Motor Comparison – ASG Ultimate v SHS High Torque

I built a complete BCM KMR SBR for DS a while back and he had received the ASG Ultimate U-18000 motor due to its superior high-torque performance. However, after a few milsims, he brought it back, noting that the gear whine is higher than normal compared to his SHS HT/SHS 13:1 setup. After checking the shimming at least 3 times with the 3 main gears, then pinion-to-bevel, ensuring there was no interference from the tops and bottoms of the gearbox, it was determined that the actual gear profile between the ASG motor’s stock pinion gear and the Siegetek’s bevel was not a good match.


Due to a shortage of Siegetek pinions at the time, a decision was made to completely swap the motor out to an SHS High-torque motor with a hardened SHS D-type pinion gear. SHS pinion gears are known to have a good mesh with Siegeteks and a good upgrade choice for the more budget-minded client. A dramatic reduction in gear whine was evident. Attributing the reduction in noise to pinion-to-bevel gear match, and in the pursuit of the absolute ideal setup, a Siegetek pinion was finally sourced and the ASG motor was set up.


The setup:

  • Siegetek 14.09:1 single-sector gearset
  • M110 spring
  • Rocket Airsoft piston (SHS clone)
  • Turnigy Nanotech 11.1v 1300mah 25c battery (at time of testing, at 11.2V at rest – not optimal)


Notes: You will note that the guns sound “slow”, this is due to the low battery voltage, I advise most clients to swap their batteries when they notice their cyclic rate drop, and this typically happens when the battery dips below 11.6V at rest. The battery used in the tests above was at 11.2V at rest.

Here are the numbers:

  • SHS high-torque motor pulled 22amps @ 36rps.
  • ASG U-18000 motor pulled 12 amps @ 25rps.

What the numbers don’t show is that the ASG motor, while drawing significantly less power and has a lower cyclic rate, has noticeably more torque than the SHS. This is not surprising as the SHS is 16TPA while the ASG is 28TPA. However, as the videos show below, the ASG motor itself is still whiney.

The following conclusions can be drawn:

  • ASG will get more mileage out of a battery due to lower amp draw, at the expense of noise (noise is less apparent with a charged battery due to decreased cycle time)
  • ASG motors are inherently noisy, regardless of gear interface
  • SHS motors are power-hungry/less efficient with consumption figures similar to Lonex A1

The client has opted to stay with the SHS motor for the time-being. More research is warranted at this point and another combination of parts will be tested in the coming weeks.

Leave a Reply

Your email address will not be published. Required fields are marked *