If a bicycle chain is rusty, squeaking or running dry, should you grab a can of regular WD-40 and spray it down?
The short answer is that standard WD-40 Multi-Use Product and dedicated bicycle chain lubricant serve different purposes, and regular WD-40 should not generally be treated as a replacement for proper bicycle chain lube.
That distinction becomes even more important when dealing with a commercial bicycle rental fleet, where bikes may be ridden repeatedly by different customers and exposed to rain, dirt, sand, coastal air and other harsh conditions.
For rental operators, allowing chains to become heavily rusted and simply waiting until they fail or become unusable is difficult to square with preventative-maintenance guidance from major bicycle component manufacturers.
WD-40 and Bicycle Chain Lube Are Not the Same Product
One source of confusion is the WD-40 name itself.
WD-40 sells its famous Multi-Use Product, but the company also produces dedicated WD-40 Specialist Bike Chain Lubes.
Those aren’t interchangeable products marketed under different labels.
WD-40 says its Multi-Use Product can displace moisture, protect metal against corrosion and provide lubrication. The company even identifies bicycle components among its potential applications.
But when it comes specifically to maintaining a bicycle chain for continued riding, WD-40’s own guidance makes the distinction clear.
The company recommends its Multi-Use Product for driving moisture from a wet bicycle chain, for example, but then instructs riders to re-lubricate the chain afterward using a dedicated WD-40 Specialist Bike Chain Lube.
WD-40 gives similar advice for rusty chains: its Multi-Use Product can be used as part of restoring a rusted bicycle chain, followed by the application of dedicated bicycle chain lubricant.
So using regular WD-40 on a bicycle chain isn’t necessarily the disastrous mistake sometimes portrayed online. It has legitimate uses in bicycle maintenance.
But using it instead of routinely applying an appropriate bicycle chain lubricant is another matter.
What Does Actual Chain Lube Do?
A bicycle chain consists of interconnected metal components continuously articulating against one another as the rider pedals.
Lubrication reduces friction between those moving surfaces and helps protect the drivetrain from premature wear and corrosion.
WD-40’s own dedicated All Conditions Bike Chain Lube contains corrosion inhibitors and is specifically designed to reduce friction and extend bicycle-chain life. The company recommends applying it to the chain, allowing it time to penetrate and then wiping away the excess.
Different lubricants can also be selected for different operating environments.
WD-40, for example, produces a dry chain lubricant for dusty and dry environments and a wet lubricant that provides a coating intended to repel water and mud in wet conditions.
That matters for commercial fleets because rental bicycles can experience dramatically different conditions depending on where they’re operated.
A bicycle regularly used near a beach may encounter moisture, sand and salt-laden air. A bicycle in a dry inland environment may accumulate dust and grit. Bikes left outdoors may encounter rain and condensation.
There isn’t necessarily one perfect lubricant for every fleet.
But never lubricating the chains at all isn’t the solution.
Shimano Recommends Cleaning and Lubricating Bicycle Chains
The recommendation isn’t limited to lubricant manufacturers trying to sell chain lube.
Shimano, one of the world’s major manufacturers of bicycle drivetrain components, tells users to regularly clean chains and QUICK-LINK components with an appropriate chain cleaner. Shimano also states in its technical documentation that periodically cleaning a chain with neutral detergent and lubricating it can be an effective way of extending the life of both the chain and gears.
Maintenance intervals can vary depending on how and where a bicycle is used.
That makes sense.
A bicycle ridden five miles a month under ideal conditions doesn’t necessarily require the same maintenance schedule as a rental bicycle being ridden repeatedly by customers.
The important distinction is between condition-based preventative maintenance and simply allowing a component to deteriorate until it stops working.
What If the Chain Is Already Extremely Rusty?
This is where lubrication alone may no longer be enough.
A small amount of surface discoloration doesn’t automatically mean a bicycle chain is dangerous or about to snap. Rust exists on a spectrum.
A chain showing extensive corrosion, stiff links, significant wear or other deterioration should be properly inspected before the bicycle is returned to service.
Adding lubricant can reduce friction and help protect a serviceable chain, but lubricant cannot replace metal that has already been lost to corrosion or repair a mechanically damaged link.
A heavily rusted chain may need cleaning and inspection and, depending on its condition, replacement.
For a commercial rental operation, this distinction is particularly important.
The question shouldn’t simply be: Can we make this rusty chain move again?
The more appropriate question is: Is this chain still in suitable condition to be placed back into rental service?
Why “We’ll Replace It When It Fails” Is a Problematic Fleet Strategy
Bicycle chains are wear items.
Every chain eventually reaches a point where it should be replaced.
But there’s an important difference between replacing a chain because routine inspection identifies excessive wear or deterioration and intentionally waiting for the component to fail before doing anything.
The latter is essentially a run-to-failure maintenance strategy.
That strategy may be appropriate for certain noncritical equipment where failure has little consequence.
A bicycle drivetrain carrying a member of the public is different.
A chain can fail by breaking, but it can also develop stiff or damaged links, skip, derail or otherwise stop operating properly.
A rider also doesn’t necessarily know that a chain is approaching failure.
That’s particularly relevant to rental bicycles because the customer usually hasn’t maintained the bicycle, doesn’t know its history and may reasonably assume that the company renting it has inspected major mechanical components.
How Dangerous Is a Chain Failure?
Not every bicycle-chain failure results in an accident.
A rider could experience a chain problem, stop the bicycle and walk away without injury.
But chain failure can create an unexpected change in the bicycle’s behavior.
Imagine a rider standing on the pedals while accelerating when the chain suddenly breaks or comes off. The resistance the rider was pushing against can disappear immediately.
The consequences depend heavily on the circumstances.
At low speed on an empty bicycle path, the result might be little more than an inconvenience. During acceleration, climbing, riding near traffic or maneuvering around pedestrians and other cyclists, an unexpected drivetrain failure could contribute to a loss of balance or control.
This is why preventative maintenance matters more than simply asking whether a bicycle can technically still be ridden.
Rental Bikes Can Have a Hard Life
Commercial rental bicycles may experience considerably more abuse and environmental exposure than the average privately owned bike.
One customer may ride through a puddle. Another may take the bicycle near the beach. Someone else may shift aggressively under load. The bike may then sit outside overnight before being rented again the following morning.
Rental companies also can’t necessarily rely on customers to report developing mechanical problems.
One rider might immediately tell an employee that the chain is squeaking or skipping.
Another may return the bicycle without saying anything.
That puts more responsibility on the inspection and maintenance process itself.
Chain Maintenance Doesn’t Have to Be Complicated
For a large commercial fleet, preventative chain maintenance can be incorporated into normal service procedures.
Mechanics can visually inspect chains for rust and damage, check for stiff links or abnormal operation, monitor chain wear, clean excessively dirty drivetrains, apply an appropriate bicycle chain lubricant and replace chains that have deteriorated beyond acceptable limits.
The exact maintenance interval will depend on mileage, weather, storage conditions, bicycle design and manufacturer recommendations.
There is also such a thing as improper lubrication.
Excess lubricant can attract dirt, and lubricant should be kept away from braking surfaces. WD-40 specifically cautions users to protect disc-brake rotors while applying its bicycle-chain products.
The goal isn’t to soak every bicycle in lubricant every day.
The goal is to inspect, clean and lubricate components appropriately based on their condition and use.
A One-Minute Maintenance Item Can Protect a Much Larger Investment
There’s also an economic argument for preventative chain maintenance.
A chain isn’t operating by itself.
It interfaces with other drivetrain components, including chainrings and rear sprockets. Shimano specifically notes that cleaning and lubricating the chain can help extend the life of both the chain and gears.
Allowing chains to operate dry, contaminated or badly deteriorated therefore isn’t necessarily saving a fleet money.
It can simply defer maintenance while increasing wear elsewhere in the drivetrain.
For a rental company maintaining dozens, hundreds or potentially thousands of bicycles, small preventative-maintenance decisions can multiply across an entire fleet.
So, Should You Use WD-40 Instead of Chain Lube?
For routine bicycle-chain lubrication, use a lubricant designed for bicycle chains rather than treating ordinary WD-40 Multi-Use Product as a permanent substitute.
Regular WD-40 can have legitimate uses during bicycle maintenance. It can displace moisture and assist with rust and corrosion. WD-40 itself, however, sells dedicated bicycle chain lubricants and specifically recommends re-lubricating chains with those products after certain uses of its Multi-Use Product.
And if a chain has already become heavily rusted, simply spraying either product onto it shouldn’t automatically end the maintenance process.
It should be inspected.
For an individual rider, neglecting a chain may mean additional wear, poor shifting or eventually walking the bicycle home.
For a commercial rental fleet putting members of the public on bicycles every day, preventative maintenance carries an additional responsibility.
A rental bicycle shouldn’t have to experience a chain failure before its chain receives attention. The boss at work not ordering chain lube for the rental bicycle fleet? We want to know!
