Predictions of the CMB spectrum from a bimetric gravity theory ( BGT ) [ 1 ] are presented .
The initial inflationary period in BGT is driven by a vanishingly small speed of gravitational waves v _ { g } in the very early universe .
This initial inflationary period is insensitive to the choice of scalar field potential and initial values of the scalar field .
After this initial period of inflation , v _ { g } will increase rapidly and the effects of a potential will become important .
We show that a quadratic potential introduced into BGT yields an approximately flat spectrum with inflation parameters : n _ { s } = 0.98 , n _ { t } = -0.027 , \alpha _ { s } = -3.2 \times 10 ^ { -4 } and \alpha _ { t } = -5.0 \times 10 ^ { -4 } , with r \geq 0.014 .