Question about installing wheel studs

RJ80

RJ80

True Classic
I'm replacing my lug bolts with studs from MWB. My plan is to torque the studs into the hubs at factory lug bolt spec and use red Loctite to make sure they don't come out. Anything I should be aware of or do differently?
 
Probably obvious, but complete one wheel install with no torquing or loctite-ing to be sure you are happy with the results. Then go ahead with your plan.

I never loctited my studs, but I have only had one of them come loose. fortunately it was while I was trying to remove the wheel, not when I was driving down the road. :)
 
Some studs can be threaded right threw the hub because the threads are longer than needed. If put in too far they will hit stuff behind the hubs. So you cannot torque them and must use loctite. I don't know if the ones from MWB have a shoulder to stop them from going in too far. Check to see if they stick out the back. But if they don't then you can torque against that shoulder.
 
JimD said:
Probably obvious, but complete one wheel install with no torquing or loctite-ing to be sure you are happy with the results. Then go ahead with your plan.
Click to expand...

Yep, will definitely do a trial run before torquing and using thread locker. Thanks for that!

Dr.Jeff said:
Some studs can be threaded right threw the hub because the threads are longer than needed. If put in too far they will hit stuff behind the hubs. So you cannot torque them and must use loctite. I don't know if the ones from MWB have a shoulder to stop them from going in too far. Check to see if they stick out the back. But if they don't then you can torque against that shoulder.
Click to expand...

I know this to be true because my car originally came with studs where this had happened, hence my reversion to properly fitting lug bolts. The ends were fouling on the hub body. The MWB ones do have a shoulder, but I'll be sure to check clearance when I thread them in. Excellent point, thanks.
 
I, too, am switching to lug studs; I plan to loctite the stud threads and run them in until they won't run in any more, with just a little torque to make sure they stay in place and depend on the chemical reaction to lock them in place (after a short run and retorquing the wheels) as this will happen with the wheel change.
 
Yes, I wouldn‘t torque them with wheel nut torque.
You are likely to damage the threads in the hub.
 
There is no "shoulder" as such on these, just a threaded and a non-threaded portion like any other ordinary stud. I would agree that you could possibly damage threads in the hub with too much torque. I installed mine (MWB) using blue loctite and a 3/8" allen key bit in a ratchet wrench until they felt reasonably tight but not over-tightened. I didn't like the idea of ever having to remove them with red loctite on them which would probably mean having to heat the flange on the hub. I guess if you figure your studs are going to be in there forever, red loctite will work. I think blue is plenty strong enough and you could always test it.

Worst thing that could happen is the stud may come out one day when you go to remove a lug nut. No damage done. Then you'll know you need some loctite and/or to tighten it more. Tightening all the lug nuts with a torque wrench might be a good idea. When I got my studs from MWB, the set came with one spare.

'Course, if you keep your car long enough, they'll simply rust in place, lol.

watermark.axd
 
Here's the word from Matt @ MWB, appreciate him getting back to me so quickly: "Studs typically do not get torqued into place. They are simply threaded in so that they are fully seated and “snug”. It’s the nut that goes onto the stud that binds the entire thing together and applies equal thread binding force to both ends of the stud. For lug studs you will want to apply some Loctite blue or Red (preferred) before you thread them into the hub, since you will have multiple nut on/off events with changing wheels."

Thanks for everyone's input!
 
On my 1980 car, I cut threaded rods to make studs. This was before studs became more popular and available, probably 25 years ago. I spot welded them behind the hubs. On my 1987 car, I bought some long studs from Serpent or MWB, I can't remember around 10 years ago. I just installed them handtight and torqued the open nuts. Some time, the stud came with the nut when I changed wheels. I just screw the stud back in. If there were some restrain, I used tap and die on the studs and or nuts, whichever needed. Never lost a stud or a nut in 10 years.

I don't have to tell, but I never lost a stud on my 1980 car either (with the welded studs... ) :D
 
Just lost a wheel on my spider. I have mwb 56mm studs on the way. I don't remember where I got the current ones from. But they stripped big time
20230730_122025.jpg


There was less than 5 miles on these driving. The current thought is I over torqued the nuts (100 lbs) which weakened the threads, then they came loose and BANG! Off came the wheel. Was glad it was 1/4 from my house under 25 mph. So my X also lost a wheel way back but that one I know was my mistake by not checking the nuts before I flat towed. Seeing the other wheels were not tight I am betting that was the issue. So whe. We put new studs back In (serpent auto) we tack welded each one. Now reading, I probably shouldn't have done that as apparently that makes them more bittle by ruining the heat treat.
My current thought is to use loctite red on the new ones coming in. Then torque it properly. The lug nuts I am getting say 80 lbs. I heard fiat says 65 for the wheel bolts. So what do I torque it to?
Lastly, how does one as they get older loose the fear of it happening again? Heck in my 20s I would have jb welded the wheel on and drove it as fast as I could down a winding road with no worries.

Odie
 
Odie, I have a couple of thoughts on your situation.

First, the studs that failed. I can't quite tell from the pic, did they have a "solid" section (see pic below) dividing the portion that goes into the hub vs the portion that goes through the wheel / nut? It doesn't look like they did; if not then that makes them very difficult to keep tightened into the hubs. That solid section is used to 'torque' the stud against the hub. Otherwise there's nothing to keep them in place. Also the quality of those studs may be questionable. Wheel studs should be hardened, which would prevent the threads from stripping. By the way, that's why I don't recommend using all-thread rod for this.

Second, securing new studs into the hubs. I definitely would not weld them in place. And I also would not use red loctite if you ever intend to remove them again. Blue is the most that is required....particularly for proper studs with the solid division in the middle. Some studs also have a hex recess to use a allen wrench to torque them into the hub (see pic below). Otherwise you can double nut them to tighten them into the hubs.

Third, the torque spec. It's possible the 100 lb load you used was too much, depending on the quality of the stud. I think I'd stick with the Fiat spec.

75f4b.jpg
 
autox19 said:
Just lost a wheel on my spider. I have mwb 56mm studs on the way. I don't remember where I got the current ones from. But they stripped big time
View attachment 75907

There was less than 5 miles on these driving. The current thought is I over torqued the nuts (100 lbs) which weakened the threads, then they came loose and BANG! Off came the wheel. Was glad it was 1/4 from my house under 25 mph. So my X also lost a wheel way back but that one I know was my mistake by not checking the nuts before I flat towed. Seeing the other wheels were not tight I am betting that was the issue. So whe. We put new studs back In (serpent auto) we tack welded each one. Now reading, I probably shouldn't have done that as apparently that makes them more bittle by ruining the heat treat.
My current thought is to use loctite red on the new ones coming in. Then torque it properly. The lug nuts I am getting say 80 lbs. I heard fiat says 65 for the wheel bolts. So what do I torque it to?
Lastly, how does one as they get older loose the fear of it happening again? Heck in my 20s I would have jb welded the wheel on and drove it as fast as I could down a winding road with no worries.

Odie
Click to expand...
Odie,
Looking at your studs and learning you only did 5 miles on them I wonder if you got 12x1.25 nuts. It's looking like you cross threads the studs with 12x1.5 nuts. Don't ask me how I know.
 
The wheel stud torque spec for 1300s is 50.6 ft-lbs and the spec for 1500s is 64 ft-lbs. Don't know why they are different but both are much less than 100 ft-lbs.
 
During street driving the hub temperature probably doesn’t exceed 400 deg F. Track use temps may get significantly higher depending on brake cooling arrangements and hub/rotor thermal interface conductivity. Red Loctite starts to let go at 500 deg F.
 
Last edited:
You should check the threads on your hub as well. Unfortunately the way the studs look, I wouldn't be surprised if the hub threads looked the same. You might need a new hub, or at least to repair the threads.
 
Odie,
all newer cars I know (Mercedes, BMW) use less that 100 ft-lbs of torque and they have beefier hardware.
So I guess you have low quality studs paired with way too much torque.
Also make sure the thread pitch is correct.

I agree that you probably damaged the threads in your hubs.
You could carefully inspect the threads, use a tap on them and try test fitting a new stud to feel how loose it fits.
But since you already mentioned being scared of the situation, I would err on the side of caution.
 
Studs appears to have a small shoulder in the middle, not as prominent as the ones in the picture. and will try later to see if they screw all the way through or if there is a stop. they have the allen head on them as well. then again, it is mute with the new ones I know are right coming in.
threads are/where 1.25 I validated against the other ones. Used a Tap to clean the hubs. no hard turning and very little residue form the studs. which I expected as I did have 2 older studs in there to get the car home. Studs got delayed a day so I wont be able to test fit the new ones until tomorrow and want to use those to validate rather than one of the older ones I have so I know I am using exactly what I am going to be driving with.
looks like I might be rebuilding the rear end if they are messed up. :(

Odie
 
Ulix said:
Yes, I wouldn‘t torque them with wheel nut torque.
You are likely to damage the threads in the hub.
Click to expand...
^^^ This.

The torque spec is intended to clamp the wheel to the hub with the load path through hte threads of the stud and the taper of the lug seat on the wheel. That is NOT how the load path works when torquing the studs.

Typically, the stud has threads cut only deep enough to engage the hub and then a gap before the threads for the lug nut begin. Torquing to spec mean the torque is applied directly to the threads where it meets the unthreaded band on the stud. This will damage the threads at the point of engagement and the studs will be damaged if you ever try to remove them.

There may be a torqque spec for the studs themselves. If not, there is no need to torque them beyond snug and use Loctite.


I always made studs using grade 8 all-thread, cut to length. Installed using only Loctite Red to secure them. Never had an issue.
 
autox19 said:
Just lost a wheel on my spider. I have mwb 56mm studs on the way. I don't remember where I got the current ones from. But they stripped big time


There was less than 5 miles on these driving. The current thought is I over torqued the nuts (100 lbs) which weakened the threads, then they came loose and BANG! Off came the wheel. Was glad it was 1/4 from my house under 25 mph. So my X also lost a wheel way back but that one I know was my mistake by not checking the nuts before I flat towed. Seeing the other wheels were not tight I am betting that was the issue. So whe. We put new studs back In (serpent auto) we tack welded each one. Now reading, I probably shouldn't have done that as apparently that makes them more bittle by ruining the heat treat.
My current thought is to use loctite red on the new ones coming in. Then torque it properly. The lug nuts I am getting say 80 lbs. I heard fiat says 65 for the wheel bolts. So what do I torque it to?
Click to expand...

autox19 said:
Lastly, how does one as they get older loose the fear of it happening again? Heck in my 20s I would have jb welded the wheel on and drove it as fast as I could down a winding road with no worries.

Odie
Click to expand...
Where did the idea of torque the nuts to 100ft/lb come from?

~Majority of threaded fastener failures occur due to over-torque during installation.

Fiat wheel cap screws/bolts are M12 x 1.25 thread and usually grade 8.8, this means a torque spec of 60 to 65 ft/lb dry as delivered, not oiled or lubed. If the cap screw/bolt is oiled or lubed, the torque spec is lower by about 20-30%..

M12 threaded fastener torqued to nee 100ft/lb dry will develop about 14,000 pounds of clamp load which is well above the specified ratings for a grade 8.8 M12 threaded fastener.. or strip-rip out assured.

Post threaded fastener rip-tear out, know the internal threads in the hub are wrecked and they will NOT "clean up" by running a tap into the once threaded hole. The proper fix is to remove the destroy hub, take it to a machinist, have them locate, drill, tap a new set of bolt circle holes in the hub ... or replace the hub with a know good hub.

As for installing wheel studs in place of the OEM cap screws/bolts, know the OEM thread fit is for a screw/bolt to be threaded in and out of the hub's internal threads. This means a tight specified thread fit for clearance (folks that have never made threads on a lathe or used precision threading tools have no idea of the precision/accuracy involved (typically 0.001" or 0.03mm range) with specified and proper thread fit.
Industry practice for proper threaded stud installation means the internally threaded hole is very slightly under-sized and the external threaded stud slightly over-sized producing significant friction when the thread parts are assembled. Majority of wheel studs as OEM are pressed in to a non-threaded hole with threaded studs that have a cap/head and serrations on the area under the cap/head. The stud's serrations compress producing what is essentially a friction fit to hold the stud in place..

To properly convert hubs designed for cap screws/bolts, the threaded end of the conversion stud is installed into a clean (use brake cleaner Q-tip/clean brush), ascertain the internal threads in the hub are GOOD. Repeat this cleaning procedure on the threads of the conversion wheel stud.
Apply red Loctite (# 271) on the conversion stud threads, install the conversion stud by hand.. if the stud does not easily thread in by hand, there is a problem. Stop and figure out why.. torque the conversion stud to NOT more than 4 ft/lb or 48 in/lb...

Loctite is an anaerobic adhesive, it sets once air is essentially removed, the goal is to snug up the threaded parts just enough to produce a non-air seal to allow the Loctite to set. Once the Loctite has set, it will NOT come out easily. To remove, apply heat to about 400-500 degrees F to break the bond.

Once the conversion studs are installed, lug nuts Must be torqued to no more than spec of 60-70ft/lb dry or about 20-30% less if oiled or lubed. Exceeding this on grade 8.8 threaded fasteners will greatly increase the risk of threaded fastener failure or.. the wheel comes off when least expected.

As for the wheel to hub joint, hub piloted wheels are more important than most understand. The hub centric piloting locates the wheel to the hub, the threaded fasteners apply tension to hold the wheel to the hub.... and the entire joint like any other joint is flexi.. this means metal that appears to be "solid" moves like rubber.. or why it is essential the wheel to hub is located by the hub to wheel center fit with the threaded fasteners clamping it all together as the whole assembly moves and flexes within design margins under load.

BTW, JB "weld" is epoxy... it is a glue-adhesive. The "weld" is a marketing moniker... specifically designed and intended to lure-bait potential users in need.


Bernice
 
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