It is not possible to check the chain tension yourself with the derailleur gears. When the chain is sagging, please consult with your local Carqon dealer what to do. In most cases the derailleur or chain must be replaced.

Have the sprocket and/or the chain wheel replaced by a Carqon dealer if you notice that individual
teeth are dangerously sharp (so-called shark teeth) (1) or (2).

• Contact a Carqon dealer if components show signs of damage, if you notice unusual sounds
  when shifting gears or if you are unable to shift through all of the gears in a proper manner.
• Maintain the derailleur gear components with suitable maintenance products in order to reduce
  wear and tear through weather and environmental influences. In order to obtain information,
  contact a Carqon dealer.

You can check the chain wheels yourself with the pictures below. 

Note: Go to your Carqon dealer to make adjustments to the derailleur drive, if needed.