Tech Question - 1937 Packard Springs

Dear Mike,

We met in Richmond, VA at the NSRA show last August.

My car is a 1937 Packard convertible with Fat Man suspension and Mustang II coil springs.

The springs had sagged to the point that the lower A-arms were not level but were going up toward each wheel. It had been suggested by the safety inspectors that I install taller springs and then dropped spindles.

After jacking the car up several times and taking multiple measurements, I decided that I needed a spring which compressed would measure 9.25".

My car weighs 3655 Lbs. with 1700 Lbs. on the front axle and 1960 Lbs. on the rear axle.

Using your chart, I thought that the M23908 with a loaded height of 10.25" at 1750 Lbs. would be the correct spring for this application.

I ordered the springs and installed them along with dropped spindles, new shocks and drove about 50 miles.

The springs measured 9".

I removed the springs, painted them and re-installed them.

After a 600 mile trip to Knoxville, TN, the compressed springs measured 8" and the tires are rubbing the front fender when I turn left.

Mike, I am disappointed that the springs sagged 2 Inches more than your chart indicates at 10.25".

I am looking for a solution to this problem and would appreciate any help/advice you can give. Is it possible that the wrong springs were shipped?

Thanks, Wade

Wade,

I remember the car, very nice ride. Now to getting her even nicer.

There is nothing wrong with either the springs we sent, or the chart. In the world of suspensions there is this thing called "effective wheel weight".

That is, the actual weight on the tires may not be the same weight the suspension is supporting. The weight on the suspension may be equal to, less than, or more than the actual weight on the tires.

There are a whole bunch of factors that determine the "effective weight". But based on the additional 2 Inches of drop I would say the springs are supporting the force of an additional 700 Lbs.

Our chart is a guideline for choosing springs. And believe it or not, it is accurate well over 97% of the time. But like so many other items on a custom built vehicle, every now and then theory and reality clash.

I would think that our spring number M23136 may just do the job for you.

-Mike