Split Pivot Suspension

Summary

Split Pivot is a four-bar rear suspension system developed by David Weagle and identified by a linkage pivot concentric with the rear-wheel axle. The rear axle is carried by a main wheel link, while the brake caliper is carried by a separate brake link that rotates around the same axis and connects to a control link. This arrangement allows designers to tune braking response and shock leverage with less dependence on the main-pivot location used to establish axle path and pedaling behavior. The axle still follows a fixed arc around the main frame pivot, so Split Pivot combines a single-pivot wheel path with four-bar control of braking and shock motion. Its actual anti-squat, anti-rise, progression, and ride feel remain specific to each frame.

Quick Facts

Category: Rear suspension technology
Developed by: David Weagle
Patent priority: 2006
Architecture: Concentric-axle four-bar
Defining feature: Linkage pivot concentric with the rear-wheel axis
Axle path: Fixed arc around the main frame pivot
Brake mounting: Caliper carried by a separate brake link
Primary design purpose: Separate the tuning of acceleration and braking responses
Applications: Cross-country, trail, enduro, downhill, and e-MTB
Production users: Includes Devinci and Salsa, among other licensees

Overview

Split Pivot was developed by suspension designer David Weagle. The associated patent family lists an August 25, 2006 priority date and describes a wheel link connected to a brake link through a pivot concentric with the wheel’s rotation axis. The brake link then connects to another control link, allowing its response to be shaped separately from the main wheel-supporting member. U.S. Patent 7,717,212

The name refers to the division of functions between two rear-frame members. The lower wheel link carries the axle and reacts to chain-driven acceleration forces. The upper brake link carries the brake caliper and transfers braking torque through a separate path. Both meet at the concentric axle pivot.

This does not make acceleration and braking physically independent. Both load the frame, suspension, tire contact patch, and shock. The design instead gives engineers useful freedom to tune their effects through different link geometry.

Split Pivot has been adapted to short-travel cross-country bikes, trail and enduro platforms, downhill frames, and electric mountain bikes. Devinci states that it has used the system on its full-suspension bicycles since 2011. Devinci: Troy and Troy ST

How It Works

Four-Bar Architecture

A conventional Split Pivot system contains four principal members:

Main frame
Wheel link or lower swingarm
Brake link, commonly formed by the seatstay assembly
Control link or rocker

The wheel link pivots on the main frame and carries the rear axle. The brake link pivots around the rear-wheel axis and connects to the control link. The control link connects back to the main frame and normally helps actuate the shock.

These four members form a closed linkage. The shock controls the motion but is not counted as one of the four bars.

Concentric Rear-Axle Pivot

The defining pivot occupies the same axis as the rear wheel. “Concentric” means the suspension pivot and wheel-rotation axis share a centerline; it does not mean that the suspension uses the hub bearings as frame pivots.

The wheel rotates on its own hub bearings. Separate suspension bearings or bushings allow the brake link to rotate relative to the wheel link. The thru-axle and pivot hardware pass through or around this area according to the frame’s construction.

Placing the joint at the axle allows the brake link to move relative to the wheel link without changing the axle’s position on the wheel link. This is the mechanical basis of the “split” arrangement.

Axle Path

The rear axle is fixed to the end of the wheel link. It therefore follows an arc centered on the wheel link’s main frame pivot, just as it does on a basic single-pivot suspension.

The concentric axle pivot does not create a moving virtual pivot for the rear axle. The upper control link changes brake-link rotation and shock motion, but it does not redirect the axle away from the main-pivot arc.

Main-pivot height and fore-aft position determine:

Initial direction of axle travel
Chainstay-length change
Chain growth
Pedal feedback
Much of the anti-squat behavior

This is why Split Pivot can accurately be described as both a four-bar linkage and a single-pivot axle-path system.

Acceleration and Anti-Squat

Pedaling force enters through the chain and rear cassette, then reacts through the hub, axle, and wheel link. The main-pivot position relative to the chainline and rider center of mass is central to anti-squat.

A higher main pivot can increase chain growth and anti-squat in common gears, while a lower pivot generally produces different chain-growth and axle-path characteristics. These effects also change with chainring size, cassette position, wheel size, sag, and rider position.

Split Pivot does not prescribe one anti-squat curve. Designers can use the same architecture for an efficient short-travel bike or a more active long-travel platform by changing the main pivot, gearing, shock tune, and other dimensions.

Braking and Anti-Rise

The disc-brake caliper is mounted to the brake link rather than directly to the wheel link. When the rear brake is applied, caliper torque loads the brake link and is transferred through the control link toward the frame.

The lines of force through the brake and control links define an instantaneous force center. Moving the control-link pivots changes how braking torque tends to compress or extend the suspension. This allows anti-rise to be adjusted without moving the main pivot that establishes the axle path. The Split Pivot patent describes this distinction as controlling braking forces through an instant force center while acceleration response is controlled by the swinging wheel link. U.S. Patent 8,002,301

Manufacturers often describe the result as braking and pedaling independence. That language should not be interpreted as zero interaction. Weight transfer still changes suspension load, braking torque still passes through the linkage, and the brake link may also drive the shock. Split Pivot provides separate tuning paths, not complete isolation from physics.

Shock Actuation and Leverage Ratio

The brake link or control link normally drives the shock. Its pivot locations and shock attachment determine the leverage curve.

Because the axle remains on the wheel link, engineers can revise control-link and shock geometry to change progression without necessarily changing the main-pivot axle path. The variables are not completely independent: modifying the control link can affect anti-rise, leverage ratio, frame loads, and packaging at the same time.

Split Pivot can be paired with air or coil shocks when the specific frame provides suitable progression, dimensions, clearance, and damping. Shock compatibility belongs to the model, not the suspension name.

Why It Exists

A basic single pivot has a simple axle path and load-bearing structure, but mounting the brake caliper directly to its swingarm ties brake reaction closely to that member’s movement. Split Pivot retains the structural and pedaling characteristics of a main swingarm while adding another path for brake torque and shock actuation.

The layout allows designers to pursue:

A chosen single-pivot axle path and chain-growth profile
Model-specific anti-squat
Tunable anti-rise and braking response
A broad range of shock leverage curves
A rigid wheel-supporting swingarm
Packaging suitable for different travel classes and frame materials

The additional freedom comes from the concentric brake link and control link rather than from a more complex axle path.

Rider Experience

A well-tuned Split Pivot bike may retain useful rear-wheel movement while braking over rough terrain, helping the tire follow the ground instead of making the suspension feel abruptly firm. Near sag, the main-pivot and chainline relationship can provide pedaling support without requiring a heavily damped shock platform.

Those sensations vary substantially between bicycles. A short-travel Salsa, a mid-travel Devinci, and a long-travel or high-pivot application may share the concentric axle pivot while using different anti-squat, anti-rise, progression, geometry, and shock tunes.

Riders are more likely to notice the complete chassis and setup than the pivot location by itself. Tire pressure, sag, rebound, compression damping, spring curve, frame stiffness, and rider position can overwhelm differences attributed to the suspension name.

Setup Considerations

Sag places the linkage at the intended operating point. Too little sag can reduce sensitivity and extension travel; too much can move the bike into a less supportive part of its leverage and anti-squat curves.

Use the frame and shock manufacturer’s baseline rather than a universal Split Pivot percentage. After setting sag with normal riding equipment:

Cycle the shock to equalize air chambers and reduce seal friction.
Set rebound fast enough to recover between impacts without kicking.
Begin with compression damping open or at the specified base position.
Test braking behavior and repeated-hit recovery on familiar terrain.
Record pressure or spring rate, damping clicks, and volume-spacer configuration.

Changing eye-to-eye length, stroke, link position, or fork travel may alter geometry, clearance, progression, and frame loads. Salsa’s newer Split Pivot+ method permits specific travel changes on designated frames, but that does not make every Split Pivot bicycle travel-adjustable. Salsa Split Pivot+

Mechanic’s Perspective

The concentric rear pivot sits in an exposed area near the hub, rotor, and wheel spray. Its bearings also support relative movement between the wheel and brake links while the assembly experiences suspension and braking loads.

Common inspection points include:

Side-to-side play at the rear wheel
Movement between the wheel link and brake link
Rough or seized concentric-pivot bearings
Loose or damaged pivot and thru-axle hardware
Brake rub that changes as the linkage is loaded
Worn main-pivot or control-link bearings
Shock-eyelet or trunnion-mount play
Creaking from pivot axles, bearing seats, or link interfaces
Brake-hose contact or tension through the travel

Wheel-bearing play, a loose thru-axle, and suspension-pivot play can feel similar. Check the hub independently, then hold the wheel link and brake link while applying lateral load at the rim. Movement at the concentric joint can also change caliper alignment relative to the rotor.

Before disassembly, obtain the service diagram for the exact model and year. The rear axle may pass through a multi-piece concentric assembly containing bearing covers, spacers, seals, axles, and threaded hardware. Similar-looking parts may have different shoulders, orientation, or torque requirements.

During service:

Record the order and direction of all axle-side hardware.
Support the dropout or link close to the bearing bore.
Use the specified puller, press, and drifts.
Apply force through the correct bearing race.
Use only the specified grease, retaining compound, or threadlocker.
Tighten pivots in the manufacturer’s sequence and to the listed torque.
Reinstall the wheel and align the brake after confirming smooth linkage motion.

Devinci notes that its Split Pivot bearing service may require a special extractor and directs mechanics to model-specific torque specifications. Devinci Squeaks and Creaks Technical Guide

There is no universal replacement interval. Bearing size, sealing, frame alignment, climate, washing, rider load, and brake use all affect service life. Do not overtighten the rear axle or pivot hardware in an attempt to remove play.

Buying Considerations

The Split Pivot name should not determine a purchase by itself. Compare the complete bike’s geometry, travel, shock specification, anti-squat, progression, weight, stiffness, and intended use.

On a used frame, inspect the concentric pivots carefully and confirm that bearing kits, axle hardware, control links, and shock mounting parts remain available. Persistent rotor rub, lateral rear-wheel movement, or uneven bearing resistance can indicate more than a simple brake adjustment.

Buyers considering shock or travel changes should verify written manufacturer compatibility. The architecture can support many configurations, but an individual frame is engineered around specific shock dimensions, link positions, and clearances.

Advantages

Separate wheel and brake links provide additional braking-response control
Retains a predictable single-pivot axle path
Main-pivot position can be selected for the intended pedaling behavior
Control link provides leverage-curve tuning options
Adaptable across multiple travel and use categories
Rigid wheel link can provide a direct structural load path

Engineering Trade-Offs

More pivots and hardware than a basic single pivot
Concentric bearings operate in a contamination-prone location
Axle-side hardware can be proprietary and model-specific
Changes to brake-link geometry can also affect leverage and frame loads
Fixed main-pivot axle path offers less axle-path freedom than axle-carrying dual-link or Horst systems
Bearing wear can influence both suspension movement and brake alignment
Service may require specialized pullers or presses

Comparison with Other Layouts

Layout	Structural distinction
Split Pivot	Brake link pivots concentrically around the rear axle; axle remains on the main wheel link
Basic single pivot	Axle and brake caliper are carried by the same swingarm
Linkage-driven single pivot	Axle remains on one swingarm; additional linkage primarily shapes shock motion
Horst Link	Rear pivot is ahead of the axle, which is carried by a separate seatstay member
Dual short link	Rigid rear triangle and axle are guided by two short links around a moving instantaneous center
Trek ABP	Also uses a pivot concentric with the rear axle, with Trek-specific linkage geometry and implementation

Split Pivot and ABP share the visible concentric-axle concept. Their branding, detailed geometry, patents, frame structures, and shock layouts should not be treated as interchangeable.

Common Questions

Is Split Pivot a single pivot or a four-bar suspension?

Both descriptions can be useful. It is mechanically a four-bar linkage, but the axle follows a single-pivot arc because it remains fixed to the main wheel link.

Is the suspension pivot part of the rear hub?

No. The hub rotates on wheel bearings. Separate suspension bearings or bushings allow the brake link to rotate around the same axis relative to the wheel link.

Does Split Pivot completely isolate braking from suspension?

No. It separates the force paths enough to provide additional tuning freedom, but braking still changes weight distribution and loads the suspension and frame.

Does it eliminate pedal bob?

No. Pedaling behavior depends on main-pivot placement, chainline, gearing, sag, rider movement, and shock tune.

Is Split Pivot better than Horst Link?

Not universally. Split Pivot retains a simple fixed-pivot axle path and offers brake-link tuning. Horst Link provides a moving instantaneous center for the axle. Each can be tuned well or poorly for a given use.

Can every Split Pivot frame change travel?

No. Travel adjustment is available only where the manufacturer explicitly designed and approved it, such as designated Salsa Split Pivot+ applications.

Do the concentric bearings require special tools?

Some frames can be serviced with standard bearing tools, while others require specific extractors, drifts, or supports. Consult the model’s service documentation before removal.

Industry Context

Split Pivot emerged during a period of extensive suspension patent development and brand-specific linkage identities. Its distinguishing contribution was not a new rear-axle path, but the use of a concentric axle pivot to create separate wheel and brake links within a compact four-bar system.

The architecture has since appeared across several manufacturers and travel categories. Devinci has used it extensively since 2011, while Salsa applies it to both conventional and travel-adjustable Split Pivot+ platforms. The range of implementations demonstrates that Split Pivot is a design framework rather than one fixed kinematic tune.