The god delusion, awesome. Being a student of philosophy for a long time, and avid cyclist for longer, and someone who's shed the childish notion of the vengeful god, I can say for certain there is no god and therefore, there's no reason to worry about 'him' being 'real'.
However, if you round a corner on your bike and slam into an oncoming car, THAT is real. God will not magically make your molecules pass through that car and leave you unharmed. God will not fill up your energy when your climbing those hills nor will he fill up your stomach whenever you want. You have to do that, because THAT is real.
Yes, we live mostly by the ego. So it is and we continue forward finding happiness here and there (sometimes all over - the universe to me is far more beautiful than the notion of a vengeful, side-taking god), just 'living' the human experience. People let 'god' ruin that, always have, (sadly) always will.
Cycling helps us produce endorphins. If our body holds out and we don't feel like puking after that one or many hills, we can feel elated. That's brain chemistry. There's no magic switches and god has nothing to do with any of that. He saves no one from accidents, stops no wars, does not magically wave his hand/wand and turn that homeless guy into a 'cured' millionaire. Just like he will not magically lift me up so I can fly thru the air to the top of a nasty hill.
No, he's definitely not real, nor does he need to be. When I was young and realized organized religion was a sham, a veil was lifted over my eyes. Human existence has so much beauty (and sure, plenty of pain and suffering, just ask the Buddha) and I'm just happy being a part of that. I only have one shot to experience all of it. So, for me, cycling is a part of that beauty, just like the OP said. Stop robbing everyone of their experiences with beauty just because you believe in a hypothetical, invisible, vengeful, biased, super being. Leave us mortals who have to deal with reality every day to enjoy our postings in peace.
Thank you.
(edited for typos)