Another quick tip for getting more weight moving - take a deep breath, fill your belly with air, and squeeze your abs.
This will help you move more weight with any suspended pulling (chinups, pullups) or any standing exercise at all, from squats and deadlifts to overhead presses and kettlebell snatches.
You might think, "but if I stay tight, I'm going to be slow." You won't, your tight "core" will allow you to most efficiently transfer force from the ground to the weight.
Give it a try - and combine it with gripping the bar hard for maximal benefits.
2 hours ago