it`s either gripping/griping
The two consonants (pp) make the preceding vowel (i) short (sounds like "ih"). A single consonant (p) keeps the vowel (i) long (sounds like "eye").
So, you were correct with
griping.
I`m a high school drop out,but boy can I drive a big rig.
I'm a High School drop-out too but boy can I write.