Aluminum 4 bar?

[anothersteveg]

I'm planning the front end for my '27 coupe. I'm looking around for parts and trying to figure out how I'm going to do the front. I'm leaning towards a 4 bar using heims on the frame and clevises for the mount on the axle (F100 I beam). I found a place right around the corner from me that has great prices for custom length and tapped radius rods. www.rodendsupply.com

They sell steel and aluminum. I'm wondering about the strength of the aluminum rods? This place sells them for sprint/midget race cars and I kind of like the idea of the aluminum appearance. I'm trying to make my coupe a little different from the norm, yet still safe and on a budget. Comparing like sizes the aluminum is cheaper, but obviously I'd need a thicker size to be comparable in strength to the steel.

So what do you think about using aluminum for the radius rods? If you were to use it, what size/thickness would you go with?

Thanks!

Steve

 

[Old Iron]

With it being 6061-T6 it wouldn't bother me to use it at all. I know there's others on here who would disagree and that's perfectly fine.
I'd use the tapered 6838XX - 7/8 .156 wall with the 1/2 thread size.
A better choice would be the non tapered 20-XX 1" with 3/4" threads. jmo

 

[anothersteveg]

Thanks OldIron. I was leaning towards the 1" myself. I've been batting this around in my head for awhile now when I found this place, and the best part is it's right down the street.

On another note:

I'm using a Suzuki Samurai frame and am in the process of cleaning and preparing it (I know, build thread is coming soon). The front spreader/x-member is
2" OD round tube from the factory. Every other car I've seen with a round front bar is 3". I'm going to use a spring behind front end and am wondering about the spring perch. Mounting it on 2" vs 3" round tube? Does anyone have concerns with this as far as strength?

The other option is to cut it out and weld in a rectangular 2x4 which will match the frame rails. I've also got enough 2.5 " round tube to use, but kind of seems silly to go to all that work just to add .5 inches.

 

[WickedFast1]

I used 1 inch with 3/4 rod ends on the 4 link on the dirt late models and 5/8s on the tie rod ends but that was on a race track. I never had a failure but also the driver had a cage around his butt! motor made 840 hp and used titanium axels it the quickchange! bent a few but never broke one the 4 bar links that is!
myself i'm afraid to run them on the street anything can happen, a jam nut come loose and the threads will pull out well you know what happens then, you become a passenger!
think about this, are you willing to check nut and bolts before you drive? how often? this is not a bash just thinking. use your best judgement.

 

[anothersteveg]

I'm a pilot by trade, so preflights are the norm.[cl

Are you mentioning the threads and jam nut backing out because of the aluminum aspect or the heim/clevis joints? I'm not trying to be argumentative, just trying to get my head around what the concerns with aluminum might be. As far as jam nuts backing off I don't see how that would be any different than steel?

I've never seen aluminum radius rods on a rat/street rod before and am just wondering if I'm missing something obvious why nobody uses them. I also don't see many 4 bar front setups either, but I think that's an aesthetic thing?

 

[WickedFast1]

no I was telling you about my set up on the rear end and how much abuse they will take, but also I have had jamb nuts come and the threads pull out.

 

[anothersteveg]

Oh, I gotcha. Yeah, I can see how that would be a concern with aluminum, especially in the back where you can't see them easily, but that's good to hear they can take the stress. In fact the place that has them looks like primarily a sprint/midget race shop.

I just liked the idea of the aluminum finish for the front as far as a different look.

 

[Dirtyrat]

Why not use polished stainless? I would shy away from the aluminum for a street car personally, but I do know that they can hold up to the stresses if sized properly...

 

[anothersteveg]

That's what I'm asking I guess. What is the proper size? I like the polished stainless idea, but that would overshadow the rest of the car. I'm definitely not going the chrome/shiny route.

In fact the aluminum may not even go with the rest of it, just thinking along the lines of different from all the other cars. It's half model T coupe, half 27 Dodge, sitting on a Samurai frame with homemade doors.

I'm also really trying to get this done (properly and safely) as cheap as possible. I can get tapped radius rods (steel or alum.) cheaper than any other place I've found, including making them myself. If the aluminum is cheaper and unique, then that appeals to me. But not if they have to be 4 inches wide to be safe.

Other than race cars, has anyone seen or used aluminum?

Thanks again for the input!

 

[Kurtm333]

Stainless scary...

Stainless is a very brutal metal. Stainless bolts are considerd grade 2.

I race off road cars, aluminum is the way to go, 7071 is very flexible their for takes the abuse. I would use 1" solid with good Hiem joints. The width of the axle mounting points are more important than your choice between steel or aluminum.

And check your nuts every once in a while!

Kurt

 

[anothersteveg]

Thanks Kurt.

It's 6061 Aluminum. I don't know much about Aluminum grades, so.....?

What are your thoughts on the mounting width? More=better or worse? I will have to measure tomorrow to give a better idea on the specifics. The plan was to set them up as close to parallel with the frame as I can. I will also run a panhard. Since they are custom, I can go with whatever length is best.

 

[Kurtm333]

Width

You can't beat 6". [cl

But if they were 7" you could brag about it. Parallel is ok for the front with little travel. 6061 is just fine, doubt your going to be scraping them over rocks and sidewalks on purpose. Made your panard as long as possible or go with a watts link.

If you angle your upper or lower links you wouldn't need a panard. I've thought about running a crankshaft as a front cross member and using some rods for an upper wishbone (3 link). Wouldn't need a panard then either but would have to be a suicide axle or the lower links.

Kurt

 

[anothersteveg]

Now that would be different!