Belt Tension Check

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Krikit Tension Gauge

Zero recommends the Gates Krikit belt tension gauge to check belt tension.

Krikit Tension Gauge invoice and box
Krikit Tension Gauge gauge and instructions
Video Guide
MostlyBonkers made a How-to video:
Tips
  • Turning the back wheel backwards before measuring will give different readout compared to turning the wheel forwards before measuring using the same spot.
    The difference may be significant to the (pre-2017) 20-30kg belt tension specification.
    For wide-belt 2017+ models, the tension specification is very wide (~25-75kg) and thus has a lot of leeway but seems worth a rotational check anyway.
  • The center of the belt can be reached from below, without removing the mudguard.
    This is described as a note in 5.14 in the 2015 manual
Steps
More detailed generic instructions for the Krikit deflection device
  1. Ensure the blue indicator arm is pressed down.
  2. Place the gauge in the center of the belt span, such that it is aligned longitudinally with the belt length.
  3. Place a finger on the blue pressure pad and depress this pressure pad.
  4. Keep pressing the blue pressure pad until you feel and hear a distinct 'click'. When this 'click' sound is heard, do not press any further.
  5. Remove the gauge and read the belt tension by observing the point where the top side of the blue indicator arm crosses the numbered scale on the gauge body.
  • Care must be taken to ensure that the gauge is not 'rocked' when pressing down on the blue pressure pad. The strap above the pressure bar is provided to attach snugly over the finger and prevent any 'rocking' motion.
  • Due to the fact that this device requires some amount of practice and operator skill, the accuracy and repeatability of the tension readings are not high.
Improvement
Because this procedure is not trivial to perform consistently, there is a modification to make the tension gauge easier to align
Gates' Carbon Drive mobile app
As of 2017, the Official Owners Manual also includes a procedure using Gates' Carbon Drive mobile app to check belt tension.
Usage
  • Use the application in a quiet environment.
  • Pluck the belt near the center of the lower belt span, so it vibrates like a guitar string.
Recommended Belt Tension
Belt Type Years Resonant Frequency Tension Range
Narrow 2013-2016 42.5 Hz – 73.6 Hz 20 – 30kg
Wide 2017+ (except S 13.0) 96.3 Hz – 124 Hz 26 – 75kg

The frequency can also be checked with instrument tuning apps such as Tuner-gStrings for Android.