Hi, Hopefully someone can kindly offer some advice. I have a Boardman CX team 2016 which has a SRAM Rival 1x11 gearing. I think SRAM call this system "X-Sync". The rear derailleur is marked as SRAM rival 1 long (exact actuation???) I have knackered my lower jockey wheel and need to replace it. My question is what replacement is compatible ? The choice is quite confusing for a novice like myself. I assume that the pulleys for this X-sync system may differ from others but any assistance anyone can give would be very much appreciated. Thanks.