The Big Questions - How Should I set up my Suspension?

Published: 19th July 2013 | By AngusMcIntosh

For the next in our series of Big Questions we are posing on MoreDirt, Angus is delving a little deeper into setting up your suspension for the trails and busting the jargon behind both your forks and shocks…

There’s a whole load of technical words and jargon when it comes to suspension such as compression, sag, rebound and loads more that to ensure you get the most out of your bike you are going to need to understand how to manipulate your settings to suit your needs.

Some of the words and terms discussed won’t be 100% relevant to everyone as some forks and shocks have more adjustability than others. Like almost everything mountain bike related in this world… The more money you are willing to spend the more control over your set up you will have!

Just because your forks aren’t Kashima coated and don’t feature high and load speed compression dials doesn’t mean this article isn’t going to be for you! So read on…

We shall start from the very beginning…

First things first before you even think about changing anything on your suspension you have to ensure that you understand your tyre pressures. If you have your tyre pressure wrong grip and rolling speed are going to be massively affected.

You have to remember you almost have an inch of travel in your tyres at your disposal before your suspension even begins its stroke. Just because it says you should be running your tyres at 65psi on the side wall of your tyre that doesn’t mean that’s where you will get the best performance!

If you start at 30psi as a baseline figure. If you are above average in weight go for a little more, below average weight a little less. Its very hard to put an exact figure on this kind of thing so many may argue that I’m sticking my neck out generalising tyre pressures to this extent but it’s a good starting point and something you should take time to work around yourself.

Once you are happy with your tyre pressures, We’ll move onto the actual suspension settings…

Find your way around your forks and locate some of the components that make up a front fork we will talk about later on in the article...

Just a few of the many components that make up a simple mountain bike air shock...

Sag

One of the most important things you have to ensure you get in the right place is your sag. Somewhere close to about 30% of your travel is a good starting point.

Getting the correct 30% of sag basically means that the “spring” (whether that be air or coil) has the correct set up to your weight. When you sit on the bike 30% of the travel on the shock or fork is put to use…

You can do this by changing the air pressure in your fork or shock, changing the spring on the fork or shock or even adjusting the preload on the coil.

A quick word on Preload...

As a spring compresses closer to being fully compressed it takes more energy to continue compressing... This is called “Ramping up” Imagine a curve that exponentially increases and looks a little like a ramp for your bike!

In very simple terms by adjusting the preload on the spring you are effectively making the starting pressure required to compress the spring stiffer which would translate into reducing the level of sag. Reducing the preload will make your fork or shock feel softer and increase the level of sag…

The guys at Mojo have a handy video on setting the correct amount of sag on your bike that you can find below...

Rebound –

Changing the rebound on your fork or shock will control how fast the fork or shock returns back to its starting point after compressing.

So many riders love very fast rebound and feel that there shock or fork isn’t set up or working correctly unless its pogo sticking and either smashing your seat into your backside or bouncing your front wheel into the air. This is not the case at all!

Different riders have different personal preferences for set up but one thing is for sure… Have your rebound set super fast you’ll be in for a pretty wild ride and will struggle for grip over roots and technical section as your wheel is fired into the air.

Forks and shocks are horribly complicated on the inside to the untrained eye... That doesn't mean dialling your set up has to be!

On Fox systems Mojo recommend 6 clicks from negative as a good starting point. Rockshox and other brands will be something similar but once again it’s not an exact art and the only way you will find out what’s perfect for you is by getting out on the bike and testing a few different settings, getting a feeling for it and seeing what works best for you and your bike.

Compression –

On more basic products you may only have the facility to adjust your sag via air pressure or changing the actual springs and rebound adjustment via a knob on the bottom of the lowers.

More complicated forks or shocks will allow you to adjust compression… This will really enable you to dial in the suspension to your exact personal preference!

What does compression mean and what does it mean to me?

Compression in its most basic and simple terms is oil flow around the suspension. By changing the compression settings you are managing how the oil moves around the shock and therefore how it behaves under different conditions you put the fork or shock through.

Not every suspension product on the market has compression adjustment but if your forks and shock do it’s worth spending some time experimenting with them to get the most out of the product.

Sometimes the compression is split into 2. Low speed and High speed.

Low speed compression –

This is going to come into play when your riding bits of trail like steep off cambers when the speed you are actually travelling on the bike will tend to be a bit slower. Changing your low speed compression will have an effect on how the fork or shock behaves when the lowers are sliding up the stanchions at a lower speed. This should change how your bike feels and behaves under pedaling.

A lot of riders go for very little low speed compression to get a very supple feeling at the beginning of the stroke and cope with small bumps but to counteract this they will have their high speed compression wacked right up to have a plush response on the small bumps and roots but be stiff on landing from big jumps and in brake bumps.

High Speed Compression –

This comes into play during the big hits like braking bumps at high speed and hard landings. High speed compression comes into play as the lowers get slammed up the stanchions very quickly at a "high speed" which is normally when your traveling at a high speed!

Adding more high speed compression will stiffen the feel of the forks up as its exposed to those high speed large impacts and should give you more control.

Conclusion

The only way I think there really is of understanding the settings in real detail is by tinkering with everything and seeing litteraly what changes what. Eg. If I run with both the high speed and low speed compression completely off at the negative side how does it feel and the bike behave. If I run them both all on how is that different... It could take a while but if your interested to learn and gain a greater understanding this is the way to do it!

Don’t be scared to tinker with the dials! You aren’t going to break your suspension by adjusting the knobs to far! It's important to remeber that there is no magic set up that will be perfect for everybody on every trail.

The last and most important thing to remember...

A rider who is comfortable with their set up is a faster and better rider… That doesn’t mean to say their suspension gives them the most comfortable ride but they have a comfortable understanding of their own set up and how it’s going to perform on the trail.

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