Secondary Chains

Rear wheel chains for Harleys

When we talk about the secondary chain, we mean the chain from the transmission to the rear wheel. Often, it is only referred to as "the chain" in this context, but air-cooled Harley-Davidson V-twin engines also have a chain from the engine to the clutch (the so-called primary chain).

The rear wheel chains were available in different lengths ex works, but for almost all models in 5/8“ x 3/8” pitch. This pitch means the links measure ~16 mm from rivet to rivet and 9.5 mm between the inner link plates. (For those interested in history: exceptions are rear wheel chains 1912-1914 and those of the singles 1926-1927.) On the Big Twins, the secondary chain was phased out with model year 1985, and with the Sportster with model year 1992. Since then, the factory has stopped using free-running steel chains – although the latest generation with water-cooled 60° engine is entering the market with 530 chains again. One wonders what the reason could be …

Our Wrecking Crew swears by Tsubaki chains for their durability and reliability. They are available in different lengths as a “normal” roller chain without seals or as X-ring chains with sealing rings, in different tensile strengths, with a spring link or a rivet link.

What is the difference between an X-ring chain and a "normal" one?

In a motorcycle chain, there are the outer plates, which are held together by the rivets, and in between them there are the inner plates, with two spacers in between. On top of each spacer there is a loose bushing, called the roller. The rollers are responsible for the chain's smooth movement ("rolling") on the sprockets. The rivets are the actual links and slide in the inner links. This requires a lot of good lubricant inside the sleeves, which unfortunately is pushed outwards during the course of a chain's life. In an X-ring chain, the spaces between the inner and outer plates are sealed with rubber rings so that the lubricant stays inside. If the chain is regularly lubricated with chain spray, only the rollers are lubricated. Incidentally, the sealed-ring chain originally comes from America. It was invented by a Mr. Joseph Montano while working for Whitney Chain in Hartford, CT around 1971.

How long does a rear wheel chain last?

To be honest, there is no general answer to this question. The lifespan depends on several factors: seal-ring chain or not? 100 hp stroker or 22 hp sidevalve twin? Does the rider often crack the throttle or does he tend to use a lighter touch? Is the chain regularly maintained or left to itself? Well-maintainedseal-ring chains on bikes with a lighter touch and lower horsepower tend to last the longest. Anyone who always rides on the fast lane will face extra cost, one may call it express-train-surcharge.

What type of connecting link do I need? Does it not matter what type of connecting link I use?

Our Tsubaki rear wheel chains aren't endless chains, they always come with a connecting link. To avoid any risk, we strongly suggest to use the supplied connecting link. For sealing ring chains, Tsubaki always supplies a riveted connecting link. Spring clip links are only supplied with unsealed low horse-power chains. Connecting links are always matched to the specific dimensions of a chain, so you should only use those with the same dimensions from the same manufacturer. And to rivet a link correctly, use the appropriate Kellermann tool.