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View Full Version : Radius Arms Vs Trailing Arms



__Z__
10-07-2015, 12:31 PM
Both using spherical bearings/heim joints on frame side, and u bolts on axle side.

Pros/Cons of one over the other for handling purposes?

I've been doing a fair amount of research on the interweb, and seen comparisons on them for off road use, but not much as far as street/track use.

I would like to hear some of your feedback from experience.

Thanks,
Zac

dontlifttoshift
10-07-2015, 01:52 PM
Forgive me, can you tell me what the difference is? Bonus points for pictures of each setup.

__Z__
10-07-2015, 02:21 PM
Both are technically a radius arm, however, I typically see trailing arms mounted inside the frame rails pointing outwards, and "radius" arms (like a lower control arm) mounted directly below the frame or outside the frame and running parallel with the frame.

dontlifttoshift
10-07-2015, 02:58 PM
Got it, just wanted to make sure we were on the same page.

Trailing arms are more commonly know as truck arms and can be made to work quite well. You see them mostly on oval cars.

Radius arms, commonly seen in the bagged truck world as a 2 link, are wrong. They essentially turn your axle housing into a giant anti roll bar. The enitre suspension is in a bind when the body rolls. Broken parts, terrible handling, and heartache is the result. See also, ladder bars.

__Z__
10-07-2015, 04:10 PM
What a friend and I were looking to do was take a set of square tube control arms, put in spherical bearings, mount them in the location of the factory front leaf spring mounts and run them under a rear axle and attach it with U bolts.

And use that setup with a panhard and rear swaybar.

Opinions?

dontlifttoshift
10-07-2015, 04:57 PM
I wouldn't. It doesn't work. The slightest bit of body roll and the whole rear suspension is in a bind.

Truck arms work (pretty okay) because 1. the two front mounts nearly converge, 2. they have rubber bushings, and 3. they are made of I beams so they can twist. Any deviation from that and the system is broken. Yes, NAPCAR runs monoballs in their truck arms, they don't have 5-6" of suspension travel either.

Someone was selling a setup similar to what you are describing......I don't believe it is available any longer.

Carl @ Chassisworks
10-08-2015, 08:45 AM
Truck arms work (pretty okay) because 1. the two front mounts nearly converge, 2. they have rubber bushings, and 3. they are made of I beams so they can twist. Any deviation from that and the system is broken. Yes, NAPCAR runs monoballs in their truck arms, they don't have 5-6" of suspension travel either.

This.

COPO-RAT
10-15-2015, 08:16 AM
hotrodstohell.net sells truck-arm kits