FAQ: Extended Wheel Studs / Lugs

[anders8]

Want longer studs? You probably should learn everything in this thread.



L1: What we will call "length", from the base to the end of the usable threads.
L2: The thickness of the stud head.
L3: The length of the nose. For stock studs, this is zero, there is no nose. However, some other studs call their "length" L1 + L3, which is confusing, because part of their "length" is unusable as it has no threads.
L4: Distance from the base to the end of the knurling.
L5: Distance from the base to the start of the threads.

D1: This is the knurl diameter.
D2: Diameter of the top of the stud head.

Here's a table of data that I've come up with. I'm sure some of it needs to be modified, and there are missing spaces as well. I'd appreciate if folks with calipers and studs that I don't have could add information. PM me with it please.

Green means that I think this stud should work (but note that I'm not finished making these determinations... there are bunch on the table that might work)
Red means I think this stud won't work because of this measurement.
Bold means this is the stock stud
Gray means that this measurement came from an image (counting threads, coming up with a pixel/millimeter ratio, etcetera)




Some other little notes I'm still working on...

58mm Subaru extended wheel studs from TrakStore in the UK. ~2GBP each + shipping from UK

"Extra long group N" studs
http://www.tegsport.co.uk/showpartde...ype=Suspension


American Fastener Journal? (Vol.22/#3 May June 2005) titled "Wheel Bolts, Studs, and Nuts" by Guy Avellon.

Member Feedback on studs:

Originally Posted by austinpike about Kyo-ei KYO-SBN-AZ

The kyo-ei studs do not work.Thought they were close enough; they gripped at first but started to spin as I tightened them down.

Originally Posted by Storm about Dorman 610-404

I can say that in our case it has been working without any problems for 4+yrs of weekly wheel changes with a cordless impact and torquing to 85 ft/lbs. I've made this switch on a 98RS and a 96L-RS with the same results.

Anders: keep in mind everyone, my "won't work" criteria is based only on theory, which is why it's great to get feedback on particular stud.

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[anders8]

How thick a spacer will the stock length studs safely support?

Short answer: you can't safely use any spacer with the stock studs.

Long answer:

Well, that's pretty easy to determine. With your wheel on, put a lug nut on the recommended number of safe turns (8 for 12x1.25), and then count how many extra turns you get till the nut is all torqued down. Then multiply the number of extra turns by the thread pitch, 1.25mm.

For example, if you turn your lug nut 8 times, and then it turned an extra 4 times till it was snugged and torqued, you could safely use a (4 turns) x (1.25mm per turn) = 5mm spacer and still have 8 turns when it was installed.

So how what are the measurements on a stock stud and wheel? For my 1995L with stock alloys, I got an extra 0.66 turns, meaning I can safely use a spacer that's 0.825mm thick. Fortunately for me, those are both useless and non-existent.

I would enjoy getting measurements of number of extra turns from other vehicle/wheel combinations.

Please PM me (don't add to the thread) and I'll add them here:

Car / Wheel / number of total turns / number of extra turns
1995 Impreza / Stock Alloy / 8.66 / 0.66

What else does this mean for us? Since the stock studs essentially support zero extra space, when choosing new studs, the length will have to be that much longer than the stock. So with stock being 41.5mm length, if you want to use a 10mm spacer, you'll need lugs that are (41.5mm + 10mm - 0.825mm) = 60.675 minimum to still get the safe 8 turns of engagement. Since that last little piece doesn't really make much difference, the better rule of thumb would be (stock length + spacer thickness).

[anders8]

What is the proper knurl size?

The info I found on this was in the Dorman catalog, which said that the knurl should be 0.017" to 0.027" larger than the hole you're pressing the stud in to. So for us:

14mm hole (stock)
min knurl: 14.43mm
max Knurl: 14.68mm

if you drilled your hubs out to a 9/16 hole, then:

9/16" = 14.2875mm
min knurl:14.72mm
max knurl:14.97mm

So, that gives us a total range of 14.43mm to almost 15mm, with a little gap in between, if you are willing to consider drilling your hubs with a 9/16" bit. Of course, I'd recommend that you do this with a drill press.

I'd bet that studs at the larger end of the allowable range will need to be pressed in, and may not work with the "screw it in from the other side" method.

I found another reference in the Lefthander Chassis that a 43/64" drill bit was the proper size to use for a .690" knurl, and that is a difference of 0.018", consistent with the Dorman range.

[anders8]

"Upgrade/larger" wheel stud possibilities

M12x1.25 - that's not an upgrade, that's stock
M12x1.50 - no measurable difference in fatigue strength (footnote 1)
M14 won't fit through wheels
7/16x20 - that's a downgrade, only 11.11 mm diameter
1/2x20 - 12.7 mm in size, so it's slightly larger.

So, that leaves switching to a 1/2x20 as the only possible "upgrade".
Switching to 1.50 from 1.25 thread is ok, but won't gain you
anything except use of an apparently more common lug nut.


Footnote 1: Nuts, Bolts, and Fasteners, by Carroll Smith. If you haven't read this book, you should. The only possible exception is if you were doing something like aluminum lug nuts, but the point here is to upgrade strength, so we'll leave combining an strength upgrade with a strength downgrade out of it.

[anders8]

Wheel Stud Myths

There are some Nissan truck studs that work.

Nope. The Nissan studs are the correct thread and pitch, but the knurl is way too small. (I checked the stud for a Frontier, and another stud they had floating around back there. That was all they had. Neither worked. Until someone comes up with part numbers for these mystery studs, this is a myth.)

ARP makes some studs that we can use.

Nope.
1) ARP doesn't make anything in a 12x1.25
2) ARP's 12x1.50 are for a smaller hole
3) ARP's 1/2x20 has a shoulder that is too long and would interfere with the wheel.

(Until someone finds ARP studs with part numbers outside the 100-7701 to 100-7713 range, usable ARP studs are a myth.)

[anders8]

ARP Sources:
www.summitracing.com

Dorman Sources:
Advance Auto Parts
www.rbinc.com
www.dormanproducts.com

Nismo Sources:
www.performancenissanparts.com
www.courtesyparts.com

Moroso Sources:


Kyo-ei Sources
www.projectnissan.com

[anders8]

Source: TireRack.com

Hardware Size Torque in Ft/Lbs
10MM 45-55
12MM 70-80
14MM 85-90
7/16" 70-80
1/2" 75-85
9/16" 135-145

Size of Bolt or Stud Mininum Number of Turns
14x1.5mm 7.5
12x1.5mm 6.5
12x1.25mm 8
1/2" 8
9/16" 8

Of course, now everyone is going to say "Ah ha! See, the 1.25 thread is weaker, it needs more turns!"

Well, let's see:
8 turns times 1.25mm pitch = 10mm of engaged fastener
6.5 turns times 1.5mm pitch = 9.75mm of engaged fastener
The difference between the two is 1/5 the distance between two individual threads... I wouldn't say that's significant.

[anders8]

The Wheel and hub:
Hub thickness: 10.07 mm
Wheel thickness: 12.8 - 13.2 mm (stock 95L alloy rim)
Conical Depth: ~4 mm
Disc brake "hat" thickness: 6.8 mm

Conical depth being how far in from the outside of the wheel the cone of the nut goes before the 60 degree plane of the nut contacts the threads of the stud.

Thus, anythreads on the stud located at less than:
(hub thickness + wheel thickness + disc brake hat) - conical depth
can never be engaged by the lug nut.
For us, this distance should be considered 25.67 mm.

Of course, if you have a steel spare and want to be able to use it, this
distance will be smaller.

Diameter of hole in wheel for wheel studs to go through:
between 13.6 and 13.8 mm.

This means no upgrading to 14mm studs without modifying the wheels.
However, it does allow upgrading to 1/2x20 studs. ( 12.7 mm)

[anders8]

If you do some searching, you'll find more info on long studs. Most of the info is in rough agreement. Here's what you'll find:

Beliefs on Stock thread:
M12x1.25

Beliefs on Stock length:
41.5 mm
~42 mm

Knurl Diameter Beliefs:
14.28 mm
14.30 mm
14.43 mm

Beliefs on shoulder/knurl length:
14.5 mm

[anders8]

You'll see some studs listed with a "strength" of 190,000 psi. That doesn't really tell you much, since they don't say if it's ultimate or yield strength. Also, metal tends to get brittle as it gets harder...

For reference, here are the standards for ISO metric bolts

ISO A B
8.8 116,000 92,800
9.8 130,000 104,000
10.9 145,000 130,000
12.9 174,000 157,000

A: Minimum Ultimate Tensile Strength
B: Minimum Yield Tensile Strength

[anders8]

Stud replacement

Front studs can be done without hub removal.
Rears can't, say some. Depends on ABS sensor hole size, say others.

I'm going to get some pictures and add them to this post.

[anders8]

Spacer Kits

H&R kit
http://shop.store.yahoo.com/import-s...er-subaru.html

OMP also makes a kit
Someone have the source?

Recommendations:

For a 5mm spacer kit:
Dorman 98361.1 5016657
M12x1.25, gives you 4.40 + 0.8 = 5.2mm more than stock length, fits in stock hole, available at Advance for a couple bucks each, should be able to use your stock lug nuts (when the spacer is on, anyway).
Someone please try them and report.

For a 10mm spacer kit:

For a 15mm spacer kit:

[anders8]

If you have info on any of the following, please PM me:

-other studs you've used
-actual caliper measurements on some of the studs I've listed
-other manufacturers that have studs that work
-you've successfully used studs that I said wouldn't work

I'd like this thread to be as complete as possible. I haven't ordered any studs yet, as I haven't picked one. So please contribute!

Cheers,
Anders

[Fish]

you are a man possessed..
you stud.

[austinpike]

holy crap.

fwiw, the kyo-ei studs do not work.
http://www.projectnissan.com/shoppin...&idproduct=353

Thought they were close enough; they gripped at first but started to spin as I tightened them down. I still have 10 of them if someone wants them.

[austinpike]

don't know if you have seen these, possibly the ultimate Subaru studs...
http://www.motordrive.com/acatalog/Accessories.html

about 3/4 down the page.

[Storm]

I PMd you regarding the Dorman 610-404.

Jay Storm

[ratt_finkel]

FYI, I've been using a 3mm/ 1/8 inch spacer in the rear of my suby this entire autocross season with no propblems. I had a 1/4 ince or 6.75mm spacer that I test fitted and visually It just didn't seem like a good idea.

I have no clue on actuall threads left and technical specs, but take it for what it's worth.

[austinpike]

^^^ A bit off-topic, but regarding wheel spacers - I recently ordered a Weds SA-90 to test-fit on my STi. It came with a 3mm spacer and a hubcentric ring. I noticed that with the spacer installed, the hub ring no longer actually contacted the hub. Which would mean that all the vertical stresses are being absorbed by the lugs, and not the hub as intended.

(an aside, I am not even sure why they included the spacer, since the wheel cleared the brakes just fine without it.)

[anders8]

Originally Posted by ratt_finkel

FYI, I've been using a 3mm/ 1/8 inch spacer in the rear of my suby

Hi ratt_finkel.

Can you please count for me how many turns you get when you put on your lug nuts, and then pm me the year/wheel/spacer? Thanks.

Anders

[ratt_finkel]

Originally Posted by anders8

Hi ratt_finkel.

Can you please count for me how many turns you get when you put on your lug nuts, and then pm me the year/wheel/spacer? Thanks.

Anders

I'd be happy to. I'll try to have it done by the end of the week.

[LyveWRX]

Anders- can you link to that AFJ article I sent you?

[ratt_finkel]

I apologize for taking so long.

After further review. I found with the spacer on that about 6-7 threads lay exposed. Roughly 5 turns to hand tighten and another .5 turn for torquing.

[ratt_finkel]

Update bump.

[adhowe70]

Anecdotal evidence from elsewhere on this site regarding Nismo studs:

http://forums.nasioc.com/forums/show...ng+wheel+studs