Bike Suspension Fundamentals

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Bike suspension offers improved management, traction and luxury on rooty, rocky singletrack or potholed roads. It’s one in every of many components that contribute to your using enjoyment.

This text covers the fundamentals of suspension for brand new bike buyers or anybody contemplating an improve. We then go on to supply a extra detailed have a look at how suspension works.

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Full Suspension or Hardtail?

If a motorbike (normally a mountain bike) provides suspension, then it has 1 or 2 shock absorbers designed to melt the affect of tough terrain by compressing and rebounding.

Shopping for a brand new mountain bike? You could select between bikes with entrance suspension solely (a “hardtail”) or full (entrance and rear) suspension. Some factors of comparability:

Full suspension vs. hardtail bike

Full Suspension

Hardtail

Upfront value
Greater
Decrease

Upkeep value
Greater
Decrease

Weight
A bit heavier
A bit lighter

Path suitability
Rougher trails with roots, rocks and drops
Doubletrack, smoother singletrack, pavement, fireplace roads

Greatest for
Onerous rides on tough trails;
riders with again or joint points; tough, high-speed descents
All-purpose use (path and pavement); environment friendly hill climbing; comparatively clean trails

Notice: Bicycle producers don’t make their very own suspension merchandise. As an alternative, they flip to main suspension manufacturers equivalent to Fox, RockShox, Marzocchi, Manitou, DT Swiss, SR Suntour and X-Fusion to outfit their bikes.

Upgrading Your Suspension

In case your present entrance suspension wants changing because of non-serviceable put on or harm, you should know these four specs to interchange it:

  1. Axle compatibility: Does your entrance wheel have an ordinary 9mm quick-release? Or a 15mm or 20mm by means of axle? Select the proper axle dropout dimension in your wheel.
  2. Journey: Many bike frames are designed to work with a suspension fork that includes a certain quantity of journey. The quantity of journey will change the dealing with traits of the bike. An older mountain bike could have an 80mm fork, which is tough to seek out now. A 100mm fork could also be an appropriate substitute, however a 120mm fork will most likely alter the bike geometry considerably to the detriment of protected dealing with. As well as, some absolutely inflexible bikes include the proper body geometry angle to improve to a suspension fork. All the time verify along with your bike producer for substitute fork suggestions.
  3. Steerer tube: An ordinary steerer tube (see parts diagram, beneath) is straight with a 1-1/eight” diameter. Very outdated bikes could have a 1” diameter tube; newer bikes could have a tapered or outsized steerer tube. Be sure that your new fork has a suitable steerer tube.
  4. Brake kind: Most mountain bikes now have disc brakes. If you wish to substitute a fork that has rim brake mounts, your selections will probably be restricted to some very fundamental suspension fashions until you improve your wheel and brakes as effectively.

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Paying for Efficiency

Shopping for a brand new bike? Suspension high quality has a serious affect on its worth. Changing your current fork? You’ll discover a vary of choices and costs. Here’s what could also be value paying extra for:

Much less weight: That is primarily achieved by transferring from a coil to an air spring.

Extra changes: Compression and rebound changes allow you to fine-tune your suspension to fit your weight, using type and terrain. Such “adjustable journey” helps you to regulate to shorter journey for climbs and fewer tough trails. A lockout characteristic is often included; one improve is a handlebar-mounted distant management for the lockout.

Construct high quality: Excessive-end fashions have superior technical design and building and provide an extended life with common upkeep and servicing.

Trip high quality: Hunt down a responsive suspension system providing a clean journey. How will you understand? Evaluating costs is a fairly dependable information. A pricier fork goes to supply a superior expertise in comparison with a reasonable one.

Entrance Suspension Defined

Nearly all mountain bikes are outfitted with entrance suspension, in addition to some hybrid or “consolation” bikes and youngsters’ bikes. Variations:

  • Suspension on mountain bikes provides a spread of changes to fine-tune the using expertise. Variations embody the kind, quantity of journey, robustness and technique of bump absorption, in addition to the changes that may be made.
  • Suspension on hybrid and youngsters’ bikes provides fundamental performance with minimal or no adjustment.

Sorts of Suspension

The commonest kind of entrance suspension is the “fork.” It’s comprised of two struts that join the entrance wheel to the body’s head tube. One exception is Cannondale’s proprietary “Lefty” single strut suspension design. The Lefty typically garners appears of disbelief and skepticism, however it’s a longtime and confirmed design.

Parts


Steerer tube:
connects the fork to the body.

Crown: connects the two stanchions collectively.

Stanchions: every travels out and in of the sliders; inner workings include a spring or air chamber, damper rod, oil, valves.

Sliders or lowers: every connects on the backside to the entrance wheel; it additionally connects to the brakes.

Brake mounts: for rim, disc or each.

Dropouts: to carry the wheel axle.

Journey

This refers back to the quantity of distance the suspension will transfer earlier than it’s absolutely compressed.  As a result of the entrance suspension is telescoping, the suspension journey equals the resultant wheel journey.

Journey Distance

Inches
Millimeters
Sort of Bike

1 – 2
30 – 50
20″ and 24″ children’ bikes

2 – three
60 – 80
24″ children’ bikes, hybrid bikes

four – 5
100 – 120
“Cross nation” and “path” mountain bikes

5 – 6
120 – 160
“All mountain” mountain bikes

7 – eight
180 – 200
“Freeride” and “downhill” mountain bikes

Suspension could also be known as brief or lengthy journey:

  • Quick-travel suspension (lower than 120mm) suspension offers all-round using efficiency with an emphasis on clean trails and going uphill.
  • Lengthy-travel suspension (higher than 120mm) is greatest for descending tough terrain at excessive speeds with higher management. The longer the entrance journey, the stronger the emphasis is towards descending.

Some entrance forks characteristic adjustable journey to supply extra versatility: You may shorten the journey for going uphill and lengthen it for sustained or steep downhill sections. Adjusting the journey not solely impacts the bump-softening capability of the bike, it additionally impacts the steering and management. A brief-travel bike is extra conscious of steering enter, which may translate to twitchiness going downhill. An extended-travel bike has slower steering which feels extra secure when descending.

Stanchion Diameter

A super fork absorbs impacts vertically with out undue lateral flex which may detract from the steering and management of a motorbike. The diameter of the stanchion tubes impacts this lateral stiffness. A slim tube will flex extra underneath the identical drive than a wider tube. Conversely, wider tubes will probably be heavier and stiffer to soak up the higher impacts generated from excessive speeds on tough terrain and leap landings.

Bike producers will select a fork that gives the suitable diameter and stiffness for the meant using objective of a specific bike mannequin.

Sort of Bike
Stanchion Tube
Diameter (mm)

Children’
28

Hybrid
30

Cross nation (XC) and Path
32

All mountain
34-36

Free journey and downhill
38-40

Spring System

Two widespread strategies utilized by a fork to soak up affect after which rebound again:

A coil spring (wound metal coil) offers a linear compression price, giving clean, constant affect absorption over the vary of spring journey. Coil springs can be found with totally different resistance charges and are matched to an “common” rider for the scale of body the fork is on. In case your coil spring feels too comfortable or too agency in your weight and using type—and the out there changes haven’t corrected the difficulty—your bike store might be able to substitute your present springs with a softer or firmer model (if one is accessible for the mannequin).

An air spring (pressurized air in a chamber) has a progressive compression price, which means it’s softer within the first a part of the journey after which will get stiffer as extra compression is utilized. The primary benefit of an air-sprung fork is its lighter weight, which interprets to much less effort when pedaling, particularly uphill.

Coil Spring
Air Spring

Efficiency
Good to excellent
Superb

Changes
Much less
Extra

Reliability
Wonderful
Superb

Materials choice, design and manufacturing high quality all contribute to a fork’s efficiency. For instance, a low-budget coil-sprung fork is just not going to supply the identical journey high quality as a costlier coil fork.

Fork Changes

A fork could provide no adjustability, or it might have a number of knobs and dials to tweak.

Lockout: Many forks have a stanchion high lever (proven at proper) to lock out the fork, which eliminates the journey. This minimizes your power loss when using paved surfaces or on lengthy uphill climbs on clean dust surfaces. An improve choice for some forks is a handlebar-mounted lever to remotely management the lockout through a cable.

Preload: A coil-sprung fork typically has a knob on high of one of many stanchions to permit for the unweighted pressure on the spring to be elevated or decreased. Enhance the preload if the fork feels too spongy.

Air strain: An air-sprung fork doesn’t have a preload knob; as a substitute it has a Schrader valve for adjusting the air strain, and subsequently firmness, of the fork.  A particular “shock pump” is required for this; don’t use an everyday tire pump. The valve could also be both on the high of a stanchion or on the backside of a slider.

Damping: Along with a coil or air spring, forks include a damper rod and oil tub that reasonable the velocity of the compression and rebound to clean out the journey. Changes could also be out there for each the compression and rebound. Adjusting damping settings are known as “tuning the fork.” With out right damping, you might really feel like you might be astride a pogo stick on wheels.

  • Compression damping controls how shortly the spring absorbs an affect.
  • Rebound damping controls the velocity at which the fork re-extends after compression. This reduces overly quick bounce-back.

See Fundamental Suspension Setup later on this article.

Rear Suspension

Rear suspension is just discovered on full-suspension mountain bikes, and is often known as the rear shock, or “shock” for brief. The shock permits the rear wheel to absorb impacts, serving to to maintain the tire involved with the bottom, growing rider management and lowering rider fatigue.

The rear body triangle, which holds the rear wheel, may have a number of pivot factors to allow the wheel to journey by means of a spread of movement. The shock itself is positioned inside the primary body triangle, with one finish hooked up to the primary triangle and one finish hooked up to the pivoting rear triangle.

Numerous pivot designs and configurations can be found. Every has its execs and cons on the way it impacts a motorbike’s journey high quality. Backside line: All of them work effectively, and the typical leisure rider is unlikely to note vital variations in suspension efficiency.

As with the entrance fork, rear suspension fashions characteristic variation in journey, spring system and changes.

Stroke journey: That is how a lot a rear shock compresses.  It’s comparatively brief: 1.5” to three”. The shock is on the brief finish of the body lever, and the rear wheel is on the lengthy finish of the lever, so the precise wheel journey will probably be a lot higher than what’s indicated by the stroke journey.

Wheel journey: In distinction to stroke journey, the precise wheel journey will probably be much like that discovered on the entrance wheel (the quantity is determined by the kind of bike). On a full-suspension bike, anticipate finding comparable journey for the entrance and rear wheels.

Spring system: That is both coil or air, as per the entrance suspension. Air-sprung shocks are widespread on cross-country and path bikes; coil-sprung shocks are sometimes used on “freeride” and downhill bikes. “All mountain” bikes are within the center and will characteristic both type.

Changes: Just like the entrance suspension, adjustment choices rely upon the mannequin.

On older fashions, rear shocks produced “pedal bob,” which means that the pedaling exertions of the rider activated the suspension, inflicting an ongoing cycle of compression/rebound that decreased pedaling effectivity. This situation has been largely addressed by means of design advances and a collection of 2 or three settings for ascending, descending or normal using.

Fundamental Suspension Setup

Be sure that your suspension is correctly adjusted. Take into account that not all of the settings described right here can be found on all suspension models. Verify the producer’s handbook (normally discovered on their web site) in your particular mannequin.

Sag refers to how a lot the suspension compresses with simply the rider’s weight on the bike. Regulate the coil-spring preload or the air strain to attain the producer’s advisable quantity of sag for each entrance and/or rear suspension. Sag is expressed as a share of the overall suspension journey and varies by the type of motorbike. Basic pointers:

Sort of Mountain Bike
Suspension Journey
Really helpful Sag*

XC race
80 – 100mm
15 – 25%

Path, all mountain
100 – 160mm
20 – 30%

Freeride and downhill
160 – 200mm
25 – 35%

* As a p.c of suspension journey

Sag allows the wheel to comply with undulations within the floor extra successfully, permitting the suspension to increase in order that the wheel can drop into depressions within the path. Extra sag equals a softer journey.

Rebound damping is crucial damping setting. Again all of it the best way out, then progressively add extra till the suspension compresses and bounces solely as soon as because it returns to regular sag, when using off a curb.

Low-speed compression damping holds the suspension greater up in its stroke vary to maintain some compression in reserve when doing berms, G outs or stair-step drops. That is additionally what a platform setting does on rear shocks.

Excessive-speed compression damping is greatest set all the best way out until you expertise bottoming out or touchdown jumps.

Suspension Upkeep

Something that strikes wants periodic upkeep, and suspension can do quite a lot of transferring.

Our suggestions:

  • Stop or cut back scratches to the stanchions. If these get nicked from a rock or device, the tough edge can tear up the mud seal and bushings because it slides previous, diminishing the efficiency and lifetime of the suspension.
  • Clear the stanchions after each journey with a comfortable material and delicate cleansing resolution, flossing across the tube and right down to the seal within the high of the lowers.
  • Verify your proprietor’s handbook for another common upkeep that may be carried out by the proprietor. Some will suggest a mild lube across the mud seal on the high of the sliders.

Tip: Finishing a dismantle/inspection/rebuild is normally not for the final rider, significantly as suspension designs have turn out to be more and more subtle.

Suspension models are costly to interchange; suspension lifespan may be prolonged by having periodic service carried out by a suspension specialist. Should you journey often, have your suspension serviced yearly or after 100 hours of using time. Common service can even lengthen the lifetime of your bike body.

An expert suspension service can also be extremely advisable everytime you expertise the next:

  • Extreme oil leak onto the stanchions across the high of the sliders.
  • An air-sprung unit not holding air and dropping all journey.
  • Play or knocking between the stanchions and the decrease sliders.
  • Any uncommon collapse or resistance to regular operate.

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