Anti-Squat

Summary

Anti-squat is a suspension kinematic property that determines how much a bicycle’s rear suspension resists compression under pedaling forces. It plays a critical role in how efficiently a full-suspension bike climbs and accelerates, especially on technical or loose terrain.

Key Facts

  • Category: Concepts
  • Also known as: Pedal-induced squat resistance
  • Used by / Found on: Full-suspension mountain bikes
  • Defined by: Suspension geometry + drivetrain forces
  • Measured in: Percentage (%) relative to chain force and center of mass

Overview

Anti-squat describes how a suspension system counteracts pedaling-induced movement — specifically, the tendency of the rear suspension to compress, or “squat,” when torque is applied to the drivetrain. It’s one of the most important elements of full-suspension design, with a direct impact on climbing efficiency, acceleration, and how the bike feels under power.

When you pedal, chain tension pulls backward on the drivetrain. That force can either compress the rear suspension, keep it neutral, or extend it slightly — depending on how the suspension pivots are arranged. Anti-squat is the term used to measure how much that force pushes against compression.

A high anti-squat value makes the bike feel firmer and more efficient when pedaling. A lower value allows the suspension to stay more active, which can help traction but may lead to unwanted movement, especially on climbs. While 100% anti-squat is considered “neutral,” most bikes are tuned either above or below this depending on the discipline and intended terrain.

Cross-country and trail bikes often sit above 100% at sag to resist movement and improve energy transfer. Enduro and downhill bikes, on the other hand, are often tuned to have less anti-squat to keep traction consistent when pedaling through rough sections. Understanding anti-squat helps explain why certain bikes feel crisp and others feel planted — and why neither is inherently better than the other without context.

How It Works

Anti-squat is built into the frame. It has nothing to do with the shock or any adjustments you can make post-purchase. It comes down to where the pivots are located, how the linkage moves, and how the drivetrain interacts with the suspension.

1. Chain Force and Center of Mass

When a rider accelerates, two things happen at once: the chain pulls on the rear triangle, and the rider’s weight shifts rearward. These forces influence how the suspension reacts.

The direction and amount of force from the chain depend on gear choice, chainline, and suspension layout. This chain force acts against the natural tendency of the rear suspension to compress due to the rider’s weight shift. If the upward component of that chain force perfectly cancels out the compression from the weight shift, you get 100% anti-squat.

If the chain force pushes up harder than the suspension wants to compress, the bike resists movement — that’s above 100%. If it doesn’t resist enough, the suspension compresses under power — below 100%.

This balance is what designers use to tune how efficient or supple a bike feels when you put power down.

2. Measuring Anti-Squat

Anti-squat is expressed as a percentage, and it changes depending on travel position and gear selection. A few key numbers to understand:

  • >100% – Suspension resists compression. Bike stays higher in travel under power. Good for pedaling efficiency.
  • 100% – Neutral. Chain force and weight transfer cancel each other out.
  • <100% – Suspension compresses under pedaling. Can improve traction but may result in pedal bob.

Most full-suspension bikes aim for high anti-squat in the first third of travel, especially around sag (roughly 25–30% of travel). That’s where most pedaling happens. As the bike moves deeper into travel, anti-squat is usually reduced to let the suspension stay active and absorb hits without interference from the drivetrain.

Designers also consider how anti-squat behaves in different gears. Bikes are often tuned to have slightly lower anti-squat in the easiest climbing gears to avoid harshness when spinning up steep sections.

3. Factors Influencing Anti-Squat

Several parts of the suspension layout affect anti-squat. Designers manipulate these elements depending on what kind of riding the bike is intended for.

  • Linkage Design: Multi-link systems like VPP, DW-Link, and Switch Infinity allow designers to fine-tune how anti-squat changes through the travel. These platforms can create curves that start high and drop off smoothly — useful for balancing efficiency and traction.
  • Instant Center Position: The “instant center” is the theoretical pivot point created by the linkage at any moment. Its position relative to the chainline determines how chain force interacts with the suspension. Higher and farther forward = more anti-squat.
  • Chainring Position and Gear Ratio: The chain angle plays a big role. Higher anti-squat often comes from steeper chainlines (like when you’re in a harder gear). Lower gears can reduce anti-squat, especially when the chain is pulling more horizontally.
  • Axle Path: Rearward axle paths (like on some high-pivot bikes) tend to generate more anti-squat early in the stroke. Vertical or slightly forward axle paths usually produce less anti-squat.

Suspension modeling software is used to dial in all these variables during the frame design process. It’s a balancing act between efficiency, traction, and how the bike behaves in technical terrain.

4. Tradeoffs

There’s no perfect anti-squat number. What works well for one type of riding might feel wrong for another.

  • High Anti-Squat: Great for riders who want strong pedaling response and minimal energy loss. But if it’s too high, the bike can feel harsh, especially over chattery climbs or technical sections where the rear tire needs to stay glued to the ground.
  • Low Anti-Squat: Offers excellent traction, especially when climbing loose or uneven terrain. But without some form of damping support, it can lead to excessive pedal-induced movement, which saps energy and makes the bike feel sluggish.

Many modern bikes are designed with anti-squat curves that drop off as the suspension compresses. That way, you get support when pedaling and traction when descending or cornering hard.

Notable Implementations

  • DW-Link (Pivot, Ibis): Known for high initial anti-squat that helps prevent bobbing, while transitioning to a more active feel deeper in the travel.
  • Switch Infinity (Yeti): Uses a translating lower pivot to keep anti-squat high across more of the stroke, especially in the mid-range gears.
  • Maestro (Giant): Balanced design that delivers moderate anti-squat and consistent pedaling feel without requiring much shock tuning.
  • VPP (Santa Cruz): Dual-link setup tuned per model — typically sits around 110–120% at sag, tapering off smoothly through the travel.

Related Terms

See Also on BBB

References

  • Linkage Design Suspension Analysis Tools
  • “Understanding Anti-Squat” – Pinkbike Tech
  • Santa Cruz VPP Technical Documents
  • Pivot Cycles Suspension White Papers
  • Bikerumor Suspension Deep Dive Series
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