"Suspension tuning" is a big word. Everyone immediately thinks of the complex inner workings of modern suspension elements, special tools and clinically clean workspaces. However, tuning doesn't just start when you're only talking in technical jargon, but often starts with very simple things. The basic prerequisite for any meaningful suspension tuning is that you first understand how modern MTB suspension works and are familiar with finding the optimum setup for your own bike.
The Basic concepts relating to suspension and damping and the customised suspension setup have already been covered several times (see Set up MTB suspension correctly). If you have understood all this and implemented it on your bike, you can be sure that you are already utilising the greatest potential of your suspension elements - the clever engineers of the suspension fork and shock manufacturers have already made sure of that.
But even if you have complied with all of this, it sometimes happens that, for example, the full suspension travel cannot be utilised, that the suspension fork dips too much in steps despite the correct sag or that the shock still responds insensitively even when freshly serviced. These are all problems that readers contact us about on a daily basis. And that's where tuning starts! Depending on the scope, the measures can lead to anything from slight improvements to a completely new riding experience.
As a general rule, changes to the damping that go beyond the adjustment functions are required much less frequently than you might think. It is usually only very demanding bikers (racers, for example) and those who fall into the extremes of the weight curve (under 60 kg and over 100 kg). For these riders, the set-up spectrum of the standard suspension elements is sometimes really no longer sufficient. However, such changes should really only be left to the specialists.
The greatest tuning potential lies in the suspension fork
Not so with the suspension. This can be sustainably influenced and improved with very simple measures. Unfortunately, even these tricks are rarely utilised by most bikers. It's a shame, because manufacturers have often designed their forks and shocks in such a way that you can make noticeable optimisations even without in-depth wrenching skills and special tools. We will now show you some tuning tips that experienced mechanics can carry out themselves.
1. friction-reducing measures
With the exception of exotic designs such as the few parallelogram suspension forks, all suspension forks and dampers work according to the principle of two tubes sliding into each other - in the case of normal suspension forks, the upper stanchions connected to the fork crown, which dip into the larger lower tubes. There are various points in between where friction occurs. And friction is known to slow down movement, be it air friction in a headwind or the friction of a poorly lubricated chain. And because the suspension elements are constantly alternating between being compressed and moving apart off-road, friction has a particularly negative effect on the sensitivity of the suspension elements. To eliminate this problem, manufacturers rely on elaborate surface treatments of the friction surfaces - the golden Kashima coating from Fox is a well-known example.
Installing premium seals
But you don't have to go down the expensive route of new components - it often helps to simply replace the upper wiper rings of the suspension fork with smoother-running tuning models, for example from Enduro, RacingBros or SKF. The costs are limited (30-45 euros) and the effect is immediately noticeable, especially with older or cheaper forks.
Attention: This measure only makes limited sense for the current top models, as the premium seals are already installed there.
Use premium lubricants
The use of friction-reducing lubricants is also little known. Most manufacturers offer premium lubricating greases specially adapted to their surfaces and seals, which have a positive effect on sliding behaviour. Fox has developed the high-quality Gold Oil for this purpose, Rock Shox their Butter and Magura the Fork Meister grease.
There are also various third-party suppliers such as Motorex or R.S.P., but you should always check beforehand whether the special lubricants are also suitable for the respective suspension elements. In the worst case, the lubricants could attack the seals or cause them to swell. This would then achieve exactly the opposite result. Nevertheless, it is worth asking at the next fork service in the shop or at your trusted dealer to invest in higher quality lubrication.
Utility value/effort: 2.5 out of 5
Conclusion: Anything that reduces friction in the system has a positive effect on suspension performance. Older and cheaper models in particular benefit from the installation of high-quality seals. The difference is clearly noticeable here. As long as you make sure that the lubricants harmonise with the respective seals and surfaces, you can also achieve a noticeably positive effect.
Tip: Ideally, this measure should be combined with the annual small service of the suspension fork. This is how the small fork service at Rock Shox forkfor Suspension forks from Fox here's a guide.
2. adjusting the air chamber volume
In an era of ever better bikes and more demanding tracks, we are demanding more and more from our suspension elements. Differences in riding style, rider weight, individual weight shifting on the bike or the route are already compensated for by sophisticated suspension elements - but not all of them. The factory set-up of the suspension fork or shock is not always easy, especially in difficult terrain. This becomes apparent, for example, when the suspension elements dip too far or bottom out too often, even with the correct basic setup. Such things indicate a spring characteristic that is too linear or too little progression. Many riders then simply increase the air pressure in the fork or shock or tighten the compression damping without further ado. This is a practical approach, but it also results in a loss of sensitivity and comfort.
The more elegant way is to increase the progression of the suspension. In the past, a harder steel spring had to be installed for this. But with today's standard air springs, this can be done quite simply by adjusting the volume of the positive spring. The following applies: the more the air volume available as suspension is reduced, the greater the progression. In a force-displacement diagram, the spring characteristic curve becomes increasingly steeper towards the rear (see diagram).
Many manufacturers (Fox, Rock Shox and Magura) offer their own plastic inserts for this purpose, which reduce the volume of the positive chamber with little effort, while others (e.g. Formula) recommend simply reducing the air volume by adding damping oil.
By tuning with volume spacers, you can maintain sensitivity at the beginning of the spring travel and still increase the bottom-out protection. In addition, the steeper spring characteristic curve ensures that the fork compresses less with the same force and is therefore "higher in its travel". This is a particular advantage when braking hard or on technical terrain. Lighter or particularly mellow riders who do not use the entire spring travel in the factory set-up can reduce the progression in the same way by removing existing spacers and thus utilise the entire spring travel.
While Rock Shox, Fox and Magura each have additional spacers in the fork or on the shock, the IVA system from Manitou The same can be achieved by simply repositioning already integrated spacers. Manitou also offers the IRT kit ("Infinite Rate Tune") for the Mattoc, with which you can set two independent pressures for the main chamber and thus adjust the spring characteristic in the middle of the travel, independently of the end progression. The IRT kit costs around 60 euros, the IVA system around 40 euros.
* Manitou offers IRT ("Infinite Rate Tune"), another option with two separately inflatable positive air chambers for Mattoc Pro and Dorado Pro, which allows you to individually adjust the spring characteristic over the entire suspension travel.
Value/effort: 5 out of 5
Conclusion: Adjusting the positive air chamber volume is one of the most effective methods of suspension tuning. This is why many manufacturers have made it very easy to adjust the spring characteristics to individual requirements in this way. And because it's so easy: If you don't achieve the desired effect or have overshot the mark (too many spacers installed), all changes can be reversed just as easily. So don't be afraid to give it a try!
