so i've put new wheel bearings in my sierra uprights, torqued them up to 340ish nm as per haynes. just come to fit the dome caps to seal them in and realised the flange is a lot stiff to turn than previously, is this normal?

yes its normal. they will free up once the car has done a couple of thousand miles.

sounds normal to me

as long as you can turn them 'fairly' easily by hand and they turn smoothly they'll be fine

happened on on my my hubs. Was very stiff to start with, but the knowledgeable guy at the garage said to keep an eye on it and it would ease up.

I did, and it did