Before loosening a bolt/screw is there a way to determine its torque value? In other words, in one example my saddle is mounted to a seat post by two bolts. But I was never informed of the value used to tighten the clamp on the rails. Steel rails by the way.

In another I have a motor in the front wheel of my bike. It is tightened pretty tight (vague) but if I get a flat I will have to loosen the bolts or nuts that hold the wheel on the fork. I'd like to know the value needed to affix the wheel back to the fork.

Is there a way of using a torque wrench by stepping through various torque values and seeing where it clicks to in tightening it.

Or another method?

Thanks in advance.