ARP D44 Steering Studs

[Hossbaby50]

Any word on the ETA for the ARP steering studs for D44 crossover? I need to get the studs that are 1" extended to work with a spacer under the steering arm. How much stronger should the ARP studs be then the standard 1" extended studs?

I sheared the front 2 of the 3 studs today when I was out wheeling? I only have 2 runs on a fairly mild trail with the stock extended studs. Or should I use Grade 8 bolts instead of studs?

Thanks
Harley

 

[Stephen]

Which studs are you using now?
We're not actually working on any D44 studs at this point, it's some other D44 stuff that's in the works. You might be better off working with a grade 8 or better bolt rather than a stud of unknown quality. Since the D44 uses the taper adapter you can use a bolt as long as the length is correct.
Thanks

 

[Hossbaby50]

That is cool. I am running grade 8 bolts, but I picked up some Grade 9 bolts yesterday. I will just run those for now.

The studs were supposed to be make of something pretty hard and where called "stress proof".

Are you possibly going to offer a 5/8" upgrade kit for D44 stuff in the future. I am just wondering. Thanks

Harley

 

[Stephen]

Stressproof (a trademarked steel) = 115Ksi tensile strength
Grade 5 bolts = 120Ksi tensile
Grade 8 bolts = 150Ksi tensile
Grade 9 isn't graded by anybody but the manufacturer so the term really means nothing but typically the higher strength bolts run roughly 180ksi.
our D60 ARP studs (not really relavent here but good to compare) run 190ksi.

Conclusion: just running a grade 8 bolt is a considerable upgrade over what you had and going with a bolt stronger than grade 8 is a nice bonus, I think you're on the right track.
I doubt we'll ever look at a 5/8" upgrade kit, there's not a lot of reason to go to that effort when you can just put a MUCH stronger fastener in the existing hole.

 

[Hossbaby50]

The bolts I got are F911 brand. This is what is claimed by the website.

"In the past, 8640 alloy was used in the manufacturing of only the most critical Aerospace and other special High Strength requirements. Now everyone can have this Superior Quality and Strength, with the "Off The Shelf" F-911 Hex Cap Screws and at prices comparable to other so called "Grade 9" bolts. What does 8640 Alloy offer? For starters, up to 50% more Chromium content and the substantial addition of Nickel, the ingredient that makes this Alloy tough. With higher Rockwell Hardness that the F-911 specification requires to achieve an over 190,000 P.S.I. Tensile Strength average, only 8640 Alloy can reach these lofty goals with superiority."

I can't find anyone in local Phoenix that carries or knows of anything tougher. So with what you have said I am more confident that the bolts will outlast the studs by far. Thanks, and I appreciate your help.

Harley

 

[Stephen]

Yup, those are good stuff and considering what you're replacing, it's a huge step up. Make sure you pay attention to the amount of thread engagement (you want as much as possible in the knuckle) and watch the lubrication condition of the threads so you can get the torque right, those bolts are going to want to be TIGHT.

 

[Hossbaby50]

My current bolts are at 140lb/ft. Do I want more when I install these Grade 9's? What type of lubricant should I use to get the torque right with?

My torque wrench goes up to 250lb/ft, so I can torque up to that and by feel after if I need to.

 

[az-k5]

Harley,
If more than 250 is required you can swing by my shop and I will get out the 3/4" wrench as it is good up to 600-700 ft-lbs (think kingpins)

 

[Stephen]

Talk to the guys you're getting the bolts from about the lube condition and what they recommend for the torque. I'm guessing that 140 is pretty good for the higher strength bolts, depending on the lube condition. The lube condition changes how much stretch you get out of the bolt for a given amount of torque since you decrease friction in the threads.
This is a good place to get fairly specific with your torque procedure. I'm guessing you could use a motor oil or something like that for a thread lube but I don't want to advise you on a torque for their bolts.
One chart I'm looking at shows 129 ft-lb for a 9/16 fine grade 8 bolt in a lubricated condition giving a 18,300# clamp load and is estimated at 75% of the proof load which is usually the yield strength.
Going from this info, you're safe with the 140 ft-lb in a lubed condition but may be able to get more if they recommend it. You also need to watch your thread engagement in the knuckle so you don't strip the threads. Luckily knuckle threads are typically pretty deep.

Just to show what the lube does, the example above with dry threads would require approx 172 ft-lb of torque.

Torque-tension relationships are surprisingly vague for the importance put on them.

 

[Hossbaby50]

The bolts I am running right now go all the way threw the knuckle and stick out a little on the other side. So I have full engagement on the threads. Thanks

Harley