straitjacker
BANNED
I believe that were lead shots.
Which, besides the permanent direct effect on oxygen carrying capacity, affected the vestibular system in the way you're mentioning. So he needed to ride fast just to keep himself upright.
Also, the side effect of the lead shots on his extremities allowed him to develop a rare ability. Inequality of his legs have caused an unique, a flywheel-like, effect on the pedals. This effect balanced the vestibular deficit a bit, as well.
Now, it makes sense.
Which, besides the permanent direct effect on oxygen carrying capacity, affected the vestibular system in the way you're mentioning. So he needed to ride fast just to keep himself upright.
Also, the side effect of the lead shots on his extremities allowed him to develop a rare ability. Inequality of his legs have caused an unique, a flywheel-like, effect on the pedals. This effect balanced the vestibular deficit a bit, as well.
Now, it makes sense.