Orbea R10 El Manual Del Propietario página 11

The attempt to pull the helmet off, by pulling on the
front then the rear of the helmet. If the helmet comes
off, increase strap tension and examine if the pads
being used are thick enough. The helmet should not
roll forward or backward excessively.It should not be
possible to remove the helmet without unfastening the
buckle.
Final check
The important thing to remember is that the helmet fits
snugly. If you can tilt it forward or backward you need
to tighten the strap adjustment.
It is important for the helmet to fit snugly on your head
and must be fastened to provide maximum protection.
NOTE: All adjustments should be checked each
time the helmet is worn, making sure it fits snugly
at all times.