Thread: 4 Bar, Triangulated or parallel

Tweet

I guess on a cruiser I prefer the triangulated. Main reasons are that they are extremely stable and smooth handling, will tolerate a considerable amount of horsepower, and because of their configuration totally eliminate the need for a panhard bar (yuck) or watts linkage (way better). I've built them both ways, in 90% of the cars I've seen a triangulated is by far the better choice.....JMO

Pat: Judging by the workmanship on your Stude, I don't think much is beyond your fabrication abilities. What is probably making you leary is that this sort of technology is a little foreign to you, and to me too. But I will try to get you this info when my kid comes home from work. He has done quite a few bagged cars and trucks, and knows the ins and outs of what makes one work better than another.
As I have posted before, his latest bagged car is his '29, and the one before that is his S10. When I look at the suspension on them it really is only slightly different from conventional springs, except that you are using airbags and the related pumps etc to control the ride. You also have to allow for additional travel as you will be able to dump the car much lower.

When he gets home I'll ask him some of these points for you and post what he says. Here are the two I mentioned below.

Don

In the absence of any other considerations I'd say pretty much the same as Dave has. I think the triangulated setup has an advantage in traversing uneven pavement (visualize one end of the axle going up while the other maintains or drops), less "bind" on the upper arms (parallel 4 bar guys will likely deny they've ever experienced this, but I would suggest that's because they have no immediate comparative to judge against).

That being said, exhaust routing with triangulated arms becomes more of a challenge, and the bulk and heat vulnerability of air bags adds to that. If you've got enough "real estate" I'd vote for triangulated, otherwise the parallel system, complete with panhard bar may make for easier/better packaging of all your component needs.

Ok Pat, I caught Dan and asked him some questions about this. He was a little reluctant to give specifics because he says there are so many variables and every car and install is different. Plus, there are lots of opinions on how best to do it.

But here are some of his thoughts:

Air Ride Technologies makes nice stuff, but they don't like to get into custom lengths and stuff. Most of their kits are application specific, and even their universal kit is one length on the bars. The are also a little pricey.

He likes Suicide Doors better. They will custom make the bars to your length, are very reasonable in price, and super to deal with. (My '39 has their stuff under it, and so does Dans '29.) Their bars are 1 and 1/2 inch DOM and built super strong.

He says if you have the room, go with triangulated, as they eliminate the need for a panhard. The install is not one of the most simple jobs and takes much planning and fabrication. You will be rebuilding the rear of the frame to accomodate them and mount them.

For bags. there are tons of choices, but one place to start would be Firestone double convoluted bags, like a number 255, but that is only one choice. Vi-Air makes a good compressor, in many models, but a number 460 is a nice one. For valves, SMC are good ones, too.

Suicide Doors can help you pick out all the right components. He does say that bags are not the hottest set up for high performance usage. Coilovers and others are better if that is one of the points you are wanting to gain.

Hope this info helps get you started in the right direction.


Don