Wheel Stud Size?

[NovaCat2005]

I'm looking to purchase some press in wheel studs for hubs that I will be designing. The rims have a 4x100mm bolt pattern with 16mm through holes for the wheel studs. My question is what diameter wheel studs should I use? Thanks in advance for answering my question. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[NovaCat2005]

I'm looking to purchase some press in wheel studs for hubs that I will be designing. The rims have a 4x100mm bolt pattern with 16mm through holes for the wheel studs. My question is what diameter wheel studs should I use? Thanks in advance for answering my question. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[95M3Racer]

Talk to Dave, I told him what to do.

[rjwoods77]

Honda 250R atv front wheel studs are really nice quality units. Forged with rolled splines. Cost 5 bucks a piece but are perfect for baja and formula. They are 10 mm threads. Go ask your local atv shop.

[NovaCat2005]

thanks, for anyone else who would find this post useful here is the link I was given. This site has wheel studs that are equivalent to 15.875mm, and so they should fit nicely enough in a 16mm hole.

http://www.1speedway.com/WHEEL_STUDS.htm

[rjwoods77]

The judges would laugh at you for using 5/8 inch studs. Get something smaller.

[Denny Trimble]

Yeah, we use 7/16 and they're a little large, but they fit our OEM-modified hubs and our several sets of wheels. I'm thinking of drilling them out this year http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Frank]

(4) of 3/8 UNF @ 100mm PCD

get 'em from mini's at the wrecking yard

http://www.uq.edu.au/fsae/2004%20Photos/DSC00091.JPG

[bigfella]

Why do so many of us use huge wheel studs? Is it just the convenience of being able to get wheel nuts on the cheap? Running 1/2" UNF studs on a 300kg car that is designed to last a few years at best, when the same thing is run on a 1400kg car that is designed to last 15+ years, seems totally insane to me. I'm going to sit down tonight and work out the right size studs to use on these cars 'cos that's a pretty decent unsprung mass reduction right there.

There we go; bit of a no-sleep rant right there. See everyone at FSAEA in a week!

[NovaCat2005]

I did not elaborate as to why I asked my question. I'll go into some detail to the logic behind the question.

The connection of the hub and rim is a shear joint. And we all know about shear joints...

"The shear load is carried by friction between the members and ensured by the clamping action of the bolts or cap screws. Should the friction be insufficient, the shear load is carried by only two of the fasteners in the pattern. This occurs because of errors in hole size and placement preclude a uniform sharing of the shear load. The analysis problem involves identifying the two fasteners that represent the worst case."-Mechanical Engineering Design 7th Ed. (Shigley, Mischke, Budynas)

I did not know if the wheel studs should be designed to take shear "should the friction be insufficient"�. If the wheel studs were to take shear that would require a close fit between the hole and wheel stud. This would require a 16mm wheel stud to fit in a 16mm hole.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> The judges would laugh at you for using 5/8 inch studs. Get something smaller <HR></BLOCKQUOTE>

From this statement, thanks for being so frank http://fsae.com/groupee_common/emoticons/icon_razz.gif , I assume that the design of the wheel stud has to "ensure the clamping action"� to maintain the shear load via friction between the two members.

My second concern was the concentricity of the wheel and rim. Are the tapered lug nuts sufficient to locate the wheel on the hub?

[Denny Trimble]

Yes, tapered lug nuts will locate the wheel to the hub, and take drive/brake torques better.

[NovaCat2005]

Can you elaborate?
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>take drive/brake torques better. <HR></BLOCKQUOTE>

[rjwoods77]

The proper way to mount a rim to a hub is to have a centering ring or centering shoulder machined into the hub(male) with the reverse being machined into the rim(female). That takes a majority of the shear load off the studs. The studs then really are for clamping the 2 pieces together which is what bolted connections are for. It also locates the the rim to the hub which makes sure the wheel rotates true. Something a bolted connection will never do. You may not notice it but non-centered wheels dont roll true. There is still a rotational shear that is applied to the studs but it is much smaller than the overall forces trying to shear the male/female connection of the hub and rim. By using a tapered nut, there is can be clearance between the rim holes and the studs. That means the studs arent subjected to sheer loads at their root. There is actually some bending at the stud root but that is where the thicker base is. That thicker base usually has no thread on it until, we'll say about .125" past the rim face.

http://www.1speedway.com/WHEEL_STUDS.htm

The sheer force transmitted to the studs is put through the tapered or straight shank nuts which puts that much more material in the true shear zone of the stud. Hence it has alot more strength. Hence you can make the studs real small. All you really have to do is calculate acceptable bending moment on this thread free zone at the point of the stud where it just passes the rim. You can use any size nuts you want which is based on the shear strength you need. Mouthfull but do you understand?

http://emporium.markwilliams.com/prodlist.asp?catid=1003

Look around at his stuff. Read some of the descriptions.

[NovaCat2005]

Here is a nice contradiction http://fsae.com/groupee_common/emoticons/icon_frown.gif
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> Yes, tapered lug nuts will locate the wheel to the hub <HR></BLOCKQUOTE>
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> [A centering ring or centering shoulder] also locates the the rim to the hub which makes sure the wheel rotates true. Something a bolted connection will never do. You may not notice it but non-centered wheels dont roll true. <HR></BLOCKQUOTE>
These two statements are in contradiction unless by "bolted connection" Rob is excluding tapered lug nuts.

[Denny Trimble]

We used a "hubcentric" locating shoulder on the front hubs last year, which we made, but we used OEM hubs on the rear which had no such feature. They both seemed to work equally well, no problems to speak of.

As for taking drive/brake torques better, torqueing down 4 tapered lugs will make sure all four are in contact with the wheel, so the "two lugs taking the torque if friction is insufficient" case isn't applicable. Also, a larger surface area contact is beneficial for an aluminum wheel center.

[rjwoods77]

Tapered lugs will locate the wheel to the hub if they are machine exactly. So will machined holes but in reality they never really are because the holes have to be a tad bigger than the bolts. Either way you wont really notice. I was just describing the "proper" way.

1: If you dont have a hub centering ring then use tapered lug nuts.

2: If you do have a hub centering ring then you options of stud sizes free up somewhat because you can mix fastener sizes.

[rjwoods77]

1: Vacation

2: Designing

3: Beer

4: Strippers(cause girlfriend went home for holidays )

[NovaCat2005]

Thanks for answering all of my questions. Now begins the fun part... stress analysis, woohoo http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

[rjwoods77]

Save yourself the trouble. Go get those studs. Youll see.

[Nate Notta]

Going back to this conversation for a moment...

How much of a press is appropriate for the splines on the wheel studs?

Thanks a lot,

[rjwoods77]

To the root diameter usually does the trick. Really it depends on the material you are using.

[Nate Notta]

Well we'll press them into 6061 probably. I wanted to get a proper press because last year it was pretty hairy... it was a major interference fit and I am still surprised the hub didn't explode as we pressed them. So does anyone know the actual number of thou interference to shoot for, or the class of fit? I think going to the root diameter must be a pretty damn tight press too.
Any info is appreciated.

[Marshall Grice]

I called ARP and they said they like approx .005 press referenced to the od of the knurling.

[NovaCat2005]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Marshall Grice:
I called ARP and they said they like approx .005 press referenced to the od of the knurling. <HR></BLOCKQUOTE>
For an aluminum hub right? Just making sure http://fsae.com/groupee_common/emoticons/icon_wink.gif

[Marshall Grice]

They didn't specify steel or aluminum, but we use aluminum.