ㆍConventional derailleur systems rely on externally exposed components, which inherently suffer from chain drop, contamination, frequent maintenance, and reduced durability :
ATB-P fundamentally addresses these limitations by adopting a fully sealed gearbox architecture.

ㆍATB-P uses the same fixed-input 1×7 architecture as ATB-L :
The input gear between the pedal shaft and the main shaft is configured with a 54:30 ratio, increasing rotational speed while reducing the transmitted torque.

ㆍThis input structure provides several practical advantages.

ㆍFaster gear engagement :
The increased rotational speed accelerates the engagement between the pawls and the internal gear teeth, significantly reducing pedal free-play and engagement delay.

ㆍImproved shifting durability :
By reducing the torque transmitted to the main shaft and shifting components, long-term durability is naturally improved.

ㆍThe key difference from the ATB-L version lies in the use of high-strength, heat-treated alloy gears :
Thanks to the fixed input structure, ATB-P achieves durability that exceeds even that of the ATB12, despite its simpler architecture

ㆍThis enhanced durability allows the gearbox to be designed with thinner gears, enabling a lighter overall structure without compromising strength.