...for a '63. Can't find it listed in the Shop Manual or the Owner's Manual. I'm installing my new Torq-Thrust D's this afternoon. Thanks!
Pete
Pete
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Re: C2 Recommended Wheel Lug Nut Torque?
Pete-----
The specified torque for both steel and factory N89 aluminum wheels is 70-95 lb/ft. So, I think that you'd be very safe usiung that same torque range with the American wheels.In Appreciation of John Hinckley -
Re: C2 Recommended Wheel Lug Nut Torque?
My Torq Thrust wheels are at 80 with no problems.Comment
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Re: C2 Recommended Wheel Lug Nut Torque?
Joe,
70-95 sounds high to me, at least for 63. Is this from a service/overhaul manual?Comment
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Re: C2 Recommended Wheel Lug Nut Torque?
I called the wheel/tire guy back. He told me to follow the manufacturer's spec, and that is 85 ft-lbs (don't know where he got it). So you were all in the ball park! THANKS!!
PeteComment
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Re: C2 Recommended Wheel Lug Nut Torque?
Michael-----
Actually, that spec came from a 1967 AIM. Here's the deal: 1963-65 Corvettes, including disc brake 1965's, had a specified wheel nut torque of 55-65 lb/ft. For 1966 and later GM changed that to 70-95 lb/ft. I believe that they had good reasons for the change and I think that it would be applicable to 63-65 models, as well. There was no fundamental difference in the nuts, the studs, or anything else that would require a need for a torque specification revision.
Also, I used the 67 specs in my first response since the question involved the use of American mag wheels. 1967 was the first year that a direct, bolt-on aluminum wheel was used on a Corvette and the torque specs for that wheel's lug nuts were the same as the steel wheel---70-95 lb/ft. So, it seems to me that this comparison is the best one considering the use of the American wheels.
The GM Service Manual specification for the 1979 aluminum wheels was 90 lb/ft while the steel wheel specification for that year was 80 lb/ft.
If I were torquing the wheel stud nuts on a 1963-65 Corvette, I sure wouldn't use a torque of less than 65 lb/ft.In Appreciation of John HinckleyComment
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Re: C2 Recommended Wheel Lug Nut Torque?
Joe -
The '67 A.I.M. shows 55-70 ft-lbs. for lug nuts for both standard steel and N89 bolt-on aluminum wheels, and the '67 Chassis Service Manual shows 65 ft-lbs. Is the 75-90 ft-lbs. spec for later cars?Comment
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Re: C2 Recommended Wheel Lug Nut Torque?
I just found the specs also. SOP 63 to Feb of 65 was 55-65 lbs. It then changed to 55-75 lbs on 2 Feb 65. I vaguely remember something about a change in the stud and it's part number for 65, which probably had to do with it's change in torque value. I don't know when the spec changed to 70-95 but it had to be after 66. I've always used 60 or 65 lbs for 66 and earlier.Comment
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Re: C2 Recommended Wheel Lug Nut Torque?
AHA, the AIM - of course! And I have found it in my '63 AIM as 55-65 also. But after reading this discussion (and following the recommendation of the wheel/tire guy),I'm going for 80-85 in any case, Thanks again!
PeteComment
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Re: C2 Recommended Wheel Lug Nut Torque?
The manufacturer's specification for '63 wheel nuts is 55-65 lb-ft per the AIM, NOT 85, and 55-65 is what you should use.
Recommended bolt torque is based on clamping force requirement, and studs with suitable hardness are selected to meet this spec. Overtorquing the nut places the stud under higher than design stess.
As Michael said, the later studs would have been "upgraded" to a higher hardness to accept a higher torque for greater clamping force, but you should not use this higher torque unless you are certain that the studs have been changed to the later, harder type that are designed for greater installation torque.
dukeComment
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Very ill-advised...
... read my 12:39 post. The "wheel/tire guy" is not the design engineer who established the torque spec. "Bigger" is not always better!
When in doubt, follow Chevrolet Engineering's recommendations. The wheel/tire guy, the hot rod shop guy, the NAPA counter guy etc, are not engineers and didn't design the car.
DukeComment
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Excellent response ! *NM*
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Re: C2 Recommended Wheel Lug Nut Torque?
John-----
Yes, I misread it; it is as you mention.In Appreciation of John HinckleyComment
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I Have A Better Idea......
Peter,
If you replace all of the studs with the latest style GM part that's designed to handle that kind of load, I would then feel much better about winding these nuts down to 80#. Also, I believe their a bit longer than the 63 studs. This is an easy job on a drum brake 63 or 64 and shouldn't take long at all. I think the peace of mind would be well worth the time and effort. I don't have the latest part number but I'm sure Joe Lucia can provide that for you. I would definitely save the original studs tho, as they're unique to 63-64 and are marked as such with, I believe, a zero stamped into the exposed end.Comment
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Re: C2 Recommended Wheel Lug Nut Torque?
Duke-----
There were 3 different wheel studs used over the 63-82 period. The only difference between them is a very slight difference in several dimensions, including length. All are manufactured to GM 300M material specifications. The longest of the studs, which was the late 67 to 82 stud had a length of 1-3/4". It later became the SERVICE stud for all 1960 through 1982 Corvette applications.In Appreciation of John HinckleyComment
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