It's absolutely ridiculous that there is no bicycling mode but it has it as a Move IQ event? This makes no sense. A lot us like to bicycle for fitness and if we choose cardio it doesn't track distance…
It has the functionality since version 4.0. Check on device settings-info-software. Since the device only have 4 activity type besides walk and run (which are fixed) you have manage which one you want…
Found how to add cycling - not tested yet - phone open garmin connect - garmin devices - open vivosmart 4 - activity options - edit - add bike - then sync
we all need to test now!
That's impossible - there's no way to even estimate cycling distance without GPS or a direct connection to a speedometer, neither of which the Vivosmart line can do (nor is the Vivosmart line intended to have those features - you want something like the Vivoactive or Instinct if you want integrated GPS and sensor connectivity). It estimates steps and walking using the motion of your wrist plus stride length, but your wrists are mostly stationary while cycling, and the wrist movement (for shifting, braking, comfort repositioning) has no relation to traveling speed/distance.
That's really unfair - they added a cycling profile once connected GPS was implemented, which was necessary to make it in any way useful (beyond simply using the generic activity profile and changing the activity type later). It can't auto-detect cycling because there aren't unique wrist movements that indicate cycling, and stationary wrists plus elevated heart rate PLUS increased speed (necessary to distinguish from e.g. high stress that elevates heart rate while sitting still, though it's still difficult to differentiate between cycling and a motor vehicle traveling at bicycle speeds in stressful traffic) that would give cues to auto-start a cycling activity is only possible with connected GPS, which has to be manually activated (which is good, else it would rapidly drain the battery on both your watch and phone).
Garmin does make a device (several, actually) with more cyclign features, but it's more expensive because it needs more integrated sensors (and the ability to directly connect to additional sensors, like speed, cadence, and crank power). With the hardware that the VS4 DOES have, they've actually done a very good job of supporting cycling tracking - you just need to manually activate it. If you want more features, you need more hardware, which means you need a different smartwatch/tracker.