Ultimate CNC Gear Set, 18.5:1

The Ultimate CNC Gear Set 18.5:1 is a complete set of three gears – spur gear, sector gear and bevel gear – for AEG gearboxes from ASG's Ultimate upgrade series. The 18.5:1 ratio is close to the classic standard ratio of 18.72:1, which makes this set the obvious choice when worn or stripped stock gears need replacing with something stronger without changing the character of the gun.

The gear ratio determines how many revolutions the motor has to make each time the piston is pulled back. Low ratios give a high rate of fire, high ratios give more torque. 18.5:1 is the balanced middle ground that works well with a standard motor and most common springs. The bevel gear is made to mesh with the pinion gear on ASG's own Ultimate motors.

Why the Ultimate CNC 18.5:1

Five technical advantages of the set:

• Standard ratio: 18.5:1 is almost the same as stock 18.72:1, so rate of fire and battery consumption stay roughly as before – you get stronger gears without having to change motor or spring.
• CNC-machined steel: The gears are CNC-milled rather than cast or sintered like many stock gears. This gives more precise teeth and smoother meshing between the gears.
• Differential hardening: Each gear is vacuum-hardened and heat-treated so the hardness suits each contact point, and the surface is black-oxidised.
• Complete 3-piece set: Spur, sector and bevel come as a matched set, so you avoid mixed ratios and uneven wear between old and new gears.
• V2 and V3: The set fits AEGs with V2 and V3 gearboxes – by far the most common standard on M4, AK, G36 and MP5.

Maintenance and safety

• Gears must always be shimmed correctly when fitted – incorrect shimming causes noise, wear and at worst stripped teeth. Bearings and shims are not included.
• Check the AOE (angle of engagement) between the sector gear and piston after the swap, and adjust if needed with a new piston or an AOE pad.
• Lubricate the gears with a thin layer of gear grease – too much grease collects dirt in the gearbox.
• If you are unsure about fitting and shimming, our workshop in Aulum, Denmark is happy to do the job.