How to Change Oil in Mountain Bike Fork | Mountain Bike Fork Oil Change

Your mountain bike’s fork oil is the life of its suspension. But how does one get the best of a mountain bike fork without dampening the milliliters?

Hidden deep inside the recesses of your mountain bike’s suspension system, fork oil is an underappreciated yet powerful fluid dynamic that directly influences your bike riding experience.

Like everything else, the suspension technology of mountain bikes has dramatically advanced and is expected to continue to do so.

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Today, almost all modernized mountain bikes are equipped with a suspension system responsible for providing the mountain biker with a smoother ride by softening the roughness of the terrain. Here is everything you need to know about mountain bike fork oil change.

What Are Mountain Bike Forks? | Why Are They Important?

Commonly known as front shocks or front suspensions, mountain bike forks are responsible for holding the front wheel. A mountain bike fork typically consists of two blades which are co-joined with the bike’s suspension at the top by a fork crown.

Mountain bike fork oil has two primary functionalities: damper compression and lubrication. A mountain bike fork comprises a seal that enables the stanchions to slide out and in the lowers and protects the fork internals against contamination.

However, the mountain bike fork seals also create friction which isn’t good, especially when you want your mountain bike to be buttery smooth on all types of terrains. This is where mountain bike fork lubrication comes in.

By lubricating your mountain bike fork with the manufacturer’s recommended amount of oil, you will not only be reducing friction but will be making your mountain bike smoother without diminishing the inherent protective function of the forks. The mountain bike forks also play a key role in regulating its movement.

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How Do I Know that My Mountain Bike Fork Needs Oil Change?

As stated earlier, mountain bike fork oil is the blood for your bike’s suspension system. So, how does one know when it’s time for a mountain bike fork oil change? Here are five signs that indicate your mountain bike fork requires an oil change as soon as possible:

1. Leaking Oil

Leaking oil from the forks is one of the most prominent mountain bike fork oil change indicators. The first sign is oil coming out from the adjusters or the central air seals, which will cause damping shortly afterward.

Moreover, because oil attracts direct, you will soon notice that nasty black slimy stuff will start to accrue around the end of the mountain bike’s suspension shaft. If not dealt with in time, the black slime can cause severe damage to the shocks of your mountain bike.

2. No Damping

Even though the most mechanically unsympathetic riders would easily notice no or less damping when riding their mountain bike. It’s not always the case.

Have you felt like getting pinballed around more than usual, or are you feeling out of control when riding your mountain bike? If yes, there’s a great possibility that the mountain bike fork oil is leaking or needs to be changed as soon as possible.

3. Leaking Air

Typically, your mountain bike’s air shocks and fork can go a long way without losing any pressure. However, in case you need to top up the mountain bike shocks every time before you go on a ride, chances are that you require a mountain bike fork oil change.

If you keep delaying the leaking air, it won’t be too late before you, and your bike is left deflated on a trail’s side.

4. Squelchy Noises

Ideally, your mountain bike forks should be silent when riding. Therefore, if you notice an unusual squelchy sound with riding on terrains, there’s a possible chance that the rebound and compression fork seal has separated, and the damping for oil from the pressurized nitrogen charge needs to be changed.

Having your mountain bike fork oil mixed with natural gases isn’t the ideal damping control formula. Therefore, before the damage prevails and ends up burning a hole in your pocket, park your mountain bike at the side and check the fork oil and seal. 

5. Adjusters Not Moving Properly

Although lose adjusters might not sound like a big deal, they are a prominent sign that you need a mountain bike fork oil change.

The loss of oil within the forks of your mountain bike will create friction, resulting in a direct impact on the shocks, forks, and overall suspension system on the ride quality of the mountain bike.

According to experts, keep an eye on the blue CTD adjuster of your mountain bike and check the oil levels as soon as if it starts spinning around.

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How to Change Oil in Mountain Bike Fork | Step-By-Step Guide

Want to learn how to change the oil of your mountain bike fork. Here is a complete step-by-step mountain bike fork oil change guide to help you out:

Tools You Need:

  • Rubber-faced mallet (or hammer and block of wood).
  • 5mm Allen Key.
  • Caliper.
  • Fork Oil (as recommended by the manufacturer).
  • A container to drain the old fork oil in.
  • Collection of rags.
  • A measuring tool to measure the level of the mountain bike fork oil.

Step for a Mountain Bike Fork Oil Change

Step 01: Even though you can easily remove the forks of your mountain bike, it isn’t recommended if you are planning to conduct a mountain bike fork oil change. Start by cleaning the fork and the suspension system.

Step 02: In order to disconnect the brakes of your mountain bike, unhook the cable at the lever if you have v-brakes or unbolt the caliper if your mountain bike has a running disc.

Step 03: Keeping the mountain bike forks clean prior to the oil change is critical. Although the wiper seals are very effective and that they keep most of the grime and debris out, some contaminating particles do end up sneaking inside.

For this, the mountain bike fork oil change experts recommend checking the fork and its seal every 20 to 30 hours of riding. To make sure that the fork is always clean, wrap a rag around the stanchion to prevent any slippage from getting inside, and use a small screwdriver to gently lift the wiper seals and check for any underlying grime.

Step 04: When you push the wiper underneath the leg of the fork, you will notice a foam ring. Ideally, the foam ring should be well lubricated in oil as it this layer acts as a barrier between the internal components of the fork and the contaminations of the outside world.

Pro Tip: Some manufacturers sell specific oil to keep the foam rings lubricated. This oil is a bit thicker than the standard fork oil.

Step 05: Now that you have checked the foam ring, it’s time to get the lower casting off your mountain bike fork legs. To do this, simply pull up the rebound adjuster knob, which is located at the right-hand leg. Keep the knob somewhere safe while you do undo all the bolts of all the four fork legs.

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Step 06: As the mountain bike fork reveals itself, you will see spring shafts and a damper wedged at the bottom of the lower leg. To release them, either use a mallet or tap the bolts upwards (whatever the settings of your mountain bike suggest).

In case you don’t have a mallet use the combination of a hammer and a brick. Note that, while undoing all the bolts, some fork oil might start dripping. Therefore, have a container by your side to store it.

Step 07: Although it might be a bit reluctant to come off, by now, you will be able to slide the casting of the stanchions. In case it is reluctant to come off, use a hammer/piece of wood.

Once it’s open, you will see that the fork oil that lubricates the spring rods and the damper will start coming out. If no oil comes out, you have neglected the fork for too long!

Step 08: Now that the fork of your mountain bike is in two bits, it’s time to clean everything up. Start by taking the wipers off the stanchions and foam rings. Clean, wash, and wipe all the components.

Use a degreaser and a long bottle brush to clean the inside of the fork’s lower legs. Moreover, before you re-attach them, ensure that all the components are completely dry.

Step 09: With all the components of your mountain bike fork serviced, the next step is to reassemble them and change the fork oil. Push the foam rings and the wipers back onto the stanchions and gently slide the lower leg casting. You may feel a bit of resistance when attaching the bottom of the stanchions.

Step 10: Flip the mountain bike fork over and pour the manufacturer-approved fork oil inside the right-hand leg. As you pour the oil, you will notice that it will start lubricating the space between the fork leg and the stanchion tube.

Now pour the fork oil over the left-hand fork leg and ensure that it coats the spring completely. Push the lower leg back inside and use a trench to reattach the bolts.

Pro Tip: If you are too lazy to do follow the entire mountain bike fork oil change process, simply remove the cap, place the bowl under to drain out the dirty oil, and refill the fork with the recommended level of fluid.

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Wrapping It Up!

Forks are a vital part of your mountain bike and allow smooth suspension, guaranteeing an enjoyable ride. Keep an eye on the mountain bike forks and make sure to service them every 20 to 30 hours of bike riding.

Even though you can undertake the arduous task of changing the oil of your mountain bike fork all by yourself. If you want to get both the forks and seal replaced, it’s advised to hire a professional to ensure that the job gets done correctly.

When riding your mountain bike, keep in mind that the environmental conditions also significantly affect the mountain bike fork oil breakdown. The mountain bike fork oil will break down slowly in the summers.

However, it will decompose at a much faster rate in wet or cold weather. To ensure that your mountain bike’s suspension system works effectively and smoothly, follow the recommended fork oil and seal replacement intervals to the tee.

Also, instead of experimenting, it is advised to always replace the mountain bike fork oil with a manufacturer-approved product.

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Mountain Bike Fork Oil Change | Frequently Asked Questions (FAQs)

Q: How often should mountain bike forks be serviced?

Ans: Ideally, your mountain bike forks should be serviced every 20 to 30 hours of riding. This includes disassembling the forks, inspecting them, and cleaning and re-greasing them. However, in case the mountain bike fork appears to be relatively clean, you can easily ride it for 40 hours without the need of stopping in between for servicing. As recommended by Fox, mountain bike forks and shocks can last for 125 hours.

Q: How much does a mountain bike fork oil change service cost?

Ans: A basic mountain bike fork oil change service will cost you approximately $80 to $150, depending on the amount of damage done and the servicing tools that you need.

Q: How do I know that my mountain bike fork needs an oil change?

Ans: Some signs that your mountain bike fork needs oil change include; excessive oily dirt goo built-up that appears on top of the seal, leaking around the fork seals, and visible wear on stanchions.

Q: Can I change the oil of my mountain bike fork without removing the forks?

Ans: Yes! To do this, start by determining if your mountain bike fork has oil drain plugs. If it does, you are in luck, as all you have to do is remove the caps of the fork tubes and refill them with oil.

Q: Can I change the seal of the mountain bike fork without disassembling them?

Ans: Yes! In order to change the mountain bike fork without assembling, all you have to do is pull out the bolt that secures the cartridge to the lower fork leg. Now, place a seal inside the fork using a split-type fork seal driver. Lastly, to separate the driver from the cartridge, pull the cap and the spring to set the fork oil level.

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