Bicycle Mechanics - general torque specs?

How important is it to have everything properly tightened down to the right torque?

Is there any kind of list of recommended torque settings?

I ask because the bike I ordered has some parts I can't find this info for (Vincolo stem and handlebars). I'm wondering if there are any rules of thumb for this stuff or if every manufacturer has specific settings.

Thanks.

Stems and handlebars usually come with instructions that say how much torque you need to apply to the various bolts. It varies a bit depending on the material (aluminum, CF, steel, etc) and the style of stem (quill vs clamp-on, pop-top vs pinch-bolt).

Everything is aluminum. Threadless stem to 31.6 mm bar dia.

But I'll have another look through the boxes and packing material when I get home to see if I missed anything useful.

See http://www.volvoclub.org.uk/faq/ImagesSpecialTools/TorqueSpecs.htm

But remember, these torques are for steel into steel. Most joinst on bikes are steel into aluminum, which is much softer than steel, so stay well below these torques when going into aluminum..

And this does not apply to carbon fiber parts. Get those specs from the manufacturer.

I would say that for a "typical" pinch-bolt stem, I put about 20 ft-lbs of torque on the handlebar clamp. It's less for a two-bolt pop-top stem, maybe 10-15 ft-lbs.

For the steerer clamp bolts on a threadless stem, I would do about 20 ft-lbs of torque. For the wedge bolt on a quill stem, I'd do about 15 ft-lbs of torque.

Obviously, do a sanity check after torquing the bolts. Is anything loose? If so, go a little tighter. With aluminum stem and handlebars, you don't have to worry too much about excessive torque. I don't think most experienced mechanics use a torque wrench or consult tables of torque data unless they're working with fragile carbon fiber parts and such. The size of the Allen wrench used to tighten a part gives a pretty good idea of how tight it should be: a derailer usually needs a 4 mm wrench, while a square-taper crank bolt usually needs an 8 mm wrench :).

I would say that for a "typical" pinch-bolt stem, I put about 20 ft-lbs of torque on the handlebar clamp. It's less for a two-bolt pop-top stem, maybe 10-15 ft-lbs.
Took me a second to figure out what you meant. It's a 4-bolt pop-top stem.

But, yeah, I guess I am getting a little too anal about this. It's just 1. This is my first new build and 2. I'm trying to find a good excuse to buy a torque wrench.

Took me a second to figure out what you meant. It's a 4-bolt pop-top stem.

But, yeah, I guess I am getting a little too anal about this. It's just 1. This is my first new build and 2. I'm trying to find a good excuse to buy a torque wrench.
Torque wrenches look cool and fancy, but are surprisingly useless for most bike-related things. It's a lot easier to just grab an ordinary allen wrench. The only thing I use them for is tightening bolts for high-vacuum gaskets.