I upgraded my Sram XO1 11 spd to 12spd going with E13's 12spd upgrade kit. I've been running it with minimal issues. Their upgrade kit requires you to partially disassemble the shifter. Changing out the 11 spd spool with a 12 spd one. Simple enough right? It took several tries before I got it dialed. Once within the first few hundred miles an internal screw in the shifter that holds the geared spool in place backed out while I was riding and got stuck with a single speed for the rest of the ride. I was able to put it back together myself successfully back at home. It took several tries and the whole shifter pod assy came apart several times. Which shouldn't happen according to E13's instructions. Fast forward to the Plunge ride we did last Saturday. Right before we got to the cabin it happened again, the same screw backed out allowing the geared spool to rise above the indexing arm. I managed to get two gears from the cabin all the way to the end. It sucked but, it was still a kick ass ride overall. Earlier this week I attempted to rebuild the shifter a second time. I had it almost fully put back together several times and at the last moment the damn thing would come apart from the pressure of one of 3 springs inside the shifter pod. Anyhow, I got really frustrated and decided to call E13 hoping they had some secret video or instructional pdf or something that could guide me CORRECTLY on how to reassemble the shifter without issue. They have nothing in instruction that details how to reassemble the whole shifter from step 1. Chris @ E13 was my savior for this fiasco. He offered to send me (overnight) a loaner 12 spd shifter. And, for me to send my blown apart shifter back to E13 postage paid. They are going to put my shifter back together and make sure I don't have this issue again. In the meantine, I got a 12spd shifter to use until they send mine back. They are also picking up the postage when I return the loaner. Just wanted to share my experience with their customer service, especially Chris. Thanks E13 for saving my sanity, my knuckles, and my blown apart shifter. E13 for the win! @Redman can ride his bike this weekend! YAY!!!!!