LONGER FRONT WHEEL STUDS

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hoser said:
I've always been under the impression the wheel studs mainly see tensional forces which clamp the wheel to hub (and rotor). The friction between the hub to wheel interface resists the torque force associated with braking and acceleration... like a clutch and flywheel.

As we know, most modern vehicles have the rotor mounted over the hub and practically floating. Usually one screw just keeps it aligned. Remove the screw and there is play between the studs and the rotor. That one screw does not resist the torque forces. If there was any movement between the rotor and hub or wheel mounting surface, there would be evidence of scuffing.
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You are correct. The screw (or bolt) is for alignment, then the studs applying enough tension to create sufficient friction between the rotor and hub (and wheel with modern cars) to transmit braking force. In the case of the 60/62, the rotor is aligned with the bolts, then the rotor is pulled against the hub with the tension from the studs, providing similar friction forces through the back of the hub to transmit braking power.

My whole point is that this guy @xlogre has removed the studs from the rotor equation, so that the only thing holding the rotor to the hub assembly is two M10 (or M12, can't remember) bolts. It is physically impossible for those two bolts to apply enough clamping force to the rotor to keep it firmly attached to the hub under braking. I suspect that the reason his rotor hasn't fallen off is because the rotor has slipped against the hub face and is now contacting the shoulder if his new stud. Thus, when the retaining bolts of the rotor shear, the rotor will pop off.

cruisermatt said:
Yes this is true but on the 60 the rotor is BEHIND the hub so there is no frictional force beside the 6 studs with 0.01" gap on each.
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Partially correct. The frictional force is between the rotor and the back of the hub only, instead of sandwiching the rotor between the hub and wheel.
 
I comprehend what you're saying about "taking the studs out of the equation" but i haven't. I have only moved the contact area of the stud to the rotor, and i have made the area of contact with the stud larger. The fastening bolts have been replace with bolts in excess of grade 8. The shear strength on them is in excess of 17000 psi, and the tensile strength in excess of 22000 psi, both of these are conservative numbers in terms of strength. Now, there is also 6 studs worth of contact area, each having been pressed into location, preventing slippage. Now, i don't have the actual figures and forces at work here, but i will have them by tomorrow. I do know that the forces at work are well below the 17000psi threshold of each alignment/fastening bolt. Combined, these two bolts, torqued to spec, and loctited in place leave me with enough peace of mind, in knowing that their shear strength is in around 34000psi and backed by the mathematics and physics of an engineer's research before i did my modification.

To put it shortly, i understand the concerns and risk with modifying toyota's design, but i am not afraid of failure, because it was researched before being put into effect, and has been thoroughly tested to date.
 
xlogre said:
To put it shortly, i understand the concerns and risk with modifying toyota's design, but i am not afraid of failure, because it was researched before being put into effect, and has been thoroughly tested to date.
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Accounting for emergency brake from lets say 70mph (freeway speed) locking both wheels if not all four with the truck loaded for a 1 week camping trip in the mountains?
Let alone testing heavy emergency braking, locking both front wheels from a sensible and doable speed?

I am with the rest here, your design sound directly dangerous to you and every one else on the road. If you really want floating rotor designs for your 60, then do as I did. Convert to the biggest six bolt Tundra/Sequoia calipers and rotors.
That setup have better braking force and a lot bigger rotor mass with a lot bigger cooling fins. Stays cooler under any braking circumstances avoiding brake fade when you least want it.
You get about same thread stud length as stock doh so not any helpful for cruisermatt.
 
xlogre said:
I comprehend what you're saying about "taking the studs out of the equation" but i haven't. I have only moved the contact area of the stud to the rotor, and i have made the area of contact with the stud larger. The fastening bolts have been replace with bolts in excess of grade 8. The shear strength on them is in excess of 17000 psi, and the tensile strength in excess of 22000 psi, both of these are conservative numbers in terms of strength. Now, there is also 6 studs worth of contact area, each having been pressed into location, preventing slippage. Now, i don't have the actual figures and forces at work here, but i will have them by tomorrow. I do know that the forces at work are well below the 17000psi threshold of each alignment/fastening bolt. Combined, these two bolts, torqued to spec, and loctited in place leave me with enough peace of mind, in knowing that their shear strength is in around 34000psi and backed by the mathematics and physics of an engineer's research before i did my modification.

To put it shortly, i understand the concerns and risk with modifying toyota's design, but i am not afraid of failure, because it was researched before being put into effect, and has been thoroughly tested to date.
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So where are pics showing this setup? and your modifications.... I can see potentially adding bigger rotors and and larger piston calipers...etc... but I'm a little lost on what you are describing as an improvement, pictures would illustrate far better.
 
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Elbert said:
So where are pics showing this setup? and your modifications.... I can see potentially adding bigger rotors and and larger piston calipers...etc... but I'm a little lost on what you are describing as an improvement, pictures would illustrate far better.
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I'm not claiming this as an improvement in braking, just a modification, that doesn't take away from braking safety. All i did was modify to fit extended front lig studs, based on an engineer's research and an offroad race shop's guidance. No armchair engineering, or going with my gut. Simply modified to fit longer wheels studs.
 
I'm completely lost here, I got new wheel studs about 18 months ago that were metric (m12x1.5) and the place I purchase from had multiple different lengths.
I ended up getting 100mm from memory to accommodate the thicker JDM alloys.
The knurl was exactly the same as OEM and if anything they were still a little too long, I only ended up doing the front with all new brakes (and the inevitable axle seal) so I'm sure I've still got a dozen floating around somewhere.

Long story short (not that it helps you sepos) is "nice products" in Sydenham/Marrickville Sydney has all of this kind of stuff on tap at the right price.

I'm not sure where you guys are heading with drilling things out but it's absolutely not required if you get the right part to begin with.

2c paid in full.
 
Crick60 said:
I'm completely lost here, I got new wheel studs about 18 months ago that were metric (m12x1.5) and the place I purchase from had multiple different lengths.
I ended up getting 100mm from memory to accommodate the thicker JDM alloys.
The knurl was exactly the same as OEM and if anything they were still a little too long, I only ended up doing the front with all new brakes (and the inevitable axle seal) so I'm sure I've still got a dozen floating around somewhere.

Long story short (not that it helps you sepos) is "nice products" in Sydenham/Marrickville Sydney has all of this kind of stuff on tap at the right price.

I'm not sure where you guys are heading with drilling things out but it's absolutely not required if you get the right part to begin with.

2c paid in full.
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The problem I think is that metric fasteners are harder to come by in the US. Does the place you got your studs from sell online?
 
Yeah they do sell on line but shipping would be a bitch.

I know you guys deal mostly with imperial but I find it hard to believe with the amount of cnc fabricators in the states that getting someone to turn some studs up with the most basic of specs would be a difficult task especially given mud is full of fabricators.
It may be the case of getting a group buy together or just getting a few hundred made and selling them on fleabay.
 
Actually, Standard is fading fast in the US, In the engineering world we still use Standard for the most part but medicine and food is in metric, and it's only a matter of time.
 
I have been using Moroso #46150 7/16 by 2 7/8 studs on my 1976 FJ-55 for years just had to drill right size hole, forget the size but you can find out easy. In a few weeks I am going to try on a 85 FJ60 did they change the 60 that much from the 55 that it will not work??
 
Should be the same process on either truck.
 
There's not a lot of options with the fronts if you stay 12mm x 1.5. The Toyota Matrix studs are 2.5mm longer ( 610.-294 ) but that's about it.
The rears have options up to 3/8" longer.
You could go to 1/2" studs but you'd probably want to change all 4 corners. Considering the 1/2" stud is a little over 1/2mm larger diameter,
I guess you could say that's a tiny upgrade. Although the 14mm/9/16 offers more long stud options I don't know that you'd want to go bigger than that without checking the hole diameters in your rims
 
xlogre said:
I'm not claiming this as an improvement in braking, just a modification, that doesn't take away from braking safety. All i did was modify to fit extended front lig studs, based on an engineer's research and an offroad race shop's guidance. No armchair engineering, or going with my gut. Simply modified to fit longer wheels studs.
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xlogre, I am a degreed mechanical engineer with 25+ years of experience. What you have described doing is NOT safe! Not even remotely.

Even if you upgraded the two positioning bolts, the threads in the grey cast iron hub are not any stronger. Consider that there were 6 steel lug nuts attaching the disk with Toyota's design. Even if the hub threads hold those 2 little assembly line bolts would have to be 3 times as strong to replace the shear of the 6 studs. More than 3 actually, because the crosssectional area of each of the studs is considerably larger than of the positioning bolts. Plus they would have to be torqued ridiculously high to offer the psi necessary to provide the same friction between the disk and the hub. And that friction is reduced by half compared to 'floating' disks, like on IFS setups, because your system doesn't have it clamped between the hub and wheel.

Please reconsider your numbers or ask your 'race shop' tech to reevaluate with regard to the above. Your or someone else's life depends on it.
 
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