darrell, since this seems to be a "high interest" topic we will
comment. background. we supply a measurable amount of the total
"uprated" tr3-6 coil springs sold in the country and have for many
years. there are 2 seperate issues. one is the ride height and the
other is spring rate. ride height is always based on the original
factory dimension with oe tires and sitting in a level, unladen positon.
a tr6 sits at 28 5/8" measured from the fround to the highest point of
the rear wheel arch. the front dimension is about 1" less. this would
hold true for the 4A and 250. visually, ride height can fool the eye.
example - you replace the original tires with a low profile set - say 2"
shorter than the original tire. you now have an extra inch of space
above the top of the tire and the wheel arch (2" taller equates to 1"
above the tire). your car is now sitting 1" closer to the ground burt
you have also increased the distance fro m the top of the tire to the
wheel arch. spring rate is the amount of weight needed to deflect the
spring a given amount - normally 1". the springs we produce are 25%
stiffer in the rear and 20% stiffer in the front. this equates to 475
for the rear springs and 392 for the front. there are some issues that
come ito play on rate. normal spring industry standards are +/- 5% so a
500 ppound spring could be 475 on one side of the car and 525 on the
other - a 50# spread. our springs are held to 2%. this is the tightest
in teh spring industry. the other thing that can hapen is springs can
"set" or sag. this normally occurs when a lve coil - one that is not
touching another coil in the normal ride position - contacts andother
coil. this is called coil bind. when this happens, most springs will
then take a set and not return to their original free length. as part
of the mfg process, our springs are set solid - all coils are amed
against each other. if the spring returns to the original free length
after this step, they are guaranteed never to set or sag. we have
spirngs in use that are over 25 years old and still retain all the
original characteristics. sorry for the commercial but you needed to
know these points to better understand the dynamics of the spring/ride
height/rate. we have seen springs made in the uk that actually sagged
within a few months. what you need to do is measure your car. see what
you actually have for ride height,. if it is near the 28 5/8", you are
in the ballpark. if not, rear ride height is adjusted by the notched
trailing arm brackets. it can be raised or lowered. when you do this,
you also alter the front ride height. grab a ruler and start in. ted
Fax: 419/ 384-3272 (24 hrs.)
Phone: 800/ 543-6648 (US & Canada)
Tech/Gen Info/Worldwide: 419/ 384-3022
New - used - rebuilt - performance British car parts.
200-300 cars in our British salvage yard.
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