How To Set Up Your Mountain Bike Suspension

by | Aug 28, 2020 | Bike Setup, Bike, Skills & Setup

We are going to walk you through the basic steps for mountain bike suspension setup. This can often be thought of as an overly complex task or is otherwise misunderstood, but with the right tools and a bit of guidance it will take you 10 to 15 minutes to sort out. Good suspension setup is essential to having an efficient platform for pedalling and absorbing the terrain you’re riding over, giving you more control over your bike!

How to Set Up Your Mountain Bike Suspension

Tire pressure

The first thing you want to do is set up your tire pressure. If your tire pressures are too hard, it is going to result in a very harsh ride with a lack of grip and will actually increase your rolling resistance over uneven terrain, contrary to popular belief.

If your tire pressures are too soft you’re not going to get enough support, you’ll probably get some pinch flats and damage your rims. Over 30 psi or 2 bar is very high and we wouldn’t recommend that the average rider go too much beyond that. On the lower end of the scale, 20psi or 1.4 bar is getting quite soft and unless you are quite a lightweight rider we wouldn’t recommend you go below that.

Tire Pressure Is A Crucial Part Of Your Mountain Bike Suspension Setup
Tire pressure is a crucial part of your mountain bike suspension setup.

Heavier riders will need more pressure in their tires and maybe even a tougher casing. For reference I weigh in at around 80 kg on the bike and I run about 22psi up front and about 26psi in the rear. Experiment with different pressures to see what works for you, balancing support and traction.

A heavier casing will increase your tire’s dampening performance which will give you more support and more traction as the tire performs better on the ground. So, if you are a heavier or more aggressive rider and downhill performance is important to you, definitely look into getting a tougher tire casing.

Spring rate

Next up we are going to have a look at the spring rate of your suspension. Possibly the most overlooked part of bike setup that we see out on the trails! This is the air pressure or coil weight that you will have in your suspension and gives you the support that you need. This will be dependent on the weight of the rider. The air valve on your fork is usually located on the top left and the air valve on your shock will probably be quite easy to find, it just has a little dust cap on it.

Setting Up Suspension Sag In Your Mountain Bike
You may need a tape measure to set your sag correctly if your suspension products don’t have markers not them.

Setting the shock spring rate

Before you set up your sag you want to make sure that you have set your tire pressure and that you are kitted up in your typical riding gear to get an accurate measurement. Find some level ground to put your bike on and dial back your compression anti-clockwise, that will be the blue dial on your fork or shock.

I like to set up the sag on my rear suspension first. I’ll do this by dropping my seat post and then sitting on the bike and gently settling into the suspension, making sure the O ring is right up against the shock body once I am settled in. I will then gradually get off the bike trying not to compress the suspension any further. If you have RockShox suspension, you will see there are markings on the shock that indicate the percentage of sag that you are sitting at.

If not, you will need to take a tape measure and measure the total stroke length of the shock and then the distance from the shock body to the O ring and work that out as a percentage. That will give you the sag number. On trail bikes you’re looking at about 30% sag on the rear. If you are more marathon or cross country orientated, that will be around 25%. Your sag shouldn’t be any lower than 20% or any higher than 35%.

Setting the fork spring rate

On your fork you are going to have a similar process. You want to push that O ring right down the stanchion and get onto your bike in a neutral riding position. This is standing up on your pedals with some weight on the bars in a natural riding position. Lean your weight backwards as you get off the bike to avoid compressing the fork any further and then measure that O ring distance again as a percentage of the total fork travel.

You’ll be looking for about 15-20% sag on your fork. 20% if you are looking for more squish and comfort, 15% if you are riding quite aggressively on trail or a more marathon style. When you are setting up suspension on your bike front or rear, make sure that you are doing slow and gradual movements so as not to bounce the suspension and get an inaccurate reading.

If your suspension is sagging too much then you will need to add air pressure and if it is not sagging deep enough into its travel you will need to reduce the air pressure. Do this in increments of 5 to 10 psi on the rear and 2 to 5 psi on the fork.

Mountain Bike Suspension Setup Guide

Compression damping

Next up we are going to look at compression damping. Adding compression damping will increase the resistance to your suspension compressing into its travel. Too much compression damping will result in a harsh ride and a lack of traction. Too little will result in suspension that is diving too much and doesn’t give you the support that you need. 

Setting Compression Damping On Mountain Bike Suspension
Setting compression damping on mountain bike suspension

Most stock suspension will come with one compression dial and that would typically be your low speed compression and so for now we are going to just talk about low speed compression. You’ll want to turn that dial (blue) and count how many clicks there are and then start off with a base setting at about a third of your way into those clicks from the anti-clockwise (open) position.

While you are out riding, make small adjustments of 1 or 2 clicks to work out what feels best for you, whether you prefer the increased support or something a bit more supple. You can also check your manufacturer’s recommended settings on their website to give you an idea of what you are looking for.

Rebound damping

Finally we are going to look at your rebound settings. Rebound will determine the speed with which your suspension will recover after compressing. If it is too fast you might find that you are going to get kicked by jumps and other features on the trail. And if it is too slow, your suspension will not recover properly after a hit. This is always the red dial on your suspension. Turning it clockwise will increase the rebound damping which will result in a slower rebound.

To set your rebound on the fork, turn the dial clockwise all the way in so it is very slow and then push down on the handlebars to compress the suspension and then quickly release pressure off the handlebars to let the suspension kick back. Keep increasing the speed of your rebound and repeating this process until the front wheel is just lifting off the ground and then dial it back in 1 click.

Setting Rebound Damping On Mountain Bike Suspension
Setting rebound damping on mountain bike suspension.

Likewise when you are setting up rebound on your rear suspension, you want to dial it all the way in so it is slowest and then either drop your weight quickly onto the seat or roll off a small ledge such as a pavement. You ideally want the suspension to be returning just past the sag point and then settling down to sag again. Not bouncing around too much or failing to recover back to sag.

Once again, while you are out on the trail, pay attention to how your bike is feeling. If the suspension feels like it is wallowing a bit and not recovering properly then speed up the rebound by 1 or two clicks. If it feels like it is too fast and kicking back at you, you can slow it down by 1 or 2 clicks.

Want to go deeper?

If you are looking for a more in depth look at suspension set up we recommend you check out the “Dialed” videos on Fox Suspension’s YouTube channel. We’re sure a lot of you have questions after this bike setup series.

Feel free to use the comments section to ask any of those questions or let us know what you found helpful. Also be sure to check in with your local bike shop for any advice or help in setting up your bike. 

We’ll see you on the trails! J-Dogg.