In any literal sense, I'd say not really — to cheer in its first sense means 'to cry with encouragement', so the image of 'cheering with a smile' is not an entirely applicable; the first instance of 'cheering on' is being used in this very literal way.

However, it could certainly be argued that 'to cheer someone with your smile' is an unusual enough metaphor to make it actually quite an interesting one to use.

Then again, there is another consideration, from another sense of 'to cheer', which means 'to cheer up, make happier, make less unhappy; encourage' — as in 'a cheery fire'. In this sense, 'to cheer someone up with your smile' is an entirely appropriate image. This would be particualrly applicable if, say, the spectator was for some reason sad, and the sight of the riders smiling back cheered them up.

I suspect that these metaphors do not necessarily convey exactly your intended meaning, which is why I say "with reser
vations" — although the metaphors can be used, I'm not sure they mean quite what you think they do?