We prove a concentration inequality for the
ℓ
q
n
\ell _q^n
norm on the
ℓ
p
n
\ell _p^n
sphere for
p
,
q
>
0
p,q>0
. This inequality, which generalizes results of Schechtman and Zinn (2000), is used to study the distance between the cone measure and surface measure on the sphere of
ℓ
p
n
\ell _p^n
. In particular, we obtain a significant strengthening of the inequality derived by Naor and Romik (2003), and calculate the precise dependence of the constants that appeared there on
p
p
.