Wheel stud knurl diameters

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60jerry

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3 or 4 years ago I installed a disc brake kit on my '63 Dart Wagon, /6 and three on the column. The rotors are about 11/16 thick at the stud mounting point and with steel wheels the stud threads extend well under an inch from the wheel mounting surface. With the steelwheel (14x6 from a Ford maverick) tightened down, the lug nut is roughly a quarter inch from a good thread contact. It looks like I have about the thickness of the stud in threads but it bothers me. I've been driving with no issue and all the lug nuts were still tight after a couple thousand miles. I've not been able to find longer studs with the correct knurl diameter of 0.620 inch. I'm considering a couple approaches to this and one is to find a stud with knurl diameter a bit bigger, 0.625, 0.627 if I can find studs that are about 3+ inches long under the top fat part. Is this advisable?
 
60jerry said:
3 or 4 years ago I installed a disc brake kit on my '63 Dart Wagon, /6 and three on the column. The rotors are about 11/16 thick at the stud mounting point and with steel wheels the stud threads extend well under an inch from the wheel mounting surface. With the steelwheel (14x6 from a Ford maverick) tightened down, the lug nut is roughly a quarter inch from a good thread contact. It looks like I have about the thickness of the stud in threads but it bothers me. I've been driving with no issue and all the lug nuts were still tight after a couple thousand miles. I've not been able to find longer studs with the correct knurl diameter of 0.620 inch. I'm considering a couple approaches to this and one is to find a stud with knurl diameter a bit bigger, 0.625, 0.627 if I can find studs that are about 3+ inches long under the top fat part. Is this advisable?
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I'm not sure I follow when you say you are roughly 1/4" from good thread contact?

At a minimum, a stud or bolt should always have at least 2 full threads protruding beyond the nut. This is an industry standard and I believe it is per ANSI...not that it applies to cars which I believe fall under SAE but it is a good rule to live by anyways. Personally I would not be as concerned with the knurl engagement as I would be the thread engagement of the lug nuts but then like I said I'm not sure I totally understand what you meant by good thread contact.
 
ACME SS said:
I'm not sure I follow when you say you are roughly 1/4" from good thread contact?

At a minimum, a stud or bolt should always have at least 2 full threads protruding beyond the nut. This is an industry standard and I believe it is per ANSI...not that it applies to cars which I believe fall under SAE but it is a good rule to live by anyways. Personally I would not be as concerned with the knurl engagement as I would be the thread engagement of the lug nuts but then like I said I'm not sure I totally understand what you meant by good thread contact.
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Thanks for the response. The stud did not protrude at all. With the nut tightened on the wheel I could look into the nut and see three to five threads. This bothers me. My idea is to get new studs of the correct, or at least close, knurl diameter. The stud I removed from the rotor measures 0.620 outside of the knurls. As 33IMP suggested, it seems installing a 0.625 knurl diameter stud should be fine. I'll get really long studs and trim for thread protrusion and clearance from the hubcap. You guys made me feel better.
Jerry
 
60jerry said:
Thanks for the response. The stud did not protrude at all. With the nut tightened on the wheel I could look into the nut and see three to five threads. This bothers me. My idea is to get new studs of the correct, or at least close, knurl diameter. The stud I removed from the rotor measures 0.620 outside of the knurls. As 33IMP suggested, it seems installing a 0.625 knurl diameter stud should be fine. I'll get really long studs and trim for thread protrusion and clearance from the hubcap. You guys made me feel better.
Jerry
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The rule of thumb is 1 1/2 times thread size for thread engagement, so for a 1/2x20 studs, you should have 3/4" of thread in the lug.
It sounds like you really NEED longer studs.
I have three inch (or longer) studs, front and rear, on three of my cars, along with open end lugs. Even with 3" studs, I can get doggie dishes on steel wheels.
 
OK I understand. I had the same issue when I purchased my Demon and also on a 54 chevy I purchased. I seem to remember buying studs from ARP that were slightly larger diameter and they pressed in just fine.
 
Just checked UPS tracking for my 3" studs & open end nuts to make my new Cordoba rotors match the rear axle. - arriving tomorrow.
 
33IMP said:
The rule of thumb is 1 1/2 times thread size for thread engagement, so for a 1/2x20 studs, you should have 3/4" of thread in the lug.
It sounds like you really NEED longer studs.
I have three inch (or longer) studs, front and rear, on three of my cars, along with open end lugs. Even with 3" studs, I can get doggie dishes on steel wheels.
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I just ordered studs that are .005 larger knurl diameter, 3 inch length. Sounds like I may not need to shorten them to clear my dog dish caps.
Another time that this site has been very helpful.
Thanks all,
Jerry
 
Mine, with 3"studs, front and rear.....

20181218_120000.jpg
 
33IMP said:
Mine, with 3"studs, front and rear.....I like the steel wheels with hubcaps. My '63 Dart has 14x6 Ford Maverick wheels with Mercury caps with no markings telling what car they're from. I'd like a set of 4 14x6 with the smallest backset possible to fit my factory Dodge hubcaps. That's a few dollars away from me. Have to find Mopar centers and put 6 inch rims on. That'a '62. Is that correct? Looks really cool.onoView attachment 1715936465
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Yep, 62 savoy, with the wheels and tires to go on my rr on it temporarily. Those are 67 barracuda hubcaps. I don't know if you know, but there are two different sizes of poverty caps, generally called 9" and 10" . The early caps are 10" (pre 66). The caps have to match the wheel centers.
The 62 usually wears centerlines or torque thrusts with slicks.
 
33IMP said:
Yep, 62 savoy, with the wheels and tires to go on my rr on it temporarily. Those are 67 barracuda hubcaps. I don't know if you know, but there are two different sizes of poverty caps, generally called 9" and 10" . The early caps are 10" (pre 66). The caps have to match the wheel centers.
The 62 usually wears centerlines or torque thrusts with slicks.
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Thanks for the info on poverty cap diameters. The caps that came on mmy Dart were on the13 inch wheels and look small to me, but I've been looking at the poverty caps on my Ford wheels. I'm going to try my poverty caps on the ford wheels. Not optimistic. I have many Chevy poverty caps that measure the same as the Mercury caps I now have on the Dart and those Chevy caps were a bugger to put on the Ford wheels and very difficult to remove--really tight. I'm installing tubular upper control arms right now and it's a good opportunity to test fit on the table top. This control arm install is taking days since I need many rest periods. I'm 77 and not quitting cars yet, just slow.
 
60jerry said:
Thanks for the info on poverty cap diameters. The caps that came on mmy Dart were on the13 inch wheels and look small to me, but I've been looking at the poverty caps on my Ford wheels. I'm going to try my poverty caps on the ford wheels. Not optimistic. I have many Chevy poverty caps that measure the same as the Mercury caps I now have on the Dart and those Chevy caps were a bugger to put on the Ford wheels and very difficult to remove--really tight. I'm installing tubular upper control arms right now and it's a good opportunity to test fit on the table top. This control arm install is taking days since I need many rest periods. I'm 77 and not quitting cars yet, just slow.
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Yeah, sorry, I basically forgot I was on the A side. The 5 on 4 small pattern wheels use different caps than the larger 4 1/2 pattern . You will just have to experiment a little to find what works for you.
 
33IMP said:
Yeah, sorry, I basically forgot I was on the A side. The 5 on 4 small pattern wheels use different caps than the larger 4 1/2 pattern . You will just have to experiment a little to find what works for you.
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Oh rats!! I didn't know about 13 inch wheels having smaller poverty caps. Any old poverty caps are sorta rare so I have an additional hunt coming up. I much prefer steel wheels with original caps. I disliked poverty caps when I was a kid. Spinner wheel covers were the hot items in the sixties. My wheel setup is just fine for now. I like your wheels and caps.
Jerry
 
60jerry said:
Oh rats!! I didn't know about 13 inch wheels having smaller poverty caps. Any old poverty caps are sorta rare so I have an additional hunt coming up. I much prefer steel wheels with original caps. I disliked poverty caps when I was a kid. Spinner wheel covers were the hot items in the sixties. My wheel setup is just fine for now. I like your wheels and caps.
Jerry
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I may be wrong about the early A caps being different. There ARE two different cap sizes, 9 and 10 inch. You will just have to play with what you have .
(The caps on my savoy are from a small pattern 67 barracuda, on a big pattern wheel.
 
33IMP said:
I may be wrong about the early A caps being different. There ARE two different cap sizes, 9 and 10 inch. You will just have to play with what you have .
(The caps on my savoy are from a small pattern 67 barracuda, on a big pattern wheel.
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I'll just figure it out. My wagon spare is a big bolt circle 14" mopar wheel. When I take the stands out I'll be able to get to the spare and check fit. Why do we do this stuff?
 
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