Dear Welder Series… Help with rear suspension please

Dear Welder Series…
Please recommend one of your kits to replace the existing crappy, poor handling, death trap rear suspension set up I currently have on my ’30 Ford roadster. I would like to keep the buggy spring set up if possible. If not, would your 4 -link rear triangulated universal kit fit my needs? maybe the 4- link kit Modal A with rectangular frame rails be better?

rear suspension

Dear David…
This is a great looking roadster. In trying to get a good ride, there are a number of things working against you.

Heavy spring. My guess is that the back end of the car doesn’t have much suspension. You could try removing some leaves from the middle of the spring pack to see if that gives a softer ride.

No shocks. This is probably because with the size of the spring, the suspension is pretty solid and so shocks would only be going along for the ride.

Short bars will produce a choppy ride. The layout is interesting and I don’t have a problem with the 3 bar system. The nature of the car means the bars have to be short and this causes a choppy ride.

The upper bar clevis likely doesn’t have a bearing. If the bolt is tight, the clevis will pinch the mounting plate and won’t want to let the suspension work. If the bolt is not tight, the wear will be on the bolt, the mounting bracket, or both. Clevises are not designed to do the same type of job done by a spherical rod end (Heim). A rod end would be the thing to use at the front of the upper bar.

I don’t see how the frame is stabilized left-to-right, except by the spring shackles. A transverse spring will let the frame move left to right as the shackles rock. This will give a weird, ill-handling feel. A Panhard bar will correct this problem.

Our rear 4-link kits will give a much better ride but I don’t see how there is room for one. The frame brackets would have to be changed so there would be enough ground clearance.

My suggestion is to see if you can make changes to some of the areas noted above. The car seems to have some clever workmanship and it might only require some tweaking to improve the ride.

Thanks for looking at Welder Series parts.

Paul Horton

One comment

  1. Wayne Cole says:

    Very interesting read Paul,…and exactly what I am up against here at the moment with my ’30 “A”, 2 Door Coach.

    I had a ” Posies ” Rear, Transverse Super Slide – Reverse Eye Low Spring ( Identical to a Stock Model A Spring ) installed on my 8″ Ford Rear,…while still using the stock Model A Frame Crossmember,..on a stock ( Boxed ) Model A Frame. Thankfully I had already installed the Welder Series Model A Rear 4 Link kit to my axles. The Posies spring leaves the rear of the frame way too High,and I didn’t need a test drive to tell me that it would be a problem with handling / and even looks for that matter, I am going full fendered with this project.

    I removed the Posie spring, and purchased a Brand New Model T Transverse Rear Spring,…thinking that with the shape of it being less vertical than the Model A style spring that it would help in lowering the rear,…it did some,..but still not enough. I have decided to remove 4 or even 5 of the (9) leafs from the Model T spring, ( to get it lower yet….and install the Heidts 250# Coil Overs on the rear. I feel safe with removing 5 leafs as the spring will be the component that is ” Just going along for the ride ” in my case,…yet adding to the lateral stability some. I am also installing the Welder Series Panhard Bar.

    Someone has demonstrated some quality engineering on David’s frame, and it certainly does appear well, and ( safety wise ) built,…but I too believe that the Transverse spring is the culprit causing his problems too. According to Posie,..the ” Ideal ” measurement from Perch, Eye to eye center is I believe 48.5 “,…due to lack of room on the Ford 8″ Rear in my case,…I could only get 46.5″ width to perch eye Centers. The stock Model A rear spring is meant to attach to the rear backing plates on a stock model A,..which is way out there,…so I am not saying that the Posies spring ” Won’t ” work,…you just definetely need the recommended ( Stretched ) width to make it work right.


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