Replacing Shocks On Trek Fuel: A Step-By-Step Guide

Changing the shock on a Trek Fuel mountain bike is a complex process that requires careful consideration and mechanical expertise. It is important to note that adjustments to the front suspension forks and rear shocks are necessary to optimise performance for the rider. While some riders choose to adjust their suspension according to recommendations, others opt for personal preferences and ride styles. When it comes to replacing shocks, compatibility and clearance are crucial factors. For example, the Fox Factory DPX2 shock may not fit certain Trek Fuel models due to seat tube clearance, while the RockShox Super Deluxe Air shock does not fit due to lock-out lever interference. It is always recommended to refer to official guides, forums, and experts for specific instructions and compatibility information before attempting any modifications.

Use the Trek Suspension Calculator to find your ideal sag measurement

The Trek Suspension Calculator is an important tool to help you optimise your suspension settings for your riding weight. It is a crucial component of getting the best performance out of your mountain bike.

To use the calculator, you will first need to put on your full riding gear, including shoes, a helmet, and a pack, to ensure accuracy. Next, set the compression damping to "open" by turning the blue knob on your fork and the blue lever on your shock counter-clockwise.

Now, use the Trek Suspension Calculator to find a good starting PSI for your MTB and your weight. Then, use a shock pump to adjust the shock's PSI to match the starting point. With the shock pump attached, push down on the saddle to engage the shock. Check the gauge and adjust the PSI if necessary.

At this point, you can mount the bike, either with a friend holding you up or by leaning against a wall. Move the rubber o-rings on the fork and shock up against the seals. Now, carefully dismount without further compressing the suspension—leaning the bike to one side will help with this.

Finally, measure the distance in millimetres between the o-rings and the seals. This is your sag measurement. Input this measurement into the Trek Suspension Calculator to find your ideal sag measurement in millimetres. If your measured sag is not within 2-4mm of the recommended sag, adjust the PSI using your shock pump. If the o-ring travelled too far, add air. If it didn't move far enough, use the bleed valve to remove air.

Set the compression damping to open

Setting the compression damping to "open" is an important step in adjusting the suspension on your Trek Fuel mountain bike. This process will allow you to control the speed at which your wheels move up and down and optimise the performance of your bike.

To set the compression damping to "open", you will need to turn the blue knob on your fork all the way counter-clockwise, and the blue lever on your shock counter-clockwise. This will decrease the compression damping, allowing your suspension to compress more quickly. As a result, your bike will feel softer and more supple, responding more readily to bumps on the trail.

It is important to note that decreasing the compression damping will also increase the movement of your bike under body movements, pedalling, and braking. Additionally, very light compression settings that feel comfortable over small bumps at low speeds may feel uncontrolled when taking high-speed hits. Therefore, it is crucial to find the right balance that suits your riding style and the types of impacts you expect to encounter.

After setting the compression damping to "open", you can use the Trek Suspension Calculator to find a good starting PSI for your weight and adjust the shock's PSI accordingly. This will ensure that your suspension is properly set up for your riding needs.

Adjust the PSI with a shock pump

Adjusting the PSI with a shock pump is a crucial step in achieving the optimal performance of your Trek Fuel mountain bike's suspension system. Here is a detailed guide on how to do it:

Firstly, ensure you are in full riding gear, including your shoes, helmet, and pack, to accurately set the sag. Set the compression damping to "open" by turning the blue knob on the fork counter-clockwise and the blue lever on the shock in the same direction. This will allow you to adjust the air pressure effectively.

Next, use the Trek Suspension Calculator to determine a suitable starting PSI for your MTB based on your weight. This calculator is designed to optimise your suspension settings for your specific weight. Once you have the starting PSI value, use the shock pump to adjust the shock's PSI accordingly.

With the shock pump still attached, push down firmly on the saddle to engage the shock. Check the pressure gauge and make any necessary adjustments to the PSI. This step ensures that the shock is activated and functioning correctly.

Now, you will need assistance. Mount the bike and ask a friend to hold you up, or alternatively, lean the bike against a wall. Move the rubber o-rings on the fork and shock so they are against the seals. This step is important for measuring the sag.

Carefully dismount the bike without compressing the suspension further. Leaning the bike to one side can help with this. Once you have dismounted, it's time to measure the distance in millimetres between the o-rings and the seals. This measurement is your sag value.

Finally, refer to the Trek Suspension Calculator again to find your ideal sag measurement. If your measured sag is not within the recommended range of 2-4mm, adjust the PSI using the shock pump. If the o-ring travelled too far, add more air. If it didn't move far enough, use the bleed valve to release some air.

Remember, these initial settings are just a starting point. You may need to experiment with different PSI levels and sag measurements to find the combination that suits your riding style and preferences.

Measure the distance between the o-rings and the fork and shock

Measuring the distance between the o-rings and the fork and shock is a crucial step in setting up your Trek bike's suspension. This process ensures that your mountain bike performs optimally for your riding style and weight. Here's a detailed guide on how to approach this:

Firstly, it's important to understand the role of o-rings in your Trek bike's suspension system. O-rings are used to monitor shock and fork travel, allowing you to adjust your suspension settings for optimal performance. They are typically placed on the fork and shock to measure sag, which is the amount of downward travel the suspension experiences under your weight.

To begin measuring the distance between the o-rings and the fork and shock, start by putting on your full riding gear, including shoes, a helmet, and a pack, to ensure accurate measurements. Next, set the compression damping to "open" by turning the blue knob on your fork and the blue lever on your shock counter-clockwise. This will allow you to make adjustments to the suspension.

Now, you'll need to use a shock pump and a measuring tape to fine-tune the settings. First, use the Trek Suspension Calculator to find a suitable starting PSI for your MTB and weight. Then, attach the shock pump and adjust the shock's PSI to match the recommended starting point. Firmly push down on the saddle to engage the shock and make any necessary adjustments to the PSI.

The next step is to carefully mount the bike. You can do this by having a friend hold you up or by leaning the bike against a wall. At this point, you should move the rubber o-rings on the fork and shock so they're firmly against the seals. Remember to be gentle and avoid further compressing the suspension during this step.

Once the o-rings are in place, carefully dismount the bike without compressing the suspension. You can make this easier by leaning the bike to one side. Now, take your measuring tape and measure the distance in millimetres between the o-rings and the seals. This measurement is your sag measurement and will be used to fine-tune your suspension setup.

After obtaining the sag measurement, use the Trek Suspension Calculator again to find your ideal sag value in millimetres. If your measured sag is not within 2-4mm of the recommended value, you'll need to make adjustments to the PSI. If the o-ring travelled too far, add air using the shock pump. On the other hand, if it didn't move far enough, use the bleed valve to release some air.

Finally, after a few rides, it's important to re-check your setup by measuring the distance between the o-rings and the shock body or fork lowers. Over time, you may need to experiment with different levels of sag and rebound to find the perfect combination for your riding style and preferences.

Experiment with different levels of rebound and sag

The rebound is how your fork or shock returns to its original setting. The rebound damping controls the rate at which your suspension rebounds.

Setting up your rebound

The best way to set up your rebound is to get out into your street. In your street, you'll find the perfect obstacle for setting rebound - a kerb. Rolling off a kerb is pretty similar to the general hits your bike will get when riding down a trail.

Setting your rebound to fully open/fast

Set your rebound to fully open/fast. RockShox has a picture of a hare to let you know you're heading in the right direction. Other manufacturers have their own symbols, so check your manual and see what it is.

Rolling off your kerb

Roll off your kerb. You don't want to be moving your body around as you do this, you want to stay as still as possible and try and use the same position as you used when you set your sag.

Adjusting your rebound

If you feel your fork go up and down more than once, add some more rebound damping.

Do this until your fork only goes through one shock cycle. You now have a baseline setting.

If you have rear suspension, now do exactly the same all over again.

Keep your rebound in harmony

You will also want to make sure your fork and shock match each other. Setting one with a fast rebound and the other slow will give you a little flying lesson out on the trail. It will also feel horrible. You want your suspension units to work in harmony with each other.

You can check your rebound settings are similar by bouncing down and back up while still in your street. You'll want most of your weight on your feet when you try this. If your bike tries to throw you over your bars, then speed up your fork or slow down your shock's rebound. If you feel you're getting thrown backwards, then speed up your shock or slow down your fork. Eventually, you'll get there, and you'll be rewarded with great trail time.

Frequently asked questions