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MTB Suspension: Everything you need to know

21 November, 2020

MTB Suspension technology has advanced dramatically over the years and will continue to do so, therefore the sheer wealth of information available is seemingly infinite. It certainly takes an expert to understand the intricacies of suspension, but we are here to explain the basic need-to-knows for all mountain bikers.

A bicycle fork is a component that connects the front wheel to the bike frame, there are two of them in the design. The front is located in front, which is logical. 

Modern mountain bikes are nearly all equipped with suspension. The purpose of suspension is to dampen the roughness of the terrain, providing the rider with a smoother, more controlled ride.

A bike with just front suspension (a suspension fork) is referred to as a hardtail, a bike with both front and rear suspension is referred to as a dual-suspension, or full-suspension bike and a bike without any suspension at all is known as a rigid mountain bike.

The new Olympia F1 2021 Carbon XC Hardtrail

Glossary of some common MTB suspension references

How to Set Up Mountain Bike Suspension | Liv Cycling Official site
  • Arch: The arch connecting the two legs of a suspension fork.
  • Axle: The axle holding the front wheel in place on a set of forks.
  • Axle path: The direction the rear axle moves as the suspension is compressed.
  • Bottom-out: When the suspension unit reaches the limit of its travel. As a very general rule of thumb, a fork or shock shouldn’t be regularly hitting the end of its travel harshly (too soft) but should be getting there occasionally (otherwise it’s probably too hard).
  • Bottom-out bumper: A rubber bumper that stops the suspension being damaged if it bottoms-out harshly.
  • Bushing: A lining used at the interface between shock eyelet and hardware (rear), and between stanchion and lower (fork). Reduces friction and wear.
  • Compression damping: Adjusts the feel of the suspension as it compresses. More compression damping means more hydraulic resistance, so the shock or fork will feel firmer.
  • Crown: The brace that holds a fork’s stanchions in place. Single crown forks are found on most mountain bikes. Dual-crown forks, which are stiffer and more suited to longer-travel bikes, are mostly found on downhill bikes.
  • Damping circuits: A reference to the internal damping system (compression or rebound).
  • Eyelet: Hole at end of rear shock through which the mounting bolt passes.
  • Eye-to-eye length: The length of a rear shock, measured from the centre of the bolt holding it in place at each end.
  • Trunnion mount: A trunnion-mount shock is mounted directly onto a set of bearings in the bike’s frame via two bolts that bolt directly into either side of the shock. Under compression, the shock then pivots on the bearings (instead of a bushing).
  • Upside-down fork: The fork is reversed compared to most typical mountain bike offerings, with the stanchion at the bottom.
  • Volume spacers/tokens: Adding volume spacers, or ‘tokens’, decreases the volume of an air-sprung fork or shock’s spring, affecting its characteristics. These ‘tokens’ are easily added by the user with minimal technical know-how.
  • Wiper seal: A tight seal to minimise dirt entering the suspension unit.

Different MTB Suspension for Different Disciplines

MTB Suspension

When it comes to front and/or rear suspension, the functions and adjustment options are often very similar. Below we outline what these functions are.

Air pressure: ‘Air-suspension’ equipped suspension use a Schrader valve to allow air to be pumped in using a special shock pump. On a fork, this valve can be found on the top of the left fork crown (above the stanchions) or sometimes on the bottom of the lowers.

On a rear shock, the valve is normally visible at the top of the shock. Bikes will often come with a manual to help you choose the right amount of air pressure for your bike and weight.

Different riding disciplines place different demands on the bike and the rider, so the suspension will vary accordingly, with the amount of ‘travel’ – which is the amount the suspension is able to compress (more travel = more give = more impact absorption).

See our table for an explanation of the amount of travel and the corresponding type of bike.

Riding StyleTerrainTravel in mmTravel in inchesStanchion DiameterRecommended Sag
Cross CountrySmoother trails, good for going uphill100-120mm4 – 5″30 – 32mm15-25%
Trail/All MountainMixed terrain, including more trail features but still lots of pedalling120-150mm5 – 6″34mm20-30%
EnduroGravity based trails, bigger drops, rugged root or rock gardens150-180mm6 – 7″36 – 38mm25-30%
DownhillSteep, rough technical gravity trails, large rocks, drops and jumps180-200mm7 – 10″40mm25-35%

MTB Suspension Settings

MTB Suspension

Complex forks, which are intended to be used on racing equipment or on the technique of understanding amateurs, have a large number of settings. 

Blocking (lockout). Allows you to block the system if its work on certain sections of the path interferes.

Spring preload . This is true for steel springs. Twisting or unscrewing the adjuster on your left foot makes the fork stiffer or softer. In air versions, the pressure is simply changed using a pump.

Low speed compression . Its adjustment makes the fork stable to swing, sacrificing sensitivity to small bumps.

High speed compression . Tuning it minimizes fork breakdown, but makes the compression at the end overly elastic.

Rebound speed . Adjusts the speed at which the structure will return to its original position after working off a bump. 

Gate. Found on Rock Shox forks. The twist bar allows you to adjust the force at which the locked suspension will straighten out and work off irregularities. Made in order to minimize the effect of swinging the suspension under the influence of pedaling. Relevant on flat surfaces and with active screwing into slides.

Brain. The blocking is disabled in this case, but the buildup does not occur. In this case the fork is triggered when hitting bumps. The device for such forks is rather complicated, although it justifies itself with incredible comfort. 

Component differences

MTB Suspension

Generally speaking, the differences in components between a trail, all-mountain and enduro bike will be relatively subtle and there is a small amount of componentry overlap.Trail bikes will generally be specced with lighter components compared to all-mountain or enduro bikes.

For example, if all three types of bike had Maxxis Minion tyres fitted, the trail bike would most likely get the lightest casing tyre, the all-mountain bike would probably be specced with a mid-weight casing tyre while the enduro bike should have a heavy weight casing model of the same tyre.

Similarly, you might see a RockShox Pike specced to both trail and all-mountain bikes, but with varying amounts of travel to reflect the bike’s indented purpose. The enduro bike will more likely be fitted with a heavier and longer travel Lyrik or Fox 36 fork though.

MTB SuspensionManufacturers

MTB Suspension

The most popular MTB Suspension manufacturer is Rock Shox. A good entry-level to professional product for a reasonable price.
There are more budgetary options for the RST and SR Suntour.
Magura is known to many for its braking systems, but pays attention to forks too.
Manitou are good entry to mid-range forks for little money.
Marzocchi, X-Fusion and Fox are the elite of bicycle forks. They are highly respected among professionals.