I've had about half a dozen sent over and they've all attracted import duty.
As said above, you can ask the seller to mark the value down - some will, some won't- but then you won't be fully insured.
To fit USPS's max dimensions you will need to send in two boxes, frame , forks and stuff in one and wheels etc in the other.
Make sure they are marked as bicycle components, which attract 5% duty, and not (complete) bicycle, which attracts 20%.
Both will, though, attract 20% VAT on the full cost plus a few quid "handling" fee.
I keep saying "never again" unless it's something very special.
And guess what's just turned up..?
Give a man a gun, and he can rob a bank.
Give a man a bank, and he can rob everybody.