Discontinued items archive
The 40t is available only for Shimano as SRAM does not offer a 34 tooth cassette. We find that these combinations work best./hc/en-us/articles/204774975-Why-do-you-only-have-a-42-tooth-42t-EX-Cog-for-SRAM-cassettes-
Old drivetrain components could cause poor shifting performance. We recommend a new chain and a new or well-cared for cassette./hc/en-us/articles/204774955-I-have-a-really-worn-drivetrain-Will-the-EX-Cog-work-ok-on-my-bike-
It’s a replacement B limit screw for your rear derailleur. The longer screw may be needed for proper derailleur set-up. If you are unsure about setting your B limit, refer to our how to guide, or head to your local bike shop./hc/en-us/articles/204127689-What-is-the-extra-screw-included-with-the-EX-Cog-for-
It's really not too hard, but keep in mind that you are working at the extreme limits of your rear derailleur, so small changes can make a big difference.
We have some great how-to guides here to help you out.
If you are still struggling with the setup and adjustment, we recommend heading to your local bike shop.
We recommend a medium or long cage derailleur for use with the EX Cog. If you are not sure about maximum derailleur capacity, check here to reference our handy compatibility chart./hc/en-us/articles/204127769-I-have-a-short-cage-derailleur-on-my-bike-Will-that-work-with-an-EX-Cog-
The 42 tooth (42t) EX Cogs WILL NOT work with 34 tooth (max) cassettes. A 6 tooth jump is the maximum for excellent shift performance./hc/en-us/articles/204127779-Can-I-use-the-42-tooth-42t-EX-Cog-with-a-34-tooth-cassette-
We don't recommend using the 40 tooth (40t) EX Cog with a 36 tooth cassette. Shift performance will be compromised as the timing of the shift features relative to the cassette will not be correct./hc/en-us/articles/204774995-Can-I-use-the-40-tooth-40t-EX-Cog-on-my-36-tooth-cassette-
Click below to download/hc/en-us/articles/204101109-EX-Cog-compatibility-chart
How to install the EX cog with a Sram 10sp drivetrain/hc/en-us/articles/208906406-How-to-install-the-EX-cog-with-a-Sram-10sp-drivetrain
How to install the EX cog on a Shimano 10sp drivetrain/hc/en-us/articles/210525723-How-to-install-the-EX-cog-on-a-Shimano-10sp-drivetrain
How to adjust your derailleur for Ex Cog/hc/en-us/articles/208906386-How-to-adjust-your-derailleur-for-Ex-Cog
Ex Cog Troubleshooting guide/hc/en-us/articles/210525663--Ex-Cog-Troubleshooting-guide-