Pedal Kickback — Drivetrain Smoothness
K-Volve Kinematics / Pedal Kickback
K-Volve / Metric 04
Pedal Kickback Relief
3.0–3.5° in the working zone. Achieved by geometry, not by idler — the concentric pivot keeps the chain quiet while protecting the Maxon motor freehub from cyclic back-driving forces.
3.0–3.5°
Working Zone
Best-in-class non-idler
8.14°
Full Travel
At 34/28t — perfectly linear
15.93mm
Chain Growth
Linear, smooth, predictable
0°
At Sag
Zero kickback at rider position
On my old bike the pedals would kick back on every root. It's like the drivetrain is fighting you. On the Paratu the drivetrain is just... quiet. You forget it's there. That's what 3 degrees feels like versus 12.
— Fil Palmer, DIRTLAB Test Rider
Concentric Pivot: Kickback by Geometry
The Paratu CP's concentric pivot is positioned at the motor/BB axis, keeping the chain's effective pivot close to the chainring's rotational axis. This means chain-length variation through the stroke is minimised at the source — no idler pulley needed, no additional drivetrain complexity, no bearing maintenance.
The kickback curve is perfectly linear: 0° at sag, rising smoothly to 8.14° at full travel. No spikes, no abrupt transitions. The chain growth curve follows the same linear profile: 0mm at sag to 15.93mm at full travel. This linearity means the drivetrain load on the suspension is predictable and does not spike in the middle of the working zone, where repeated-hit harshness actually appears.
Maxon Motor Protection
Precision Freehub Defence
The Maxon BikeDrive Air S motor uses a precision freehub mechanism rated for specific cyclic loading patterns. High pedal kickback (10–15°) creates back-driving forces that exceed the freehub's comfort zone, accelerating wear and creating potential failure modes. The Paratu CP's 3.0–3.5° working-zone kickback keeps the motor within its design envelope even on the roughest terrain. Combined with 97.3% anti-squat, the motor experiences near-zero suspension-induced disturbance during normal operation.
Why Chain Growth ≠ Harshness
15.93mm chain growth sounds high compared to high-pivot bikes with idler pulleys that approach zero. But chain growth and pedal kickback are not proportional — the relationship is governed by pivot geometry relative to the chainline, not growth magnitude alone.
The 97.3% AS Factor
At ~100% anti-squat, the chain force and gravitational compression force on the shock are near-balanced. The 15.93mm of chain growth acts on a system where the kinematic baseline is already neutral — the residual felt disturbance is much smaller than it would be on a bike with the same growth but 70–80% anti-squat.
Smooth Distribution
11mm distributed smoothly across 80mm of working-zone travel is ~0.14mm per mm of wheel travel — a near-constant rate. VPP frames typically show chain growth that accelerates hard as the virtual pivot rotates. A smooth rate means no mid-stroke spike where repeated-hit harshness actually appears.
Flow Trail Feel
Some riders on flow trails prefer moderate kickback — it makes the bike feel "supportive" when pumping. The Paratu CP delivers support differently: the 97.3% anti-squat keeps the rear from sinking when you pump, not the kickback. The felt difference is a quieter drivetrain with the same pop. Some riders coming off bikes with 10°+ kickback may initially read this quietness as "less alive." A test ride resolves the difference within one run.
Competitor Comparison
Kickback measured at 10T engagement (standard 12-speed cassette). Chain growth in the working zone (sag → +80mm) is the rider-felt metric.
Frequently Asked Questions
What is pedal kickback and why does it matter?
Pedal kickback is the backwards rotation of the cranks caused by rear suspension compression. It's felt as a 'kick' through the pedals when hitting bumps. High kickback (10–15°) fights the rider's pedal input and can damage eMTB motor freehubs. The Paratu CP's 3.0–3.5° is low enough to protect the Maxon motor while keeping the drivetrain quiet through rough terrain.
How does the Paratu CP achieve low pedal kickback without an idler?
The concentric pivot places the main suspension pivot at the motor/BB axis — close to the chainring's rotational axis. This minimises chain-length variation through the stroke. An idler pulley design achieves the same result by mechanically decoupling the chain path, but adds 2–3W of drag, bearing maintenance, and ~100g of mass. The Paratu CP achieves comparable results through geometry alone.
Is 8.14° of total kickback a problem?
No. The 8.14° at full compression is never experienced during normal pedalling — riders don't pedal through the final 40% of travel. In the working zone (sag to +80mm), kickback is 3.0–3.5°, which is best-in-class among non-idler frames and comparable to idler-equipped designs. The relationship between chain growth (15.93mm) and kickback (8.14°) is governed by pivot geometry relative to the chainline, not growth magnitude alone.
Does the Maxon motor benefit from low kickback?
Directly. The Maxon BikeDrive Air S uses a precision freehub mechanism. High kickback creates cyclic back-driving forces through the freehub, accelerating wear and creating potential failure modes. The 3.0–3.5° kickback means the motor freehub operates within its design envelope even on the roughest terrain. This is a reliability feature, not just a comfort one.
