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[Jakeporter]

In an attempt to install a more heavy duty rear suspension spring I have run in to a few questions. Any feedback would be appreciated.
Questions are:
1.What is the over all effect on ride height and handling by installing a heavy duty spring? I have the reduced height coil springs on the front suspension.
2. Since the spring has an extra leaf the overall height of all the leaves combined is greater than the stock spring. This causes a problem to install the Tube/spacer and bolt through the holes in the retaining plate with the insulator pad installed. To get the bolt through the retaining plate I had to eliminate the insulator pad and replace it with a thin piece of rubber. Even then I had to C-clamp the spring leaves together to get close to a point where the bolt would begin to engage. The bolt then had to be manipulated into position. It does not feel right to force the bolt through and to replace the insulator pad with a thin piece of rubber to reduce the overall height (spring and pad).
3.Are there negative consequences with this?
I see that Rimmer Bros no longer offers a 20% uprated spring. I am intending to give them a call to see if there is any correlation to my questions and them no longer carrying the heavier duty spring

[Jakeporter]

Went on the British Northwest site and found a heavy duty spring listed. In the text it stated the following....
"This is a heavy duty 6 leaf spring for a Triumph Spitfire 1971 to 1980. The spring also has the spring bushings installed. The spring has an extra leaf but will give you a stock ride height. The only modification you have to make it to elongate the mounting cage hole. 159640"
Perhaps this is the answer I was looking for.

[arunkle]

I am also interested in the heavy duty spring.  I had gotten all the information about same ride height, and according to a flyer I just got from Rimmer Brothers, they have the 20% spring.  I was more interested in the benefits of the heavy duty spring (does it reduce body roll, or does it just make it longer till you need to replace it again) and what are any downsides.

[Jakeporter]

I received the same flyer from Rimmer and see the uprated spring so not sure why the web site says no longer available.
I also seem to remember the Britsh Northwest description of the heavier spring used to say "never replace your spring again" so perhaps it has some % more life over the stock version.
Now I have also seen statements that if the stock rubber pads of the stock spring are replace with the teflon version a stock spring can be recovered. This in my mind however really only addresses ride heigth. What to believe??? It would nice to see some spring deflection data under load for both versions of the spring. More leaves means more stiffness.
Perhaps the best solution is a stock spring with teflon pads. At the end of the day a spring is pretty easy to replace so if not happy with a heavy spring then a stock spring could be installed. We would just be out a couple hundred bucks and a couple of hours of a Saturday.