Do not overtighten it.
Bike stem top cap torque.
This is precisely why almost all stems have torque values printed on the actual part.
If you feel play loosen the pinch bolts tighten the top cap another 1 8th turn re tighten the pinch bolts and check again.
I still only torqued my stem front cap and stem bolts to 4nm.
150 180 lb in 17 20 3 nm handlebar clamp.
100 lb in 11 3 nm steerer clamp.
The top cap bolt just snugs up the crown headset assembly the stem bolts do the actual job of holding the fork steerer tube.
In other words a torque wrench set for 100 in lbs might tighten to 96 in lbs or 104 in lbs.
A torque wrench is a good idea at this point.
Torque wrenches available to general industrial work including bicycle work are typically accurate to plus or minus four percent.
There are basically three types of torque wrenches the beam type the click type and the dial type.
150 170 lb in 17 20 3 nm tandem stoker stem.
You can absolutely over tighten the bolts it is after all most likely lightweight aluminum you re working with.
With carbon fiber handlebar.
Fsa megaexo crank adjusting cap 0 4 0 7 nm 32 53 in lbs fsa megaexo crank bolt pinch screws 9 8 11 2 nm 87 100 in lbs campagnolo 3 piece 32 38 nm 282 336 in lbs campagnolo ultra torque 42 nm 371 in lbs race face 54 nm 480 in lbs shimano 34 44 nm 305 391 in lbs shimano octalink xtr crank arm bolt 40 3 49 nm 357 435 in lbs.
A typical torque spec is 4 6 nm.
Never had anything close to an issue with the lower than max torque.
5 just seems like way to much.
Torque the pinch bolts.
Do up the headset top cap until it is just tight at this point you should be unable to turn your stem spacers.
100 120 lb in 11 3 13 6 nm stem angle adjustment.
Verify that the bars still turn freely with little resistance.
100 120 lb in 11 3 13 6 nm handlebar clamp.