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.
Old drivetrain components could cause poor shifting performance. We recommend a new chain and a new or well-cared for cassette.
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.
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.
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.
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.
Click below to download
How to install the EX cog with a Sram 10sp drivetrain
How to install the EX cog on a Shimano 10sp drivetrain
How to adjust your derailleur for Ex Cog
Ex Cog Troubleshooting guide