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Author Topic:   rear control arms 4link
I-B-RACIN
Dirt Maniac

Total posts: 132
posted November 23, 2004 04:28 PM  
switching over to a 4 link what size tubes and heims. do i need 5/8 or 3/4
thanks

[This message has been edited by I-B-RACIN (edited November 23, 2004).]

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted November 23, 2004 04:39 PM  
You can use either one. 3/4" is kind of overkill if you ask me though.

donslink1
Dirt Freak

Total posts: 318
posted November 23, 2004 06:18 PM  
Our Pierce car has all 3/4 heims in the back.

sdracer12
Dirt Maniac

Total posts: 180
posted November 23, 2004 06:34 PM  
Mine are all 5/8" heims and tubes, works fine, and didn't break any of them in 40+ nights of racing, lol.

boas51
Dirt Maniac

Total posts: 190
posted November 23, 2004 07:48 PM  
my car is 1/2"
when i designed it i decided 2 link ran 3/4" so twice the arms should only require 1/2 the rod end. also the weight of the entire back of the car is supported by a couple of 1/2" rod ends on a shock or coil slider on most cars.
i have wrecked and bent several arms, and have bent rod ends, but have never broke any.
you can use 3/4" .120 wall tube tapped to take a 5/8" rod end with a 5/8 or 1/2" hole, works good. you will have to run a drill bit through the ends of the tube, it isnt quite big enough to tap 5/8".

zeroracing
Dirt Forum Champ
Total posts: 1875
posted November 23, 2004 08:21 PM  
I run 5/8ths or 3/4. depends on the track or what bars are laying aroudn the shop. on rough tracks i run the 3/4 stuff, also if the track might get really rough i like to run the lr lower as a swing arm link, 3/4, and very very strong, plus if it gets too rough for the 4 bar i can flip the upper bar over and turn the car into a swing arm in about 2 min max.
i would be weary of using 1/2 tubes and hiems, if it works then great but i would be weary on very rough stuff. you must remember that the load on the 2 bars in not equally distributed.

andykmod
Dirt Freak

Total posts: 351
posted November 24, 2004 01:12 PM  
5/8 on 4-bar. 3/4 on 2 link and z-link.Half inch sounds kind of weak to me,also make sure to use good rod ends on the 4-bar they will not wear out or get sloppy as quick.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted November 24, 2004 01:46 PM  
On the 1/2" stuff i personally wouldnt worry so much about bending or breaking the heim as much as the tube, especially on the longer bars. The longer they are the weaker they are in the middle, at least in bending, and if for some reason you get a little dent or kink started in one it will prob go ahead and fold up on you.

donslink1
Dirt Freak

Total posts: 318
posted November 24, 2004 03:01 PM  
I think if you are worried about the size you put in your car, Then it is too small.
I mean 3/4 is a little over kill but it doest seem to slow down Paul Harelstad and Denny Schwartz and those guys. It is kind of nice because everything is the same. You dont have 1/2 here and 5/8 there and 3/4 on that, It is all the same. Grab two 1 1/8 wrenches and check the whole rear suspension

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted November 24, 2004 03:49 PM  
When we brought our new car home we changed ours from 3/4 to 5/8 right away. The smaller tube and ends gave more clearance inside, and around the birdcage(A1) brackets, without doing this the 3/4 stuff was close to causing bind problems. I did it just for peace of mind and saved a little weight in the process. There really isnt a cost difference either. If it hadnt been for the clearance issues I wouldnt have bothered changing them.

The other advantage of it is if you are making your own 4 link brackets or ordering them you can get brackets with 5/8" holes that are spaced closer together than 3/4". Giving you more adjustment options.

FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted November 24, 2004 06:11 PM  
my car uses 5/8" I guess its just personal preference though. 3/4" is ok like donslink1 says 1 wrench size does it all. I don't know about 1/2" never seen anyone run them. Its all up to you but I wouldn't go any smaller than 5/8"

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