Longer Wheel Studs on Front Disc Brakes (1 Viewer)

[stringtwelve]

I have been doing some research on longer wheel studs for a front disc brake setup. Unless I've just missed the right thread, there is no stud in current production that will work. My goal is to use 1/4" spacers with the American Racing Mojave 17x8 wheel. I've been unable to find any kind of aftermarket stud that has the same shoulder and knurling as the stock Toyota stud without changing over to a SAE style stud.

I had ordered the ARP part #100-7715 without considering the difference in neck styles and found that they do not seat and simply rattle in hole. From what I understand, these work fine in the rear drum brakes (haven't got there yet), but will not seat in the front discs.

My options at this point are:

Stick with steel wheels. (Give up!)

Change out to an SAE stud format. (Two sets of lug nuts to keep up with.)

Don't run the 1/4" spacer. (The wheels will barely clear the V6 rotor and TRE without them.)

I've been thinking about a solution and came up with an idea that might work for myself and others wishing to run alloy wheels with longer studs.

Here's a picture narrative of the problem and the proposed solution:

Stock vs. ARP

So loose it just drops in the hole.

How it should sit when dropped in. (Knurling contacting flange hole)

Stock Length

ARP Length

Length above convex portion of hole with stock lug (no spacer).

Length above convex portion of hole with ARP lug (no spacer).


I have a lot of pictures... continued on next post...

 

[stringtwelve]

Lug nut thread engagement. (From the pen point)

With spacer... ain't gonna work with stock.

Knurling measurement.

Disc rotor measurement.

Here's my idea... rotate the rotor and drill new holes between the existing ones to the correct size to seat the ARP bolt.

(You could still use the stock rotor holes for the two rotor to flange attachments with a slightly larger washer.)

Now, this will get the studs seated and stop them from spinning. The downside to this is that the thread portion through the hub flange will have some space around them since the stock hole was intended for the base knurling of the stock stud.

So, taking it one step further... you could drill new holes just big enough for the studs to pass through the hub flange between the existing holes at these 6 locations:

(Where the four white dots are plus the two rotor to hub bolt holes.)
This would help stabilize and center the wheel in the correct location.

Since you don't really "need" the rotor to hub connection anyhow, the loss of that function shouldn't affect anything.

The "ugly" part of this is the gap between the rotor and hub at the new lug locations:

So this leads me to my question:

Is this a viable fix? Is there anything I'm overlooking that could be catastrophic?
I know that on the surface this seems to be a bad idea... but the more I think about it, the better it sounds.

I think this method would be much safe since you're still sandwiching through the rotor, hub, and into the wheel. The gap at the new hole locations shouldn't be a problem since the overall construction of the hub is more than strong enough to support pressure on the "web".
Since they would be at the machine shop anyhow, a person could have them machine that web flat and make spacers to bridge the gap if you were worried about it collapsing (I think the wheel would break before that would happen anyhow.)

So.... thoughts? Am I nuts? If this method works, it might be a good way folks to have a better choice of aftermarket wheels with only the cost of the machine shop work.

 

[bikersmurf]

A gap between the hub and rotor would be a bad idea IMO, the studs would be more prone to shearing.

Have you considered newer Landcruiser studs, I found stock ones for the rear that were longer, and fit perfectly with my disc conversion back around 1997... I'd try the Toyota dealership.

I've got redrilled rotors on my "76" disc axle... Worked fine.

 

[Josie'sLandCruiser]

Hi all,


Try solid front axle Toyota mini-truck (1979-85) wheel studs.

Regards,

Alan

 

[stringtwelve]

Guys, I wish it was that simple... there simply isn't a stud that will work with the current configuration. I have to extend through the rotor backing into the hub flange which is about 1". The rotor has a larger hole than the stud knurling to allow it to pass through and use the hub flange as the contact location.

Several hours of searching this and other forums give the same answer. If someone can identify a stud that works I'd be glad to send you a reward! Otherwise, I'm looking for input on the above method.

Thanks!

 

[bikersmurf]

1) Can you get your hands on a couple of 76 hubs... That'd gain you a 1/2"... As the wheel studs don't go through the rotor.

2) Can the hub be machined/modified to mount like a 76 hub? In 76, the rotors were mounted with 6 bolts to the hub, and the studs didn't go through the rotor.

Having a gap will allow flex in the hub/rotor assembly leading to possible stud failure! First one, and then before you know it, all 6!

 

[stringtwelve]

I'll look into the hub idea.

I'm starting to lean towards using stock length studs and just keep an eye on the tight tolerances since that's the safest route so far. I can get 6.5 turns (hand tight) on a stock stud which is slightly over 1/2".

Do you think there would be any issues with drilling the new holes in the disc rotor for a press fit with the ARP studs and just let them pass through the holes in the hub? (without modifing the hub) I've seen drum brakes done this way but not disc rotors. Would the heat cause the rotor to crack as it expands and contracts? I'm guessing it wouldn't because the stock shoulder of the stud is the exact size of the hole just without the knurling. (see first 1/4" of stock stud in the pic)

 

[65swb45]

I'll look into the hub idea.



Do you think there would be any issues with drilling the new holes in the disc rotor for a press fit with the ARP studs and just let them pass through the holes in the hub? (without modifing the hub) I've seen drum brakes done this way but not disc rotors. Would the heat cause the rotor to crack as it expands and contracts? I'm guessing it wouldn't because the stock shoulder of the stud is the exact size of the hole just without the knurling. (see first 1/4" of stock stud in the pic)

I'm not trying to be a smart ass by saying this, but you asked. If you never go off road, or put the truck in 4WD, then there's obviously going to be a lot less of an issue. On the road, the hub housing will 'float' with the rotor.

HOWEVER, once the hubs are locked, then the hub housing will 'drive' the rotor, and applying the brakes will pit rotor vs. hub, with undersized wheel studs providing the fusible link.

Since those don't look like rims that are intended to go off road anyways...

 

[stringtwelve]

Thanks for the input. I know it's a controversial topic anytime you discuss modifying a stock part.

If it makes you feel better, I've decided to use the stock studs for now and run without a spacer on the fronts to ensure I get plenty of thread engagement until I see how things fit and work together with the new discs and wheel/tire combo.

However, the latest idea I have come up with after consulting several engineers is to drill new holes in the brake rotor between the existing holes to the correct dimensions for the knurling of the new ARP studs. Effectively moving the "interference" to the rotor and out of the hub. Then the assembly will slip onto the hub through the stock holes (so no gap between rotor and hub like the original idea).

The only play in this assembly would be the slightly larger hub holes vs. the studs. Which is no different than a modern hub-disc assembly where the disc rotor holes are slightly larger than the studs anchored through the hub. Braking will be the greatest strain on either one of these configurations but as long as proper torque is maintained at the lugs, the whole assembly should never shift.

You would have to exert enough force to shift the "pancake" of rotor, hub, and wheel under the pressure of all 6 properly torqued lugs, then break 6, ARP 190,000 PSI cadmium-plated 8740 chrome moly studs (all at the same time) before the wheel would come off. Seeing as how this more of a highway and mild off-road application... I doubt that would ever happen.

One other risk with this method would be the slightly softer material of the rotor not holding the stud knurling in place during bolting and un-bolting. I would probably use red locktite on the knurling (couldn't hurt) and anti seize on the lugs, just to make sure I didn't strip the connection in the future. I really don't foresee this being an issue though.

This is just my theory at this point based on in-depth conversations with multiple engineers. I'm still open to suggestions. Keep in mind that this is all in an effort to NOT use bolt-on spacers and grant myself (or others) the ability to bolt on other types of wheels and spacers without adding another link in the chain.

Until someone starts producing a stock shouldered lug in a longer length our options are few if any. This mod would only cost about $100 - $150 of machine shop work (actual quotes) plus the ARP bolts.

 

[bikersmurf]

I like your new plan, and feel much more confident in it.

One thing I'll mention is you'll only need to break one stud... The others soon will follow.

 

[YSG2017]

They make them down under...

S3330 – Long wheel studs | Nice Products

The Aussies love their landcruisers. Way more selection and aftermarket options there than here in NA.

 

[lc69hunter]

SOR has studs 9mm (.35 inch) longer than stock. That is what I am doing for my disc brake conversion.

 

[White Stripe]

Ive been down this road. Toyota pickup studs are longer, Ive used them in the front of my 40 without issue running 2" spacers. Dorman: #6102651. They should be about 6.5mm longer than stock 40 studs. Rockauto has them for like 1.27 per stud. Look under 1983 toyota pickup wheel stud. And I just realized this thread is very very old.

 

[loosechange]

I love all these great ideas and they really work and they help me with my own issues for my truck.

However here's my idea to come at this issue.

Many years ago I purchased an aftermarket front disc brake conversion through Manfre I know manafre has been sold however, the disc brake conversion that I purchased has the rotor going behind the hub ...so in a fact the studs you get a longer. I suggest that maybe if you get with Manfre a call they should have a set of the longer studs that come with the kit . I bought extras back then and you could get them desperate without buying the disk conversion kit

Unfortunately my studs are being used right now but if I do find some extras lying around I can try to take a picture of those next to my normal studs and see if that's what you require if so you can always pm me if manafra doesn't have what you require

And yes they work with my 1/4" spacers, but I don't use the spacers

 

[loosechange]

Holy smokes thread is 2013? Wow! I'm so late to the party

 

[Chris Versteegh]

They make them down under...

S3330 – Long wheel studs | Nice Products

The Aussies love their landcruisers. Way more selection and aftermarket options there than here in NA.

Thanks for the link. Those are exactly what I've been searching for. They almost match the ones that came on my Colombian 1974 40 series that has a disc conversion on it. Only they are 3mm shorter.
A Dorman 610-264 is pictured as reference.

 

[YSG2017]

No problem. I searched everywhere in North American for the right sized studs for a ‘79 BJ40 and I can confirm that these Aussie studs are the ONLY ones that bolt right in and are of the correct extended length without needing any modification. Australia, Russia, and Japan are still great places to get rare available parts for old FJ’s and BJ’s.