I think it's important to listen to your body rather than try to adapt some generic rules or guidelines. Everyone's different. If you are waking up every morning looking forward to your workout, showing progress, etc. etc. there's no reason not to go ahead with it.
On the other hand if you have a sense of dread about your workouts, are feeling sore and tired all the time and are not making progress in your fitness, your body might be telling you to lay off a bit. Take an extra rest day or two.
At only ~1.5 hours/day you are not really in any kind of dangerous territory for "overtraining". If anything I'd increase the time/day cycling but I don't know what your fitness goals are so that may not be applicable.