2 link or 4 link,pros and cons

[SCOTI]

Originally Posted by thekid54

I agree with bagged_gmc on the pinion angle comment.

However, 2-links aren't as bad some people make them out to be. For example, c-10's were produced for many years with a 2-link suspension, and it worked, and still works good. If you are going to bag your truck then pinion angle will be an issue. I personally went with a 2-link for my truck because I don't plan on varying my ride height that much while driving. I set it up for a ride height of 4.5" (lowest point of frame to the ground) and when aired out will lay frame. I set the pinion angle at this ride height because that's how I plan to drive it most of the time. If you max out your bags to get over a bump or go up a drive way momentarily, then it's not going to be too hard on your u-joints. Just my 2 cents.

The main reason the 62~72 2-link (aka trailing arm suspensions) work is because of the length & orientation of the arms within the chassis.

Most 2-link 'kits' are actually 2 'links' that are typically parallel to the frame/chassis & less than half the length of the 62~72 trailing arms. There was a thread @ bagit.com (or baginit.com?) about pinion angle change during suspension extension/compression when using this shorter style 2-link. It is a very good read. I did the little experiment that was suggested & was suprised to see almost 12deg of pinion angle change @ less than 4" total suspension movement w/a typical length 24" link (the 24" link is what would typically be used if swapping a leaf suspension over to a 2-link using the stock front leaf hangers).

That's a lot of change & even if you set the proper pinion angle @ the avg ride height, theres still a bunch of change w/the typical 2" of rebound or extension you'll experience driving down the road.

Just food for thought. I would suggest a 4-link for something that sees regular street duty & the 2-link for the weekend show warrior unless it's the 62~72 truck arm 2-link. We all know they work quite well.

[thekid54]

Yes SCOTI is right. I forgot to mention how the length of the arms factors in. I made my arms as long as possible without interfering with the cab mounts. Mine are about 10" shorter than the stock ones. My friend adapted a '62-'72 truck susp. into his '51 chevy coupe with air bags, works real nice!

[Tony@AirRideTech]

Originally Posted by SCOTI

The main reason the 62~72 2-link (aka trailing arm suspensions) work is because of the length & orientation of the arms within the chassis.

Most 2-link 'kits' are actually 2 'links' that are typically parallel to the frame/chassis & less than half the length of the 62~72 trailing arms. There was a thread @ bagit.com (or baginit.com?) about pinion angle change during suspension extension/compression when using this shorter style 2-link. It is a very good read. I did the little experiment that was suggested & was suprised to see almost 12deg of pinion angle change @ less than 4" total suspension movement w/a typical length 24" link (the 24" link is what would typically be used if swapping a leaf suspension over to a 2-link using the stock front leaf hangers).

That's a lot of change & even if you set the proper pinion angle @ the avg ride height, theres still a bunch of change w/the typical 2" of rebound or extension you'll experience driving down the road.

Just food for thought. I would suggest a 4-link for something that sees regular street duty & the 2-link for the weekend show warrior unless it's the 62~72 truck arm 2-link. We all know they work quite well.

Good post man The trailing arms and a two link realy have nothing in common other than they look similar and have two connecting point. The geometry of a trailing arm system accounts for pinion angle change and axle articulation by the length of the arm being equal or close to equal length of the driveshaft. Plus the mounting of the arms angling inboard towards the center of the chassis from out on the axle ends allows for articulation. A conventional 2- link does not account for either of these scenarios.

[BigShoe24]

So I could get away with a kpcomponent step-notch, cpp trailing arms in the stock location, and mount my bags on front of the rear end? I have a 70sw and was worried about driveshaft problems, single driveshaft? Thanks for any suggestions.