Full-face rider helmets are widely used these days, but the shock abso
rption and safety performance of them have not been discussed yet. So
we examined the shock absorption performance and the safety of three f
ull-face rider helmets (samples A, B, and C) of which the laminated co
nstitutions of the FRP shell part were respectively different. The eff
ect of the hybrid lamination, composed of aramid and glass fabrics, on
the shock absorption performance has been discussed also. Testing was
performed twice for the same impact site of a helmet hit flat and wit
h semi-spherical anvils, according to the JIS-C shock absorption test
method. The following results were obtained: The acceleration waveform
measured at the forehead part of Helmet-A, which was hit on a semi-sp
herical anvil, behaved flatly while the part on the left side of the h
ead behaved parabolically. In the case of Helmets-B and -C, which have
an aramid fabric layer, they behaved conversely, such that a flat wav
eform was observed on the part on the left side of the head. All helme
ts hit on the semi-spherical anvil showed a flat acceleration waveform
regardless of the impact site of the helmet, and showed a maximum acc
eleration of less than 120 g, which is exceedingly small compared to t
he results from the case with the flat anvil. For all the helmets, the
maximum acceleration and the elapsing time of more than 150 g in the
second test were higher values than the values in the first test. The
values of Helmet-B, in particular, were recognized to change remarkabl
y. The hybrid lamination, composed of aramid and glass fabrics, was no
t so effective. However, it was remarkable that the maximum accelerati
on and the elapsing time at the forehead of Helmet-B in the first test
were the smallest values in all of the data collected from hitting a
flat anvil.