Meaning of Chain Sizes

[djalbin]

Ever wonder what the 520 and 530 chain sizes mean?

Generally, roller chain is denoted as follows:

The first digit specifies the chain's pitch, in 1/8-inch increments. The remaining digits correspond to the width of the chain in 1/80 of an inch. A 530 chain, then, has a pitch of 5/8 inch, and a width of 30/80 inch, or 3/8 inch. A 520 chain is 1/4-inch wide.

There are some exceptions to this for racing chains; for example, 125GP machines utilize a 428 chain, which is a 425-sized chain with slightly thicker sideplates.

Always match the sprockets to the chain and vice-versa (e.g 520 vs 530)

In addition to the chain size, you will need to select a chain that meets the minimum tensile strength (ft/lbs) for your bike and has the correct number of links. The number of links, links per foot, and tensile strength are included in the bike specs for your bike.

You also need to decide the sealed ring type you want (o-ring, x-ring, RX-ring, XW-ring, etc ...) The more advanced sealed rings will last longer and produce less drag/friction.

[F5]

125GPs typically run 415. Think they also stuff around with roller dimension like in 532

[djalbin]

125GPs typically run 415.

Ok then ... would you believe 250GPs utilize a 428 chain ?