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Issue with bolt on wheel conversion

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geezer Avatar
geezer Silver Member charles durning
Magee, MS, USA   USA
1958 MG Magnette ZB "Chick Magnette (sold)"
1967 Morris Minor 1000 Saloon (2-door) "Marvin"
1974 MG MGB GT
18 months ago I converted my 74 CBB GT from wire wheels to bolt on wheels. Since the rear wheels need spacers and longer studs I opted to go to 12mm studs on all 4 wheels. The application for the studs was for late model GM cars. The specs for the knurled area for the GM studs that I used on 3 wheels was .501" and for the ARP 100-7708 studs it used on the right rear was .509".

The original 1/2-20 studs had a firm press fit. The GM spec Dorman studs on 3 wheels has a snug fit but was no way near the press fit of the original studs. The ARP studs on the right rear had a much firmer fit. The first spirited adventure for the GT was April 2017 for 5 days in NW Arkansas. During that time I had a recurring issue with the lug nuts coming loose on the left rear. When I got home I found the studs in the left rear hub to be loose. I welded the loose studs into the hub to see if that will be a fix. That was not a fix so I replaced the hub and installed ARP 100-7708 studs as I had done in the right side. The ARP studs have firm fit in the replacement hub. No more issues so far.

A week ago I got back from a spirited 5 days in AR. I pulled the front wheels this past weekend and found some loose studs in the front hubs. Those studs are the Dorman studs spec'd for late model GM cars with the .501" knurl dia. I have now ordered some ARP 100-7726 studs for the front.

Aside from the possibility of losing a wheel, should a loose fitting stud could spin in the hub. A spinning stud might necessitate the destruction of the wheel to get it off of the car. Not a pleasant thought.

If converting to bolt on wheels and going to 12mm studs it would be wise to consider using the ARP studs instead of using OEM spec studs. ARP is more expensive compared to the OEM spec studs but less costly in the end.



Who's version of right are we talking about? When you get 10 LBC owners in a room you'll get 12 different answers.

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B-racer Avatar
B-racer Jeff Schlemmer
Shakopee, MN, USA   USA
1950 Willys Jeep Pickup "Ratrod"
1971 MG MGB
2014 Dodge Charger
5-packs of ARP studs are under $20. Good investment.



jeff@advanceddistributors.com

geezer Avatar
geezer Silver Member charles durning
Magee, MS, USA   USA
1958 MG Magnette ZB "Chick Magnette (sold)"
1967 Morris Minor 1000 Saloon (2-door) "Marvin"
1974 MG MGB GT
The rears were $15.00 for a 5 pack at Amazon. The best I could do for the shorter fronts was $33.00 + freight for a 5 pack. The Dorman studs at $1.50 each appeared to be a bargain at the time. Not so much now.



Who's version of right are we talking about? When you get 10 LBC owners in a room you'll get 12 different answers.

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tvrgeek Avatar
tvrgeek Silver Member Scott S
Hillsborough, North Carolinia, USA   USA
1965 MG MGB
I would worry with them coming loose, the holes are no longer to spec and even good studs may not fit as required.



Cogito ergo sum periculoso

GMB3 Avatar
GMB3 Silver Member George Badger
Soquel, CA, USA   USA
1965 Jaguar E-Type Coupe "1QUICK E"
1968 MG MGB "1QUICK B"
Why 12mm, .472"? That is smaller in diameter than.50".

Aren't the studs pushed in from the back of the hub? How could they come loose? When the lug nuts are tightened the studs are in tension.



---
GEO

geezer Avatar
geezer Silver Member charles durning
Magee, MS, USA   USA
1958 MG Magnette ZB "Chick Magnette (sold)"
1967 Morris Minor 1000 Saloon (2-door) "Marvin"
1974 MG MGB GT
.472" is too small. The 12mm studs for GM cars are .501". The ARP studs are .509". That makes a big difference. The studs are in fact pressed in from the backside and yes with the nuts tight the wheels will stay on. The issue here is the Dorman studs with the .501" serrations do not fit well in the hub and can become loose. Once loose they could spin in the hub making it difficult or impossible to remove the lug nuts.



Who's version of right are we talking about? When you get 10 LBC owners in a room you'll get 12 different answers.

B-racer Avatar
B-racer Jeff Schlemmer
Shakopee, MN, USA   USA
1950 Willys Jeep Pickup "Ratrod"
1971 MG MGB
2014 Dodge Charger
You can quickly cut those long studs down with a cut-off wheel on a right angle grinder.

George, there is a larger, fluted/knurled step at the base of each stud that press fits into the hole. The thread size is always smaller than the press-fit section. If you put a .501" press fit into a
.504" hole, yes they will come loose. Almost no press fit.



jeff@advanceddistributors.com

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Be Coming Avatar
Be Coming Kelvin Dodd
So. Calif., USA   USA
Timely advice - Thank you.

GMB3 Avatar
GMB3 Silver Member George Badger
Soquel, CA, USA   USA
1965 Jaguar E-Type Coupe "1QUICK E"
1968 MG MGB "1QUICK B"
Thanks Jeff. I converted my E-Type bolt-on hubs to long studs years ago. That was a PITA trying to find the studs.



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GEO

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