Minimum size rod end for suspension fabrication

[jode]

Somebody gots to start out this forum, so here we go....

What size would you say is the best for the rod ends on a 3 or 4 link setup and where is (generally) the best place to find them?

What about the big spherical "johnny joint thingy" that you use on a 3-link?

What does it cost to buy this material?

Also, what types of shops have the equipment to thread the ends of the rods for the end joints?

PS...cool forum... ;)

[nxcj]

Most of the guys I know run the basic 3/4" rod ends for steering and suspension links. Johnny joints are stronger with out a doubt....but they're also a lot more expensive. They've held up very well regardless. And, when they do break, they're only $12.00 to replace! I buy mine from a local shop that specializes in stock cars. They have 'em in stock and they're five minutes away!!!!!!!

[dnixon]

Yeah when you buy these there are different kinds. You can buy them at the local "farm supply" or you can buy them from a race/offroad place. The AG ones are WAY cheaper but the quality suffers greatly. I have heard to sides to the story. Some say hey i just keep replacing them they are that much cheaper and the others say why take the chance. I think its up to the user. I personally might use the AG ones for less important ones like LINKS and such but for steering (if I were to go to all Johnny Joint steering) i would have to go with the Race/offroad made ones..

Here is a good local (local for me) source of high end offroad parts:
www.polyperformance.com (http://www.polyperformance.com)

They have everything that this catoagory is all about...

[rockjeep44]

When it comes to any kind of link, SPARE NO EXPENSE. Trust me. There is no substitute for quality, strong, beefy parts. Personally I like heims but regardless of what you use, get good ones. If you break a link offroad have fun using chains and a winch to locate the axle. I've done it before and in some of the worst conditions. It SUCKED HARD. I broke a main leaf but same concept. Jode, if you're building your own links you don't need a shop. Just order some rod ends from one of these guys
http://www.spydercustoms.com/ps_index.html
http://www.mountainoffroad.com
weld it into your tube, and screw your heims right in and lock it with a jam nut.
-Andrew

[scotty]

i definately agree you get what ya pay for when it comes to heims,just like every thing else. cheap ones are made of cast,low grade steel and can wear out quickly. look for words like "chromemoly" and "graphite impregnated" when reading a heim joints description in the parts book

i used some cheap heims in my steering from a local supplier. they are allready starting to wear and have alittle movment of the outer part around the ball.

steering and suspension links are right up there with stuff that you should over build,especially if you have to drive it on the streets to the trails. i plan on upgrading to qualitly heims(will cost me $45 apiece or so) and id like to upgrade my grade 8 bolts to aircraft quality titanium bolts since they are mounted in a single shear setup.

3/4 sounds alittle small for links like control arms and such. the johnny joint was deisgned for this purpose,and they are rebuildable.not sure if they come in different sizes. i used to have a link,but i lost it when my puter crahsed awhile back.

[jode]

Hey Scotty....R U sure that Titanium is stronger than Steel? I know that it has a better strength-to-weight ratio, but as far as overall strength, I can't remember if Titanium beats a good steel alloy...

[blt2krl]

Originally posted by rockjeep44:
When it comes to any kind of link, SPARE NO EXPENSE. Trust me. There is no substitute for quality, strong, beefy parts. Personally I like heims but regardless of what you use, get good ones. If you break a link offroad have fun using chains and a winch to locate the axle. I've done it before and in some of the worst conditions. It SUCKED HARD. I broke a main leaf but same concept. Jode, if you're building your own links you don't need a shop. Just order some rod ends from one of these guys
http://www.spydercustoms.com/ps_index.html
http://www.mountainoffroad.com
weld it into your tube, and screw your heims right in and lock it with a jam nut.
-AndrewMy buddy just bought MORE ends and built his links. This is what I plan on doing myself.

[dnixon]

*Excuse me on this matter I in no way have much experince regarding this* But the way I understand it is that titanium is a stronger metal but not a ductile one. So its not good with impacts just like a grade 8 bolt its as good with impacts. They are more likely to just shear off when hit rather then bend like a lets say grade 5. From my basic research I have found a "GENERAL" numbers for Titanium and Stell Alloys. The Modulus of Rigidity (also know as the Shear Modulus) of a Titanium Alloy is 6.2 Mpsi where as a Steel Alloy has on of 11.5 Mpsi. This says that the Steel Alloy can handle roughly 85% more shear stress then then the Titanium. Depending on the Alloy composition, the titanium usually has a larger Yeild Strength (the strength before plastic deformation occurs), however; the Ultimate Strength (the strength when fracture is going to occur) is VERY CLOSE to the yeild strength..

Okay well this is just what I have found from some charts I have if you have a specific alloy in mind that you want me to look up must PM or email me..

[jode]

So SloWag....what are you trying to say? :confused: That grade 8 and titanium will shear faster than a grade 5, and that because of that, a grade 5 is better in applications where a high shear point is req'd?

tongue.gif

[dnixon]

Originally posted by jode:
So SloWag....what are you trying to say? :confused: That grade 8 and titanium will shear faster than a grade 5, and that because of that, a grade 5 is better in applications where a high shear point is req'd?

tongue.gif Like I said before I am NO expert when it comes to this at all but from what i have been reading:
The thing about impacts is that it introduces a lot of energy into the bolt. The ability for the bolt (or metal) to absorb the energy is determined by the Modulous of Resilience. You find the modulus of Resilience using the Yield strength and the slope of Stress-Strain in the Elastic Region. The area under the stress-strain curve is the Modulous of Resilience.
Okay well that is all jiberish to me.. But this might help
The Slope of Stress-Strain for "strong" metals (such as a Grade 8 Bolt) is steeper then that of a "soft" metal (such as a Grade 5 Bolt). So although the Grade 8 has a higher yield strength the slope is so steep that the area under the curve is less then the area under the curve then the "soft" metaled Grade 5. And the more area the better the metal is at absorbing energy... So I hope that makes sense...

Okay here are some figures..
Grade 8-
Yield Strength:130 ksi
Ultimate Strength:150

Grade 5-
Yield Strength: 92 ksi
Ultimate Strength: 120 ksi

I'm not able to find the composition of the different grades of bolts if i could i could give you the Stress-Strain slope as well..

[scotty]

how often is there a impact force on steering? i can see how maybe suspension links could be subjected to impact forces,but i have a hard time picturing it in the steering. im pretty sure a tube would bend before id shear off a grade 8 or titanium bolt. id think the same about suspension links as well-unless youve made your control arms out of some reeeeeallly haeavy,thick wall tubing,a good bounce is prolly more likely bend a link than shear off a grade bolt

im definately not disputing the validity of your reserach-some good points. there are plenty of situations where a grade 5 bolt is prolly a better.long body lift bolts come to mind,i did use grade 5 for them for that exact reason. but i think the guys that build multilink suspensions do not run grade 5 bolts in steering and suspension links,and i just kinda figured that if its good enuff for an airplane its prolly good enuff for my steering smile.gif

due to the nature of the forces exerted,i believe the extra strength of grade 8+ bolts is of greater value then the longer stress-strain slope of lesser bolts. also do not forget that suspension links(and steering links when possible) should ALWAYS be mounted in a double shear fasion,wich greatly decreases the liklihood of the bolt bending or shearing off

my thots on that,anyway smile.gif

maybe we could find out what the auto manufactures use. my xj has bolts tha hold on the control arms-wonder what they are? what is the tapered stud mad of on your typical tie rod end?

[ April 25, 2003, 05:15 AM: Message edited by: scotty ]