diff --git a/lib/rollbar.rb b/lib/rollbar.rb
index 4f09c2c3..a0985783 100644
--- a/lib/rollbar.rb
+++ b/lib/rollbar.rb
@@ -423,7 +423,14 @@ def enforce_valid_utf8(payload)
         value = object.to_s
 
         if value.respond_to? :encode
-          encoded_value = value.encode('UTF-8', 'binary', :invalid => :replace, :undef => :replace, :replace => '')
+          options = { :invalid => :replace, :undef => :replace, :replace => '' }
+          ascii_encodings = [Encoding.find('US-ASCII'), Encoding.find('ASCII-8BIT')]
+
+          args = ['UTF-8']
+          args << 'binary' if ascii_encodings.include?(value.encoding)
+          args << options
+
+          encoded_value = value.encode(*args)
         else
           encoded_value = ::Iconv.conv('UTF-8//IGNORE', 'UTF-8', value)
         end
diff --git a/spec/rollbar_spec.rb b/spec/rollbar_spec.rb
index 9bfd61be..e76e6b97 100644
--- a/spec/rollbar_spec.rb
+++ b/spec/rollbar_spec.rb
@@ -943,7 +943,7 @@ def backtrace
 
     context 'with invalid utf8 encoding' do
       let(:extra) do
-        { :extra => "bad value 1\255" }
+        { :extra => force_to_ascii("bad value 1\255") }
       end
 
       it 'removes te invalid characteres' do
@@ -1336,27 +1336,40 @@ def backtrace
   end
 
   context 'enforce_valid_utf8' do
+    context 'with utf8 string and ruby > 1.8' do
+      next unless String.instance_methods.include?(:force_encoding)
+
+      let(:payload) { { :foo => 'Изменение' } }
+
+      it 'just returns the same string' do
+        payload_copy = payload.clone
+        notifier.send(:enforce_valid_utf8, payload_copy)
+
+        expect(payload_copy[:foo]).to be_eql('Изменение')
+      end
+    end
+
     it 'should replace invalid utf8 values' do
-      bad_key = "inner \x92bad key"
-      bad_key.force_encoding('ASCII-8BIT') if bad_key.respond_to?('force_encoding')
+      bad_key = force_to_ascii("inner \x92bad key")
 
       payload = {
-        :bad_value => "bad value 1\255",
-        :bad_value_2 => "bad\255 value 2",
-        "bad\255 key" => "good value",
+        :bad_value => force_to_ascii("bad value 1\255"),
+        :bad_value_2 => force_to_ascii("bad\255 value 2"),
+        force_to_ascii("bad\255 key") => "good value",
         :hash => {
-          :inner_bad_value => "\255\255bad value 3",
+          :inner_bad_value => force_to_ascii("\255\255bad value 3"),
           bad_key.to_sym => 'inner good value',
-          "bad array key\255" => [
+          force_to_ascii("bad array key\255") => [
             'good array value 1',
-            "bad\255 array value 1\255",
+            force_to_ascii("bad\255 array value 1\255"),
             {
-              :inner_inner_bad => "bad inner \255inner value"
+              :inner_inner_bad => force_to_ascii("bad inner \255inner value")
             }
           ]
         }
       }
 
+
       payload_copy = payload.clone
       notifier.send(:enforce_valid_utf8, payload_copy)
 
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index bf69293c..748cd9de 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -17,6 +17,7 @@
 RSpec.configure do |config|
   config.include(NotifierHelpers)
   config.include(FixtureHelpers)
+  config.include(EncodingHelpers)
 
   config.color_enabled = true
   config.formatter = 'documentation'
diff --git a/spec/support/encoding_helpers.rb b/spec/support/encoding_helpers.rb
new file mode 100644
index 00000000..03942f1d
--- /dev/null
+++ b/spec/support/encoding_helpers.rb
@@ -0,0 +1,8 @@
+module EncodingHelpers
+  def force_to_ascii(string)
+    return string unless string.respond_to?('force_encoding')
+
+    string.force_encoding('ASCII-8BIT')
+    string
+  end
+end