diff --git a/src/Buffer.php b/src/Buffer.php
index 120cbc1..642a5a1 100644
--- a/src/Buffer.php
+++ b/src/Buffer.php
@@ -214,7 +214,24 @@ public function read($length = null)
     }
 
     /**
-     * @param $data
+     * @param string $data
+     * @param int $maxLength
+     *
+     * @return int
+     */
+    public function lengthBytes($data, $maxLength = null)
+    {
+        if (strtolower($this->streamCharset) != strtolower($this->systemCharset)) {
+            $data = mb_convert_encoding($data, $this->streamCharset, $this->systemCharset);
+        }
+        if (isset($maxLength)) {
+            $data = mb_strcut($data, 0, $maxLength, $this->streamCharset);
+        }
+        return \strlen($data);
+    }
+
+    /**
+     * @param string $data
      * @param int|string $length
      *
      * @return false|int
@@ -224,7 +241,9 @@ public function writeString($data, $length = '*')
         if (strtolower($this->streamCharset) != strtolower($this->systemCharset)) {
             $data = mb_convert_encoding($data, $this->streamCharset, $this->systemCharset);
         }
-
+        if (isset($length) && ($length != '*')) {
+            $data = mb_strcut($data, 0, $length, $this->streamCharset);
+        }
         return $this->write(pack('A' . $length, $data));
     }
 
diff --git a/src/Sav/Record/Info/LongStringValueLabels.php b/src/Sav/Record/Info/LongStringValueLabels.php
index e804588..5fcb696 100644
--- a/src/Sav/Record/Info/LongStringValueLabels.php
+++ b/src/Sav/Record/Info/LongStringValueLabels.php
@@ -45,15 +45,17 @@ public function write(Buffer $buffer)
                 throw new \InvalidArgumentException('values required');
             }
             $width = (int) $data['width'];
-            $localBuffer->writeInt(mb_strlen($varName));
-            $localBuffer->writeString($varName, mb_strlen($varName));
+            $varLengthBytes = $buffer->lengthBytes($varName);
+            $localBuffer->writeInt($varLengthBytes);
+            $localBuffer->writeString($varName, $varLengthBytes);
             $localBuffer->writeInt($width);
             $localBuffer->writeInt(Utils::is_countable($data['values']) ? \count($data['values']) : 0);
             foreach ($data['values'] as $value => $label) {
                 $localBuffer->writeInt($width);
                 $localBuffer->writeString($value, $width);
-                $localBuffer->writeInt(mb_strlen($label));
-                $localBuffer->writeString($label, mb_strlen($label));
+                $labelLengthBytes = $buffer->lengthBytes($label);
+                $localBuffer->writeInt($labelLengthBytes);
+                $localBuffer->writeString($label, $labelLengthBytes);
             }
         }
 
diff --git a/src/Sav/Record/Info/VariableAttributes.php b/src/Sav/Record/Info/VariableAttributes.php
index 46a90b2..5a1e088 100644
--- a/src/Sav/Record/Info/VariableAttributes.php
+++ b/src/Sav/Record/Info/VariableAttributes.php
@@ -44,7 +44,7 @@ public function write(Buffer $buffer)
 
         if ($lines !== []) {
             $data            = implode('/', $lines);
-            $this->dataCount = mb_strlen($data);
+            $this->dataCount = \strlen($data);
             parent::write($buffer);
             $buffer->writeString($data);
         }
diff --git a/src/Sav/Record/ValueLabel.php b/src/Sav/Record/ValueLabel.php
index d2dad5d..88deb16 100644
--- a/src/Sav/Record/ValueLabel.php
+++ b/src/Sav/Record/ValueLabel.php
@@ -96,22 +96,16 @@ public function write(Buffer $buffer)
         $buffer->writeInt(self::TYPE);
         $buffer->writeInt(\count($this->labels));
         foreach ($this->labels as $item) {
-            $labelLength      = min(mb_strlen($item['label']), self::LABEL_MAX_LENGTH);
-            $label            = mb_substr($item['label'], 0, $labelLength);
-            $labelLengthBytes = mb_strlen($label, '8bit');
-            while ($labelLengthBytes > 255) {
-                // Strip one char, can be multiple bytes
-                $label            = mb_substr($label, 0, -1);
-                $labelLengthBytes = mb_strlen($label, '8bit');
-            }
-
+            $labelLengthBytes = $buffer->lengthBytes($item['label'], self::LABEL_MAX_LENGTH);
+            $labelLengthBytesRound = Utils::roundUp($labelLengthBytes + 1, 8) - 1;
+            
             if ($convertToDouble) {
                 $item['value'] = Utils::stringToDouble($item['value']);
             }
 
             $buffer->writeDouble($item['value']);
             $buffer->write(\chr($labelLengthBytes));
-            $buffer->writeString($label, Utils::roundUp($labelLengthBytes + 1, 8) - 1);
+            $buffer->writeString($item['label'], $labelLengthBytesRound);
         }
 
         // Value label variable record.
diff --git a/src/Sav/Record/Variable.php b/src/Sav/Record/Variable.php
index bab4cc6..2a1373e 100644
--- a/src/Sav/Record/Variable.php
+++ b/src/Sav/Record/Variable.php
@@ -141,17 +141,10 @@ public function write(Buffer $buffer)
         $buffer->writeString($this->name, 8);
 
         if ($hasLabel) {
-            // Maxlength is 255 bytes, since we write utf8 a char can be multiple bytes
-            $labelLength      = min(mb_strlen($this->label), 255);
-            $label            = mb_substr($this->label, 0, $labelLength);
-            $labelLengthBytes = mb_strlen($label, '8bit');
-            while ($labelLengthBytes > 255) {
-                // Strip one char, can be multiple bytes
-                $label            = mb_substr($label, 0, -1);
-                $labelLengthBytes = mb_strlen($label, '8bit');
-            }
+            $labelLengthBytes = $buffer->lengthBytes($this->label, self::REAL_VLS_CHUNK);
+            $labelLengthBytesRound = Utils::roundUp($labelLengthBytes, 4);
             $buffer->writeInt($labelLengthBytes);
-            $buffer->writeString($label, Utils::roundUp($labelLengthBytes, 4));
+            $buffer->writeString($this->label, $labelLengthBytesRound);
         }
 
         // TODO: test
@@ -180,10 +173,10 @@ public function write(Buffer $buffer)
                 $buffer->writeInt(0); // No missing values
                 $buffer->writeInt($format); // Print format
                 $buffer->writeInt($format); // Write format
-                $buffer->writeString($this->getSegmentName($i - 1), 8);
+                $buffer->writeString($this->getSegmentName($buffer, $i - 1), 8);
                 if ($hasLabel) {
                     $buffer->writeInt($labelLengthBytes);
-                    $buffer->writeString($label, Utils::roundUp($labelLengthBytes, 4));
+                    $buffer->writeString($this->label, Utils::roundUp($labelLengthBytes, 4));
                 }
 
                 $this->writeBlank($buffer, $segmentWidth);
@@ -215,13 +208,13 @@ public function writeBlank(Buffer $buffer, $width)
      *
      * @return string
      */
-    public function getSegmentName($seg = 0)
+    public function getSegmentName($buffer, $seg = 0)
     {
         // TODO: refactory
         $name = $this->name;
-        $name = mb_substr($name, 0, 6);
+        $name = mb_strcut($name, 0, 6, $buffer->systemCharset);
         $name .= $seg;
 
-        return mb_strtoupper($name);
+        return mb_strtoupper($name, $buffer->systemCharset);
     }
 }