SRAM X01 Eagle 12s RD adjustment to work with 11s cassette + shifter?

There are two things that must be correct to move the derailleur the right distance for each shift.

• Cable length pulled per shift
• Derailleur actuation ratio - ratio of lateral cage movement to cable length pulled.

The 11 speed shifter will pull the correct amount of cable for the 11 speed cassette sprocket spacing through a matching 11 speed derailleur. If the 12 speed derailleur has a different actuation ratio the cage will not move the correct distance. There is no adjustment for this.

The X01 Eagle uses what SRAM calls ‘x-actuation’ ratio, GX seems to use x-actuation and ‘exact actuation’ ratios for different components. The Exact actuation ratio is a little different and not compatible.

Check which exact model I’d grip shifters you have on the SRAM site. If they use x-actuation your proposed setup will work. If they use exact-actuation the setup will not work.

Respectfully, I think you are putting the cart before the horse. It would be advisable to decide about the more expensive components first, and then get the appropriate less expensive components to match, rather than the other way around.

If you happen to have the the eleven speed chain and shifter, which are usually the less expensive pieces in a drivetrain, I would suggest you either give on the idea of the the 12speed derailleur, or start over with a complete 12 speed system.

For what it is worth, and this is totally my opinion here...I used to run 12 speed Eagle with a 10-50 range. Now I run 11 speed Shimano with a 9-46 range (E-thirteen cassette), and I can't tell the difference. I only went with Shimano because I care about the dual release for upshifting. Otherwise, both systems work great.

good luck.