Suspension Essesntials

Suspension Essesntials

Being Quenstown's local bike shop we get asked a lot of questions around setting up a bike, were always keen to help however we thought we would try and help you understand some of the things you can do. We’re not getting into complex suspension tuning, this is just about getting a good base set up that will allow your bike to work properly and hopefully make riding it more enjoyable.

It doesn’t matter if you have a $3000 or a $15000 bike, both will ride like a complete lemon without the suspension set up correctly. Luckily it’s pretty easy to get it in the ballpark, and it won’t cost you a thing… at least to begin with.

There are so many new and exciting accessories and upgrades available that you too can join the vicious circle and search for the holy grail of perfect mountain bike suspension.

Shall we begin?

What do we want to gain from our suspension?



Most (unfortunately not all) bike manufacturers have spent a lot of time designing the geometry of your bike specifically the angle of the forks, the height of the bottom bracket to make sure the suspension works well.

When the fork or shock compresses this changes those angles and measurements, so getting the fork and shock working together will allow the geometry of your bike to handle as it was intended.


Balance between the front and back of your bike is key. This will keep the handling of your bike consistent, allowing you to become familiar with its reactions in different situations. Keeping your body centered on the bike, feeling more stable and ideally more confident.



It’s easy to think suspension is just for going downhill and doing sweet jumps.

While these are made easier with suspension, the biggest advantage of well set-up suspension is traction.

It’s all about keeping you wheels on the ground when you need them there.

There’s no braking, turning or accelerating if your tyres aren’t on the ground.

Allowing your tyres to conform to rocks, roots and holes will give you more grip in corners allowing you to carry more speed. When you brake on loose or rough ground the suspension will allow you to brake harder and slow down sooner.


So the end result of a good suspension set up is comfort, control, stability, speed and more fun.





Before we even think about touching our suspension, we need to do the single most important thing to your bike… check your tyre pressure. Don’t laugh.


You need to find a tyre pressure that works well on the terrain you like to ride with your tyres and then set that pressure EVERY time you ride. This is hands down the easiest and best thing you can do to improve the handling of your bike. It creates a consistent feel that you will become accustomed to, increasing your confidence and it will provide a base level for you to adjust your suspension from. Tyre pressure also has an effect on how your suspension works and feels, so having it set the same every ride is one less thing to think about.

Get yourself a digital tyre pressure gauge before you do anything below this sentence.


Righto, now that we’ve got that out the way lets start setting up your suspension.

There are lots of factors that effect how your suspension works. The speed you are moving, the size of the bumps, the steepness of the trail. But the one thing that effects it the most is you; your weight, height and position on the bike.

So the best place to start is by setting the rear shock to the rider.

Most modern trail/enduro bikes will have an air shock fitted rather than a shock with a coil spring. Air shocks use a small chamber of air as a spring; these can be easily adjusted by changing the PSI to suit the rider. To do this you will need a specific “shock pump” rather than a normal tyre pump. Coil shocks require different weight springs to be fitted to adjust how soft or firm they are.


To keep it simple we will just talk about air shocks for now, although the principles are the same for both.




Sag is the amount the shock compresses when the rider sits or stands on the bike when it is stationary.

To set sag correctly make sure the lock out lever is fully open in descend mode if your bike has one. These are usually blue levers with markings on the shock letting you know what each position does. Have a look.

Most bikes have a recommended amount of sag they are designed to sit at. For example some have a range between 30-35%, and others are very specific like “23mm”. So check the manufacturers recommendations online for your model of bike.

What does 30% sag even mean? And why is the other number in millimeters not percent?


Short answer:

None of the companies in bike world can agree on anything.


Proper answer:

We measure sag on the shock, not the amount the rear wheel moves.

Have a look at you’re your shock, there should be a little rubber O-ring on the outside of the shaft (shiny, slippery bit). Push this O-ring towards the middle of the shock until it stops, then push on your seat. Hopefully the O-ring has moved down the shaft of your shock, that is sag…sort of.

The amount the O-ring moved down the shaft is the Percentage (%) of sag.

So if the shaft is 65mm long, 30% of that is 19.5mm. So there’s your millimeter measurement.

Some shocks have handy little markings on the shaft with 20/30/40%, others you will just have to bust out your ruler.

Now its time to sit on your bike, it is important to be dressed in what you would normally ride in so shoes, helmet and backpack if you ride with one.

Once sitting on your bike give it a few bounces then lean against something or have a friend hold you up, if they’re a really good friend have them push the O-ring up the shaft… on the shock. Otherwise you can reach down and set it.

Now carefully climb off your bike without bouncing or bobbing and have a look where the O-ring is sitting.

Does it match up with the manufacturers recommendations?

If it doesn’t you can add or remove air using your shock pump via the air valve on your shock and repeat the process.

Once you’ve got the desired sag, write down the amount PSI in the shock. It’s good to know and you may need it later.


I mentioned at the beginning that we weren’t going to get into the complex side of suspension tuning, turning dials etc… but we do need to touch on the Rebound adjustment.

Rebound is usually a red dial/knob on your shock, it controls the speed at which the shock returns to full extension after it has been compressed (hit a bump etc).

So the heavier the rider, the stiffer the spring (the more air you have in there) the faster that spring will rebound.

We can use the rebound adjustment to control the speed of return, clockwise to slow and anti clockwise to speed up.

There is no perfect setting for this; the general rule of thumb is the more air you add the more you will need to slow it down. Or if removing air, you should speed it up.

Too fast and it will feel like a pogo stick and bounce you off the track, too slow and the bike will begin to feel like your suspension isn’t working.

A lot of suspension manufacturers have base settings for these adjustments on their websites so check them out for your model of shock.


Now that we have your shock sag set, up next is your fork:


Like I mentioned earlier we need to find a balance between the fork and shock on your bike.

If your fork is noticeably softer than your shock it will dive down when braking or on steep trail, this tends to throw you forward.

If it is to stiff it won’t have much traction and tends to push out from under you in the corners.

We want the riders weight to be centered in the bike. So by having the suspension balanced, the weight will be distributed correctly to the front and rear wheel providing traction and control.

With a lot of things, there are different ways of achieving the same goal but this is our tried and tested recommendation for setting up your fork.

Most modern forks use an air spring; the valve is usually located under a cap on the top of the left leg. You’ll need a shock pump again to make adjustments.

Some forks have an air pressure chart on the left leg, with rider weights and corresponding recommended air pressures. These are a good starting point.

A lot of forks run roughly the same PSI per Kg of rider weight, so if you are 70kgs start with 70psi.

Once you’ve added or removed air, give the fork a bounce up and down. Your fork may also have a pedal/descend lever, make sure this is in the open descend position, usually anti clockwise.

Your fork should have a rubber O-ring on the leg; push this all the way down to the bottom of the fork leg. While you’re at it slide the shock O-ring back to the middle as well.

Now for the super technical part, get on and ride up the road/driveway and bounce up and down on your bike making sure your weight is centered. Is it compressing evenly? Does it feel balanced?

Check the little O-rings, hopefully they have both moved a similar percentage front and rear, you can make small adjustments of 5-10psi to the fork pressure if needed.

Write the fork pressure down 

The rebound control works the same as the shock, and usually found at the bottom of the right leg.

Now that we have your suspension at least in the right ballpark, go ride it on some trails and take note of what you feel.

Push the O-rings down every ride and regularly check where they are afterwards.

I would give it a few rides before making more adjustments, allow yourself to get familiar with the changes. A centered, confident riding position will give different results to a nervous, hanging off the back of the bike riding position. A lot of the time small adjustments in body position can improve the way the bike handles better than turning dials. Ideally it’s a combination of adjusting both riding style and bike set up that will achieve the best result. 

With so many adjustments and settings available, it’s easy to get very confused and end up going in circles.


Just make one small change at a time.


Once you’ve been riding confidently and consistently for a while, you may want to make some small changes to your set up, to get a little extra performance, stability or traction out of your bike.

The most common, and simplest is fitting volume reducers to either your fork or shocks air spring. These are usually little plastic spacers, that when installed change the feel of your suspension as it compresses. These are particularly useful for heavier or more aggressive riders.

Bikeaholic stock volume reducers for most models of fork and shock, and they are best fitted by a mechanic. So come chat to us and see whether you’ll benefit from having some installed.


You may have a bunch of other dials on your shock and fork; some models have more adjustments, which allow for fine-tuning. I’m not going to get in to these otherwise we’ll be here all day. For information on these you can either jump online to check the manufacturers set up guide, or pop into Bikeaholic for a talk.

Here in Queenstown we are lucky to have some of the best riding anywhere in the world, and because there are so many people riding we also have some of the roughest trails out there. These provide a great test to mountain bike components, some of which aren’t always up to the test. To keep the overall price of your bike down, some models will have more basic parts fitted. This applies to your suspension as well. Sometimes no matter how good you set up your suspension, if you are riding hard on rocky, brake bumped terrain it just won’t be up to the task of keeping you in control.

Because the suspension industry is constantly evolving and advancing, there are plenty of upgrades and improvements available for most forks and shocks. For example if you have a slightly older fork, we can install an updated air spring, which massively improves the feel and performance of your fork.

Bring your bike into Bikeaholic and we can see if any of these upgrades can improve your ride. It’s a relatively cheap way of improving the handling of your bike, allowing you to ride more without beating up your hands and body on rough trails.



Speaking of cheap, keeping the moving parts of your fork and shock clean costs practically nothing.

Use a good bike cleaner and water to remove dirt, mud and debris (avoid using a water blaster). Wipe away built up dust and grim from around the seals with a soft cloth will mean less wear on the seals and longer intervals between servicing.

Apply a suspension lube on fork and shock seals; they flush out hidden dirt from the seals preventing excess wear and improve performance by reducing friction.


Your fork and shock have a lot of moving parts, oil, air and seals.

Without regular maintenance they will begin to lose their performance, start to feel sticky or harsh and eventually begin to wear out. This not only affects the way your bike rides, but also becomes very expensive.

In a typical Queenstown summer of riding I would recommend getting your fork serviced twice and shock serviced at least once.


There are different levels of suspension servicing available starting with basic cleaning and lubing and going right up to full strip down and custom tuning. Bookings can be made online

The best place to start is preventative maintenance; don’t wait until there is oil leaking or signs of wear showing. Basic servicing is relatively inexpensive and will not only allow you to get the most enjoyment out of your bike, but also years of use.

Hopefully this gives you a better understanding of the squishy things beneath you, the main thing is you cant dial anything in if your bike is in your garage so get out and hit some trails. Remember advice costs nothing (sometimes a pack of Timtams help though) so pop by any time and have a yarn about what your finding and we will endeavour to put you right.

100% Service, 100% MTB, 100% Bikeaholic.