144 VS 130 BCD

BCD is the diameter of the circle the chainring bolts sit on. Five bolts, one circle, one measurement. If the crank is 144 and the ring is 130, the bolts do not line up and there is nothing to be done about it — no adapter, no washer, no talking your way around it.

144 BCD is the traditional track size

This is what track cranks have used for decades: Sugino 75, Shimano’s Dura-Ace Track, and most NJS-stamped equipment. If you are riding a Keirin frame with the crank it came with, you are almost certainly on 144.

The catch is the floor. The teeth have to sit outside the bolt circle, and a 144mm circle is large, so there is a smallest ring that can physically exist. In practice that is around 44T. Sugino’s own 144 BCD rings start at 44T and run to 55T.

130 BCD came from the road, and has more choice

130 is the long-running road five-bolt standard, but plenty of manufacturers make track rings in it. The smaller circle means smaller rings are possible, so the usable range is wider at the bottom. Street-oriented track cranks tend to be 130 — Sugino’s Messenger series among them.

Wider choice is the whole argument. There is no performance claim hiding here: a 48T ring is a 48T ring whichever circle its bolts sit on.

Tooth thickness is a separate question

Matching BCD does not mean the ring is right. Chain width is chosen independently.Track drivetrains are usually 1/8″; anything derived from a geared bike is usually 3/32″. You can have a correct 144 BCD ring that is the wrong thickness for your chain.

Which direction mixes and which does not is covered in 1/8 vs 3/32.

Counting the bolts is not enough

Five-bolt cranks in 144, 130 and 110 all look alike in a photograph taken from an angle. If a listing does not state the BCD, measure it: the distance between two adjacent bolt centres times 1.701 gives the circle diameter for a five-bolt pattern. On a 144 that adjacent spacing is about 84.6mm; on a 130 it is about 76.4mm.

To check a specific crank against a specific ring, use the fit check — a BCD mismatch comes back as not compatible. The standards themselves are at 144 BCD and 130 BCD.