Originally Posted by
kahn
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.
Yes but hat's assuming that the current torques are "proper" and there's no after the last tightening corrosion of other changes to the friction between the parts. A similar method is to note the wrench handle's "clocking", loosen the fastener and retighten to the same clocking angle but use a beam type of torque wrench.
There have been various charts of bike fittings and their torque ranges over the recent years, IIRC Park has one, None have motorized bikes that I know of...
Experienced mechanics tend to have a more trained "feel" for loosening and tightening levels then newbies do. This "feel" includes the understanding to materials and stresses each fitting has (or should have
)
In the end torque levels used are more about having a fitting tight enough but not too much more. Published levels are more frequently about max levels especially when non metallic materials are at play. Andy