diff --git a/chain/gen/gen.go b/chain/gen/gen.go
index 35bf58a38..384a89bde 100644
--- a/chain/gen/gen.go
+++ b/chain/gen/gen.go
@@ -519,10 +519,7 @@ func IsRoundWinner(ctx context.Context, ts *types.TipSet, round int64, miner add
 
 	var winners []sectorbuilder.EPostCandidate
 	for _, c := range candidates {
-		sectors := types.BigDiv(pow.MinerPower, types.NewInt(ssize))
-		challangeCount := sectorbuilder.ElectionPostChallengeCount(sectors.Uint64())
-
-		if types.IsTicketWinner(c.PartialTicket[:], ssize, pow.TotalPower, int64(challangeCount)) {
+		if types.IsTicketWinner(c.PartialTicket[:], ssize, pow.TotalPower) {
 			winners = append(winners, c)
 		}
 	}
diff --git a/chain/sync.go b/chain/sync.go
index dbf974cfa..abf8fe26d 100644
--- a/chain/sync.go
+++ b/chain/sync.go
@@ -545,7 +545,7 @@ func (syncer *Syncer) ValidateBlock(ctx context.Context, b *types.FullBlock) err
 	}
 
 	winnerCheck := async.Err(func() error {
-		mpow, tpow, err := stmgr.GetPower(ctx, syncer.sm, baseTs, h.Miner)
+		_, tpow, err := stmgr.GetPower(ctx, syncer.sm, baseTs, h.Miner)
 		if err != nil {
 			return xerrors.Errorf("failed getting power: %w", err)
 		}
@@ -556,10 +556,7 @@ func (syncer *Syncer) ValidateBlock(ctx context.Context, b *types.FullBlock) err
 		}
 
 		for _, t := range h.EPostProof.Candidates {
-			sectors := types.BigDiv(mpow, types.NewInt(ssize))
-			challangeCount := sectorbuilder.ElectionPostChallengeCount(sectors.Uint64())
-
-			if !types.IsTicketWinner(t.Partial, ssize, tpow, int64(challangeCount)) {
+			if !types.IsTicketWinner(t.Partial, ssize, tpow) {
 				return xerrors.Errorf("miner created a block but was not a winner")
 			}
 		}
diff --git a/chain/types/blockheader.go b/chain/types/blockheader.go
index 79585f1d2..03b03c0f3 100644
--- a/chain/types/blockheader.go
+++ b/chain/types/blockheader.go
@@ -172,7 +172,7 @@ func CidArrsEqual(a, b []cid.Cid) bool {
 
 var blocksPerEpoch = NewInt(build.BlocksPerEpoch)
 
-func IsTicketWinner(partialTicket []byte, ssizeI uint64, totpow BigInt, sampleRate int64) bool {
+func IsTicketWinner(partialTicket []byte, ssizeI uint64, totpow BigInt) bool {
 	ssize := NewInt(ssizeI)
 
 	/*
@@ -189,7 +189,7 @@ func IsTicketWinner(partialTicket []byte, ssizeI uint64, totpow BigInt, sampleRa
 
 	lhs := BigFromBytes(h[:]).Int
 	lhs = lhs.Mul(lhs, totpow.Int)
-	lhs = lhs.Mul(lhs, big.NewInt(sampleRate))
+	lhs = lhs.Mul(lhs, big.NewInt(build.SectorChallengeRatioDiv))
 
 	// rhs = sectorSize * 2^256
 	// rhs = sectorSize << 256