Torque on Wheels Lug Nuts?
Le Mans Master
Joined: Sep 2003
Posts: 8,812
Likes: 2,029
From: eastern NC
Originally Posted by big_G
My '68 Chevy shop manual says 65, I use 85 ft/lbs.
Why do you suppose GM calls for 100 ft/lbs on the C5? I have a friend that stripped 3 of the studs on his 2003 using a calibrated torque wrench at 100 ft/lbs. He even had the wrench rechecked after this disaster. I'm confused as to why the big increase since the studs are so close to the same size...
Curious... GUSTO
Le Mans Master
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
Not the same size...C-3 is 7/16, C-4 and C-5 lugs are 13 millimeter. (About 1/2 inch.) I have never stripped a C-4 or C-5 lug/stud at 100 ft/lbs., and I've torqued more lugs than I care to remember. I don't know why your friend had that trouble. 
Le Mans Master
Joined: Sep 2003
Posts: 8,812
Likes: 2,029
From: eastern NC
Originally Posted by big_G
Not the same size...C-3 is 7/16, C-4 and C-5 lugs are 13 millimeter. (About 1/2 inch.) I have never stripped a C-4 or C-5 lug/stud at 100 ft/lbs., and I've torqued more lugs than I care to remember. I don't know why your friend had that trouble.
I sort of assumed he must have set the torque wrench wrong since I have torqued them to 100# and never stripped one... I'm just not comfortable doing it in light of the torqe required for earlier Corvettes.
Thanks... GUSTO
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Thread Starter
Pro
Joined: Apr 2005
Posts: 666
Likes: 5
From: Mt. Pleasant SC
Originally Posted by Big Fish
My torque chart has it at 70-90 ft/lbs for aluminum wheels and 65-85 ft/lbs for the steel wheels
Chris
Drifting
Joined: Jun 2005
Posts: 1,950
Likes: 498
From: Chino Hills CA
Remember that the torque specs assume you have clean dry threads with no binding. Oil on the threads will give a false reading. Also make sure there is no rust on the hubs or back of the wheels. Lastly, always use a star pattern when removing and installing wheels. In fact put your lug nuts on in a star pattern snug, then torque them down in the same pattern. Many manufacturers have a +/- 20 ft-lb range. For example, Chrysler products with a 1/2" stud recommend 85-115 ft-lb. Many Hondas, Toyotas, Mazdas, and GM vehicles all have 12 X 1.5 mm studs, however Honda says 80 ft-lb, Toyota says 76, Mazda says 87 and GM says 100, go figure. ( I do this for a living, I know these specs by heart.) The 7/16" studs on older Chevy's should be 80-85 ft-lb.
Thread Starter
Pro
Joined: Apr 2005
Posts: 666
Likes: 5
From: Mt. Pleasant SC
Originally Posted by lowbuck72
Remember that the torque specs assume you have clean dry threads with no binding. Oil on the threads will give a false reading. Also make sure there is no rust on the hubs or back of the wheels. Lastly, always use a star pattern when removing and installing wheels. In fact put your lug nuts on in a star pattern snug, then torque them down in the same pattern. Many manufacturers have a +/- 20 ft-lb range. For example, Chrysler products with a 1/2" stud recommend 85-115 ft-lb. Many Hondas, Toyotas, Mazdas, and GM vehicles all have 12 X 1.5 mm studs, however Honda says 80 ft-lb, Toyota says 76, Mazda says 87 and GM says 100, go figure. ( I do this for a living, I know these specs by heart.) The 7/16" studs on older Chevy's should be 80-85 ft-lb.
