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My 1935 Miller-Ford V8 build is started

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1908Rick Avatar
1908Rick Rick Eggers
Cape Coral, Florida, USA   USA
1900 Ford Model 01 "Quadricycle"
1908 Harley-Davidson Pre-War
1965 AC Cobra
Brian,
All I know about original suspension on the '35 Miller's is they used a transverse leaf spring and were front wheel drive.
When I chose that car to build, I decided I had to come up with suspension that would fit inside the bodywork of the car, so I wouldn't have the leaf springs hanging out underneath ruining the look.
I'm going with torsion bars running longitudinally like an old Chrysler.
Now that Charles taught me how to figure out the spring rate, I need to decide what spring rate to run. Has anybody ever checked the rate of those buggy seat springs that so many people use? Do they seem OK, or too soft or stiff?

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gearguy Charles Schultz
Oil City, Pennsylvania, USA   USA
My No-Weld drawing was intended to show multiple suspension types. The torsion bar arrangement eliminates the cross spring and uses one of the torsion arms as a panard bar. This is the system used on my first midget race car, a tube chassis built by Otto Hamburger in 1946. It has a cross spring front with a parallel bar rear suspension. Early Kurtis midgets had parallele bars front and rear.
As the cars got more powerful they needed stiffer wheel rates and many cars were refitted with shorter "cross" torsion bars. Eventually coil over front suspensions with cross torsion rear took over for dirt cars; Four coils are more common on pavement specific chassis.

For 900#, 300 HP midgets we ran 185 to 195# springs on the front with 125 to 140 pound bars in the rear. On pavement we were 325 to 400# on the fron and 175/225# in the rear. The mantra was "the harder you go into the corner the higher the front spring rates."

With 500# vehicles and 10 hp we are not going to go into corners very hard. Around 100# seems a good starting point.

gearguy Charles Schultz
Oil City, Pennsylvania, USA   USA
Here is a chart I made of commercially available leaf springs. IIRC, the buggy springs are around 125 to 175 pounds per inch.

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Attachments:
leafchart.jpg    38.3 KB
leafchart.jpg

1908Rick Avatar
1908Rick Rick Eggers
Cape Coral, Florida, USA   USA
1900 Ford Model 01 "Quadricycle"
1908 Harley-Davidson Pre-War
1965 AC Cobra
Charles, you've been a tremendous help. I was thinking I wanted somewhere in the 80-100 pound range, and your calculations show my guess at torsion bar length and size put me in the lower range of that.
I never thought of using one of the torsion bar arms for a panhard bar. That's pretty ingenious. Now I'm looking at modifying my design to do that. My original design has the torsion bar arms attached to the axle with heims, requiring a panhard bar to center the axle.. If I eliminate one of the heims and rigid mount the end of the arm, it should accomplish the same thing. That will save a little weight and a few bucks. Every little bit helps.



Edited 1 time(s). Last edit at 2017-10-09 05:14 PM by 1908Rick.

Denny Graham Silver Member Dennis Graham
Sandwich, Illinois, USA   USA
1950 Chevrolet 3600 "Old Blue"
Jeeze Charles....that chart does look familiar!
http://www.pbase.com/dennygraham/image/164909633/large

I made it up last January from data I gathered from the
Auto-Ware leaf spring calculator. http://www.auto-ware.com/calcs/leaf.htm
dg

gearguy Charles Schultz
Oil City, Pennsylvania, USA   USA
My apologies for the mis-attribution, Denny. I had intended to post this summary of my own calculation of commercial leaf springs. Not enough detail in my file names. How is your spring project going? Test the quench tank yet?
My only involvement with quench tank design resulted in a 30,000 gallon system with four 40 hp impellers capable of producing a surfable wave across its 15 foot diameter. Yours is a bit more reasonable.


Attachments:
leafchart.pdf    336.6 KB

Denny Graham Silver Member Dennis Graham
Sandwich, Illinois, USA   USA
1950 Chevrolet 3600 "Old Blue"
No sweat, thanks for your chart, I'll add it to the my reference file.
Quench tank turned out great. http://www.pbase.com/dennygraham/image/166371432
Haven't had the time this summer to work on any kart related projects.
Had a lot of domestic work to take care of. Finishing the heat out to the barn
so I'll have a little heat this winter. I'm sure you're finding out how much work
it is to get settled after a major move.....especially late in life.
dg

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