Spring Modifications for my 30 Speedster

[Jay Ess]

I am finally ready to re-spring my Speedster. I will be using a T rear, and a Posies A reverse eye and lower arc spring which is said to lower the front end by 2". I understand that the T spring should accomplish the same drop in the rear.

I am also interested in making the ride as compliant as possible. I am trying to figure out how I can at least be in the ballpark with initial modifications as I would like to eliminate as much trial and error as possible and hopefully minimize the number of times I will need to repeat the assembly/test/dis-assembly process.

The drive train is 100% stock with regard to its weight. It began its life bodied as a 4 door sedan. It is now aluminum bodied and the skin weighs about 50lbs (on the high side). There is a steel 1x1 sub-frame to which the body is attached and in total the materials weigh about 40lbs. The wood floorboards are still in place, and the fuel tank is the same weight as stock.

What I am trying to calculate is the difference in sprung weight between a 4 door sedan (body/interior) and my car as it stands now. I have searched the site, but I have been unable to find the weight of a 4 door sedan body, fenders, bumpers, etc..

Any help with that measurement would be appreciated!

Once that weight is a given, I will try to guesstimate a benchmark ratio of the stock spring rate, to the stock sprung weight. Once a baseline is established I will start removing leaves in an attempt to match the ratio.

I am hoping that the local spring shop will be able to help me with the measurements of my initial, and modified spring packs, using their shop equipment. I would hope that this get me in the right zone before I begin testing on the car.

Am I on the right track? Any input, insight, criticism, or comments are welcome.
Thanks,
js

[Brentwood Bob]

2462-2475 lbs on the 4door sedan. Roadster was 2155 lbs.

[Mike V. Florida]

You may also want to post this in the HAMB site to get the question before the greatest number of people with experience on non stock A's.

[gz]

This roadster has an 8 leaf T rear spring and a reversed eye 7 leaf front spring. Being a roadster, it should be much heavier than the speedster you described. It rides fine and does not bounce, sway or bottom out. It has standard Model A shocks although I am not sure what condition they are in or if they are really even absorbing any shock. I have driven the car thousands of miles, most on the road but also on some very twisting and turning road race courses.

I had a 1928 tudor with the same spring configuration. The extra weight of the tudor body caused the car to sway left and right as well as bottom out when on rough roads-which we have a lot of in Detroit. Tube shocks and a panard bar helped to remedy this.

[Jay Ess]

Originally Posted by Brentwood Bob

2462-2475 lbs on the 4door sedan. Roadster was 2155 lbs.

Bob, thanks for the response. Would you know the weight of just the body, fenders and bumpers as this would be sprung weight. Thanks, js

Originally Posted by Mike V. Florida

You may also want to post this in the HAMB site to get the question before the greatest number of people with experience on non stock A's.

Thanks Mike. I am a member and will be posting over there as well. I thought that this would be the best place to ask about the weight of just the body. I also know that a number of members have dabbled with speedsters over the years and have shared their knowledge in the past.
js

Originally Posted by gz

This roadster has an 8 leaf T rear spring and a reversed eye 7 leaf front spring. Being a roadster, it should be much heavier than the speedster you described. It rides fine and does not bounce, sway or bottom out. It has standard Model A shocks although I am not sure what condition they are in or if they are really even absorbing any shock. I have driven the car thousands of miles, most on the road but also on some very twisting and turning road race courses.

I had a 1928 tudor with the same spring configuration. The extra weight of the tudor body caused the car to sway left and right as well as bottom out when on rough roads-which we have a lot of in Detroit. Tube shocks and a panard bar helped to remedy this.

Thanks for the seat of the pants guidance! js

[gz]

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Keep in mind you are doing what thousands of other people have done since the day the first Model A became a used car. No real reason for calculations or analysis!!!! Just do it and get on the road!!!!

[Jay Ess]

Originally Posted by gz

Keep in mind you are doing what thousands of other people have done since the day the first Model A became a used car. No real reason for calculations or analysis!!!! Just do it and get on the road!!!!

Boy I wish I could! I have this personality disorder that will not allow me to consider having fun unless I anguish over every detail. It sucks...

[Brentwood Bob]

no clue on chassis weight. IMHO 1500-1700 lbs. I have lifted alot of the parts separately.

[Big John]

discuss some issuses with parts suppliers... they should know what sheet metal weighs they have to ship it to you....

[john in illinois]

For the front spring,you might want to contact posies direct when you have your weight . I put a posies front spring on my Tudor and they sent a different number spring than I ordered . I called and they said that number would work better. Car sits and rides good. Nice folks to deal with.

John