Torque specs.

[ralphpam]

What do I torque the lugs nuts on the 16" 110 lb. wheels and the u bolts on the 7000 lb. axles?

 

[westxsrt10]

110 lb on the lug nuts sounds real close, I have my u-bolts @ 75lb but they are a fraction larger than stock. I think factory specs is 65# done in 3 steps.

 

[Bighurt]

What do I torque the lugs nuts on the 16" 110 lb. wheels and the u bolts on the 7000 lb. axles?

Third cycle is 90-120 ft lbs, I set mine at 120 and follow the prescribed pattern each trip. Only sense in doing the first and second cycle is a fresh mount or spare install.

As for the U bolts the Lippert manual says 3500-8000 lb axles 65 ft lbs on the u bolts. 35 for the hanger and shackle bolts.

 

[jnbhobe]

I think you are suppose to add 5# for every inch of extention you use also

 

[RollingHome]

Jon, help me out here. I can't believe I missed this before. I typically use a 4" extension, should I be adding 20 pounds on the clicker to get what I want ? i.e. I want 120 (wheels) should I set the torque wrench clicker at 140 if I use a 4" extension ? man have I messed up ??? and if I used a 8 inch extension I should add 40.... so 120 becomes 160... Wow, ignorance is bliss huh ? Once again the I have learned something from the forum...

 

[Bighurt]

I think you are suppose to add 5# for every inch of extention you use also

That's incorrect.

If using a crow's foot or adapter that extends or shortens the distance center of handle to center of nut than the original center of handle to center of drive lug. There are calculations to adjust the applied torque to reach the desired finish torque. I can give you the formulas if you need. However using an extension doesn't change the rotational applied force to the nut.

If you think of the nut, handle, and drive lug as three points on a triangle the leg from lug to nut can be any length and achieve the same torque assuming the leg from lug to handle has a fixed length.

 

[jnbhobe]

I was told it was the twist on the extention that had to be made up for. But I don't have any facts

 

[jmgratz]

I was told the lugnuts on G rated rims should be 120 pounds.

 

[RollingHome]

OK guys, you are confusing me now... Join forces as a team and agree. Does an extension multiply or subtract Pounds per square inch of torque ? Don't make me go to the library, you're smarter then dat...

 

[Bighurt]

There is a twist but 1/2 drive extensions less than 30" in length will have very little twist at 120 lbs, as such the industry doesn't account for it. In fact we anticipate it by not snatching the wrench rather than pull gently along the entire torque motion. Remember the given torque on the nut is over calculated to account for these errors. Running torque on the threads, fatigue on the fastener and of course the industrial standard plus or minus 4% clockwise calibration.

My 1/2" 20" extension exhibits less than 20 degrees of twist over its entire length at 120 ft lbs.

 

[Bighurt]

A straight extension attached 90° to the torque wrench doesn't effect the torque enough to require a separate calculation. Only lateral adapters will effect the applied force either, plus or minus from the setting depending on weather they are creating a shorter or longer lever.

 

[RollingHome]

Thanks BigHurt, do I need to adjuust for a 4" extension ? Hope I don't sound dumb...

 

[Bighurt]

Thanks BigHurt, do I need to adjuust for a 4" extension ? Hope I don't sound dumb...

No you do not. The torque applied to the fastener will be within 4% of the setting on the torque wrench.

 

[RollingHome]

BigHurt, great ! because I have every thing torqued up and I just want to turn key and go next weekend... Thanks ! We're kinda antsee... Tom

 

[Bighurt]

BigHurt, great ! because I have every thing torqued up and I just want to turn key and go next weekend... Thanks ! We're kinda antsee... Tom

Me too! I can say its a bit cramped under the rig torquing the u-bolts. If it wasn't for the full belly liner....

 

[Recovered from 25-May-2010]

Re: Torque Specs.

120 LBS is correct.