Hi Everyone,

I need help with an update to my '68 rear suspension. Who are the lucky souls out there that have had experience of the following?, what you would recommend and why?... Over here in the UK our roads can be very twisty, so although my car is a street car (it may be used for track days too) it will need to corner very well. Here's the list of possible rear suspensions:

DSE leafsprings/mini tub kit.
DSE Quadra Link
HRTH Truckarm Kit
Leaf springs with Watts linkage or panhard bar
..any other suggestions?

My car currently has monoleaf springs, so this would be converted to multi leaf if I stay with this type of suspension. I've ruled out IRS (far too expensive and heavy). My front suspension will consist of DSE coilovers, 1 1/8" Addco sway bar (I also have an Addco 7/8" Rear bar).

I know there are several postings on the above, but opinions of people who have had experience of them would be much appreciated. If I have not provided enough info, then let me know.

Thank you all in advance.

BTW: This site is excellent ! :beers:

DSE leaf springs/mini tub kit Basically stock suspension with wider tires. Improves traction and lateral acceleration if tires do not roll under (side wall stregnth).

DSE Quadra Link I'm not familiar with their Quadra link but I will assume you are talking about a four link suspension; which isn't really the ideal set up for twisty roads (especially with hemi joints).

HRTH Truckarm Kit The Hot Rods From Hell traction arms are ideal, offering superb linerar as well as lateral accelertion. But they will probably depreciate the value of the car if we are talking about a first gen Camaro, as most wouldn't recognize them or appreciate the advantages of running them.

Leaf springs with Watts linkage or panhard bar are not a vialble option unless you are running sliders under the shock plates which I would advise against.

..any other suggestions? Doug Adams book on hot rod suspension. (He wrote the book as they say, being the chief engineer on the firebird TransAm project and the one who turned the F-body from a muscle car into a well rounded sports car (especially in the 3rd gen cars).


Larger Dave

Hi uk68327,

can't answer your question but wanted to say hello- I'm in South East london just down the road from you- 68 camaro/ 396 BBC...be good to meet up if you want to talk camaro!!!
0208 850 9566
Cheers
Lol

For what your looking for I would suggest either the DSE leaf springs/mini tub kit If you want wider rear tires or; Hotchkis, DSE, Global West, three leaf rear springs.

You did not mention the Lateral Dynamics three link.

The DSE leafs can do wonders w/o the need for a watts.

Thanks for your input guys, I have narrowed it down to the DS&E Quadra link or the HRTH Truckarm kit, anybody have either of these installed (or have 2 cars with each one!), and could give an opinion on their experiences with these upgrades?

BTW I'm not that concerned about cutting the underbody to install - just as long as there are no mods to the bodyshell :eek:
Thanks again,

Mark

you'd be better off picking between DS&E quadra link and LD's 3 link

Can you give me a reason? Do you have experience of the HRTH setup or LD/DSE's?

Thanks,
Mark

Leaf springs with Watts linkage or panhard bar are not a vialble option unless you are running sliders under the shock plates which I would advise against.
I'm not sure I understand why the watts link needs "sliders under the shock plates" nor do I understand what "sliders under the shock plates" are. Could you elaborate?

A Hotchkiss rear end (two parallel leaf springs which support and constrain a live rear axle) has been found under virtually every modern car since the 1930's. They are simple and cheap which is why they replaced the other viable alternative the chain drive.

Hotchkiss has a couple of geometry problems associated with how it attaches to the frame which the automotive industry has over come by providing a splined propeller shaft and a loose (flexible) mounting system consisting of spring shackles and rubber bushings. This looseness allows for movement in reaction to the bumps, jolts, and torque reactions encounter in driving. This same looseness contributes to all of our handling problems.

If we constrain the rear end to gain control we loose flexibility and the suspension binds (stops working as suspension). By adding Watts linkage you are exchanging side to side (transverse motion) for up and down motion. Which sounds great until you actually observe that the rear end doesn't go up and down; it swings in an arc. That means that by adding the additional linkage you have over constrained the movement of the rear end and it binds. To alleviate this binding we have to allow the rear end to slide back and forth on the spring pads. A simple, easy fix; but now we no longer have the springs constraining the fore and aft movement, allowing the axle to pivot (steer). Clearly this can not happen, so we throw a few more rods, a few more Heim joints at it to constrain that movement.

Opps we did it again.

The Hot Rods From Hell set up replaces the entire Hotchkiss rear with two torque tubes (I-beams) and suspends the car with a set of coil springs. The coil springs are like Jello they go in any direction. Throw in a Panhard rod, or a Watts linkage and the rear end is constrained to move in only straight lines (the instant centers for the torque tubes are set at infinity). Torque is controlled by the arms, jounce and rebound by the HD shocks. That is why they make such a great rear end that NASCAR has been using them for decades in roundy round and road racing.


Larger Dave

If Nascar allowed the teams to use difrent set up, do you think they still would be using truck arm?