The SR Suntour Aion 35 [paid link] is a standout choice for mountain bikers seeking performance, durability, and comfort on rugged [paid link] terrains. As a versatile [paid link] and highly regarded suspension fork, the Aion 35 [paid link] is engineered to meet the demands of trail riders, all-mountain enthusiasts, and even downhill riders who require consistent and responsive shock absorption. This guide will delve into the key aspects of the Aion 35, including its installation, adjustment, maintenance, troubleshooting, customization options, and compatibility with other drivetrain components.

Features and Design of the Aion 35

The Aion 35 features a 35mm stanchion diameter, offering greater strength and stability compared to narrower forks. This robust design ensures that it can handle the most aggressive riding styles while maintaining a smooth and controlled ride. With a travel range of 120mm to 160mm, it provides excellent suspension for various types of terrain, from rocky descents to technical climbs.

Additionally, the Aion 35 utilizes SR Suntour’s proprietary Air Spring technology, which allows for a more consistent and predictable performance across varying terrain conditions. The fork’s sealed cartridge system helps protect against dirt and water ingress, ensuring a longer lifespan and better performance even under harsh conditions.

Tools Required

• 5mm Allen wrench [paid link]
• 8mm Allen wrench [paid link]
• Torque wrench [paid link]
• 10mm spanner
• Suspension fluid
• Shock pump
• Rags for cleaning
• Fork oil
• Grease

Installation of the Aion 35

Installing the SR Suntour Aion 35 suspension fork is a relatively straightforward process, but it requires some technical know-how and the right tools to ensure everything is done correctly.

Step-by-Step Installation

1. Remove the Old Fork: If you’re replacing an existing fork, begin by removing the front wheel and the brake components. Use a 5mm Allen wrench to remove the fork’s crown race and the stem. You may need to remove the headset to fully release the fork.
2. Prepare the New Fork: Before installing the Aion 35, check the length of the fork’s steerer tube. Use a pipe cutter if necessary to trim the steerer tube to the required length for your frame.
3. Install the Headset: Apply grease to the headset bearings and headset race before placing them on the bike frame. Carefully slide the fork into the headset, making sure the bearings sit correctly in their respective places.
4. Attach the Stem: Once the fork is secured, place the stem on the steerer tube and tighten it with the appropriate torque using a torque wrench [paid link]. Ensure the stem is aligned with the front wheel.
5. Install the Front Wheel: Attach the front wheel to the fork, ensuring that the axle is securely fastened. Make sure the wheel spins freely and that there is no play in the hub.
6. Adjust the Brake System: Install the brake caliper and rotor onto the fork. Ensure that the rotor is aligned correctly with the brake pads and that the brakes are functioning smoothly.
7. Test the Fork’s Travel: Before finalizing the setup, use a shock pump to adjust the fork’s air pressure based on your rider weight and desired compression settings. Check the fork’s travel by compressing it gently to ensure it moves smoothly without any sticking.

Adjusting the Aion 35 for Optimal Performance

Once installed, fine-tuning your Aion 35 fork is essential for achieving optimal performance. The Aion 35 comes with several adjustments to help customize the suspension to your riding style.

Key Adjustments

• Air Pressure: The Aion 35 uses an air spring system, which allows you to adjust the fork’s air pressure for different rider weights and preferences. Use a shock pump to increase or decrease the pressure, starting with a general recommendation based on your weight, then fine-tune it to your preference. A higher air pressure is generally stiffer, while lower pressure provides a plusher feel.
• Rebound Damping: Adjust the rebound damping to control how quickly the fork returns to its original position after compression. Too fast of a rebound can lead to a bouncy ride, while too slow can cause a sluggish feel. Find the setting that provides a smooth ride while maintaining control.
• Compression Damping: Adjust the compression damping to set the firmness of the fork during compression. A firmer setting works well for larger hits and aggressive riding, while a softer setting offers a more plush feel over smaller bumps and technical sections.
• Lockout: If you’re climbing, the lockout feature on the Aion 35 is incredibly useful. It prevents the fork from compressing and helps to conserve energy, allowing you to maintain better pedal efficiency on smoother surfaces.

Maintenance of the Aion 35

Proper maintenance ensures the longevity and performance of your SR Suntour Aion 35. Regular upkeep is essential to prevent wear and ensure smooth operation.

Cleaning and Lubing the Fork

• Clean Regularly: After every ride, wipe down the fork with a rag to remove dirt and grime. Pay special attention to the stanchions, as dirt accumulation can damage the seals.
• Lubrication: Apply fork oil to the stanchions and lower legs to keep the seals properly lubricated. This reduces friction and prevents premature wear.

Replacing Suspension Fluid

Over time, the suspension fluid in your Aion 35 fork will degrade. It is recommended to change the suspension fluid every 50 to 100 hours of riding, depending on how aggressively the bike is used. Follow these steps:

1. Remove the fork from the bike and place it on a stable surface.
2. Use a 10mm spanner to remove the bottom bolts and allow the suspension fluid to drain.
3. Clean all parts thoroughly, ensuring no dirt remains.
4. Refill the fork with fresh suspension fluid as per the manufacturer’s recommendations.

Checking for Leaks

Inspect the fork’s seals for signs of leakage, which could indicate wear. If oil begins to leak from the seals, it’s time for a seal replacement. The process involves disassembling the fork and replacing the old seals with new ones.

Troubleshooting Common Setup Issues

Several common issues can arise when setting up or maintaining the Aion 35. These include air pressure problems, noise during travel, and loss of suspension responsiveness. Here’s how to address them:

Air Pressure Issues

If the fork feels too soft or too stiff, check the air pressure and adjust it accordingly. If you experience sudden pressure loss, inspect the air valve for damage and ensure it is properly tightened.

Noise During Travel

If your fork makes unusual noises, it may be due to dirt or debris trapped in the seals. Cleaning the stanchions and applying lubricant should resolve this issue. If the noise persists, check the fork’s internal components for damage or wear.

Suspension Loss

If you notice a decrease in suspension responsiveness, it could be due to low or old suspension fluid. Replacing the fluid can restore the fork’s performance. Also, check that all bolts and parts are properly tightened.

Customization for Better Performance

The SR Suntour Aion 35 offers several opportunities for customization. Beyond air pressure and damping adjustments, consider the following:

• Upgrade the Air Spring: For riders seeking an even more responsive fork, upgrading to a higher-end air spring can improve performance.
• Adjust Travel: The Aion 35 allows for travel adjustment between 120mm to 160mm. Experiment with different settings to find the best balance between comfort and performance for your style of riding.
• Custom Fork Seals: For riders who regularly encounter wet conditions, upgrading to aftermarket seals designed for better water resistance can help extend the life of the fork and improve performance in muddy or rainy conditions.

Compatibility with Other Drivetrain Components

The Aion 35 is compatible with a wide range of mountain bike components, but it is important to ensure that your bike frame and wheelset are designed to work with a fork of this caliber.

Key Compatibility Considerations

• Headset Size: Ensure that the headset is compatible with a 1.5-inch to 1 1/8-inch steerer tube, which is the standard for the Aion 35 fork.
• Brake Mounting: The Aion 35 supports both post-mount and IS (International Standard) brake mounts. Check your brake system and ensure that your rotors and calipers are compatible with these mounts.
• Axle Type: The fork uses a standard 15mm through-axle, which should be checked against your wheel’s specifications to ensure compatibility.

Comparison with Similar Models

When comparing the SR Suntour Aion 35 to other suspension forks in its class, such as the RockShox Recon and Fox 34, the Aion 35 offers a more budget-friendly price without compromising on performance. It excels in terms of durability and ease of maintenance, thanks to its simple yet effective air spring and damping systems. However, it may not offer the same high-end tuning capabilities as more expensive models like the Fox 34, which features a more advanced damping system. For riders seeking a reliable, cost-effective fork for general trail and all-mountain riding, the Aion 35 is an excellent choice.