Is it possible to use USB port on Kettler Ergo Race II to hook up a bluetooth device (smart watch) by plugging in a bluetooth dongle?

Hello,

you can't connect your watch directly with a Bluetooth Adapter. You need a bridge to connect your watch with your ergoracer. Take a look at the App from Uwe Böhm. You find more information here:
http://ergo.ub-online.de/index.php/de/

Unter der Woche ab 19:00 Gruppe Alb. Touren bis 90 min.