Close up front detail
The two gutter mounted bars are 58" long, and the two rail mounted bars
are 48" long.
The gutter mounts are located at the front and rear of the rack, and
the rail mounts are
located directly under the rack's original load bars, and support the
center section of the rack.
This give me eight attachment points, and distributes the load between
the roof and the gutters,
and adds rigidity to the rack, making the whole setup very strong.
I used a 40x50" Surco,
which left just enough room to mount two bike carriers to the outside
of the rack.
Close up detail of rear with fork mount
The addition of the fork mount at the rear of the bike carrier allows
for two
ways to carry a bike, either facing forward with front wheel on, or
facing aft
with the wheel off, (a more secure mounting for rough roads and long
trips).
This also allows me to carry up to 4 bikes at a time. With one mounted
facing forward
on each carrier, I can attach the fork of a second bike to the fork
mount at the rear
of the carrier, and the rear wheel can be secured to the spare tire
carrier.