Torquing lugnuts

[Mark]

I have a torque wrench, but I have not yet tightened my lug nuts since I got in the the Spring.

I plan on a longer trip than usual to Letchworth, SP, in New York, so I want to do all the safety checks properly.

I was wondering if anyone knows the size of the lug nuts so I can make sure I have the right socket for my torque wrench.

Who has done this recently?

[nickster60]

I torqued mine I dont remember what size but used 115 lbs. I have a full 1/2 inch set in the truck. Something makes me think 7/8 but I could be wrong.

[Sunline Fan]

The size of all the Sunline nuts I've had are 13/16". I didn't torque the nuts on the car trailer (also 13/16") seen in the Dexter Over-Under post because I didn't have a torque wrench where I was at. I just tightened them as tight as I could (I don't use an impact) and thought it would be good enough. I'm leaving tomorrow for a 4 hour trip and haven't checked them. I think I remember the torque rating being 90-110 ft-lbs for steel wheels, but I'm afraid to tighten the nuts on the aluminum wheels that much. If anyone has the aluminum wheel option and has something in your owner's manual about it, please post it here.

Jon

[Mark]

Mine were indeed 13/16's.

My manual torque wrench only goes to 100, so I may need an upgrade there too

[JohnB]

Here is what I have found.

Our TT axles are what they call “lug centric” verses “hub centric” like you find on an auto.

On the auto and hub centric setup the rim center bore is machined on center and pilots the axle with a very close fit. In the case of alum rims in time it sets up on there with a little corrosion and you have a heck of a time getting it off the hub. With this setup the center hub takes the vehicle load and the lug nuts provide the turning torque. This setup once torque'd, holds that torque well and generally does not loosen up as the studs are only driving.

HOWEVER

On the normal TT axle which are a “lug centric” setup, there is no center hub that is machined to a precision fit and the rim ID it not machined either. In this case the wheel studs and lug nuts are taking the weight of the camper plus providing the rolling torque in a breaking situation.

Dexter axles use grade 8 studs according to the axle manual. I do not know about the other brands. In the Dexter manual they also say they stopped making rims a while ago and to use the wheel manufacture ratings for lug torques as a cover yourself note.

On mine I use the Dexter recommendation of 120 ft lb and torque the “steel” rim in a torque pattern, which is what I use. See here on page 67 and 68. http://dexteraxle.com/i/u/1080235/f/...-07_72_res.pdf That file may take a minute to down load. Alum rims may have a different torque.

Now here is the problem. On this leg centric setup, whenever the wheel is put back on, changing a flat, changing a tire, brand new etc. the first torqueing does not last very long. Like 50 miles. And they will start to loosen some. So you go back and do it again, then at about 75 miles, do it again. By the 3rd time, they settle down and the 4th torque'ing and on they do not move much more.

By the studs holding the load up and working to provide the braking torque, the lug nut works on the rim until it is fully seated. Then it stops moving. Generally after 3 re-torque'ings. Once they stop moving, well then they are OK. Failing to do this can leave you with a real problem if it goes long enough the wheel will come off.

Most US based lug nuts are 13/16. Next common size is ¾ and then 7/8” until you get up into heavy trucks and industrial.

Hope this helps.

John