long distance towing

[133bhp]

I use an infrared heat detector at each fuel stop to check bearings, tires, and brakes temps.

what sort of figures are you getting for the particular ambient temp/distance at time of checking? single or dual trailer?

[Catigale]

I posted a thread on a single axle trailer that the air temperature in the tire stabilized at an ambient temperature of 85 Celsisus (about 187 Fanrenheit) after two hours on highway at 60 mph, ambient temp 85 F, dry road

The wheel and rubber doesn't get so hot...probably about 130-140 F

[kmclemore]

Which then begs the question, what exactly IS the torque of a typical 1/2"-20 lug nut supposed to be?

Trailer lug torque:
http://www.countrytrailer.com/wndisplay ... ?number=25

I generally use 90 ft. lbs. on mine, torqued dry. This was the manufacturer's recommended torque. Never had a problem with a stud breaking or a wheel coming loose.

"Don't use lube on the threads" one of those wives tales that just won't die no matter how much you beat it.

Beg to differ, but there's real science regarding oiled versus non-oiled torquing of bolts and studs.

See the chart on this page: http://raskcycle.com/techtip/webdoc14.html

Note the torque differences for oiled versus dry. A 1/2"x20 Grade 5 stud (like what's on many trailers) would be torqued to a maximum of 90 ft. lbs. when dry, but when oiled should only be torqued to 65 ft. lbs. to obtain the same 'stretch' in the stud.

Bolts and studs are like springs. You introduce torque because you want to 'stretch' them enough to retain the fastener - it's that 'spring' in the bolt/stud that keeps them tight (the 'spring' is technically called the 'proof load' or 'elastic range'). But like any spring, you can over-stretch it, and as we know when we over-stretch a spring we can pull it so hard that it eventually does not spring back and loses its temper. This can happen to a bolt/stud too... if you over-torque it, it can become so stretched that it no longer keeps the proper torque (stretch) no matter how much you tighten it (this is technically called the 'plastic range')... it just keeps stretching until it snaps (this is technically called the 'tensile fracture point').

So... an oiled bolt/stud can be easily over-torqued if you're not using the oiled torque setting and you're using the dry setting instead.

For example, if you do oil your lug studs and then tighten them to 90 ft. lbs. (which many folks do) you've just over-torqued that stud by almost 40%.

By 'oiled' most manufacturers mean a lightweight machine oil (5w or less). Not graphite, not moly, not Mobil1, not lithium, not axle grease, not pencil lead, etc... basically, it's just "3-in-1" oil and that's it.

The reason for only using lightweight machine oil is because different oils have different viscosities and different lubricasity, and since you can never be certain what your specific oil is doing to the torque value (i.e. how 'slippery' the oil is), you will therefore have a high likelihood of over or under-torquing the bolt/stud.

Since you can't be certain your oil has the same 'slip' as that which was tested, torquing dry is always a sure thing. Hence I say, for God's sake, torque them dry. You'll never go wrong.

If you want to read more, Fastenal has a good PDF on the subject:
http://www.fastenal.com/content/documen ... eGuide.pdf