diff --git a/frames/stream_frame.go b/frames/stream_frame.go
index 647bdaf9..dc337691 100644
--- a/frames/stream_frame.go
+++ b/frames/stream_frame.go
@@ -14,7 +14,6 @@ import (
 type StreamFrame struct {
 	FinBit         bool
 	StreamID       protocol.StreamID
-	streamIDLen    protocol.ByteCount
 	Offset         protocol.ByteCount
 	Data           []byte
 	DataLenPresent bool
@@ -40,9 +39,9 @@ func ParseStreamFrame(r *bytes.Reader) (*StreamFrame, error) {
 	if offsetLen != 0 {
 		offsetLen++
 	}
-	frame.streamIDLen = protocol.ByteCount(typeByte&0x03 + 1)
+	streamIDLen := typeByte&0x03 + 1
 
-	sid, err := utils.ReadUintN(r, uint8(frame.streamIDLen))
+	sid, err := utils.ReadUintN(r, streamIDLen)
 	if err != nil {
 		return nil, err
 	}
@@ -104,14 +103,12 @@ func (f *StreamFrame) Write(b *bytes.Buffer, version protocol.VersionNumber) err
 		typeByte ^= (uint8(offsetLength) - 1) << 2
 	}
 
-	if f.streamIDLen == 0 {
-		f.calculateStreamIDLength()
-	}
-	typeByte ^= uint8(f.streamIDLen) - 1
+	streamIDLen := f.calculateStreamIDLength()
+	typeByte ^= streamIDLen - 1
 
 	b.WriteByte(typeByte)
 
-	switch f.streamIDLen {
+	switch streamIDLen {
 	case 1:
 		b.WriteByte(uint8(f.StreamID))
 	case 2:
@@ -153,16 +150,15 @@ func (f *StreamFrame) Write(b *bytes.Buffer, version protocol.VersionNumber) err
 	return nil
 }
 
-func (f *StreamFrame) calculateStreamIDLength() {
+func (f *StreamFrame) calculateStreamIDLength() uint8 {
 	if f.StreamID < (1 << 8) {
-		f.streamIDLen = 1
+		return 1
 	} else if f.StreamID < (1 << 16) {
-		f.streamIDLen = 2
+		return 2
 	} else if f.StreamID < (1 << 24) {
-		f.streamIDLen = 3
-	} else {
-		f.streamIDLen = 4
+		return 3
 	}
+	return 4
 }
 
 func (f *StreamFrame) getOffsetLength() protocol.ByteCount {
@@ -192,11 +188,7 @@ func (f *StreamFrame) getOffsetLength() protocol.ByteCount {
 
 // MinLength of a written frame
 func (f *StreamFrame) MinLength(protocol.VersionNumber) (protocol.ByteCount, error) {
-	if f.streamIDLen == 0 {
-		f.calculateStreamIDLength()
-	}
-
-	length := protocol.ByteCount(1) + f.streamIDLen + f.getOffsetLength()
+	length := protocol.ByteCount(1) + protocol.ByteCount(f.calculateStreamIDLength()) + f.getOffsetLength()
 	if f.DataLenPresent {
 		length += 2
 	}
diff --git a/frames/stream_frame_test.go b/frames/stream_frame_test.go
index f013151d..35ac5cd0 100644
--- a/frames/stream_frame_test.go
+++ b/frames/stream_frame_test.go
@@ -248,16 +248,6 @@ var _ = Describe("StreamFrame", func() {
 		})
 
 		Context("lengths of StreamIDs", func() {
-			It("returns an error for a non-valid StreamID length", func() {
-				b := &bytes.Buffer{}
-				err := (&StreamFrame{
-					StreamID:    1,
-					streamIDLen: 13,
-					Data:        []byte("foobar"),
-				}).Write(b, 0)
-				Expect(err).To(MatchError(errInvalidStreamIDLen))
-			})
-
 			It("writes a 1 byte StreamID", func() {
 				b := &bytes.Buffer{}
 				err := (&StreamFrame{
@@ -320,26 +310,22 @@ var _ = Describe("StreamFrame", func() {
 	Context("shortening of StreamIDs", func() {
 		It("determines the length of a 1 byte StreamID", func() {
 			f := &StreamFrame{StreamID: 0xFF}
-			f.calculateStreamIDLength()
-			Expect(f.streamIDLen).To(Equal(protocol.ByteCount(1)))
+			Expect(f.calculateStreamIDLength()).To(Equal(uint8(1)))
 		})
 
 		It("determines the length of a 2 byte StreamID", func() {
 			f := &StreamFrame{StreamID: 0xFFFF}
-			f.calculateStreamIDLength()
-			Expect(f.streamIDLen).To(Equal(protocol.ByteCount(2)))
+			Expect(f.calculateStreamIDLength()).To(Equal(uint8(2)))
 		})
 
 		It("determines the length of a 3 byte StreamID", func() {
 			f := &StreamFrame{StreamID: 0xFFFFFF}
-			f.calculateStreamIDLength()
-			Expect(f.streamIDLen).To(Equal(protocol.ByteCount(3)))
+			Expect(f.calculateStreamIDLength()).To(Equal(uint8(3)))
 		})
 
 		It("determines the length of a 4 byte StreamID", func() {
 			f := &StreamFrame{StreamID: 0xFFFFFFFF}
-			f.calculateStreamIDLength()
-			Expect(f.streamIDLen).To(Equal(protocol.ByteCount(4)))
+			Expect(f.calculateStreamIDLength()).To(Equal(uint8(4)))
 		})
 	})
 
diff --git a/integrationtests/chrome_test.go b/integrationtests/chrome_test.go
index f4f018a9..55fae526 100644
--- a/integrationtests/chrome_test.go
+++ b/integrationtests/chrome_test.go
@@ -45,7 +45,7 @@ var _ = Describe("Chrome tests", func() {
 		close(done)
 	}, 5)
 
-	PIt("loads a large number of files", func(done Done) {
+	It("loads a large number of files", func(done Done) {
 		err := wd.Get("https://quic.clemente.io/tiles")
 		Expect(err).NotTo(HaveOccurred())
 		Eventually(func() error {