Builds Spyduh's Crawler80 Build (2 Viewers)

[spyduh]

Torque specs for ARP 7/16 bolt is 80-90ft/lbs.

Recommended Torque to Achieve Optimum Preload (Clamping Force) Using ARP Ultra-Torque® Fastener Assembly lubricant*​

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If you are only going to torque to 40-45ft/lbs a 7/16 bolt is kind of a waste in this application. IMO.

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I originally went to 60-70lbs that and I felt that was really tight and near maximum before stripping out that HUB. You know that feeling when you're snugging it up REALLY tight and if you go just a hair more and it's on the verge of SNAP or STRIP. That's what it felt like and I didn't really like that. Yes I eye balled them cause I knew I was taking them off anyway to install the longer studs.

I did verify my "hand" torque job with my digital TQ wrench before I remove the flange. I was in the ball park between that range. 61, 63, 65 and 68 was is where it landed.
I didn't want to go that high so set it and it felt pretty good at a 50 click. I did the other side at 45 click just to see the difference and it felt like it needed a hair more
I did see @cruisermatt comment about him deforming his HUB and flange at 70 and he dropped it down to 40lb.

I'm not sure where I want to keep it, but with 6 studs and 6 7/16. Even if it did loosen, the 6 STUDS better hold those F******* in place.

I bring my s***ty harbor freight $20 TQ wrench with me at all times and it does a pretty good job. It's about 2-3lbs off. I ain't bringing my $200 digital tq wrench wheeling to get banged up! I'm just going to check the TQ for the next few wheeling trips and see where my new hardware likes to be snugged down too.

 

[scottryana]

I originally went to 60-70lbs that and I felt that was really tight and near maximum before stripping out that HUB. You know that feeling when you're snugging it up REALLY tight and if you go just a hair more and it's on the verge of SNAP or STRIP. That's what it felt like and I didn't really like that. Yes I eye balled them cause I knew I was taking them off anyway to install the longer studs.

I did verify my "hand" torque job with my digital TQ wrench before I remove the flange. I was in the ball park between that range. 61, 63, 65 and 68 was is where it landed.
I didn't want to go that high so set it and it felt pretty good at a 50 click. I did the other side at 45 click just to see the difference and it felt like it needed a hair more
I did see @cruisermatt comment about him deforming his HUB and flange at 70 and he dropped it down to 40lb.

I'm not sure where I want to keep it, but with 6 studs and 6 7/16. Even if it did loosen, the 6 STUDS better hold those F******* in place.

I bring my s***ty harbor freight $20 TQ wrench with me at all times and it does a pretty good job. It's about 2-3lbs off. I ain't bringing my $200 digital tq wrench wheeling to get banged up! I'm just going to check the TQ for the next few wheeling trips and see where my new hardware likes to be snugged down too.

Yeah the dowel pins are what are going to help from spinning, the bolts are just there for clamping force. All I was saying is that if you are only going to go to 40-45lbs of clamping force there is nothing gained between a 7/16 vs a 3/8 or 10mm and the head might fit better on the flange. It is a moot point for you since you already have the setup but for people in the future it might be a little easier.

I can't imagine you will have issues. Your next breaking point will likely be a shaft or 3rd. lol.

 

[cruisermatt]

Yeah the studs are what are going to help from spinning, the bolts are just there for clamping force. All I was saying is that if you are only going to go to 40-45lbs of clamping force there is nothing gained between a 7/16 vs a 3/8 or 10mm and the head might fit better on the flange.

This is incorrect

 

[scottryana]

This is incorrect

Please enlighten

 

[Zjohnsonua]

As you stated, the clamping force is moot as it isn't doing the work. The torque simply serves to lock the fastener and pre-load the joint. The difference is that when push comes to shove 7/16 hardware will carry nearly 25% more shear load than 10mm hardware. 3/8 carries even less.

7/16=97mm^2
10mm=78.5mm^2

But, both are significant improvements over the ~50mm^2 the 8mm stockers provide.

 

[scottryana]

As you stated, the clamping force is moot as it isn't doing the work. The torque simply serves to lock the fastener and pre-load the joint. The difference is that when push comes to shove 7/16 hardware will carry nearly 25% more shear load than 10mm hardware. 3/8 carries even less.

7/16=97mm^2
10mm=78.5mm^2

But, both are significant improvements over the ~50mm^2 the 8mm stockers provide.

Shearing force is on the dowel pins.

General design practice is for dowels to carry shear forces while bolts/screws carry tension forces. That is why dowels are tight tolerance and bolts/screws are loose tolerance.

But really the friction between the two faces as created by the clamping force of the bolts is the key. Using large bolts but not increasing the clamping force means the same result can be accomplished with smaller bolts at the same torque.

 

[Zjohnsonua]

Yup, right up until the dowel yields. Then the bolts do the work.

 

[Broski]

What about the hole it's going into, that would be my concern. with a 8mm stud the threaded hole is sufficiently away from the edge of the hub by design.
Turn that same hole into a 7/16 hole how that hole is closer to the edge of the hub = a easier pull out or failure
I am by no means an engineer, I do have five decades experience breaking sh* t

 

[cruisermatt]

Using large bolts but not increasing the clamping force means the same result can be accomplished with smaller bolts at the same torque.

This is still WRONG, stop repeating this

 

[cruisermatt]

What about the hole it's going into, that would be my concern. with a 8mm stud the threaded hole is sufficiently away from the edge of the hub by design.
Turn that same hole into a 7/16 hole how that hole is closer to the edge of the hub = a easier pull out or failure
I am by no means an engineer, I do have five decades experience breaking sh* t

It’s fine. No one has blown a 7/16” hole out of the hub. Ive modded almost 10 pairs of hubs for others and myself at this point for those who have broken the 8mmhardware

The bigger flange bolts hold up. Period

 

[scottryana]

This is still WRONG, stop repeating this

You saying it is wrong in caps does not make it wrong. The formula for clamping force of bolted interfaces is simple.

The equation is T=cDF

Where the torque equals the coefficient of friction times the diameter of the bolt times the bolt tension.

Since there will be less tension in a larger bolt there is actually less clamping force in a large diameter bolt torqued to the same value as a smaller diameter bolt.

It is not wrong it is pretty obvious really when you think about it.

If you dispute this, don't write that it is wrong in caps again please show me how it is wrong.

Additionally the bolts should not be in shear unless they come lose. Adding additional material is fine but the benefit is that they can be torqued to higher values creating more clamping load if you are not increasing the torque you are not doing yourself any favors.

Rough calculations of clamping load on an 7/16 bolt torqued to 40ft/lbs vs the stock 8mm stud torqued to 26ft/lbs is only a 10% increase in clamping load. If you torque that same 7/16 bolt to 60ft/lbs the increase is 66%. And if you torque it to 70ft/lbs it is a 93% increase! The benefit is in being able to torque the larger bolt to create more clamping load.

And I am not going to argue it any longer. If anyone really believes that it is the cross section of the bolt that makes this system work, go ahead and just put them in finger tight. The cross section doesn’t change, the dowel pin size doesn’t change but the system won’t last a day. It’s the clamping load creating the frictional force between the hub and flange that transfers the power.

Not arguing the 7/16 upgrade is bad. It is an upgrade. I was simply saying that if you can’t torque it down past 45ft/lbs because of deformation you could use a smaller ARP bolt so it might clear more wheel types and get the same benefit.

 

[cruisermatt]

You saying it is wrong in caps does not make it wrong. The formula for clamping force of bolted interfaces is simple.

The equation is T=cDF

Where the torque equals the coefficient of friction times the diameter of the bolt times the bolt tension.

Since there will be less tension in a larger bolt there is actually less clamping force in a large diameter bolt torqued to the same value as a smaller diameter bolt.

It is not wrong it is pretty obvious really when you think about it.

If you dispute this, don't write that it is wrong in caps again please show me how it is wrong.

Additionally the bolts should not be in shear unless they come lose. Adding additional material is fine but the benefit is that they can be torqued to higher values creating more clamping load if you are not increasing the torque you are not doing yourself any favors.

Rough calculations of clamping load on an 7/16 bolt torqued to 40ft/lbs vs the stock 8mm stud torqued to 26ft/lbs is only a 10% increase in clamping load. If you torque that same 7/16 bolt to 60ft/lbs the increase is 66%. And if you torque it to 70ft/lbs it is a 93% increase! The benefit is in being able to torque the larger bolt to create more clamping load.

And I am not going to argue it any longer. If anyone really believes that it is the cross section of the bolt that makes this system work, go ahead and just put them in finger tight. The cross section doesn’t change, the dowel pin size doesn’t change but the system won’t last a day. It’s the clamping load creating the frictional force between the hub and flange that transfers the power.

Not arguing the 7/16 upgrade is bad. It is an upgrade. I was simply saying that if you can’t torque it down past 45ft/lbs because of deformation you could use a smaller ARP bolt so it might clear more wheel types and get the same benefit.

Yes, your are doing your math correctly. I just ran the same numbers and double checked.
What you are wrong about is that everything is about clamping load.

Your other critical misunderstanding is that the dowels are there for shear. They are there for alignment.

What you are also missing is that these bolts we are using (that I machined @spyduhs hubs for, and told him the part number to buy) have a 1/4” long shank that the shafts/flanges are machined for as well. these are now the “shear dowels” not only clamping the flange but also keeping everything in ridgid alignment.

I would highly recommend you go look at a few other full float axle designs. Like a Dana 60, or a 14 Bolt. No dowel pins. Big domestic axles usually a ring machined under the flange that indexes them to the hub.

Additionally, that formula is a guideline. It is leaving out that these are flange bolts, with more surface area under the flange, it leaves out the bolt grade, etc.

and yes i used to torque mine to 70 as recommended by ARP, however as mentioned it would start to deform the Aisin hubs (i am running these front and rear) and Toyota shaft flanges a bit.

 

[scottryana]

Yes, your are doing your math correctly. I just ran the same numbers and double checked.
What you are wrong about is that everything is about clamping load.

Your other critical misunderstanding is that the dowels are there for shear. They are there for alignment.

What you are also missing is that these bolts we are using (that I machined @spyduhs hubs for, and told him the part number to buy) have a 1/4” long shank that the shafts/flanges are machined for as well. these are now the “shear dowels” not only clamping the flange but also keeping everything in ridgid alignment.

I would highly recommend you go look at a few other full float axle designs. Like a Dana 60, or a 14 Bolt. No dowel pins. Big domestic axles usually a ring machined under the flange that indexes them to the hub.

Additionally, that formula is a guideline. It is leaving out that these are flange bolts, with more surface area under the flange, it leaves out the bolt grade, etc.

and yes i used to torque mine to 70 as recommended by ARP, however as mentioned it would start to deform the Aisin hubs (i am running these front and rear) and Toyota shaft flanges a bit.

I don’t really need to go look at other designs. The same thing remains if the dowel pins are only for location why does RCV include additional dowels? To make it locate better? lol... And the bolts are not there for shear It’s all the friction between the hub and flange. The bolts simply allow you to generate that friction through clamping force. The only way the dowel pins or bolts see shear forces is if they are loose. Same reason steering arms studs break off if they come loose. The diameter or strength of the fastener doesn’t suddenly change. You just lose the frictional force that actually carries the load.

I have given you the correct information what you do with the information is up to you. Like I said 7/16 is an upgrade since you do go from 26ft/lbs to 45ft/lbs but I still say if you’re not using the additional clamping force possible with a 7/16 bolt you could down size snd still have the exact same benefit.

This is not my truck and it’s not really my concern. I was just trying to make it easier for people in the future who wanted to do something similar. If the limitation is in the hub deformation why not make it easier?

 

[spyduh]

Im not an expert. All I know is I already snapped brand new ARP studs at Rubicon prior to me blowing up brand new 300m shafts this yr

This led me down the rabbit hole of hub upgrade and 7/16. It's been done before by Jose and Cruisermatt and many before me. I claim no expertise and follow in the footsteps of the hardcore 80 crowd.

If you follow my build. I was already going to upgrade to 7/16 but had an hiccup having all parts ready before SierraTrek.

I ran OEM hubs and ARP OEM sized hardware during SierraTrek. During this trip, I blew up my new 300m shafts at Fordyce. None of the studs broke during this trip. But during disassembly on WH3 and troubleshooting. 4 out of 6 ARP studs worked loose on each side.

I re tourqed all 4 hubs and bolted OEM shafts back on and drove out WH 4 and WH5 on its own power with no issues. Then to continue back down WH 4 and 5 the next day and back up to camp.

When home, I tore it apart and again found the ARPs have worked loose. I was not happy with how fast these worked loose compared to OEM studs and hardware. Let alone the ridiculous price of the ARP stud kit.


What I do know is the 7/16 ARP hardware feels Beefy compared to those baby OEM sized studs. I already doubled the amount of tq already. I did try 60-70lbs and it felt really tight to me and I backed down.

Am I at the suggested ARP tq spec?
No and it's suppose to be 70.

Did I loose some clamping force? Mathematically it seems that I have.

Does that matter in the long run?



All I can do is wheel it and test and report my findings. Any of my information is YMMV and every truck and build is different.

I've driven 5 different 80s and each of them drive a little to extremely different.

And for those that think I maybe upset my build page got hijacked. I am not. I don't care. It's the freaking internet and MUD for me is about sharing information and learning. All I can say is the information is YMMV and anyone that added information to this hub upgrade only adds to building knowledge.

Thanks for everyone that participated in this and your wealth of knowledge.

 

[chappysfj40]

one ton updates :")

 

[spyduh]

one ton updates :")

lol. no ton's yet.

I've wheeled the 80 with the new RCV's a few times already and no more issues. Recent trip was to Moonlight Madness and she did great.

 

[nukegoat]

If anyone really believes that it is the cross section of the bolt that makes this system work, go ahead and just put them in finger tight. The cross section doesn’t change, the dowel pin size doesn’t change but the system won’t last a day. It’s the clamping load creating the frictional force between the hub and flange that transfers the power.

For the record, my brother in law ran all his hub bolts finger tight on his 14b like a moron. It had plenty of gear oil pouring out but didn't break.