The Suspension Sag Issue – Free Performance Upgrade In 10 Minutes

by | Apr 14, 2022 | Bike, Bike Setup, Skills & Setup

We are addressing one of the most common issues that we see at mountain biking events and the trailheads around the country.
Is it lycra pants? Is it noisy brake pads? No.. It is suspension sag.
Now before you eyes glaze over and you return to scrolling your instagram reels, trust us when we say that this isn’t difficult to fix and that it is a real game changer!
We have covered a range of topics recently in the build up to the KAP sani2c Adventure and Race on the 11-14th of May and this one could be the most crucial.

Clever engineers from around the world have gifted us highly efficient full suspension mountain bikes that promise to absorb boulders and craters all the while “climbing like a hardtail” or some sort of mountain goat. Now exaggerations aside, they’ve developed some impressive machines that balance support, efficiency, and bump absorption! The design is not fool proof though and requires a little bit of attention from us, the owners of said machines.

The Suspension Sag Issue - Free Performance Upgrade In 10 Minutes
The pros will take time to ensure their suspension pressures are dialled in properly to maximise the efficiency of their ride on the climbs and descents!

So on the issue of suspension sag. We’ve seen countless riders slogging their way up what I like to call ‘two hills’ when the air pressure in their rear shock has slowly depleted over time and meaning that the bike is sitting deep in its travel. The result is a slackening of the bike’s geometry, your weight moving back over the rear axle and the relative gradient of the hill increasing. Unnecessary energy is spent and performance is sub-optimal. Not what I would call a good time. If you’re finding this relatable then continue on, and if you’re thinking of your mate who doesn’t know where to find the shock on his bike send them the link!

The Suspension Sag Issue - Free Performance Upgrade In 10 Minutes
The rear suspension on your bike relies on the shock being accurately pressurised in order to provide the balance of support and compliance it was designed to.

The solution to the sag issue is a humble piece of kit called a shock pump. If you have one handy, hooray! If you don’t and aren’t particularly interested in becoming the owner of one, simply pay a visit to your local bike shop or ask that friend of yours who spends way too much time talking about this kind of stuff. You could also phone Farmer Glen and he’ll happily help you sort it out! Jokes aside, please do not contact Farmer, he’s very busy sorting out some legendary trails for you to ride in May!

The Suspension Sag Issue - Free Performance Upgrade In 10 Minutes
The humble shock pump. If you own a suspension bike, it is well worth having one of these in your drawer.

Setting the sag is a fairly straightforward process. Simply pressurise the rear shock to the point where it will sink 25-30% of the way into it’s travel when you are seated on the bike. For more detail on this process click this link here. Most forks will have a pressure guide printed on them for different rider weights and some bicycles may have this on the frame for the rear shock as well.

The Suspension Sag Issue - Free Performance Upgrade In 10 Minutes
Look out for a printed guide such as this on your fork to give you a starting point for suspension pressure.

Once you have your setting, either from figuring it out yourself or getting some help from your bike shop or technically savvy friend, jot the number down on your phone’s notes app for future reference and check the pressure in the suspension every few weeks or monthly. This number should stay consistent unless your total riding weight has changed more than a couple kilograms due to adding or removing a loaded backpack, intense endurance efforts causing you to loose a lot of body mass, or intense MacDonalds efforts causing an opposite body mass response.

Now that you have an appropriate amount of air in your suspension, go and run wild enjoying the balance of support, efficiency and compliance just as those clever engineers intended you to!

We’ll catch you next time. Keep it rubber side down.

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