Switch Infinity

Summary

Switch Infinity is Yeti Cycles’ patented four-bar rear-suspension system built around a translating lower pivot. Instead of rotating around a fixed lower link, the main pivot moves vertically on two short rails and reverses direction partway through the suspension travel. This movement allows Yeti to tune anti-squat, leverage ratio, and suspension response for different trail and enduro platforms.

Key Facts

Introduced: Announced in 2014; first used on the 2015 Yeti SB5c
Category: Suspension Technology
Also Known As: Translating Pivot Suspension, Infinity Link
Developed By: Yeti Cycles in collaboration with FOX
Used By: Yeti Cycles
Found On: Selected Yeti trail, all-mountain, and enduro bikes
Core Design: Four-bar linkage with a direction-changing translating pivot
Service Requirement: Periodic cleaning and greasing of the sliding bushings
Official Website: Yeti Switch Infinity

Overview

Switch Infinity is a Yeti-specific suspension platform that uses a vertically translating main pivot to control how the rear suspension behaves through its travel.

The system evolved from Yeti’s earlier Switch Technology, which used an eccentric mechanism to reposition the lower pivot. Yeti combined that direction-changing concept with elements of its earlier rail-based suspension work to create Switch Infinity. The 2015 SB5c was the first production model to use it, followed by the longer-travel SB6c and numerous later platforms. Yeti’s bike history documents the SB5c as the first Switch Infinity model.

At the center of the system is the Infinity Link, a compact assembly manufactured for Yeti by FOX. A pivot carrier slides on two Kashima-coated rails through greased bushings. As the rear suspension compresses, the carrier initially moves upward, reaches a reversal point, and then moves downward.

This movement changes the location of the suspension’s main pivot without requiring a conventional rotating lower link. Yeti uses that additional control to maintain relatively high anti-squat through the pedaling region and then reduce it deeper in the travel, where drivetrain support is less important.

Switch Infinity should not be confused with Sixfinity. Sixfinity is Yeti’s separate six-bar platform developed around the packaging, mass, and power-delivery requirements of its full-power e-mountain bikes.

How It Works

1. Four-Bar Architecture

Switch Infinity is a four-bar suspension system. Its principal elements are:

  • Front triangle
  • Rear triangle or swingarm
  • Upper linkage
  • Translating lower-pivot assembly
  • Rear shock and its associated linkage

In a conventional four-bar design, both links rotate around fixed frame pivots. With Switch Infinity, the lower connection is carried by a slider that follows a short vertical path.

Because this main pivot changes position, the suspension’s instantaneous center, anti-squat, axle path, leverage ratio, and braking response can all evolve through the stroke. These characteristics are created by the complete linkage geometry—not by the slider alone.

2. Beginning and Middle of Travel

During the initial and middle portions of the stroke, the pivot carrier moves upward on the rails. Yeti uses this phase to produce a relatively high, controlled anti-squat curve through the normal pedaling region.

Anti-squat uses drivetrain forces to oppose suspension compression caused by acceleration and rider weight transfer. In practical terms, this can reduce unwanted suspension movement while climbing, sprinting, or accelerating out of a corner.

It does not mechanically lock the suspension. The rear wheel can still respond to bumps, with its behavior also influenced by:

  • Shock compression damping
  • Spring rate and air-can volume
  • Rider position
  • Selected gear
  • Pedaling cadence
  • Chain tension
  • Suspension friction

As with other high-anti-squat systems, some pedal feedback can be present because the axle-to-chainring relationship changes through the travel. The amount depends on the model, gear selection, and suspension position.

3. Direction Reversal

Partway through the stroke, the translating pivot reaches the top of its path and reverses direction. The carrier then begins moving downward as the suspension compresses farther.

This reversal lets Yeti reduce anti-squat beyond the primary pedaling zone. With less drivetrain influence deeper in the stroke, the suspension can respond more freely to larger impacts and repeated rough terrain.

The reversal is gradual rather than a mechanical switch between two fixed modes. There is no clutch, valve, or electronic control involved.

4. Deep-Travel Behavior

In the final portion of travel, the pivot continues downward while the shock and upper linkage control the leverage curve. Current Switch Infinity layouts are generally tuned to add support and bottom-out resistance near the end of the stroke.

The translating pivot’s downward movement does not mean the rear axle also moves downward or becomes progressively more rearward. The slider path and axle path are different measurements. The axle follows a curved trajectory determined by the entire four-bar geometry.

Similarly, pivot reversal does not automatically flatten or increase the leverage ratio. Yeti develops a separate leverage curve for each frame and shock configuration. This is why two Switch Infinity bikes can feel different even though their sliding mechanisms appear similar.

5. Infinity Link Construction

The Infinity Link contains:

  • Two Kashima-coated rails
  • Greased sliding bushings
  • Wiper seals
  • A translating pivot carrier
  • External grease ports
  • Main-pivot bearings and associated hardware

The rails are not miniature shock absorbers and do not contain an air spring or damper. They simply guide the pivot carrier along its prescribed path.

Later Switch Infinity generations use revised bushings, bearing interfaces, seals, and pivot hardware. V1 and V2 service parts are not universally interchangeable, so replacement components must be selected by frame model and year.

Performance Characteristics

Pedaling Support

Switch Infinity’s principal design objective is to retain useful anti-squat through the portion of travel most commonly occupied while pedaling. This gives the bike chassis support under acceleration without relying entirely on firm shock compression damping.

Actual climbing behavior still depends on suspension setup. Excessive sag, insufficient low-speed compression, an incorrect spring rate, or poor rider position can make any platform feel soft or inefficient.

Bump Response

As anti-squat decreases farther into the travel, chain force has less influence over suspension movement. This helps the rear wheel continue moving through larger impacts without maintaining the same level of pedal-generated support used near sag.

Small-bump sensitivity is also affected by shock setup, seal condition, pivot friction, tire pressure, and whether the rider is pedaling or coasting. Switch Infinity alone does not determine how supple a bike will feel.

Mid-Stroke and Bottom-Out Support

The upper linkage and shock tune provide much of the bike’s mid-stroke support and bottom-out resistance. Yeti can alter these characteristics between models without changing the basic Switch Infinity concept.

A short-travel SB120, for example, does not use the same leverage curve or shock tune as an SB160 enduro bike. The translating pivot gives designers additional kinematic control, but each application remains model-specific.

Braking Behavior

Switch Infinity does not completely isolate braking forces from the suspension. Rear braking behavior is governed by anti-rise, brake-caliper position, axle path, weight transfer, and linkage geometry.

Yeti can tune anti-rise through the system, but braking support and suspension activity remain a compromise. Excessive brake-induced compression can alter geometry, while very low anti-rise can allow more chassis pitch under deceleration.

Design Trade-Offs

Switch Infinity provides useful kinematic freedom, but it introduces additional parts and service requirements compared with a simple single-pivot design.

Potential trade-offs include:

  • Additional sliding surfaces and seals
  • Model-specific pivot hardware
  • Greater sensitivity to contamination or neglected lubrication
  • Higher replacement cost than a conventional lower link
  • More involved bearing and bushing service
  • Limited compatibility outside the intended Yeti frame

The system’s position near the bottom bracket also exposes it to water, dust, and debris from the rear tire. Fender coverage, intact seals, and routine cleaning therefore matter.

Maintenance and Service

The Infinity Link requires periodic cleaning and greasing. Recent Yeti owner’s manuals commonly specify lubrication at approximately 40 riding hours, while FOX’s service guidance varies the interval according to mud, dust, washing frequency, and riding conditions. The correct model-year manual should take precedence.

Routine service generally involves:

  1. Cleaning dirt from the link, rails, seals, and grease ports.
  2. Inspecting the rails for damage or abnormal wear.
  3. Injecting the approved grease through both ports with the specified needle fitting.
  4. Stopping when fresh grease begins to appear at the seals.
  5. Wiping away all expelled grease and contamination.

Overgreasing is unnecessary and can create a mess that attracts abrasive dirt. External chain lubricant or suspension spray should not be applied to the rails; FOX specifies that no external rail lubrication is required.

The link should also be checked for:

  • Lateral play
  • Rough or notchy movement
  • Damaged seals
  • Corrosion around bearings or hardware
  • Uneven rail wear
  • Persistent creaking after other pivots are inspected

Routine greasing is user-serviceable. Internal link disassembly, bushing replacement, and main-pivot bearing work should follow the applicable Yeti service manual because some versions require specific tools, preload procedures, and hardware orientation. FOX’s Infinity Link guide specifically cautions against unapproved disassembly.

Mechanic’s Perspective

Switch Infinity is reliable when kept clean and lubricated, but it should be treated as a serviceable suspension pivot rather than a maintenance-free cartridge. Its low position on the frame exposes the seals and rails to water, dust, wash chemicals, and tire debris.

When inspecting a Switch Infinity bike, a mechanic should:

  1. Check the rear wheel, hub bearings, shock hardware, and conventional frame pivots before attributing play or noise to the Infinity Link.
  2. Hold the rear brake and rock the bike while feeling each pivot individually for movement.
  3. Disconnect the shock when necessary and cycle the rear triangle slowly to identify roughness, binding, or tight spots.
  4. Inspect both rails for scoring, corrosion, discoloration, or uneven wear.
  5. Check the wiper seals for damage and confirm that the pivot carrier moves without lateral play.
  6. Verify all pivot axles and bearing hardware with the model-specific torque chart.

Creaking is not always caused by the sliding mechanism. Common sources include dry shock-eyelet hardware, worn upper-link bearings, loose pivot axles, bottom-bracket interfaces, rear-hub bearings, and contamination between hardware contact surfaces.

Routine greasing should begin with thoroughly cleaning the grease ports and surrounding seals. Use the specified needle fitting and approved grease, applying it slowly until clean grease begins to purge from the seals. If grease will not enter or does not purge normally, do not force the fitting; inspect for a blocked port, damaged seal, or hardened contamination.

Grease can restore lubrication, but it cannot correct worn bushings, scored rails, damaged bearings, or loose pivot interfaces. Continued play after the hardware has been correctly torqued generally requires disassembly and inspection using the applicable Yeti service procedure.

Parts identification is important. Switch Infinity assemblies, bearing kits, seals, axles, and hardware vary by frame generation. V1 and V2 parts should not be assumed compatible based on appearance alone. Confirm the frame model, model year, and serial information before ordering components.

For used-bike inspections, visible rail damage, neglected grease ports, persistent pivot play, or rough movement should be considered potential service costs. A clean mechanism with intact seals and documented maintenance is a better indicator than cosmetic frame condition alone.

From a shop perspective, Switch Infinity is not unusually difficult to maintain, but it is less tolerant of neglect than a basic fixed-pivot system. Regular light service is inexpensive; allowing contamination or play to continue can turn a routine grease service into a link, bushing, bearing, or hardware replacement.

Setup Considerations

Switch Infinity does not eliminate the need for normal suspension setup. Sag should be established before adjusting rebound or compression damping, using Yeti’s model-specific recommendations as the starting point.

Common setup errors include:

  • Excessive sag that places the bike beyond its intended pedaling region
  • Too little sag, reducing traction and small-bump compliance
  • Excessive rebound damping that causes packing on repeated impacts
  • Excessive air-spring progression that prevents full-travel use
  • Attempting to correct spring-rate problems with compression damping

Changing shock stroke, eye-to-eye length, or linkage components can alter frame clearance and kinematics and should only be done where Yeti specifically approves the configuration.

Notable Implementations

Yeti SB5c: First production Switch Infinity model, introduced for the 2015 model year.

Yeti SB6c: Early long-travel enduro application that helped establish the platform in racing.

Yeti SB120: Current 120 mm trail platform using a short-travel-specific Switch Infinity tune.

Yeti SB140: 140 mm all-mountain platform with model-specific leverage and anti-squat characteristics.

Yeti SB160: 160 mm 29-inch enduro race bike using Switch Infinity and revised pivot hardware.

Yeti SB165: Long-travel mixed-wheel platform that packages Switch Infinity around a freeride-oriented suspension layout.

Related Terms

References

Scroll to Top