Lets speak about Knurl Diameter

[Gil]

Hi guys,

I have front rotors with 7/16 - 20 wheel studs with 0.5639 Knurl Diameter, but too short for my wheels.
I can't find longer studs with 0.5639.

Is it safe to use 0.560 inches Knurl Diameter instead ?

Maybe safer to use 0.570 or 0.580 than 0.560 right ?

Thanks a lot for your help
Gil

[Schwartz Performance]

I would say you can use .560.
That's only 3.9 thousandths .. 1.95 thou per side.
Many different stud companies are out there.. And their harness varies. Dorman tend to be much softer than ARP or Moroso for instance.

If you decide on the .570 instead, you can file them down slightly if they have a hard time fitting in the hole.

-Dale

[Gil]

Thank you Dale
I'll go Moroso 0.560 then
Gil

[Apogee]

It also depends on the knurl count. If the studs you're using have the same number of knurls as the studs you're replacing, then the knurls will coincide with the preexisting deformation of the hub/rotor, effectively reducing or even negating the interference fit. If the knurl count is different, then some will have more interference than others and you could be fine. In my experience, most course knurl studs require about .005" to .008" interference for best results in steel or cast iron...less and they're more prone to stripping out than they would be otherwise.

Tobin
KORE3

[Gil]

Thanks Tobin,
I don't know the Moroso chart for number of knurls for their studs
P/N I wanted should be 46160, found nowhere an Email address to ask them...
Gil

[Stumann]

I would seem to me that the friction of the knurl is only necessary while you are tightening the lug nut. Once the nut is tight, the knurl no longer affects things. It's basically just the "wrench" that is holding the bolt while you tighten the nut.

[TheJDMan]

I would seem to me that the friction of the knurl is only necessary while you are tightening the lug nut. Once the nut is tight, the knurl no longer affects things. It's basically just the "wrench" that is holding the bolt while you tighten the nut.

Exactly! I would also install 1/2" studs.

[iadr]

Sure but when a stud strips loose in the hub when you are trying to remove it(probably more a risk on salt-belt daily driver's but still) let us know! :)
Not something you want to chance!

[MonzaRacer]

If i had a choice I would switch to thread in wheel studs. Tap axle/hub, install screw in studs with red lock tite. This eliminates any issues, allows for better retention of studs. If holes are too loose I have helicoild axles ten tacked the studs in.
Besides I always have preferred 1/2 studs to smaller 7/15 or 12mm.
Heck if I ever find some Impala SS wheels for my 78 C10 I will possibly swap in factory 14 mm studs.

Oh yeah remember studs have an outer knurl diameter, the should hats knurled is minimum diameter hole you need.
See knurls push the metal into ridges so they lock in to the soft cast iron or axle.
Also remember axles run looser clearances than cast iron rotors/hubs.