Nuts About Bikes

O-rings: not just for faucets, anymore

I am the first to admit it: sometimes I just don't "get it" until I get hit over the head with it.

Such was the case with the o-ring motorcycle chain. I'd heard about that mysterious o-ring for years, but I knew not where it lurked or what it did.

That changed recently when I replaced the chain and sprockets after 20K miles on my trusty steed. Decided to clean up the old chain and do a little surgery to see what makes it tick.

Metal against metal in yesteryear

Turns out it's exceedingly simple. The o-ring chain was a major innovation in motorcycle technology when the idea was first put into action in the 1970s. The idea was so good that by the early 80s, conventional chains had gone by the wayside and the o-ring reigned king of traditional bike power transfer.

In a nutshell - remember that the earliest motorcycle had their genesis in bicycle technology. The chain was a reliable and durable way to transfer power from the crank to the rear wheel. When tinkers and inventors began fitting engines to bicycles, it was a natural progression to use chains. (Of course belt- and shaft-driven bikes have evolved parallel to the chain drive.)

On a bicycle chain – or old-school motorcycle chain – all the metal bits are in direct contact with one another: rollers, links and plates. This fine for bicycles, because a chain wears comfortably slow at bicycle speeds. Motorize the beast, though, and get it out on the highway – and all bets are off.

At motor speeds, a metal-against-metal chain is going to wear faster than you can look at it. That's why chain lubrication was the life blood of the chain in the old days. Forget to oil your chain – say goodbye.

A comfy cushion

The o-ring simply puts a layer of rubber between the chain's metal-to-metal interface. If course o-ring style chains still wear out, but they are much more forgiving than the old-school chains. The o-ring acts as a bearing, keeping the metal surfaces away from one another, and also forms convenient nooks and crannies in which lubricant is trapped, extending the life of the chain even when the operator neglects it.

Show me the money

If you're anything like me, you might not be able to picture how this all goes together. Never fear - we've snapped the photos that will make it clear.

o-ring chainThe exploded view shows the relative position of the o-rings in the chain engineering. Notice how the o-rings keep the metal bits away from one another. In this chain, the o-rings are true to their name - essentially identical to those you find in plumbing applications.

Since the introduction of the o-ring chain, manufacturers have expermented with different ring shapes. You'll see x-ring and z-ring technology bandied about. These terms generally describe the cross-section shape of the o-ring. These are seen by some as an improvement over the standard O shape by offering more nook-and-cranny space for lubricant.

A word about chain lube

Before I started taking motorcycle chains apart, I realized I did not really know how to properly lube a bike chain. I was spraying it on and hoping for the best - better than not lubricating at all, of course, but not necessarily the most efficient way to go.

o-ringsNotice how the o-rings are squashed between the outside plates and the rollers.

That's where the lube needs to go. And the nice thing about the o-ring design is that once lubricant comes in contact with the ring, it tends to neatly flow where it needs to be and stay there. For a long time.

The chain we disassembled for this article is a perfect example of the staying power of lubricant in an o-ring chain. First, it was soaked in kerosene (paraffin) overnight. Then we scrubbed vigorously with a brush and rinsed in fresh parts cleaner. Next, to remove some of the odorous solvent, we soaked it in a strong solution of water and dish detergent.

After scrubbing again, rinsing and drying with heat, we brushed it down with denatured alcohol to displace the water and prevent rusting. (Keep in mind this was all done with mess and cosmetics in mind for the photographs. You won't want to give a chain in use this kind of harsh treatment.

After all that cleaning - when we started grinding and hammering out the pins, there was still lots of grease where it needed to be – where the o-rings meet the metal. Suffice to say we were duly impressed with the genius of the design.

Keeping it happy

When I first started riding, my wingman showed me how to lubricate the bike chain. What he did right was impress me about how important it is. What he failed to mention, however, is how important t is to lube your chain hot.

Simply put, those o-ring are in tight, with a practically microscopic spaces between the ring and the metal. If you lube the chain hot, the lubricant flows into the tiny gap very easily, carried along by heat of the metal parts - not unlike the way solder flows between pipe and elbow when sweating a plumbing joint.

Of course it's not the end of the world if you lube cold – when the chain heats up, some of that lubricant will be carried into the ring and into the pin/cylinder gap, where it needs to be. But better to schedule your lube after you've just come in from a ride and the chain is good and hot.

Hot wax!

We are partial to the chain wax products. It's a wax compound dissolved in solvent, in a spray can. Once you apply it to the chain, the solvent evaporates, leaving a film of tough, stable wax behind. Liquid lubricants are fine – as long as they are o-ring safe – but they tend to be pretty fling-prone. The rear wheel of a bike lubed with liquid chain lube is not a pretty site after that first post-lube ride.

The wax tends to stay put - leaving the rear wheel and surrounding area much cleaner.

Our favorite protocol

Here's how the Nuts About Bikes crew likes to do it. If you have a smaller bike with a center stand, this job is exceedingly simple. But since bikes keep growing and center stands are becoming endangered species, you'll have a bit of inconvenience without one.

First, get the chain good and hot and put the bike in neutral before powering it down. If you have a center stand, choose a solid road surface (not asphalt on a 100-degree day) and carefully flip the bike onto the center stand. Get help if you are new at it – a friend to spot the other side to keep you from tipping the bike over, away from you.

Position yourself so you are comfortable. A small garage stool is a good accessory for this job.

Protect body, exhaust, etc. from drips and overspray with sheets of cardboard or newspaper. Spread some under the bike, too, to keep from fouling the road or driveway.

oil hereAs you slowly rotate the rear wheel with one hand, use the other to sparingly apply the lube in the key areas - where the o-rings are. You can either squirt with surgical precision, or just spray away. It's a question of patience and economy. Either way you are going to need to wipe off the excess before the job is done. Be mindful of hot exhaust components.

Once you have applied lube to every link on one side, be sure you do the same to the other side. I generally do the left o-rings first, then reposition to squirt the right set.

After that it's a simple task of wiping the excess away with a clean rag. Be sure your rag is not contaminated with grit, sand, sawdust, etc. which could wreak some havoc if introduced to the o-rings. Removing the excess will both keep your rear wheel cleaner, it will also limit the amount of lube that globs around your front sprocket, under the cover. Be careful - the rear sprocket likes to grab the rag and it could take your fingers sprocket-bound if you are not paying attention. Do not lube the chain by running the engine. This is just asking for trouble, finger damage – or worse.

If you don't have a center stand, you'll need to lube a section of chain (right and left sides, if possible) then walk the bike forward a bit to expose a new length of chain. Repeat until you get it all. Once you've lubed, it's best to leave the bike for a bit to give the lube a chance to cool and set up – another strategy to keep your rear wheel tidy.

Check your owner's manual for lubrication interval. Generally it's every few hundred miles or so. On my 650, that's about every other fuel tank, so that's the habit I've fallen into. Keep it adjusted well and watch it for wear. Don't hesitate to replace the chain when the time comes. Safety first.

- Sal, Editor
September 2007