Unique's rear-mounted trailing arms

[sssnot]

Does anyone have any information about issues with Unique Motorcars' rear-mounted trailing arms? Is this an issue when drag racing, or even an issue at all?

[Russ Dickey]

Originally Posted by sssnot

Does anyone have any information about issues with Unique Motorcars' rear-mounted trailing arms? Is this an issue when drag racing, or even an issue at all?

What's the issue? I drag race my car at least 3-4 times per year, and as long as I do my job with the clutch, it launches hard and hooks up quick. Even when I've come out of the hole at too high an RPM, I have never experienced wheel hop or any other problems (except tire spin).

[sssnot]

Originally Posted by Russ Dickey

What's the issue?

That's my question!

I don't know if it's an issue or not--I don't think it is, personally.

But I remember someone telling me recently about a drag issue in reference to ERA vs. Unique. I don't remember who told me and I can't find the thread, or don't have the pm any more. In any case, when I came across this quote on the ERA site it got me thinking about the comment and I wondered what others here might say. Here's the ERA quote:

“Some other kits also use the Jag suspension, but because of space and design restrictions, don't use a trailing arm. This puts the lower control arm into stress modes for which it was never intended. With power on and power off, the arm will flex forward and back, changing the toe-in simultaneously. Not great for predictable handling!” http://www.erareplicas.com/427/rsusp.htm

As you know, your car uses a design by a chassis builder for Robert Yates racing. The guys at Unique say that their rear-mounted trailing arms "form a large a arm which eliminates stress on the rear hubs while stabilizing the center section," acccording to an email from them that I just received. I don't see anything wrong or dangerous about the design--it's just unconventional (to me) and I was wondering if ERA was referring to Unique in their quote above.

[Unique 289_FIA]

Before the rear mount trailing arm design, Unique used a front mounted design. I have it on my car. I don't think Unique ever had a design without a trailing arm at all, but I could be wrong.

[clayfoushee]

Originally Posted by sssnot

That's my question!

I don't know if it's an issue or not--I don't think it is, personally.

But I remember someone telling me recently about a drag issue in reference to ERA vs. Unique. I don't remember who told me and I can't find the thread, or don't have the pm any more. In any case, when I came across this quote on the ERA site it got me thinking about the comment and I wondered what others here might say. Here's the ERA quote:

“Some other kits also use the Jag suspension, but because of space and design restrictions, don't use a trailing arm. This puts the lower control arm into stress modes for which it was never intended. With power on and power off, the arm will flex forward and back, changing the toe-in simultaneously. Not great for predictable handling!” http://www.erareplicas.com/427/rsusp.htm

As you know, your car uses a design by a chassis builder for Robert Yates racing. The guys at Unique say that their rear-mounted trailing arms "form a large a arm which eliminates stress on the rear hubs while stabilizing the center section," acccording to an email from them that I just received. I don't see anything wrong or dangerous about the design--it's just unconventional (to me) and I was wondering if ERA was referring to Unique in their quote above.

Uh, no. They are referring to cars using the Jag suspension without trailing arms.

Think about the laws of physics. The Unique rear arms, by definition, form a strong triangle to resist twisting and deformation of the rear end and half-shafts under load. They are bolted to the frame and each rear corner.

[kris-kincaid]

Contemporary initially didn't use trailing arms. ERA mounts the Jaguar diffs the way Jaguar designed them, in a rubber isolated cage. Unique's method obviously works, but there is still some binding.

[tmareina]

My Unique, a 1993 build with front mounted trailing arms, had sheared bolts holding the left A arm to the differential, when I bought it in 2005. After replacing the bolts and adding the jack plate I have had no problems in the last 800 miles...including track day during WSCB 2006.