73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Wheels & Tires => Topic started by: Big Chip on November 10, 2017, 03:33:41 pm
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This may be a strange question but I am looking to install newer style center caps on my 79 GMC dually and I'm not sure if the lug nuts I am finding to attach the caps are compatible? The dual external thread lug nuts have a 60 degree seat and the originals have a much shallower pitch.
Has anyone had any experience with this? The caps are from an 88 GMC dually.
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Are you using retrofit lug nut? 9/16-18?
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That was the idea. It’s just the newer style with the threads on the outside to screw the black cap on that holds the center cap on the wheel.
The existing lug nut has a much shallower angle where it seats on the wheel ring.
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(https://uploads.tapatalk-cdn.com/20171110/5f4d051ad42e4651af2e23ff240df240.jpg)
The wheels are 16, not the 16.5 that I think would have been OE. They have a ring between the rim and the lug nuts and it looks like the ring is maybe 1/4" thick.
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I may not be asking the question correctly. What I’m wondering is: can I use the new style lug nuts with the 60 degree conical seat on my existing wheels?
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I guess I'm not sure what you're asking either then. The factory lug nut is 60° 9/16-18 and if you want the ones with the external thread here they are:
https://www.ebay.com/itm/32-Pc-9-16-GMC-K2500-LUG-NUTS-OEM-TYPE-DUAL-EXTERNAL-THREAD-9-16-AP-2010/272012453811?hash=item3f5534a7b3:g:JkUAAOSwcwhVK753:sc:USPSPriorityMailSmallFlatRateBox!06238!US!-1&vxp=mtr
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if i understand what your after correctly you are looking for a set of conversion lugs with the SAE thread on the inside and the outer threads for GM hub caps. if I've got the right impression you are after a set of 9/16-18 dual thread lug nuts witch would allow you to run newer center caps on your truck
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My existing lug nuts DO NOT have a 60 degree seat angle. It is a shallower angle and I will get the actual angle tomorrow.
I am asking if the nuts with the 60 degree seat angle will work?
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Well they are supposed to be 60°
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My experience with 1 ton lug nuts is that dual or single rear wheel have the same lug nuts and the spacer ring on the dual rear wheel trucks is there because while the srw rims were lug centric the dually rims are hub-centric and the spacer ring allowed GM to use the same lug nuts as on SRW trucks. For example when i went and picked up my second 88 v30 i needed to put good tires on the rear axle to be able to safely tow it back the approximately 350 km (218 mile) return journey and all i had was a set of dodge 17" lug-centric rims and tires (the center hole in the dodge rims is larger) i bolted them on with the lug nuts from the truck (i left the spacer rings off) and towed it home with zero issue with the old dual rear tires from the truck strapped down in the bed.
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Here’s the existing lug nut and a newer style with what I am going to assume is a 60 degree seat.
(https://uploads.tapatalk-cdn.com/20171112/344e8a0b97b569ce0baccb2bccf9cb00.jpg)(https://uploads.tapatalk-cdn.com/20171112/b594e7fc748d75644b095594cf94ec79.jpg)(https://uploads.tapatalk-cdn.com/20171112/2540eff1a9b7161fe69217d16a4a867d.jpg)
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Here’s a shot of the ring on the wheel.
(https://uploads.tapatalk-cdn.com/20171112/8b70ef33027cded39fdea11f099580e4.jpg)(https://uploads.tapatalk-cdn.com/20171112/135f992e34893755653ef7e92a8a951b.jpg)
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What’s the consensus on getting the new lug nuts machines to the proper seat angle for my wheel rings? It seems like that may be the easiest way to accomplish what I’m trying to do unless replacing the rings with a newer style is an option?
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the factory rings should have 60* seat angles as VileZambonie said and from what i can see in your pictures those are the factory lugs and ring so if you're getting a set of the conversion 9/16-18 dual thread lug nuts they will just swap out with your existing lugs nuts. I don't see where you are getting the idea that your lug nut seat angle and the angle of the seats in the rings are different. Newer GM lug nuts with the dual thread are METRIC and will not work on a squarebody unless you install metric wheel studs, this is why there are conversion 9/16-18 dual thread lugs available.
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The new ones are 14mmx1.50 and are also 60° so I am not sure why you are over thinking this. All you need to do are get the 9/16-18 version
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You can’t tell that my factory lug nuts and my rings are not 60 degrees from the pictures??
I am aware of the lug nut I need to make the center caps work and that was never my question.
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And to clarify, the ring and the lug seat are the same angle and that angle isn’t 60. It’s closer to 45 degrees. That was the basis of my question. Clearly you don’t see the difference in the pictures where the lug nuts are next to each other for comparison.
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And to clarify, the ring and the lug seat are the same angle and that angle isn’t 60. It’s closer to 45 degrees. That was the basis of my question. Clearly you don’t see the difference in the pictures where the lug nuts are next to each other for comparison.
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how did you figure the seat angle? Vilezambonie says factory lugs are 60* seat angle, the conversion 9/16-18 external thread lug nuts are 60* seat angle and the direct replacement lug nuts listed as for a K30 are also a 60* seat angle on the summit website, So where did you get your seat angle from? because i can not find anything suggesting any seat angle other than 60* in your application
K30 lug nuts: https://www.summitracing.com/int/search/make/chevrolet/model/k30/department/wheels-tires/part-type/lug-nuts?N=4294951398%2B4294949485%2B4294950865%2B4294947616&retaillocation=int
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Look at the pictures. One nut is the one I took off the truck and the other is a 60 degree duplex nut. Just because he says the OE nut is 60 degrees doesn’t make it so. I’m not sure if K30’s are different than C35’s but you can see as well as I can the seat angles on those two nuts are not the same.
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Correction: you can see as well as I can the seat angles on those two nuts are different.
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(https://uploads.tapatalk-cdn.com/20171112/344e8a0b97b569ce0baccb2bccf9cb00.jpg)
So, do this...
Remove one of the rings from a wheel. Burnish a couple of the tapered lug nut seats in the ring using some steel wool. Do the same thing for a couple of the "new" lug nut tapers. Smear the cleaned tapered seats with some Prussian Blue dye and reinstall the ring on the wheel, but don't install lug nuts on the two studs protruding through the holes with the dyed seats. Now, thread the 'new' lug nuts down onto the studs with dyed seats, until the nuts are seated by hand. Remove the nuts and check the witness marks left by the dye. That should reveal whether the tapered faces are making the appropriate contact and whether the lug nuts will properly seat into the ring.
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Unless you've had the truck since new it is most likely mismatched parts, wheels and or nuts from an early 70's model. Do as bd said to check your seat contact pattern.
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(https://uploads.tapatalk-cdn.com/20171112/344e8a0b97b569ce0baccb2bccf9cb00.jpg)
So, do this...
Remove one of the rings from a wheel. Burnish a couple of the tapered lug nut seats in the ring using some steel wool. Do the same thing for a couple of the "new" lug nut tapers. Smear the cleaned tapered seats with some Prussian Blue dye and reinstall the ring on the wheel, but don't install lug nuts on the two studs protruding through the holes with the dyed seats. Now, thread the 'new' lug nuts down onto the studs with dyed seats, until the nuts are seated by hand. Remove the nuts and check the witness marks left by the dye. That should reveal whether the tapered faces are making the appropriate contact and whether the lug nuts will properly seat into the ring.
Excellent idea! I will be doing as you suggested.
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In case anyone is interested for future reference, stock dually lug nuts on a 1979 C3500 have a 1” hex and a 90 degree conical seat angle. I can’t speak for other years but I believe they were the same from sometime in the 60’s to 87 with dual wheel. They are NOT 60 degrees and were never 60 degrees from the factory.
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