What size tubing for 4 link bars?

I modified a set of Speedway radius rods and they still won't work. Looks like I'm going to have to make my own four link setup. I have 5/8" fine RH threaded clevises and rod ends. I think the Speedway rods are 7/8" O.D. but I'm not sure of the I.D. All I've heard of was 7/8" O.D. with 1/8" wall. Is there another common wall size a little thicker? I have to drill it out with a 37/64 drill bit to tap a 5/8 18 hole. If I bought 7/8 O.D. by 1/8"wall, that drill bit would just fall through. So if I want to use my 5/8" hardware what size tubing do I use?

 

All of our bracket racer stuff is usually 1", .156 wall directly threaded for 3/4 rod ends. You could build bars with moly tube and weld in threaded ends available at most speed shops or through the Ch***is Shop in Mears, MI. Trying to get the right wall and OD for a 5/8 rod end might be a tough call. If .156 wall 7/8 is available that should get it done. It leaves a nominal ID of .563 and your drill is .578. I can't raise my right hand as to how common that size is.

 

7/8 .156 from Ch***is Shop. Threaded to 5/8 fine for speedway ends or heims. Speedway and TCI are all 7/8. Heidts sells 3/4 4 bar ends if you want to go with the 1" stuff. I use the 7/8 on hot rods with out any issues.

 

i use 7/8" OD .188 wall because i have a big pile of it. if i'm gonna tap 5/8-18 , i drill it out with a 37/64" drill , for 11/16-18 a 5/8" drill. you need to do this in a lathe

 

Thanks guys, I ordered 12' of 7/8" .156 today. I was a little shocked, $68.50 for the stick. That's $5.70 a foot I hate Alro Steel, but they're the only game in town.

 

1" ONLY you wont be sorry

 

They gave you the big ole' reamer on that one. I pay about $3.75 a foot - cut to the general lengths I want. I can get it a bit cheaper than this - but I'm too lazy to drive a 100+ miles to get it.

I use 7/8 .156 DOM for the radius rods (front) and 1.0" .156 for the rear (due to torque/power from the drive line). I use 5/8 rod ends on the front and 3/4 on rear.

 

Hey: Who is running hard clevis type ends on the front batwing mounts - versus urethane bushing style batwings? I'm making my own radius rods and need to decide which style of batwing to order? Thanks!

 

Question for Mr Bored & Stroked. Hard clevis style mount and your front end meets a one side only speed bump (or similar event). If the jam nuts are tight, where is the yield/flex happening?

 

Excellent question by Pitman. Worth considering.
A clevis doesn't have any arc to it, while a spherical rod end (Heim) does. That's what a suspension bar needs.

For the bars on the back of my '57 g***er, I worked backwards: called The Ch***is Shop in Mears and ordered high quality 3/4-inch Heim joints. Then asked for the weld-in threaded insert (bung) for them to screw into. Two bars, so I got two left-hand threaded bungs, and two right hand threaded. (The lefts come with wrench hexes on them to make adjustment easier).
Then I ordered the chrome moly tubing to fit the inserts. They'll help you out with the thickness...it's what they do all day long.
Ordered it all from The Ch***is Shop, including the tubing. They'll cut it to any length you specify. Figure out what you length your tubes are going to be before ordering, and they'll cut them close for you.

-Brad

 

I think that is exactly what I'm pondering. There are many mfgrs that make solid mount (clevis) style front mounts for their radius rod to batwing connection. Heck, Ford did it the same way with their radius rods mounting solid to the I-beam axle.

The only place that I can see any "give" in a clevis mounted hairpin is on the rear mount -- depending on what type you have. Some guys use a Urethane bushing in the back, some use more of the tie-rod end approach.

Even on traditional split wishbones, they usually used a tie-rod end. What I wonder about - in this hard mounted approach - is that I can't see any flex material anyplace in the radius/hairpin rod system? Nothing on the front and nothing on the tie-rod end in the rear. At least Ford had a big ole' rubber "tennis ball" on the rear ball end of the stock wishbone -- it had to take some shock and vibration out of the radius/wishbone rod system.

So - given the above, I think I'm going to use the approach of Deuce Factory batwings (that use the urethane bushing approach up front) -- so that there is some give/flex in the hairpin radius rod system. The back will be the traditional tie-rod style mount. In my way of thinking this "should" be a better setup than a non-shock absorbing mount for both front and rear.

Maybe I'm full of hot air and dumb ideas . . . what do you others think on this subject?

Dale

 

5/8 tap tube from Lefthander Ch***is. It is 7/8 OD.

It takes a 5/8 NF tap with no drilling, works well when you don't have access to a lathe.