Triumph Sports Cars

engine swaps and other performance upgrades, plus "factory" V8s (Stag and TR8)

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Richard/SIA
Richard Brengman
No. Nevada
(351 posts)

Registered:
01/17/2014 07:47PM

Main British Car:
1969 Triumph GT6+ 225" Buick V6

To let TR4A rear suspenion work, which spring leaf to pull?
Posted by: Richard/SIA
Date: September 28, 2016 11:59PM

With essentially no weight on the rear of the car the under-slung axle is against the frame at all times.
Jumping on it barely imparts movement.
So unless I want to get into some extensive redesign I need to remove one leaf from the rear to compensate for the much lighter load.
Short bottom leaf, or the one above?

Adding a fuel tank and maybe a spare tire will not be enough with the light fiberglass body I am putting on.


DiDueColpi
Fred Key
West coast - Canada
(1259 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
What if the Hokey Pokey really is what it's all about?

authors avatar
Re: To let TR4A rear suspenion work, which spring leaf to pull?
Posted by: DiDueColpi
Date: September 29, 2016 02:47AM

Depends on what you want Richard. Pulling the shorter leaves first will give you a softer more compliant spring with very little progressive action. Pulling the longer leaves first will result in a spring that has a much stronger progressive action at the expense of "wrap up" under torque resulting in wheel hop under higher power applications. Having a custom spring built isn't very expensive and gets you exactly what you need. If you are going to use the original spring, I've had the most success by reversing or "flipping" leaves starting with the longest and continuing as needed. The vehicle gets lowered with a very solid progressive action and the springs integrity remains intact.

Cheers
Fred


Richard/SIA
Richard Brengman
No. Nevada
(351 posts)

Registered:
01/17/2014 07:47PM

Main British Car:
1969 Triumph GT6+ 225" Buick V6

Re: To let TR4A rear suspenion work, which spring leaf to pull?
Posted by: Richard/SIA
Date: September 29, 2016 02:27PM

Well, it looks like I'm going to use my Alfa engine - OD five speed, and adapt the 4.56 LSD Alfa axle to keep the drive-train a matched package.
The Alfa drive-train is complete, the Buick would require me to buy another trans, flywheel, clutch, bell housing, shifter.......
I will find something to put it in eventually.

I will be modifying the rear of the frame to have a kick-up, Alfa trailing arms, upper link and coil springs.
So all that will remain Triumph is most of the lower chassis rails, front suspension and steering.
At the new expected weight I probably need to find softer front springs now.

Expecting some adjustments once on the road.


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