Community Moderator Alumni are previous members of the Moderation Team, which ensures conversations are friendly, factual, and on-topic. Moderators are here to answer questions, escalate bugs, and make sure your voice is heard by the larger Fitbit team. Learn more
Welcome aboard @Karl007. I like to see new faces around. Note that for your Spin cycle class your tracker wont work in the same way. There are activities where step count isn't the best indicator of the calories burned. If you are doing an activity that does not require steps (like cycling or swimming) so for this I recommend to log a manual activity or start the exercise mode directly from your tracker by pressing the side button for a few seconds. By doing this you will account the calories you burn during your cycling exercise.
Hope this information helps. See ya later. 
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Community Moderator Alumni are previous members of the Moderation Team, which ensures conversations are friendly, factual, and on-topic. Moderators are here to answer questions, escalate bugs, and make sure your voice is heard by the larger Fitbit team. Learn more
Indeed @Karl007. Unfortunately at the moment manually logged activities or activity records of your tracker does not count for your challenge. This is to avoid the participants doesn't log manually the steps and gain a little of advantage. 
You can find more information about the challenges here: "Challenges FAQ".
Let me know of you have more questions.
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