6.3.1.1 States
The rank of a signed integer type shall be greater than the rank of any signed integer type with less precision.
The rank of long long int shall be greater than the rank of long int, which shall be greater than the rank of int, which shall be greater than the rank of short int, which shall be greater than the rank of signed char.
So, could this not be the case
signed char has 32 bits (1 padding, 1 sign, 30 precision)
unsigned char has 32 bits (0 padding, 0 sign, 32 precision)
signed int has 32 bits (1 padding, 1 sign, 30 precision)
unsigned int has 32 bits (2 padding, 0 sign, 30 precision)