To me, it's a bit strange that they have to make them with so much clearance

The tube will rotate freely even if it was made tighter, don't you think....

Worst slop contributor is sideways - the tube ridge has a lot of extra space where it's locked in the housing.
Again, I can't see a reason for that much space.

BK: you're probably right about the grease, I'll use oil after cleaning the whole thing.

it's not as much extra as it feels like.its better to have too much than to have it bind up