy two chains.

All derailer chains are 3/32" and so could a single speed.

Ohhh, Sydney, you were wrong twice in only one sentence. Nine and ten speed derailleur bikes have to have their own narrow chains. A 3/32" chain won't fit between the closely spaced rear cogs. Many BMX-style single speed bikes have big fat chainrings that are too thick for a 3/32" chain to fit onto.

Not me, It's the inside width thats 3/32" and a single speed COULD be built around cogs/chainrings that use that same width.The first poster just muddied the water with that 3/32 stuff. Easier to have said use a 8 speed chain on 5 thru 8 speeds, and a 9 or 10 with the appropriate application(coz they are all 3/32" INSIDE) and a 1/8" on a singlespeed that reqires it. Besides, 3/32" is .093 or 2.4mm,and 10 speed chains are about 5.8 - 6.1 wide.Hope that clears it up.