diff --git a/src/circuit_data.rs b/src/circuit_data.rs
index f2935e6c..ff910ce0 100644
--- a/src/circuit_data.rs
+++ b/src/circuit_data.rs
@@ -197,8 +197,7 @@ impl<F: Extendable<D>, const D: usize> CommonCircuitData<F, D> {
 
     /// Range of the sigma polynomials in the `constants_sigmas_commitment`.
     pub fn sigmas_range(&self) -> Range<usize> {
-        // `self.k_is.len() = num_routed_wires` is the number of sigma polynomials.
-        self.num_constants..self.num_constants + self.k_is.len()
+        self.num_constants..self.num_constants + self.config.num_routed_wires
     }
 }
 
diff --git a/src/plonk_common.rs b/src/plonk_common.rs
index 62dbb487..f6e0e228 100644
--- a/src/plonk_common.rs
+++ b/src/plonk_common.rs
@@ -52,7 +52,7 @@ impl PlonkPolynomials {
             1 => Self::WIRES,
             2 => Self::ZS,
             3 => Self::QUOTIENT,
-            _ => panic!("There are only 5 sets of polynomials in Plonk."),
+            _ => panic!("There are only 4 sets of polynomials in Plonk."),
         }
     }
 }
diff --git a/src/polynomial/commitment.rs b/src/polynomial/commitment.rs
index d90b295b..ecd3e875 100644
--- a/src/polynomial/commitment.rs
+++ b/src/polynomial/commitment.rs
@@ -328,10 +328,11 @@ mod tests {
             reduction_arity_bits: vec![2, 3, 1, 2],
             num_query_rounds: 3,
         };
-        // We only care about `fri_config, num_constants`, and the length of `k_is` here.
+        // We only care about `fri_config, num_constants`, and `num_routed_wires` here.
         let common_data = CommonCircuitData {
             config: CircuitConfig {
                 fri_config,
+                num_routed_wires: 6,
                 ..CircuitConfig::large_config()
             },
             degree_bits: 0,