AFX spindle and 1/2" wheel stud

[wayne70]

insalling the afx spindle and i decided to upgrade to 1/2" wheel stud's. What stud should i use , press in or screw in ?
Anyone have a part #, i have done a search and come up empty handed.

[MonzaRacer]

if it was me knock old stud out, if its press in measure it. for me I would simply tap for 1/2 20 screw in studs, check with jegs/summit for morroso, you can install them from back and if you need clearance you can mill the heads down if needed.
Just remember you should have hub sitting in good level mill vice and use a drill press or milling machine to start the tap so it goes in straight.

[mrengineer]

Recently I avoided a near DISASTER with this same setup thanks to the former ATS. I do not reccomend these wheel studs for use in C5 hubs.

When I purchased my AFX spindles (from ATS) I too upgraded to the 3.5" ARP stud option. I was told it was a common upgrade so front & rear studs would all be the same size. After a weekend road trip (about 500 miles) with the wife & kids I was getting a loose feeling when driving about 5 miles from home. The feeling you get when you know something is seriously wrong. Fortunately I limped home.

The following day I removed both front wheels. To my disgust I find all wheel studs had backed out of the C5 hub on both sides! Upon further investigation I find out the great folks at ATS had installed ARP stud p/n 100-7703, which is a 3.5" stud with a .625 knurl diameter into the C5 hubs that have a 0.509 knurl diameter!! This is not an engineered press fit in fact it's a dangerous and not reccomended practice. And for what it's worth, I am an engineer working for an OEM here in Henry's hometown so I can speak to this subject with authority. If you must replace and or change studs use ones that have a correct knurl diameter. And for those who want to weld or use screw in studs with these hubs proceed at your own risk. The C5 hubs present challanges if you pursue those methods of attaching the studs. My advice to all, do not use 1/2 studs in C5 hubs. There great parts just not compatible.

[MrQuick]

Recently I avoided a near DISASTER with this same setup thanks to the former ATS. I do not reccomend these wheel studs for use in C5 hubs.

When I purchased my AFX spindles (from ATS) I too upgraded to the 3.5" ARP stud option. I was told it was a common upgrade so front & rear studs would all be the same size. After a weekend road trip (about 500 miles) with the wife & kids I was getting a loose feeling when driving about 5 miles from home. The feeling you get when you know something is seriously wrong. Fortunately I limped home.

The following day I removed both front wheels. To my disgust I find all wheel studs had backed out of the C5 hub on both sides! Upon further investigation I find out the great folks at ATS had installed ARP stud p/n 100-7703, which is a 3.5" stud with a .625 knurl diameter into the C5 hubs that have a 0.509 knurl diameter!! This is not an engineered press fit in fact it's a dangerous and not reccomended practice. And for what it's worth, I am an engineer working for an OEM here in Henry's hometown so I can speak to this subject with authority. If you must replace and or change studs use ones that have a correct knurl diameter. And for those who want to weld or use screw in studs with these hubs proceed at your own risk. The C5 hubs present challanges if you pursue those methods of attaching the studs. My advice to all, do not use 1/2 studs in C5 hubs. There great parts just not compatible.

why not just use the correct studs with the correct knurl? The stud backed out? Thats strange.

Vince

[Steve68]

Something must be wrong, this is common practice on the vette fourms, I've never heard of this happening anywhere else, did you bother contacting Tyler, he's been doing it on the hubs for numerous customers,

[TitoJones]

We actually milled the holes on the hubs to the correct size to make sure the press fit worked correctly. There is no drill size that will make the holes correct for the 1/2 stud we used so the factory studs get pressed out, the hub goes into a CNC and then they get milled. They are then pressed in with the correct interference tolerance. For you to say we just slam them home on a stock hub is totally inaccurate and baseless; hence the $100 upgrade charge. That's machining time. Do you have pictures of this failure? When did it happen and who did you call? Did you actually physically check the hole diameter with calipers or are you just assuming?

I had a 1/2 stud upgrade on my 68 Camaro with 2 inch wheel adapters bolted to them (putting even more stress on them) with over 22,000 miles of hard daily use and sticky tires. Not once in 6 years have we ever had a complaint or failure of which you speak.

Tyler

[GrnDragon]

I am looking to upgrade my ZR1 hubs to 1/2" studs, does anyone offer this upgrade for already purchased hubs? Or should I just go to a local machine shop and have them machined?

I am also interested in finding out which studs to use.
I have been searching too, and there are many options.

[67bird]

You may want to search the lateral-g forum as I think it was answered over there. I will see if I can find the post.

[67bird]

Here is the link:

http://www.lateral-g.net/forums/show...ats+wheel+stud

[mrengineer]

Tyler - I wish you did not make the claim in the previous post. The holes were not milled - there is evidence to prove a milling operation was never done. I know what I measured both on the hub and stud. I also I know what milling marks leave behind when magnified under microscope. You also never claimed to mill prior to installation only until now. And your invoice never stated milling maching operation whatsoever prior to stud installation! I don't care to get in a debate but please do not tell people you milled the hubs prior to installing studs, unless you can prove it. My profession deals with facts and not assumptions. In fact the new supplier of AFX spindles sent me an e-mail stating they will no longer continue the practice to install different studs because of the liability and the facts presented to him when we talked. Enough said.

[Vegas69]

ARP and Moroso both make longer 12mm studs that will press into a stock hub. If it's good enough for a Corvette, it's good enough for me.

[MrQuick]

We actually milled the holes on the hubs to the correct size to make sure the press fit worked correctly. There is no drill size that will make the holes correct for the 1/2 stud we used so the factory studs get pressed out, the hub goes into a CNC and then they get milled. They are then pressed in with the correct interference tolerance. For you to say we just slam them home on a stock hub is totally inaccurate and baseless; hence the $100 upgrade charge. That's machining time. Do you have pictures of this failure? When did it happen and who did you call? Did you actually physically check the hole diameter with calipers or are you just assuming?

I had a 1/2 stud upgrade on my 68 Camaro with 2 inch wheel adapters bolted to them (putting even more stress on them) with over 22,000 miles of hard daily use and sticky tires. Not once in 6 years have we ever had a complaint or failure of which you speak.

Tyler

actually we had an issue with studs pulling a few year back. It was result of an improper rotor hub bevel and the lug nuts not properly torqued and not to spec.

Strange to have the studs "pull" on a properly torqued lug nut.


Vince

[TitoJones]

actually we had an issue with studs pulling a few year back. It was result of an improper rotor hub bevel and the lug nuts not properly torqued and not to spec.

Strange to have the studs "pull" on a properly torqued lug nut.


Vince

That's not an issue of ATS installing the studs improperly; that's a parts fitment issue with a rotor being the culprit.

Tyler

[Steve68]

ARP and Moroso both make longer 12mm studs that will press into a stock hub. If it's good enough for a Corvette, it's good enough for me.

But there metric, much easier to run one size,

I think if there was such a issue of ARP/manufacture having studs pull out or of any wheels pulling out, wouldn't they stop making them completely.

It's Monday, excuse me if my thinks off,

if the studs are pressed in the back side of the hub, then the rotor, then the wheel, with lug nuts properly torqued, how do the studs come loose unless the the holes wallowed allowing the studs to move,

I think some pics of the hub and studs are in order,

[Vegas69]

My car has had 12mm front and 1/2 rear since it was built. They are both 13/16 and the lug nuts say what thread pitch they are. I usually throw the 1/2 inthe rear of my seat tray and the 12mm's in the front. Marginally easier to have 1/2 all the way around.

[killer69]

Tyler - I wish you did not make the claim in the previous post. The holes were not milled - there is evidence to prove a milling operation was never done. I know what I measured both on the hub and stud. I also I know what milling marks leave behind when magnified under microscope. You also never claimed to mill prior to installation only until now. And your invoice never stated milling maching operation whatsoever prior to stud installation! I don't care to get in a debate but please do not tell people you milled the hubs prior to installing studs, unless you can prove it. My profession deals with facts and not assumptions. In fact the new supplier of AFX spindles sent me an e-mail stating they will no longer continue the practice to install different studs because of the liability and the facts presented to him when we talked. Enough said.

OK i think i will clear up a couple things.
1St i spoke to the machinest Phill Hayes about the installation of the wheel studs, he has been the only person to install any wheel studs that were shipped from ATS. here is the procedure ( actually exactly what Tyler stated)
The factory studs are pressed out, the hub is ounted and the stud holes are machined to a 6 thou press fit for the new studs .625 knurl -.006= .619
once the cnc machine is finished the studs are pressed in and then straightened to ensure they are correct.

The stud holes in the rotors MUST be drilled to clear the step on the stud. Drill the rotors to .625 minimum prefered size is .637 the factory hole is .488. and this will actually fit over the installed 1/2 stud.
Failure to perform this step WILL make the rotor sit up on the "Step" of the stud and this will effectively not Clamp the rotor to the hub flange but will allow the studs to become loose. because the "Step" is consistant the rotor will install and will APPEAR to be seated but is in fact not. over time ( as decribed by mrengineer) the studs will loosen. they are infact not BACKED OFF they have been pushed out the back side of the hub by the weight of the car. not an ideal situation.

i have talked to Mrengineer and we have agreed to send him a new set of hubs with 12mm studs, i explaned to him the reason we will not install the wheel studs is from a liability stand point as well as a logistical one the machinest is in Parhump and we are in Vancouver.
fact that myself and mrengineer have talked abouot this issue had very little with our descision to NOT install studs going forward.

I would like to see mrengineer post up some pictures of the backside of the rotors so the rest of you can see what has happened.

If any one wants to install longer studs we recomend ARP part # 100-7708 (2.5" long) or 100-7713 (3.25" long) these "According to ARP) are direct replacements. Yes they are 12mm and i know it is a bit of a pain having 2 different lug nuts but hey.

[killer69]

insalling the afx spindle and i decided to upgrade to 1/2" wheel stud's. What stud should i use , press in or screw in ?
Anyone have a part #, i have done a search and come up empty handed.

use the ARP 12mm part # 100-7708 or 100-7713
ARP recomends thes as Replacement studs there will be no negligable differance in strength. all their studs have a tensil strength of 200,000 PSI

[Steve68]

on friday, my studs were supposed to pressed in, I will see when I get to work, but thats how we did it, as Blake described, but I went with the large studs,

Blake thanks for the info on the rotors enlargement.

[wayne70]

Thank's for the info. Blake. ARP#100-7708 are what i am going to use.

[Steve68]

I have mine installed, and it's very visable the area Blake is talking about, tonight calls for a rotor check, maybe I'll try to throw up a pic,