Torque Wrench Question

[Deano_1]

Hey Guys,

Mounted all four new tires and rims on without a problem, but I do have a question. When i went to put tighten the lugs with the torque wrench, I needed to add an extension onto the torque wrench, otherwise I couldn't get the wrench on the lugs. My question is, with the added length, (about 12 inches with the deep socket and extension), how much does this change the the actual reading? So by adding a foot is my reading actually less than the 100# of torque on the wrench. By the way, Sears had a 1/2 drive wrench for $39.

Thanks,

Deano

[dave54]

Rookiecamper wrote:
I believe Peter's web link refers to making the handle longer, thus increasing the torque. If I'm reading things correctly, you are just putting a basic 1/2" x 8" or so extension between the wrench and the socket. That will have negligible effect on what you are using it for.

Agree. A socket extension will have no measurable effect. A lab may find some difference out in decimal point land due to torsion on the extension, but that would make no difference in the real world.

I three step my torquing, per manufacturer specs. For 105 pounds, 1st step is to 40 (using the star pattern already mentioned), 2nd to 70, final to 105. Takes longer, but I feel better taking the time to do it right. I am the only one I know that three steps their torquing. I am sure others do to, I just don't personally know anyone. I do not recall ever seeing a shop do it.

[PenMan]

BB_TX wrote:
Torquing by hand with an extension on your torque wrench is not going to affect the torque to the nut at all. Don't worry about that.

Correct answer.

[Rookiecamper]

I believe Peter's web link refers to making the handle longer, thus increasing the torque. If I'm reading things correctly, you are just putting a basic 1/2" x 8" or so extension between the wrench and the socket. That will have negligible effect on what you are using it for.

[BB_TX]

Torquing by hand with an extension on your torque wrench is not going to affect the torque to the nut at all. Don't worry about that.

[TNRIVERSIDE]

I would be concerned using a $39.00 torque wrench. I have had some bad experiences with inexpensive tools. But Sears tools normally are good. I agree with others on using a lower setting before the final torque is applied. Also cross torque. Do not tighten lug nuts that are beside each other. On a five lug wheel I will skip a lug nut as I go around a wheel. Six lug wheels cross to the opposite side.

[gmw_photos]

Deano,
When using a simple straight extension between the socket and the torque wrench, you are not changing the leverage since the force applied at the socket is still along the centerline of the head of the wrench.
If measuring this in a lab, then yes you could likely note some small difference due to potential "spring" effect of the extension "winding up", which would vary with the length, diameter and material it is alloyed from.
For what we are doing here (lug nuts), the accuracy tolerance of the wrench and whether you are holding the wrench/extension/socket in perfect alignment would likely have far more effect. Also the relative cleanliness and accuracy of the threads.

I set my torque wrench to 70 ft-lbs, do up all the fasteners, reset to 100 ft-lbs, do them up again and call it good. Some people do them up in three stages.
I recheck them two more times after approx 50 miles, and then at 100 or 200 miles. Works for me.

That's my opinion and understanding anyway.

Edit, perhaps Ron G will chime in with the view from a mechanical engineers perspective.

[3oaks]

Technically, yes. It would be so slight as not enough to matter when applied to wheel lug nuts.

What really matters is to have all the nuts torqued the same so that each one is carrying an equal load.

[petersr58]

http://www.norbar.com/en-gb/Home/Torque-Wrench-Extension-Calculator
Go to this web site and download the phone app to fig torque. Phone app will be good to have for quick use