diff --git a/core/types/transaction.go b/core/types/transaction.go
index 6af960b8c3..6257580733 100644
--- a/core/types/transaction.go
+++ b/core/types/transaction.go
@@ -52,6 +52,26 @@ const (
 	SetCodeTxType    = 0x04
 )
 
+type TxTypeBitVec [(SetCodeTxType + 1 + 7) / 8]byte
+
+func (v *TxTypeBitVec) Set(txType byte) {
+	if txType >= byte(len(v)*8) {
+		panic("tx type out of range")
+	}
+	v[txType/8] |= 1 << (txType % 8)
+}
+
+func (v *TxTypeBitVec) Has(txType byte) bool {
+	if txType >= byte(len(v)*8) {
+		return false
+	}
+	return v[txType/8]&(1<<(txType%8)) != 0
+}
+
+func (v *TxTypeBitVec) Equals(o *TxTypeBitVec) bool {
+	return *v == *o
+}
+
 // Transaction is an Ethereum transaction.
 type Transaction struct {
 	inner TxData    // Consensus contents of a transaction
diff --git a/core/types/transaction_signing.go b/core/types/transaction_signing.go
index 01aa67c6ba..6c56c588d8 100644
--- a/core/types/transaction_signing.go
+++ b/core/types/transaction_signing.go
@@ -20,7 +20,6 @@ import (
 	"crypto/ecdsa"
 	"errors"
 	"fmt"
-	"maps"
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -183,9 +182,9 @@ type Signer interface {
 // modernSigner is the signer implementation that handles non-legacy transaction types.
 // For legacy transactions, it defers to one of the legacy signers (frontier, homestead, eip155).
 type modernSigner struct {
-	txtypes map[byte]struct{}
-	chainID *big.Int
-	legacy  Signer
+	txTypeBitVec TxTypeBitVec
+	chainID      *big.Int
+	legacy       Signer
 }
 
 func newModernSigner(chainID *big.Int, fork forks.Fork) Signer {
@@ -194,7 +193,6 @@ func newModernSigner(chainID *big.Int, fork forks.Fork) Signer {
 	}
 	s := &modernSigner{
 		chainID: chainID,
-		txtypes: make(map[byte]struct{}, 4),
 	}
 	// configure legacy signer
 	switch {
@@ -205,19 +203,19 @@ func newModernSigner(chainID *big.Int, fork forks.Fork) Signer {
 	default:
 		s.legacy = FrontierSigner{}
 	}
-	s.txtypes[LegacyTxType] = struct{}{}
+	s.txTypeBitVec.Set(LegacyTxType)
 	// configure tx types
 	if fork >= forks.Berlin {
-		s.txtypes[AccessListTxType] = struct{}{}
+		s.txTypeBitVec.Set(AccessListTxType)
 	}
 	if fork >= forks.London {
-		s.txtypes[DynamicFeeTxType] = struct{}{}
+		s.txTypeBitVec.Set(DynamicFeeTxType)
 	}
 	if fork >= forks.Cancun {
-		s.txtypes[BlobTxType] = struct{}{}
+		s.txTypeBitVec.Set(BlobTxType)
 	}
 	if fork >= forks.Prague {
-		s.txtypes[SetCodeTxType] = struct{}{}
+		s.txTypeBitVec.Set(SetCodeTxType)
 	}
 	return s
 }
@@ -228,7 +226,7 @@ func (s *modernSigner) ChainID() *big.Int {
 
 func (s *modernSigner) Equal(s2 Signer) bool {
 	other, ok := s2.(*modernSigner)
-	return ok && s.chainID.Cmp(other.chainID) == 0 && maps.Equal(s.txtypes, other.txtypes) && s.legacy.Equal(other.legacy)
+	return ok && s.chainID.Cmp(other.chainID) == 0 && s.txTypeBitVec.Equals(&other.txTypeBitVec) && s.legacy.Equal(other.legacy)
 }
 
 func (s *modernSigner) Hash(tx *Transaction) common.Hash {
@@ -236,8 +234,7 @@ func (s *modernSigner) Hash(tx *Transaction) common.Hash {
 }
 
 func (s *modernSigner) supportsType(txtype byte) bool {
-	_, ok := s.txtypes[txtype]
-	return ok
+	return s.txTypeBitVec.Has(txtype)
 }
 
 func (s *modernSigner) Sender(tx *Transaction) (common.Address, error) {