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Wheel studs for Moser axles?

16K views 66 replies 15 participants last post by  SSQATCH 
#1 ·
I was just wondering of those that have Moser axles what wheel studs did you go with?
I saw on Summit for Moser axles for my '96 SS it tries to recommend either 1.5 or 2.5in length press-in studs by Moser any benefit to going with the longer studs or would that just make it so I couldn't get my center covers on anymore?
 
#2 ·
If you plan to race, then you'll want extra length so that it extends beyond the face of the nut. I have 2 1/8" press in studs that extend about 1/4" or so and easily fit under the SS wheel cap.
 
#4 ·
If you plan to race, then you'll want extra length so that it extends beyond the face of the nut.....
The stockers DON'T extend beyond the face of the nut :confused: ?

I'm pretty sure I still have stock studs and mine do extend beyond the lug nut.

KW
 
#3 ·
I use ARP, which come in 2.5",and 3.5". I was worried about the same thing so I went with the 2.5". There is plenty of room under the caps,plus I can use spacers if needed. I probably could have gotten the 3.5", there is more room in there than you think.
 
#6 ·
Gotcha and yea 1Slow96 you read my mind I don't picture that much room under the caps but makes sense so with that in mind any benefit going with 2.5" screw-in type studs or press in do the job just fine?
Also if I eventually plan to change to a bit larger rims 19 or 20" all-around with the back in 10" or maybe 10.5" width (whatever will fit without having to notch the frame) does that play into what length studs I might be better off with or no?
 
#9 ·
I use the ARP 2.5", on my Moser axles. At the time I bought them, they were the longest ARP made. They weren't technically legal, with my Weld Draglites, too short, but with the Holeshot Holestars, I have plenty of stud:D exposed on my lug shanks.

The stock center caps fit fine, when I have the stock wheels on, which is not very often.cwm7
 
#10 ·
This comment is not a knock on Moser as they are in my back yard and those of you that know me better than others know my connections with them. They are a great company!!!

With that said the studs you get from Moser are made by ARP for Moser. BUT they are not the high grade material you get buying the best studs you can get from ARP. I sheared the drivers side studs off a few years back at one of the Hot Rod Pump Gas events. Thats when I learned what I know now. I have the best 12mm studs I can buy and it's still bending them, they just are not shearing off.

For most you don't need ARP's best but why not build it so it will never break and even the best press in studs in 12mm are not much money in the big picture.

More tips for thoses that didn't know. I didn't know at one time.
 
#11 ·
I have moser axles. I went with 1/2 inch 3 inch long SCREW in studs,

all it takes is one time for the press in stud knurl to fail to make you start praying to god.
 
#12 ·
Jeff, I'm curious to understand why it would not be a positive move to go to a larger wheel stud or some sort of drive lug setup in your case, considering the amount of power and vehicle weight involved in your situation.

I do understand there may be an interference issue using larger studs with the park brake shoe, as well as maintaining the ability to bolt on the OE (SS) wheels. It is possible to use 14mm wheel studs and still mount the SS wheels, I am pretty sure.

If you've bent wheel studs, that's enough to convince me of the need to use larger studs.

Just curious--what are you torquing the wheel studs to when you have the race setup (slicks) installed?
 
#15 ·
....... It is possible to use 14mm wheel studs and still mount the SS wheels, I am pretty sure....
That is correct. I suggested that to Jeff a while back; I thought he was going that way.
I happened to know it works because my SS wheels bolt right up to my '98 1/2 ton pickup which has 14mm studs.
 
#13 ·
I agree. 12mm studs seems like too big a risk just to say I did it with what it had from the factory. There's not much room on the edge, be safe out there. Heck I went from 1/2" to 5/8". Don't you want to add weight if you can?

 
#16 ·
The funny thing about that statement on adding weight is the cars weighs more than it ever has and it keeps going faster. It's not suppose to work that way and I know it's time to move to 5/8 or 14mm. I just hate to move away from the stock stuff or sizes because thats what this car is all about.

So Pat, Bill and Glen, you're all right on what I should do. And if I upgrade it will be the 14mm truck studs so the wheels I have will work because of the tapered seats
 
#17 · (Edited)
I suggest this source....if you stay with press-in studs. These studs have a relatively small head, for good clearance on the back of the axle shaft flange, a reasonable knurl length and diameter (over stock 12mm), and a wide range of available overall lengths--and the price is fairly reasonable.

Don't use the lug nuts listed above, as they're ball-seat design for VW. Use this one (or equivalent) instead: 611-110

For screw-in studs, I don't have a suggestion, since they generally stop at 1/2"--not really worth the effort to change to from 12mm vs going to 14mm. Plus, they'll always need more room on the back of the axle flange.
 
#20 · (Edited)
from ARP

From: "Zac Kimball" <zack@arpfasteners.com>
To: inov8r@windstream.net
Subject: RE: Website Submitted Question from Bill Harper
Date: Thursday, February 23, 2012 3:51 PM

Bill,
With our wheel studs we always recommend to use the vehicle manufacturers torque recommendations.
Regards,
Zac Kimball
Automotive Racing Products
18053392200ext. 206

Submitted: 2/22/2012 @ 23:45:42 Actually this is a wheel stud torque question. Factory wheel fastener procedure calls for "dry" fastener assembly--ie. no lube is to be used. We use ARP 100-7708 "alot", and I wanted to know what ARP's position is on this--either to follow OE procedure, or does ARP have a different recommendation? Thanks in advance for your response! Website Question
 
#23 · (Edited)
Whether a machinist does it locally, or something is worked out with Moser to supply the axles with the flange holes made to order (for the larger studs)--the stock replacement axles will not work without modification.

(quoted from catalog page linked)
Must Drill To 1/2” & Ream Hubs To 9/16” With (.562”) Reamer


Bill, the 100 LB torq is the correct amount for a 220,000 psi stud. This is using ARP moly and that spec came directly from them.

Still agree the 14mm is a better way to go. But to save the cost 5/8 would be what most would do as it's nothing special to deal with.
Jeff, the factory doesn't use lube on wheel studs for a reason. My take on ARP's reply (to my inquiry) is that they concur--whether the actual torque value in this case was correct or not wasn't what I was questioning--the GM M12x1.5 wheel stud torque value has been 100 lb/ft "forever".

Given the information from GM & ARP, I'm not sure what is the rationale to continue using moly lube on the wheel fasteners.

At this point I would want to measure the length of a new ARP stud (not sure of the PN you're using) and one installed on your car to see if they're the same length (or not)....ie. IS there a possibility that the studs ARE stretched--and, if so, why?

Not sure what the comment "save the cost" implies--no matter what size larger wheel stud is used, the flange holes will have to be enlarged, and drilling to 1/2" then reaming to 0.562" is a standard machine shop operation, whether the stud is 14mm or if other sizing increases are needed for 9/16" or 5/8"--knurl dimensions are not standardized.

An example of that which I've seen often with B-body is that many replacement front rotors (from both domestic and offshore sources) do not always use the same stud as the OE/production rotors used. When a stud breaks or the need to install longer studs comes around, the available options get more complicated, since it's not simply a matter of using the correct part listed for production rotors, and/or the appropriate ARP stud pack (100-7708, for example) or other known "direct-fit" longer stud options (Dorman 610-323, GM 22551491) that have been mentioned here on Forum in numerous other threads.

My point is that the head on the Sway-A-Way 14mm studs is not typically going to cause any clearance issues on the back side of the axle shaft flange in an otherwise 100% stock installation. I'm not sure the other larger studs mentioned would afford that same clearance while maintaining a functional park brake system, since some have larger OD and/or thicker heads that very easily could interfere with the park brake shoe(s).

My additional thoughts on this:

1. The ARP catalog wheel stud page shows knurl diameters that range significantly, depending on application. The stud kits listed were created for direct fit to replace OE studs, in most cases. A non-standard parts mix--which up-sizing to a larger stud will be typical--calls for re-sizing the holes in some way.

2. While I'm not "knocking" ARP for any lack of information in this area, Sway-A-Way at least has provided a specific recommended process for accomplishing this, whether it's REALLY important for the holes to be reamed the additional 0.062, or if the same desired interference fit could be achieved by use of a fractional-size drill that is close to but smaller than 0.562" is not for me to say--a well-equipped machine shop would typically have the proper tools to do this, but I do know that individual drill bits in "off" sizes get expensive, especially as size goes up.

3. For a specialized application, such as a 4500# "streetable" vehicle capable of running sub-9 second times in the 1/4 at 150+, having ANY issues with drive-axle wheel studs is to be avoided, and finding studs bent suggests that something is not as it should be--whether fastener size, or a torque load issue, or something else installation-related. Hearing of a shearing problem in the past, no one wants to see a car have that happen, whether at the starting line or somewhere down-track.

4. In vehicles that are not serviced on a frequent basis, and used in harsh environments on a year-round basis, I could understand using a little bit of lube of some sort, especially older vehicles. For a car that is constantly being massaged, wheels-on, wheels-off, and not typically driven in inclement weather, lube on the wheel fasteners is not needed--as there is no chance for corrosion to become a problem that could affect proper torque readings or attack and weaken the parts. Many wheel studs and nuts now in OE/production use have zinc or other coatings that suppress corrosion and provide some degree of lubricity without adding anything else.
 
#24 ·
My 5/8" studs (supplied by Moser with the axles) have a jam nut on the back of the axle flange. I don't have parking brakes on that car.
 
#25 ·
Ok.. somebody find me 1/2"-20 lug Bolts.. i have 1/2" studs. Would be nice to find a way to be able swap between bolt patterns on the fly.. was thinking of cutting the head off my screw in studs and installing them with a jam nut or castle nut...

Lug bolts would be a better option..
 
#33 ·
Thanks Bill, I looked through several catalogs, including the Dorman stuff. Seems that it's not common to make a double ended stud with the same thread pitch on both ends, and an unthreaded portion to bottom out to.. every 1/2" stud I have found seems to have a 1/2-13 thread on the other side. I know i have seen some OEM M10/1.5mm double ended studs. Exhaust manifold- y-pipe studs come to mind, and are M10 on both sides.

what would be even cooler is a 1/2-20 side with a M12x1.5 side... but I have not found that yet... even better still is the dog point being an 8mm hex to make installing easier.. that would be the trifecta... :D

Best I have found are the Moser straight 1/2-20 studs. I'll probably end up ordering them with some Jam nuts and making a dog point on one side if I feel fancy..
 
#28 ·
Bill, let me check with ARP as it's been years ago I had that conversation with them. The reason to use molly should be the same because a stud or a bolt are all the same when it comes to torque. The moly keeps the thread from building heat and resistance and those two things create false torque. Same reason we don't torque rod bolts but use a stretch gauge.

I don't see the difference with a wheel stud over any other stud or bolt you would use. The moly lets you use less/low torque and is more correct than a dry torque.

I'm not saying I'm right and will check this week but had no logical reason to question using moly with a lower torque value on whell studs.
 
#29 · (Edited)
From classic "bolted joint" design theory to every practical application I've ever come across in my life, your approach, Jeff, of using moly on the studs with a lesser torque value rather than no lube and higher torque is the correct approach. You'll always get the most preload versus stress in the studs that way.
I'm sure you already do, but the conical bearing surface of the nut should be coated too.
 
#31 ·
Bill, I'll hazard a guess that the reason the OEM doesn't specify lube is that they know it's just not gonna happen in many cases. And for 99.9% of the users, that's perfectly fine.
In Jeff's application, I'd be just as concerned about torsional shear put into studs without lube on the threads as I would about stretch.
 
#32 ·
Jeff needs a higher friction surface between the face of the wheel and the brake rotor. That, or bigger studs. Studs bend when the wheel slips on the mating face. The two ways to reduce slippage is increase clamp load (larger diameter studs torqued at the appropriate torque and therefore higher clamp load), or a higher coefficient of friction at the wheel/rotor interface. I have seen a washer impregnated with silica on crank hubs that are very effective at doing this. A two side sheet of sand paper would do this as well... I wonder if there is a "friction paper" type product out there.

Torquing is to get the proper stretch. If the stud calls for lube, then the proper stretch occurs at the torque spec with reduced friction on the threads... which mean a higher clamp load.

OEM torques are based on the first torque, the finish of the bolt and the coatings on the fasteners (many of the OEM fasteners have a dry coating with consistent lubricating properties). With the slippery nature of Moly lube, the mess it can make in a factory environment, and the slip hazard it creates, you can see why it's avoided as much as possible in the OEM realm.

If you want a more repeatable clamp load, Torque to Yield (aka TTY) fasteners offer the most consistent, non Moly-lubed alternative.

Pull out your textbooks and look at stress/strain diagrams, you'll see how the yield region of the curve has advantages. Naturally, I am not suggesting that you use a TTY arrangement for wheels studs... just that OEM's have good reasons for the way they do things..
 
#34 ·
Michael, ARP can make whatever you want--just ask.

1/2-20 studs - a few sources for 3"--cut off the heads!

http://markwilliams.com/detail.aspx?ID=523

http://video.arp-bolts.com/catalog/ARPCatalog.pdf
Pg 68
PN 100-7704
3.47" under-head length

http://www.summitracing.com/parts/ARP-100-7704/

Moser all-thread - 3"
http://www.moserengineering.com/other-parts/studs/1-2-20-x-3-all-thread.html

FWIW, the Sway-A-Way 14mm studs are available up to 100mm--usable thread length is about 3.25" after the head & knurl/shank portion is cut off.

1/2-20 thin lock nut - to install on back side of axle flange (will probably NOT clear park brake shoe)
http://www.mcmaster.com/#cadinlnord/94830a550/=gfk6ar

M14x1.5 lock nut (too thick?)
http://www.mcmaster.com/#cadinlnord/90576a147/=gfk802
 
#35 ·
Well I think I have some answers but still not positive. There is a coating that is on the wheel studs that is not on the other bolts/studs you would buy. So Bill, you are correct that you should not need moly as the extra coating provides a moly type coating thats in a dry form.

The torque rate is what I'm not sure I'm geting the right answer. The first answer was 80 for a 12mm then I questioned what I had been told some years ago and the answer changed back to 100. As you all know when you use moly or anything like it your torque amount goes down so a stub/bolt with moly or a coating on it torqued at 100 is about the same as it being dry torqued at about 120.

So going down to 80 is going to make my problem worse if not lead to shear. The 12 mm studs have been torqued 100 times over the last 5 years so I'm staying with the 100 torque to create the clamping force.

For people on here that have not been involved in race for years you need to know it's not that odd to get different answers to the same question. I use to take people to the IRP show here in Indy each year and go to each piston company, JE or Venolia or whoever and ask them the same question. Which is a better setup, a longer rod length with a higher piston pin location or a shorter rod with a lower piston pin location. I would get conflicting answers everytime. It was my way to teach people, that had not been around racing, that even companies that make the same engine part can't agree on what the right answer is for the same race engine. The leason was you have to listen to the reasons from each of them and make your mind up who was right. You can agree a shorter rod creates more side load but moving the pin up upsets the piston so everyone argues their point on this topic.

The one engineer that I have talked to in the past for special bolts was not there. I will try to get him to answer these same questions and see if the answers change again.
 
#36 ·
I'm not quite sure I get the value of the continued discussion. Even if you continue to use 12mm studs, for whatever reason, I consider the studs on your car now compromised. What CAUSED the bending can be argued, but for the application, don't keep using damaged parts.

I do wonder about the wheel aftermarket, which seems, nearly always, to quote lower torque values for (their) wheels than what OE specs are. Whether that is a lowest common denominator situation, with wheels that fit a multitude of applications with studs as small as 7/16", which DO specify a lower torque value than 12mm, or whether it's concern about the quality of their wheels when torqued beyond a certain value, and 100 lb/ft was not considered "safe" for their wheels. Could be mere supposition on my part.....

I do think Michael's comments are spot-on, and do a good job of taking what I'm thinking and TRYING to say and putting it through the engineer's mind and making the language match the reality of what is going on.

Regarding lube or no lube, my only concern is the need to have the studs properly tensioned to clamp everything as designed, which would preclude the possibility of the studs bending....personally, if a lube WAS to be used, I would go with a spray moly-lube "one time" and leave it at that....that is to say, continual re-application of lube would be excessive in "my world".
 
#41 ·
I'm not quite sure I get the value of the continued discussion. Even if you continue to use 12mm studs, for whatever reason, I consider the studs on your car now compromised. What CAUSED the bending can be argued, but for the application, don't keep using damaged parts.

I do wonder about the wheel aftermarket, which seems, nearly always, to quote lower torque values for (their) wheels than what OE specs are. Whether that is a lowest common denominator situation, with wheels that fit a multitude of applications with studs as small as 7/16", which DO specify a lower torque value than 12mm, or whether it's concern about the quality of their wheels when torqued beyond a certain value, and 100 lb/ft was not considered "safe" for their wheels. Could be mere supposition on my part.....

I do think Michael's comments are spot-on, and do a good job of taking what I'm thinking and TRYING to say and putting it through the engineer's mind and making the language match the reality of what is going on.

Bill, the reason I'm still not ready to change the studs is they have been used for years and never failed and I have an idea in my head that may have caused them to bend. The hardest thing on any drivetrain parts is doing a burn out and letting the car hook coming out of the box. I can think of the worst time that happened and it was just two years ago at the LTX shootout when I had the car in third for the burn out, by accident, and let the car roll out. I thought it took the drivetrain out when it hooked with the boom that came from under the car, hard enough to kill the engine. That could have been the cause and it's something I never do and have never done again.

I never watched the studs in the past because I had no reason to. Now I know things are not what I thought and will be checking the new studs to see if they move at all. If they do then ,as much as I hate to, I have to go with something different. For my desires the 14mm is the direction I will go. But I see no issue running the new 12mm studs at this point and watching them. If they were a real danger I would have sheared the studs and lost a wheel years ago. They may be just fine as long as you don't do stupid stuff with the car.

I always enjoy your insight so never think I don't hear what you are saying.

And Stratman, either of those ARP parts numbers will work flawlessly for you.
 
#38 ·
I know I'm late to the game on this thread, but I had Moser install the studs prior to shipment (12MM), so I didn't have a thing to worry about when I did the axle R&R (For 9C1 rear).
 
#40 ·
Wheel studs for Moser axles

The part number Bill listed (100-7708) is for 2.5" studs. ARP also offers 3.25" length studs (100-7713) which will fit under the stock caps.
 
#42 ·
Some interesting reading if you are so inclined. I came across this website a while ago when trying to explain Torque To Yield fasteners without using any internal corporate documents. There a few plots of friction torque in there to explain why alternative methods (TTY, bolt stretch etc) have been developed and why they are useful.

http://www.boltscience.com/pages/tighten.htm
 
#43 ·
Good reading and points out what most of us know about torque and bolts. If dry torque is used the actual torque rate can change based on the condition of the bolt/nut and the part the bolt head/nut is in contact with. If you can't tell I really don't trust dry torque on a part that really matters.

As much as the bolt/stud grade or quality you use is important to the seccuss or failure so is the torque method. The way to make this not count as much is to "over kill" the problem and use a bolt able to handle the load/force greater than the need. This way if the torque/load is not correct the fastener is strong enough not to fail because of this.

I'm sure this is way to much detail for most but a few of us enjoy the better understanding of whats really going on.
 
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