Jump to content
HybridZ

Chromoloy Adjustable Rear Control Arms


Recommended Posts

My A-arms are 100% tig welded in a jig after the chromoly tube is cut to blueprint specs. The rod ends you think are cheap are actually QA1 pecision (made in USA) heat treated chromoly with teflon on the front and 3pc precision on the rears. No cheap hardware on my parts ever!

$299 each on the fronts, $329 each on the rear and of course they're gold zinc plated for anti-corrosion.

The feature ON THE CAR toe adjustment on the rears plus a track adj., the front also have track adjustment plus on the car caster adj.

rarm7b.jpg

rarm8.jpg

farm7.jpg

 

dave@arizonazcar.com

http://www.arizonazcar.com

Link to comment
Share on other sites

  • Replies 60
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

Well my apologies if it's true, maybe someone had switched rod ends with some cheaper ones on the arm's I saw... though I wouldn't recommend that at all!

 

Out of curiosity Dave, how long have you had this product and how many cars are using it? (Ballpark)

Link to comment
Share on other sites

Dave wrote: "the front also have track adjustment plus on the car caster adj."

 

And, as I mentioned to Dave a few weeks ago, if he went to a left hand thread on the inner rod end, he would also have on the car camber adjustment. Are you still thinking of going that route on your next run Dave?

 

Mike Mileski

Tucson, AZ

Link to comment
Share on other sites

Dave,

 

I don't dispute that you make some sweet control arms, and I am not trying to go retail with mine. I am just a person who likes to make things for myself (As many of the people on this site are). I used to think that the prices of your control arms were way out there, but (after making a set of my own) now realize the cost and labor involved. My control arms cost me about $330.00 in materials/welding, and about 20 hours of my own time. Most of my labor went into the construction of the fixture. I could make subsequent sets in about 4 hours. Even at that, the profit would not be worth the liability or headache.

 

My control arms were designed with my own needs in mind (light, strong). I looked into making an adjuster very similar to yours, and decided that the added weight wasn't worth the extra convenience. I have to disconnect the control arm from the strut to make adjustments. I have had the rear alignment set, and it was far easier than trying to align the rear with the aluminum/delrin bushings.

 

I am glad that you have decided to join us here at HybridZ. I always wondered why you weren't an active member here since you have been playing with these cars for so long. Hopefully, you will make this site a home, and not just use it as a storefront.

 

Cheers,

Dan McGrath

Link to comment
Share on other sites

Hey Dan, I appreciate the post. A lot of people out there don't realize what it takes to make a high quality product and sell it both in enough quantity and at a sufficient price to make it worthwhile. I too started as a tinkerer making my own parts (20 some years ago), now I employ talented professionals but still never charge more than what I would (and have) paid for a similar part myself.

Anyhow I really haven't had time to post before due to the constant backlog of work I've had especially over the last 2 years.

I hope to continue post when appropriate and as time allows.

Thanks for the welcome!

Sincerely,

Dave Epstein

Arizona Z Car

2043 E. Quartz St.

Mesa AZ 85213

 

480-844-9677

dave@arizonazcar.com

http://www.arizonazcar.com

Link to comment
Share on other sites

Guest macks

One concern I have is that all of these designs put the threaded shaft of the rodend in bending under accel and braking loads... has anybody experienced a rodend failure or removed rodends and checked if they're tweaked off-true after some hard launches?

Link to comment
Share on other sites

Yeah almost all the designs out there put some kind of threaded section in bending... Man has it ever been beaten into my head by Paul VanValkenberg, Carroll Smith, Mark Ortiz, Pat Clark, etc. that I will instantly die if I ever do something like that. :roll: While that is a bit of an extreme approach it does have some basis in reality. ;)

Link to comment
Share on other sites

Arizonazcar's control arms are toe adjustable on the car because the adjuster is captured by and free to rotate in the forward tube. To adjust, you just loosen the lock-nut, rotate the adjuster, and retighten the lock-nut.

 

When I was brainstorming the design of mine, I considered doing something similar. Unfortunately, I couldn't find an internally threaded fitting like his adjuster. I could get a long hex coupler and get most of the hex machined down.... In the end, I decided it wasn't woth the hassle.

 

As far as the rod ends in bending, I had to struggle with that one. In the end, I settled for using rod ends that were WAY stronger than necessary. The rod ends I use are Aurora XAM-10T 3 piece heat treated chromoly units with a 5/8" hole and 3/4" shank. Aurora's literature lists the axial strength of these as 41,000+ lb, and suggests 4,100 lbs if the rod end has transverse forces applied. The way my arms (and Arizonazcar's) are designed, the load is always shared between the two rod ends.

 

If anything fails on my design, it won't be the rod ends. :D

Link to comment
Share on other sites

Yeah I understand that you can make use of rod ends that will handle the stresses easily... from a pure theoretical racing point of view though (uh-oh) it's an inefficient use of weight. ;) When you are building lightweight formula cars an oversized rod end, in 20-30 instances throughout the car is actually a significant gain in mass. In a 2000lbs+ Z car with 2-4 oversized rod ends, the car isn't going to notice at all.

 

My point? I have no point other than I'd dissappoint all of my teachers if I did such a thing, after what it took to bash it into my head. :D

 

Another topic, slightly related is the use of threaded bolts in double shear situations... (think of a U shaped bracket with a rod end in the middle, captured by a bolt through all 3 items, side 1 of the U, rod end, side 2 of the U) Again it's a case of just going bigger to be stronger I guess.

Link to comment
Share on other sites

When at all possible I design my connections as double shear. If you look at my front tension compression arms, they consist of a rod end (loaded correctly), a threaded tube, and a large clevis welded to the frame. The rod end fits into the clevis and is through bolted (double shear). I too had proper engineering practice beat into my thick head, and have read all of Carroll Smith's work. :D

Link to comment
Share on other sites

But what bolt design do you use that passes through the clevis and rod end? A shoulder bolt of some type? My point is that all too often someone will put a threaded section through a double shear connection like this and even though it is in double shear, the threads will still be experiencing (reduced) bending loads.

 

I'm sure most people think I'm nuts by now. :P I can't really argue that. :roll:

Link to comment
Share on other sites

Mmmmmm... shoulder bolts. 8) Do you have any more pics of your frame to share? It looks pretty darn sweet. I take it you have an internal roll cage as well that ties into this one?

 

I've got to ask, what's with the paint? Did you mask the bars off and paint them prior to welding but leave the ends bare just to get the hard to reach areas?

 

I see the TC rod mount and that does clarify things. I thought form your description you were using the stock TC bracket, a clevis bolted to that, then a rod end in the clevis with a shoulder bolt. I see now that your clevis is the bracket and welded to the frame. A very robust setup indeed. I also see the TC rod mounting area is well triangulated.

 

Very interested in seeing more pics of this setup, it's pretty cool. :)

Link to comment
Share on other sites

Just to jump in and ask a question. All of the theory about shear and threaded rods, don't you think the fact the Arizona Z car arms have been around for 20 years answers any question you might have about their durability? I have never read a single post about their failing. That speaks volumes to me.

Link to comment
Share on other sites

Dave, I notice from the pics that on your front control arms the sway bar mount is welded to the front of the arm. There has been some concern voiced here (in other threads) that that having it mounted there, rather than on top of the arm, will induce twist by the vertical forces of the sway bar. I can see this putting bending stress and wear on the T/C rod mount and may even lead to loosening of the adjustment locknut on the arm.

 

I'm not and expert in this area or a racer myself so forgive me if I'm off base. I do respect your history with these parts. Just an observation that I'd like your feedback on.

Link to comment
Share on other sites

The sway bar pickup point on the front arms is there if desired and doesn't preclude alternate methods. Since the sway bar mount is approx. 1 inch from the centerline of the lateral link it exerts very little leverage on it compared to the rod end at the new T/C bracket which is approx 12 inches from center, so it only sees 1/12th the load from the sway bar. If the clevis was on top of the lateral link the distance to the end of the sway bar would be shortened to the point where the maximum angle of misalignment may be exceeded by the endlink rod ends resulting in a possible additional failure mode that otherwise might not exist. Have had customers engage in off track excursions that undoubtedly resulted in loads exceeding the intent of the design without causing failure of the components. All critical suspension and steering components should regularly be inspected for wear, fatigue, corrosion, etc.

Keep in mind that any suspension arm no matter how strong is still bolted to a 30 year old uni-body and any load it's designed for can easily be exceeded.....I'll talk about sheer plates on an INDY car at a later date.

PS I'll have a small tent with some of my goodies at the Nationl Z Convention SAT June 19th in Gardena CA if anyone would like to stop by.

Dave

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...