The radical circle of the Stammler circles has center at the nine-point center 
,
which is Kimberling center 
. The radius is given by
 |  |  |
(1)
|
 |  |  |
(2)
|
 |  |  |
(3)
|
(P. Moses and J.-P. Ehrmann, pers. comm., Jan. 28, 2004), where 
is the circumradius, 
is the circumcenter, 
is the orthocenter, 
is the nine-point center,
and 
is the area of the reference
triangle.
Its circle function is given by
 |
(4)
|
which corresponds to Kimberling center 
.
No Kimberling centers lie on it.
The radical line of the circumcircle and Stammler circles radical circle passes through the circumcenter 
(i.e., bisects the circumcircle) and is perpendicular
to the Euler line (P. Moses, pers. comm., Jan. 28,
2005).
The radical line of the Stammler circle and Stammler circles radical circle passes through the Kimberling center
and is perpendicular to the Euler line (P. Moses,
pers. comm., Jan. 28, 2005).
The radical line of the first Droz-Farny circle and the Stammler circles radical circle passes through 
,
perpendicular to the Euler line and the radical axis of the second
Droz-Farny circle and the Stammler radical circle passes through 
, also perpendicular to the Euler line (P. Moses,
pers. comm., Jan. 28, 2005).
