Is a 5/8" rod end strong enough for a 4-link

[Probird]

I found these rod ends on speedway motors website and was wondering if you thought it would be strong enough for a 4-link build in a street car with roughly 450-500hp? It would be a triangulated 4 link with these poly rod ends on the frame side and some sort of a pivot bushing or rod end on the axle side. I am considering using 1" DOM with a .211 wall and threading directly into the tube. I am considering these because I really don't like the ones with a 3/4 bolt welded to a piece of tubing and these ones are an all forged piece. All input would be appreciated thanks.

http://www.speedwaymotors.com/Mr-Roadster-4-Bar-Rod-Ends,25122.html

[CarlC]

What are your load values?

[Probird]

What do you mean by load values and how would I calculate them? Try not to get to technical with me or you'll just be talking over my head.

[Strum]

I think 5/8 would be enough. My 34 Chevy w/ about 400 HP has 1/2" grade 8 bolts going through the control arms.

[exwestracer]

QA1 lists their 5/8" KM series Heim joint as having a radial load rating of just under 18000lb which should be more than adequate. I couldn't find any info on load rating for those Speedway ends, but if they aren't comparable to at least a 1/2" 3pc Heim, I'd think twice...

[CarlC]

That's the point I'm trying to make. Without knowing what your loading is how can you determine if the tube diameter and wall thickness is appropriate? Yes, the rod end may be able to take a maximum load of 18kips, but can your tube take that load without buckling or compression failure?

[Probird]

I called speedway and asked for some information and they don't have any information other than they are forged and made in the USA. Now the tubing should not be a problem since it's 1" with a .211 wall thickness and I notice that a lot of builders use 1" with a wall thickness of .156 for their trailing arms and thread 3/4 directly in the tubing. I was just hoping that maybe someone here has used them before. 5/8 is pretty stout especially at shear 3/4 even better but for a bolt that is just welded to a piece of tube, it's nowhere near that strong. Although the weld should still be very strong I think that a forged solid 5/8 end would be even stronger. I'll call them again and try to get some more information if they cant get me anything I'll go elsewhere. Thanks for the input.

[silver69camaro]

More than likely that will be just fine, tube size and all.

[Probird]

Coming from an engineer that makes me feel a lot better, thank you.

[ITLBTU]

For what it's worth, back in my racing days, we used 3/4" for the 3 links...

[Bryce]

NHRA I think requires a 3/4" rod end with a 1.25" x .120 wall control arms.

[Probird]

Speedway couldn't give me any technical information, so I will just go elsewhere. I'll just wind up making my own most likely. Today I found a tubing supplier real close by who can notch the tubing and everything for me. Pricing is really inexpensive and I'll weld them myself. For the trailing arms I decided to go with 1-1/4" .120 wall. At less than $3.00 a foot I figure why not. I'm going to build the lowers as non adjustable with johnny joints on the frame side and poly ends on the rear end. Uppers will be adjustable with J.J. at the frame and poly ends on the rear. For my crossmembers I'm going to use 1-1/2" .120 wall. Should be plenty strong enough. Just finished the mini tubing and it went really good. I just finished putting down the seam sealer this evening. I'll post some pictures as I get going. Thanks for all the input.

[JRouche]

Those stainless steel 5/8" poly rod ends look VERY similar to the rod ends that were supplied to me by Art Morrison with my parallel bar 4-link which is a stout 4-link.

http://artmorrison.com/2006cat/2009catalog.pdf?Download+Catalog=Download+Catalog
Look at page 63, it shows the rod ends.

I never drove the car with the rod ends. I ended up swapping them out for some QA1 rod ends for a lil added flexability.

They really look like they will hold up to what the AM rear clip is all about. 5/8" bore and a 3/4" shank. But... you will see AM wants 30 bucks a piece for them, a lil more than the 18 bucks for the other ones.

I know selling here is a no-no so I wont. But PM me if you want more info :) Got a newish (no road time) set sitting around doing nothing... JR

Sorry, I just re-read the speedway link and they are not poly but nylon and they are 1/2" rod ends. After reading that I would suggest to NOT use those. 1/2" bolt is a lil small for a trailing arm bolt.

[Probird]

Those rod ends look pretty nice. They are a 5/8" shank with a 1/2" bolt. They would probably work just fine for most street applications but just to be on the safe side of things I'll go 3/4". I would rather over build than under build and regret it later with a wrecked car. What size is the tubing that came with your 4-link?

[silver69camaro]

Those stainless steel 5/8" poly rod ends look VERY similar to the rod ends that were supplied to me by Art Morrison with my parallel bar 4-link which is a stout 4-link.

http://artmorrison.com/2006cat/2009catalog.pdf?Download+Catalog=Download+Catalog
Look at page 63, it shows the rod ends.



I think it should be noted that our stainless/poly rod ends is our own design..casting, urethane, sleeve, everything. It's tested to withstand our heavy duty specifications. Nobody else carries these. I'm willing to bet the Speedway rod ends are made in China (although I don't know for sure), while ours are made here in the US...which would account for the price difference.

To the OP, I didn't realize the rod ends in question were for a 1/2" bolt. While it would probably be OK (many OEM links use a 1/2"), I'd step up to a 5/8" bolt. Shank can be either 5/8" or 3/4" for your application.

[JRouche]

I think it should be noted that our stainless/poly rod ends is our own design..casting, urethane, sleeve, everything. It's tested to withstand our heavy duty specifications. Nobody else carries these. I'm willing to bet the Speedway rod ends are made in China (although I don't know for sure), while ours are made here in the US...which would account for the price difference.

Hi Matt. I didnt mean to make it sound like your rod ends were the same. I have your rod ends and I can say they look to be some solid pieces. And really, the entire package I bought from you guys is top of the line. Sure, Im biased :) But yup, I like art morrison products. I cant say anything bad about the product, not one word. And believe me... I would.. Im not all that politically correct... JR

[silver69camaro]

Hey, no problem. I know you're up to date with our stuff, but I didn't want others to think we use offshore stuff to cut costs.

[BANKO]

Matt, since you made these in-house, can you comment why you chose to use Polyurethane bushings rather than Delrin?