Getting your bike’s suspension dialed in makes every ride smoother and more controlled. Learning how to add air to bike suspension is the first step to getting that perfect setup. It’s a simple task you can do at home with just a few tools. This guide will walk you through the process safely and effectively.
How to Add Air to Bike Suspension
Adding air to your fork or shock is the primary way to adjust its stiffness, or sag. Getting the right air pressure is crucial for performance and comfort. Before you start, you’ll need to gather a few essential items.
What You’ll Need
Having the right equipment makes the job easy and prevents damage. You won’t need much, but each item is important.
- A high-pressure suspension pump. A regular tire pump won’t work as it doesn’t have the right gauge or fitting.
- Your bike’s owner’s manual (to find the recommended pressure range).
- A friend to help you measure sag, or a zip tie to use as a marker.
- A clean cloth to wipe any dirt away from the valve.
Step-by-Step Guide to Adding Air
Follow these steps carefully to adjust your fork and rear shock. Taking your time here ensures you get accurate results and avoid any issues.
1. Find the Recommended Pressure
Check your bike’s manual or the manufacturer’s website. Look for a pressure chart based on your weight, including riding gear. This is your starting point, not a fixed rule.
2. Prepare the Suspension
Unlock your suspension by turning the lever to the “open” or “descend” position. Wipe any dirt or debris from the air valve on the fork crown or shock body. This prevents dirt from getting inside when you attach the pump.
3. Attach the High-Pressure Pump
Remove the valve cap. Firmly press the pump’s head straight onto the valve. You should here a slight hiss as it seals. Make sure it’s on tight so no air escapes during pumping.
4. Add Air in Small Amounts
Pump slowly and check the gauge frequently. Add air in small increments, like 5-10 PSI at a time. It’s easy to add to much air, but harder to take it out precisely.
5. Check and Set Sag
This is the most important part. Sag is how much the suspension compresses under your weight. Getting it right optimizes traction and control.
- With the air pressure close to your target, get on the bike in your normal riding position. Have a friend hold you steady, or lean against a wall.
- Bounce up and down a few times to settle the suspension, then find a neutral stance.
- Have your friend push the zip tie on the fork stanchion or shock shaft down to the seal. Gently get off the bike without compressing the suspension further.
- Measure the gap between the zip tie and the seal. Compare this to the total travel. Aim for 15-20% sag for mountain bike forks, 20-30% for rear shocks, and less for road suspension.
If the sag is to deep, add more air. If it’s not deep enough, let a little air out by pressing the pump’s bleed valve.
Common Mistakes to Avoid
Avoiding these pitfalls will keep your suspension working well and lasting longer. Even experienced riders can sometimes make these errors.
- Using a tire pump. It lacks the precision gauge and can damage the valve.
- Not checking sag. Guessing the pressure rarely leads to good performance.
- Forgetting to cycle the suspension after adding air. This equalizes pressure in the positive and negative chambers.
- Ignoring temperature changes. Air pressure changes with temperature. Check it occasionally, especially on very hot or cold days.
When to Let Air Out vs. Add Air
Knowing which way to adjust is key. Your ride feel will tell you what it needs.
Add more air if your bike feels harsh, is bouncing off bumps, or if the sag measurement is to deep. This means the suspension is to soft.
Let air out if the suspension feels stiff, isn’t absorbing small bumps, or if the sag measurement is to shallow. This means it’s to firm for your weight.
Maintaining Your Suspension
Regular checks keep everything working smoothly. A little maintenance goes a long way for suspension life.
- Check pressure every few rides, or before a big day on the trails.
- Clean the dust wipers and stanchions after muddy rides.
- Listen for unusual noises like squelching or knocking, which may indicate a service is needed.
- Get a full professional service annually, or as recommended by the manufacturer.
FAQ: Your Suspension Questions Answered
How often should I add air to my bike suspension?
You should check the pressure every 2-3 rides. Suspension seals can slowly leak air over time. Temperature changes also effect the pressure inside.
Can I use a CO2 cartridge to add air?
It’s not recommended. CO2 cartridges release gas to fast and make it impossible to control the pressure accurately. They are for emergency tire repairs, not precision suspension tuning.
What if my suspension still feels wrong after setting sag?
Sag is just the starting point. You may need to adjust rebound or compression damping next. Also, consider your riding style—aggressive riders often run slightly higher pressure.
Is the process the same for all air forks?
The basic steps are universal, but valve locations and recommended sag percentages can vary. Always consults your specific fork’s manual for the best results.
My shock has two air valves. What do I do?
Some shocks have a main and a negative air chamber. Usually, you only add air to the main valve (often marked positive). The negative chamber self-equalizes. Check your manual to be sure, as some models require a special procedure.
With these steps, you can confidently adjust your bike’s suspension for any trail. Regular checks and small adjustments will ensure your bike always feels its best. Remember, the right setup makes riding more enjoyable and can even help you ride faster and with more control.