BC705-003-(40/41)-(B/R) | Installation Instructions for Triumph Street Twin Rear Sprocket

David Bumpus posted this on Jul 1, 2016

Upgrading your rear sprocket is a quick project that can really change the way your bike looks and runs. Using a sprocket made from higher quality materials means your sprocket and chain will last longer, and the added benefit of weight savings equals performance gains. Whenever you replace your rear sprocket, you will also have to replace your chian, so be sure to grab one of those. It's also not a bad time to upgrade your front sprocket while you're at it, which isn't required, but is suggested. If you want to get the most out of your new sprockets and chain, upgrade your exhaust to help increase the amount of torque being transferred to the rear wheel.


  • Triumph Street Twin

Tools required:

  • Jack or swingarm stand
  • 1 1/6" socket wrench
  • Torque wrench (for reinstalling)

Total time the job takes:

  • 20 minutes


  • Intermediate

Step 1:

Remove rear wheel. If you aren’t sure how to do this, please refer to our guide covering how to remove your rear wheel on our site’s Resource Center.

Step 2:

Use a 14mm socket wrench to remove nuts securing rear sprocket to rear wheel.

Step 3:

Pull rear sprocket off mounts.

Step 4:

Place BC Rear Sprocket on mounts.

Step 5:

Secure BC Rear Sprocket to rear wheel with 14mm socket wrench. Apply blue Loctite and torque each nut to 55 Nm.

Installation Complete!

Your new rear sprocket has been successfully installed! If you are unsure how to reinstall your rear wheel, please refer to the guide on our site’s Resource Center.