Can Motorcycle Shock Oil Be Replaced with Engine Oil?

[Isaac]

Ordinary engine oil cannot be used as a substitute for hydraulic oil in motorcycle shock absorbers. The reasons are explained below: Reasons: The viscosity of ordinary engine oil and hydraulic oil is different. If ordinary engine oil is used instead of hydraulic oil in the shock absorber, the damping effect will be significantly worse. Additional Explanation: Since the performance and functions of the two oils differ, engine oil is used in the engine's lubrication system, primarily for cooling and lubrication to prevent component overheating. Hydraulic oil, on the other hand, is mainly used in hydraulic systems for torque transmission, converting torque into force applied to the driven components. Due to their different roles, they cannot be used interchangeably.

[WalkerAnn]

I've been riding motorcycles for over a decade. Once, for convenience, I used engine oil as fork oil, and the result was disastrous—within just a week, the suspension became as stiff as an iron board, making my hands go numb from the bumps. Even worse, it started leaking oil a few days later, nearly causing me to crash on the road. It wasn't until I consulted a mechanic friend that I learned: fork oil and engine oil have different viscosities. The former is designed to lubricate and dampen high-frequency vibrations, while the latter primarily prevents wear in high-temperature engines. Engine oil lacks those special additives, so when bubbles form, it fails, and over time, it corrodes the seals. Now, I only use dedicated fork oil, changing it every 5,000 kilometers, and the ride is much smoother. Proper maintenance not only saves money but is also safer—don't make the same mistakes I did.

[DeLeilani]

As someone who frequently tinkers with motorcycles, I don't recommend using engine oil as a substitute for suspension oil—the differences between them are quite significant. Suspension oil has higher viscosity, designed to cushion piston movement during bumps, whereas engine oil is thinner and prone to overheating and thinning out in the suspension system, leading to insufficient damping—riding feels like being on a boat, wobbly and unstable. I've seen many cases where bikes were damaged due to improper oil use: seal wear and fluid leaks, requiring costly full system replacements. Regular maintenance is best—factory-specified oil is designed for shock absorbers, containing anti-foam and anti-wear additives. If budget is tight, buying affordable dedicated suspension oil is far better than forcing engine oil into the system, saving a lot of hassle in the long run.

[Ingrid]

Using engine oil as shock absorber oil? I tried it once when I was really short on cash and couldn't afford the professional product. The result was terrible. After just a few days of riding, I noticed the suspension became soft, and the brakes wobbled unsteadily – clearly the engine oil was too thin and incompatible. Motorcycle suspensions require specific viscosity for proper support. Engine oil is designed for high-temperature engines, and using it in shocks causes foaming and accelerates wear. It might work temporarily, but damaging the components costs more – a minor repair cost me over 200 extra. Temporary measures are risky; if you really need an emergency solution, check your bike's condition first or look for cheaper alternatives. Specialized oil isn't expensive, and regular maintenance can prevent major issues.