  Kaluza-Klein theory is a popular alternative theory of gravity, with both
non-rotating and rotating black hole solutions known. This allows for the
possibility that the theory could be observationally tested. We present a model
which calculates the reflection spectrum of a black hole accretion disk system,
where the black hole is described by a rotating solution of the Kaluza-Klein
theory. We also use this model to analyze X-ray data from the stella-mass black
hole in GRS 1915+105 and provide constraints on the free parameters of the
Kaluza-Klein black holes.
