A phillips screw driverYou are going to be amazed. This is the easiest thing in the world, I love the Railflex setup.
I assume bindings and connecting bar are already screwed onto the rail.
Completely loosen the center screw (it won't usually come all the way out).
Slide the bindings back until they slide off the rails.
Turn the bindings over.
On the bottom, you will see markings that match the boot sole length. Simply push the connecting rail in so that the scribed marks line up with your boot sole length. Sole length is that easy.
If you want to move the bindings more forward (or back) than the +/- 15 on the railflex, then change the binding attachment points. The marks on the binding are actually 1/2 the amount they say. If your boot sole is 320mm and you want to move forward another 10mm, then change the attachment point from 320/320(f/r) to 340/300(f/r).
CHECK THE FORWARD PRESSURE - At the rear of the heel binding there is a ruler like arrangement just above the rail. When the boot is in the binding and the bindings are set to your DIN, the mark on the binding should fall within that scale. If not, remove the boot and raise the little lever thing just above the scale and slide the binding forward or backward one notch at a time. Put the boot in the binding and check the scale again.
Understanding the boot sole length numbers. To mount a 320mm boot, you set the front and back on 320. To mount a 310mm boot, you set front and back on 310. The difference in boot length is only 10mm, but you changed both the front attachment and the rear attachment by 10, so clearly the marks are only 5mm apart. The marks are for simplifying the boot mount, they really aren't a ruler. The actual distance from one mark to the next is 1/2 of what is written on the scale.