Have you ever bought new springs for your TR in anticipation of how the car was going to look and handle, only to find your pride and joy looked like you were trying to build a monster truck 4x4?  Then go to another supplier  advertising the "correct" or lowered springs with pretty much the same results?  I went through this exercise during the front end rebuild on my 4A. I talked to Moss, to TRF, to Victoria British, looked at the factory manual, all the available catalogs from US and UK vendors, my existing springs, some other springs and finally decided...

... that if anyone ever knew what the specs for the 4A were, they've been lost along the road to the TR-250/TR6.  Even springs for the later TRs don't always give the results you thought they would.  This situation is exacerbated by the fact that often different profile tires and wheels are fitted, which WILL alter ride height and how the wheel/tire fill the wheel well.  So, I reasoned if no regular spring is going to give me the ride height and stance I wanted, then I needed some type of adjustable spring setup.  I was aware that the custom car builders used an adjustable coil over shock for their creations, so I set out to see if one of these would fit a TR.  At first I had no luck, because most coil over shocks use an eye on each end.  Eventually, I found that a coil over setup was manufactured for '74 - '81 Mustang II - which used the post top setup that the Triumph used. 

I found the Carrera coil over kits for Mustang IIs at Summit (www.summitracing.com), Jegs (www.jegs.com) and Heidts (www.heidts.com), with Heidts being slightly less expensive at the time. I chose part number MP-041 for the 375# spring rate. They also come in 500#, 600#, etc. but the 375# spring rate is closest to a stock front ride quality on the TR - if you're into autocrossing or racing (or dropped a V8 into your TR) you could try the stronger springs. The coils on the kit are 8.25 inches tall at free length.  The coil-over kit may be used as is, but to get more adjustment out of it, you could modify the spring length as in photo 1. 

As you can see above, I cut 1.25 inches off the top.  It is easiest to cut with a saw to avoid heating up the spring, which will cause it to lose it's strength.  If you do use a cutting torch, make sure to quench the spring in used motor oil to restore it's temper (an old hot rodder's trick).  I am told that if you taper the cut end of the spring you could create a variable rate spring that would give you a softer ride for small bumps, while giving you a firmer spring rate for cornering.  I don't know the mechanics of it, but if anyone would care to explain it to me I'll update this page with the details.

Photo 2 shows shock and coil after being modified.

 Photo 3 show a comparison of the springs.

For the Triumph application the length should be 7 inches so no pre-load is required.  This will allow an adjustment up to four inches of load, which means the car can be adjusted from its lowest point of about two inches off the ground to about 6 inches (or with an unaltered spring approximately 3 inches to 8/9 inches). 

The installation was fairly straightforward. Just remove the old shock and coil. Screw the new adjustable shock in from the bottom holding the bottom spring support and spring in place by hand. Bolt the shock in place and then adjust the bottom spring support up to pre-load the spring. This is a good starting point. Now you have complete control of road height and camber adjustment for the front end, and can set to suit your wheel/tire package and driving style.

I believe this same or similar kit could be adapted to the rear end of the IRS TRs as well if you desired adjustability on all corners, but I haven't explored that option yet.  If I do, or someone else wanted to do so and let me know, I'll be happy to post the results here.