diff --git a/Gemfile.lock b/Gemfile.lock
index bcedeff385..390b2a18f8 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -32,9 +32,7 @@ PATH
     actioncable (5.0.0.beta1)
       actionpack (= 5.0.0.beta1)
       coffee-rails (~> 4.1.0)
-      em-hiredis (~> 0.3.0)
       faye-websocket (~> 0.10.0)
-      redis (~> 3.0)
       websocket-driver (~> 0.6.1)
     actionmailer (5.0.0.beta1)
       actionpack (= 5.0.0.beta1)
@@ -140,9 +138,6 @@ GEM
     delayed_job_active_record (4.1.0)
       activerecord (>= 3.0, < 5)
       delayed_job (>= 3.0, < 5)
-    em-hiredis (0.3.0)
-      eventmachine (~> 1.0)
-      hiredis (~> 0.5.0)
     erubis (2.7.0)
     eventmachine (1.0.9.1)
     execjs (2.6.0)
@@ -154,7 +149,6 @@ GEM
     ffi (1.9.10-x86-mingw32)
     globalid (0.3.6)
       activesupport (>= 4.1.0)
-    hiredis (0.5.2)
     hitimes (1.2.3)
     hitimes (1.2.3-x86-mingw32)
     i18n (0.7.0)
diff --git a/actioncable/actioncable.gemspec b/actioncable/actioncable.gemspec
index 2ab8b4785a..847fcc71c3 100644
--- a/actioncable/actioncable.gemspec
+++ b/actioncable/actioncable.gemspec
@@ -23,10 +23,10 @@ Gem::Specification.new do |s|
   s.add_dependency 'coffee-rails',     '~> 4.1.0'
   s.add_dependency 'faye-websocket',   '~> 0.10.0'
   s.add_dependency 'websocket-driver', '~> 0.6.1'
-  s.add_dependency 'em-hiredis',       '~> 0.3.0'
-  s.add_dependency 'redis',            '~> 3.0'
 
-  s.add_development_dependency 'puma'
+  s.add_development_dependency 'em-hiredis', '~> 0.3.0'
   s.add_development_dependency 'mocha'
   s.add_development_dependency 'pg'
+  s.add_development_dependency 'puma'
+  s.add_development_dependency 'redis',      '~> 3.0'
 end
diff --git a/actioncable/lib/action_cable/storage_adapter.rb b/actioncable/lib/action_cable/storage_adapter.rb
index f1c395eb3a..a4fe12c770 100644
--- a/actioncable/lib/action_cable/storage_adapter.rb
+++ b/actioncable/lib/action_cable/storage_adapter.rb
@@ -1,7 +1,7 @@
 module ActionCable
   module StorageAdapter
     autoload :Base, 'action_cable/storage_adapter/base'
-    autoload :Postgres, 'action_cable/storage_adapter/postgres'
+    autoload :PostgreSQL, 'action_cable/storage_adapter/postgresql'
     autoload :Redis, 'action_cable/storage_adapter/redis'
   end
 end
diff --git a/actioncable/lib/action_cable/storage_adapter/postgres.rb b/actioncable/lib/action_cable/storage_adapter/postgresql.rb
similarity index 89%
rename from actioncable/lib/action_cable/storage_adapter/postgres.rb
rename to actioncable/lib/action_cable/storage_adapter/postgresql.rb
index 5d874533be..1d8460e2ea 100644
--- a/actioncable/lib/action_cable/storage_adapter/postgres.rb
+++ b/actioncable/lib/action_cable/storage_adapter/postgresql.rb
@@ -1,8 +1,14 @@
 require 'thread'
 
+begin
+  require 'pg'
+rescue Gem::LoadError => e
+  raise Gem::LoadError, "You are trying to use the PostgreSQL ActionCable adapter, but do not have the proper gems installed. Add `gem 'pg'` to your Gemfile (and ensure its version is at the minimum required by ActionCable)."
+end
+
 module ActionCable
   module StorageAdapter
-    class Postgres < Base
+    class PostgreSQL < Base
       # The storage instance used for broadcasting. Not intended for direct user use.
       def broadcast(channel, payload)
         with_connection do |pg_conn|
diff --git a/actioncable/lib/action_cable/storage_adapter/redis.rb b/actioncable/lib/action_cable/storage_adapter/redis.rb
index 3e0ede057a..62a3971ec7 100644
--- a/actioncable/lib/action_cable/storage_adapter/redis.rb
+++ b/actioncable/lib/action_cable/storage_adapter/redis.rb
@@ -1,5 +1,9 @@
-require 'em-hiredis'
-require 'redis'
+begin
+  require 'em-hiredis'
+  require 'redis'
+rescue Gem::LoadError => e
+  raise Gem::LoadError, "You are trying to use the Redis ActionCable adapter, but do not have the proper gems installed. Add `gem 'em-hiredis'` and `gem 'redis'` to your Gemfile (and ensure its version is at the minimum required by ActionCable)."
+end
 
 module ActionCable
   module StorageAdapter
diff --git a/actioncable/test/channel/stream_test.rb b/actioncable/test/channel/stream_test.rb
index f0b463d149..8424310ca2 100644
--- a/actioncable/test/channel/stream_test.rb
+++ b/actioncable/test/channel/stream_test.rb
@@ -62,7 +62,6 @@ class ActionCable::Channel::StreamTest < ActionCable::TestCase
   test "subscription confirmation should only be sent out once" do
     EM.run do
       connection = TestConnection.new
-      connection.stubs(:pubsub).returns EM::Hiredis.connect.pubsub
 
       channel = ChatChannel.new connection, "test_channel"
       channel.send_confirmation
diff --git a/actioncable/test/test_helper.rb b/actioncable/test/test_helper.rb
index 325305939f..65b45e0c89 100644
--- a/actioncable/test/test_helper.rb
+++ b/actioncable/test/test_helper.rb
@@ -5,7 +5,6 @@ require 'active_support/testing/autorun'
 
 
 require 'puma'
-require 'em-hiredis'
 
 require 'mocha/setup'