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micky1mo 18th October 2020 18:33

Sammio spyder front suspension set_up
When I build a SAMMIO I like to keep the cost down so the normal practice regarding the front suspension is to use standard Triumph shocks and a standard road springs with one full coil cut-out.
While this works fine and is OK for MOT's in UK it is not acceptable in Europe.

What I would like to know is what is the spec of a front suspension spring to lower the running height by about 30mm and provide reasonable driving performance on a standard 1300cc Herald chassis fitted with standard shocks and a SAMMIO BODY conversion?

I know many builders have found the own preferences but there must be a starting point/spring. :help:

andrewhush 19th October 2020 09:49

Shortening the spring restores a sensible ride height with the new lighter body. The trouble is the spring becomes stiffer, I.e. the spring rate increases. This is the opposite of what you want for comfortable road use. When I built a vitesse based Spartan kit many years ago, the kit maker's instruction was to use herald front springs with the heavier 6 cylinder engine and spifire springs (mk 3 or earlier) with the 4 cylinders. This restored the ride height and matched the spring rate to the lighter body. In those days you could find these easily at you local scrapyard. Happy days!!

Triumph Special 19th October 2020 22:12

Dolomites and Toledos had the same ID spring on the back, though I can't remember the free length offhand. The 1500FWD with the beam axle had a slightly shorter one on the rear, too.

Mister Towed 20th October 2020 17:19

The most versatile setup at a reasonable price (not cheap, though) is to use Gaz ride and height adjustable front shocks, which are typically around 180 per pair -

I've couple those with Spitfire 1500 springs (180lb) for a six-cylinder Sammio but I'm using Spitfire Mk1-3 springs (150lb) for the four pot in my Speedster.

With the rebound set fairly soft, only one or two clicks from the softest setting, on my Spyder I ended up with the ride height just right and a very compliant ride without the car bottoming out or jumping off the surface of the rollercoaster fen roads round here at speed.

On the same roads with cut down 200lb Vitesse springs it couldn't safely be driven above 50mph as the front tyres kept hopping off the road surface.

micky1mo 20th October 2020 19:38

Mr Towed Your right, the Gaz shocks are the one's to go for but I was after a spring to run with a standard Triumph shock.
The shock just do the damping it's the spring with do the work
There must be a suitable spring out there some where.:noidea:
You have pointed out the standard springs on a 4 pot is 150lb so there a start.
I'll try getting some shorter springs rated at 150lb and see what happens. :icon_idea:

Mister Towed 21st October 2020 22:18

The problem I found with short springs on standard shocks was that to get the ride height right the springs had to be too short for the shock at full extension so they were loose, which is both a safety issue and an MOT fail.

The Gaz shocks have an adjustable bottom seat which allows the correct ride height to be set with standard length springs, which is much safer and it's easier to obtain the right springs.

That was with a six-pot fitted, and I've found that in the Speedster I'm building at the moment, which has a Herald four pot up front, the 180lb Spitfire springs still ride too high even with the Gaz shocks at their lowest setting, hence switching them for earlier 150lb rated ones, which are just right.

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