SUGINO 75

The Sugino 75 has been the standard-issue crank of Japanese track racing for decades. It is NJS approved, which is why you see it on nearly every Keirin frame, and why used ones circulate constantly. If you are buying one second-hand, there is exactly one thing to get right before anything else: the bottom bracket.

The spindle taper is proprietary

The 75 uses Sugino’s own SG75 taper. It looks like a square taper. It is not one. Sugino states it plainly:

“SG75 taper is a proprietary standard by Sugino, not compatible with other standards.”

The bottom brackets Sugino specifies for it are BB-SG75 SUPER CERAMIC, BB-SG75 SUPER LAP / Standard, and CBB-SG75. That is the list.

What the rest of the numbers are

• BCD 144mm — the traditional track bolt circle. See 144 BCD for why it puts a floor under your chainring size.
• Crank lengths — 165, 167.5, 170, 172.5, 175mm.
• Chainrings — Sugino’s own 144 BCD rings run 44–55T (ZEN144) and 44–54T (SSG144).
• Pedal thread — 9/16″, the normal size.

Because 144 BCD cannot physically hold a small ring, 44T is about as low as this crank goes. If you want a lower gear, the move is a bigger cog rather than a smaller ring — or a 130 BCD crank instead. The gear inches calculator will tell you what you actually lose.

Chainline

Sugino publishes 42mm for the 75, which is the usual track figure and lines up with a 120mm rear hub built to the same standard. That is a published number, not one we derived: we do not estimate chainline from spindle length, because the estimate is wrong often enough to be useless. The chainline calculator takes measured values only.

Buying one used

Two things to check, both visible in photographs:

1. Is the bottom bracket included, and is it an SG75 one? A 75 crank sold on its own is a crank you cannot ride until the right BB turns up. The BB is often the harder half to find.

2. Is the taper damaged? A crank that has been run loose, or run on the wrong spindle, wears the taper oval. It will still slide on. It will not hold.

Listings that put another maker’s model name in the title — “for Sugino”, “Sugino style” — are usually doing it for the marketplace search box rather than describing the part. Read the title with that phrase removed and see what is left.

One more that looks the same and is not

The other classic track crank, Shimano’s FC-7710 (Dura-Ace Track), is not a square taper at all — it is Octalink, a splined interface. Same era, same shelf, completely different spindle. “It is an old track crank, so it is square taper” is the assumption that causes this whole category of mistake.

The parts we hold and the standards behind them are at the index; to check a specific pairing, use the fit check.