VPP Suspension

Summary

VPP, or Virtual Pivot Point, is a dual-short-link rear suspension design associated primarily with Santa Cruz and Juliana bicycles. Two counter-rotating links connect a rigid rear triangle to the main frame, creating an instantaneous center of rotation that moves as the suspension compresses. This gives designers considerable control over axle path, chain growth, anti-squat, anti-rise, and shock leverage. These characteristics are tuned separately for each bike, so VPP describes the suspension architecture rather than one universal ride feel.

Quick Facts

Category: Rear suspension technology
Architecture: Dual-short-link four-bar
Developed by: James Klassen and Jamie Calon of Outland
Patent priority: 1995
Current users: Santa Cruz and Juliana
Historic user: Intense
Applications: Trail, enduro, downhill, and e-MTB

Overview

The original VPP concept was developed during the mid-1990s by James Klassen and Jamie Calon for Outland. Their patents described linkage arrangements that could vary axle path and chainstay growth around the suspension’s preferred pedaling position. Santa Cruz later acquired the associated patent rights and worked with Intense on revised applications during the early 2000s. The system subsequently became closely associated with Santa Cruz and its Juliana models.

VPP is sometimes used informally to describe any suspension with a moving virtual pivot, but this is imprecise. All linkage suspensions have an instantaneous center of rotation. VPP refers to a particular family of counter-rotating dual-link designs and the branded implementations developed from it.

The original patents have a 1995 priority date and identify Klassen and Calon as the inventors. US Patent 5,553,881

How It Works

Dual-Link Architecture

A VPP frame consists of four primary members:

Main frame
Upper link
Lower link
Rigid rear triangle

The upper and lower links rotate in opposite directions as the rear wheel moves through its travel. Lines projected through the two links intersect at the suspension’s instantaneous center. Because the links change angle continuously, this center moves rather than remaining fixed like the pivot on a single-pivot frame.

Moving the link pivots by only a few millimeters can substantially change the suspension’s behavior. This gives frame designers useful tuning range, but it also means different VPP bikes can have noticeably different kinematics.

Axle Path and Chain Growth

Classic VPP patents describe wheel paths that can change curvature through the stroke, including versions commonly described as S-shaped. These paths were intended to vary chainstay growth near the normal pedaling position rather than produce the same drivetrain response throughout the travel.

Chainstay growth affects anti-squat and pedal feedback. More growth can allow chain tension to oppose acceleration-induced suspension compression, but excessive growth may increase pedal kickback when the suspension compresses. Modern implementations balance these effects according to travel, wheel size, gearing, and intended use.

An S-shaped axle path should not be treated as a guaranteed feature of every VPP bike. The amount and direction of axle movement depend on the exact pivot locations. US Patent 6,206,397

Anti-Squat

Many VPP applications are designed with enough anti-squat around sag to reduce suspension movement during acceleration. Anti-squat commonly decreases farther into the travel, allowing the suspension to respond more freely during larger impacts.

Actual values change with gear selection, chainring size, suspension position, and assumptions about rider center of mass. VPP does not guarantee a particular anti-squat percentage or eliminate the need for correct shock setup.

Leverage Rate

The links also determine how quickly the shock compresses relative to rear-wheel movement. Each frame can therefore be given a different leverage curve. A short-travel trail bike may emphasize pedaling support, while an enduro or downhill frame may use more progression for bottom-out resistance.

Some VPP generations drive the shock through the lower link, while other versions use different arrangements. Lower-link shock actuation is therefore an implementation choice, not a requirement of VPP.

Braking Behavior

Rear braking creates forces that can make a suspension compress or extend. This response is measured as anti-rise and depends on the instantaneous center, wheel path, brake position, and frame geometry.

VPP is not inherently brake-neutral or low in anti-rise. Designers can tune its braking response, but the result must be evaluated for the individual frame.

Why VPP Exists

VPP was developed to give designers more control than a fixed-pivot layout provides. Its moving instantaneous center allows pedaling, wheel-path, braking, and leverage characteristics to change through the travel.

These variables are not completely independent, but the dual-link arrangement provides a broad tuning range within a compact frame layout. That flexibility has allowed VPP to be adapted to bikes with very different travel and performance requirements.

Rider Experience

A properly set up VPP bike may feel stable while pedaling, supportive through the middle of its travel, and controlled during larger compressions. Riders may also notice that the suspension remains usable without applying heavy compression damping.

These are common design objectives, not guaranteed characteristics. Tire construction, shock tune, spring pressure, damping, geometry, and frame stiffness can influence ride quality as much as the suspension layout.

Sag is particularly important. Too little sag can make the bike feel firm and reduce traction, while too much can leave it riding low and remove useful support. Manufacturer setup recommendations provide a better starting point than assumptions based solely on the VPP name.

Mechanic’s Perspective

VPP systems contain two links and multiple bearings, making pivot condition an important part of routine inspection. Common service checks include:

Side-to-side movement at the rear wheel
Creaking or clicking under load
Rough, seized, or notchy bearings
Loose pivot hardware
Worn pivot axles or bearing shields
Shock-eyelet or mounting-hardware play that can resemble pivot wear

Disconnecting the shock or removing the links may be necessary to assess each bearing accurately. The rear triangle should be supported during disassembly, and hardware must be reinstalled using the model-specific torque values, grease, and threadlocker instructions.

Santa Cruz recommends inspecting linkage bearings approximately every 6–12 months, with more frequent checks in wet, sandy, or dusty conditions. Bearings should be replaced when they feel rough rather than according to mileage alone. Some lower links have grease fittings, but this varies by model and generation. Santa Cruz bearing and pivot maintenance

Replacement links, axles, bearing shields, and hardware are generation-specific. Mechanics should identify the exact model and frame revision before ordering parts.

Buying Considerations

The VPP name alone does not determine whether a bike will climb efficiently or descend well. Buyers should consider the individual frame’s geometry, travel, shock tune, leverage progression, weight, and intended use.

On a used VPP bike, check every pivot for movement and confirm that replacement bearings and hardware remain available. Riders planning to install a coil shock should verify frame clearance, shock dimensions, and manufacturer approval rather than assuming that every VPP leverage curve is suitable.

Advantages

Broad control over suspension kinematics
Can provide useful pedaling support without relying entirely on shock damping
Adaptable to different travel categories
Rigid one-piece rear triangle
Proven, widely supported service architecture

Engineering Trade-Offs

More bearings and hardware than a basic single-pivot system
Greater manufacturing and service complexity
Bearing condition can noticeably affect suspension sensitivity
Compact links may complicate frame packaging and cleaning
Performance depends heavily on the specific implementation and shock setup

Comparison with Other Layouts

Layout	Primary distinction
VPP	Counter-rotating short links control a rigid rear triangle
Single pivot	Rear axle follows an arc around one fixed pivot
Horst link	Pivot near the rear axle separates the chainstay and seatstay members
DW-Link	Dual-short-link system generally using co-rotating links and different kinematic objectives

The layout identifies how the frame moves, but it does not establish which bike will perform better. Pivot placement, geometry, shock tune, and intended use remain more important than the category name.

Common Questions

Is VPP better than a single pivot?

Not universally. VPP provides more kinematic tuning options, while a single pivot can be lighter, simpler, and easier to maintain. Either can work well when properly designed.

Can riders feel VPP working?

Riders can feel the complete suspension system, but they generally cannot isolate the virtual pivot from the shock, tires, geometry, and frame stiffness.

Does VPP require special maintenance?

It uses conventional cartridge bearings and threaded pivot hardware, but it has more service points than a basic single pivot. Correct torque and assembly procedures are important.

Can any rear shock be installed?

No. The shock must have the correct eye-to-eye length, stroke, mounting hardware, clearance, and suitable tune. Coil-shock compatibility should be confirmed for the specific frame.

Industry Context

VPP helped establish dual-short-link suspension as a major category of mountain-bike design. It remains strongly associated with Santa Cruz and Juliana, although not every model from those brands uses VPP. Its longevity also demonstrates how one linkage architecture can be revised for changing wheel sizes, travel ranges, shock designs, and riding disciplines.