Detect collision doesn't work

This is a weird problem. I have two meshes with their boundingshpere radii and boundingsphere centers calculated and stored. WHen the meshes are moved the transformation matrix that is applied to the mesh is applied to the bounding sphere centers. However my detectcollision function which does somewhat like this: if((mesh1.radius + mesh2.radius) > (distance_between_centers)) return true; else return false returns some wierd results. When the meshes actually appear to touch and move into each other it still doesn't return true as it should when the collision occurs. Is there something wrong with my mesh? I actually copy pasted the code from another project of mine, which works just fine except that the meshes loaded are different mesh files. What could be wrong here?