Hello,
Ever since I've had my 4A ('81), the ride height never has seemed right.
I've gone through several iterations trying to fix it, but I've never been
happy with the results. Currently I have a new set of stock springs (from
TRF) installed, and 165/15 tires (which should be very close to the stock
diameter).
Visually, it looks too high when compared to period photos. I have close to
4" between the top of the tire and the edge of the wheel well. Looking at
period photos the area around the wheel should be fairly even (accounting
for the fact that the arch isn't a circle). If I had about 3" of clearance
I think it would match the photos. Other evidence is that the manual claims
ground clearance is 6" (though it doesn't specify where that is measured).
Measuring anywhere on the flat parts of the frame (between the front and
rear suspension) I have 7". The final bit of evidence is that I have about
1/2" between the lower rear suspension bump stop and the shock arm, and
about 3-4" of upward travel. I would think that the suspension should have
a more balanced range of motion.
All of this leads me to think that I should lower my car by about one inch.
Before I do anything, could some folks with 4As take similar measurements,
include your tire size, and give me and indication of whether you think your
car rides at the right height?
So assuming I decide I do indeed want to lower the car one inch, how do I go
about it? Looking at the suspension geometry, to lower the car 1" the
spring needs to be shortened something less than 1". With careful
measurements and some math, I supposed I could figure out the exact amount.
But shortening the spring will increase its stiffness, so making it 1"
shorter will result in a compressed length of something less than an inch.
The good news is that these two effects should cancel each other out to some
extent, is it enough that I shouldn't worry about it?
My second concern is having the springs shortened. When I helped my friend
lower his Mustang years ago, the front springs where flat on one end, but
the other was sort of threaded onto the suspension. So all we had to do was
cut a coil or two off, and several hacksaw blades later, we were done. But
the TR suspension has both end flat. Is this something that a spring shop
would be able to handle, with reasonable accuracy?
Lastly, is there any other reason anyone can thing of that would make the
ride height off by so much? The quick history is that when I got the car,
the front seemed too high, and the rear too low. I'm sure the rear was too
low because I hade less than an inch of upward suspension travel. The car
did have 14" wheels at the time, so the front could have been OK. I solved
the problem at that time with some air spring "helpers" (from none other
than J. C. Whitney). Ten years ago when I did my frame-off, I installed a
set of "mild comp" springs from TRF (SAH part numbers). This seemed to also
ride too high, in fact the rear shock arm was just contacting the bump stop.
Hoping that the springs would "settle" I left them on until last year, when
I installed the stock grade. That helped a little, I didn't take any
precise measurements (and I changed wheels/tires at the same time), but I
think it dropped the car about 1/2".
I really hate changing springs, so I'd like to fix this once and for all!
Thanks!
--
Darrell Walker
66 TR4A IRS
Vancouver, WA, USA
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