If you are using lvl 50 gear in close to a lvl 60 dungeon thats one of the big issues. Lots of people are kicked from groups due to gear and being a tank you need to keep updated gear more than any other role. Farm previous dungeons for some better gear or make a PF asking for a crafter who can make HQ gear around your lvl for a decent price. Though if you are doing HQ quests you should be getting HQ gear as you progress.