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Tubing size for suspension link?

Jeff 98XJ WI

NAXJA Forum User
Location
Butternut, WI
Hey guys, I did search on this and gained a bit of inf, but I'm still wondering what opinions are on using what I've got. :) If I were to build a long three link front suspension similar to Crashes, would it be ok to use 1.25x.1875 (3/16) DOM tapped to 1-18 to fit my adjustable Currie Johnnie Joints as the one upper link? The link would be no longer than 36 inches and mounted up high so impact with other objects wouldn't be an issue. I have most of a 20' stick of this tubing taking up space in my garage and am using two stock length lower control arms made from this material right now. Crash is using 1.75"x.120 tubing for his upper link and 2x.25 tubing for his lower links. Thanks for any input. Jeff
 
Jeff 98XJ WI said:
Hey guys, I did search on this and gained a bit of inf, but I'm still wondering what opinions are on using what I've got. :) If I were to build a long three link front suspension similar to Crashes, would it be ok to use 1.25x.1875 (3/16) DOM tapped to 1-18 to fit my adjustable Currie Johnnie Joints as the one upper link? The link would be no longer than 36 inches and mounted up high so impact with other objects wouldn't be an issue. I have most of a 20' stick of this tubing taking up space in my garage and am using two stock length lower control arms made from this material right now. Crash is using 1.75"x.120 tubing for his upper link and 2x.25 tubing for his lower links. Thanks for any input. Jeff

I typically don't cut threads in tubing, i prefer to use bungs, mainly so i can type the word "bung".

the tubing specs are totally adequate. no comment on the cuttin' thread part.
 
Since the upper link will only control axle wrap and not be subject to transverse load (i.e. rocks) 1.25 x .188 wall tubing should be fine. Theoretically, the larger the diameter the stronger (within reason), to prevent buckling, however no longer than the link would be you won't have to worry about that.

I agree with Beezil on the bungs, both in use and pronunciation.

HTH
 
Personally I would use something more ridged for the lowers. When you get a link that's 30-40" long and a good part of that hangs below the frame, it's going to take a beating. Also realize that the middle will not be far behind the front tires. Drop off a ledge that's very high you will land right on the middle of the arm which will be the weakest point for bending.

I would say 1 3/4" X 1/4" would be the minumum.
 
Gee Paul. That's some good advice. :rolleyes: Lincoln, I am only talking about using the 1.25x.188 tubing for the ONE long upper link. I'll have to use some thicker/larger diameter tubing for the lowers. Maybe I should use square for the lowers? Hell, maybe I should use square for the upper too? Jeff
 
Jeff 98XJ WI said:
Gee Paul. That's some good advice. :rolleyes: Lincoln, I am only talking about using the 1.25x.188 tubing for the ONE long upper link. I'll have to use some thicker/larger diameter tubing for the lowers. Maybe I should use square for the lowers? Hell, maybe I should use square for the upper too? Jeff
Unlike Lincoln, I actually READ your post, so i knew you were talking about only uppers. But as long as were on the subject, .250 wall is what one would want for lowers.

also, there is nothing wrong with using square for arms.

they are very strong in the plane parallel to each pair of sides.
 
Beezil said:
Unlike Lincoln, I actually READ your post, so i knew you were talking about only uppers. But as long as were on the subject, .250 wall is what one would want for lowers.

also, there is nothing wrong with using square for arms.

they are very strong in the plane parallel to each pair of sides.

Beezil said:
Unlike Lincoln, I actually READ your post,

You want me to learn to read now also. Fine be that way.

3/16 is good for the upper and I wouldn't hesitate to tap it. Bungs are for bung heads. I don't like how sloppy they are and all the ones I have seen were still cut threads. Even if they were rolled the sloppyness would lose any strength gains. If you meant a 1"X8 (couldn't find 1X18) 7/8 I.D. would be good, but I would chase it with bit before tapping. 1x12 would work but you need to ream it a 1/16".

Bung head even has a lathe handy and still can't cut threads. I heard he tried to use a swiss army knife and went home crying.
 
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Just looked at my chart and it show's the 1-12 (listed as UNF) as 59/64. Pretty close to the 7/8" your using. The chart I was looking at earlier showed 15/16. I read it on the internet so it must be true.

I always chase the hole with a bit even when I'm using the correct ID. It seems every time I didn't I would chip the tap or just generally have a crappy time.

Either way I don't have a problem threading holes instead of welding bungholes. :D

I did think everyone else has been using the 3" JJ on their single uppers though but maybe that was just Texas Mark.
 
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