Geo Metro Suspension Swap (to handle extra battery weight)

[bennelson]

Hey folks!

I need to beef-up the suspension in the back of my '96 Geo Metro, which has been converted to electric.

I would like to add some additional batteries, but it's already riding low in back.

The back of a Metro has a strut, and then a separate coil spring.

I would like to find some springs that are the same size and shape, but are designed to take more weight.

Ideally, there would be some other car that I could find at a junkyard which would have those springs. I could pull them off, put them on my car, and then add in more batteries.

Somebody suggested that I just get springs off the "station wagon version" of my car. Well, I have the 2 door. Does that 4-door have a higher GVW and tougher springs? By how much?

Does anyone know of any cross-reference that might be able to help me?

I am still trying to keep costs low, so purchasing new or custom springs most likely ISN'T a good option, but let me know if you have any ideas.

-Ben

[Coyote X]

I am pretty sure the front springs are the same diameter as the rear. So if you want it jacked up a bit stick a set of front springs on the back. The spring base will probably not line up perfectly but it will fit good enough to not be an issue as long as you keep the rubber washer on there to keep the rubbing noise down. From what I can remember I think front and rear are the same diameter steel just the fronts are longer.

Just as a rough guess a front spring would prob lift the back end up 2-3 inches. If you don't want to try something quite that strange, the 96+ cars had the stiffest stock springs but they weren't that much stiffer than the older ones. The 4 door had the same springs as the 2 door.

[bikin' Ed]

I haven't sourced them so I don't have any specifics, but there are aftermarket air bags that when inflated inside your coil spring give you a heightened and stiffer ride.

[MazdaMatt]

Hey Ben,

you may want to do this a little more scientifically. Can you get the weight of your car's front and rear ends (with the new batteries loaded)? You could use this to compare to stock and select an "ideal" spring rate. Once you've got that, then you can start looking at the other options like the wagon or other cars.

You're pretty good at hacki...er... fabbing things up from scratch - have you thought about adding a second spring to each rear corner in parallel with the stock ones? Do you need front and rear to be stiffer?

[guudasitgets]

try pegasus racing , the racing springs aren't that much, if they are too long you can cut them, heat the end piece and grind it flat

[my first gmc]

I say bag it. That way you can lower it when on the highway.

[bennelson]

Originally Posted by MazdaMatt

Hey Ben,

you may want to do this a little more scientifically.........

You're pretty good at hacki...er... fabbing things up from scratch - have you thought about adding a second spring to each rear corner in parallel with the stock ones? Do you need front and rear to be stiffer?

OK - I went and scientifically did some measurements.

With a yardstick, I measured the distance from the ground to the fender, centered on the middle of the wheel.

On the back, it was 24.5 inches from the ground to the fender. One the front, it was 24" even. No I don't know what it was before I did the electric conversion. That was something I read about in a conversion book right AFTER I yanked everything out of the car.

Those height measurements are with 72 volts in the car - six batteries, motor, etc, but no people.

When I added another 6 batteries into the car (on the floor and in the back seat) the rear sat 1.25" lower than it did without. The suspension had pretty much NO bounce at that point. I don't think I measured what the front was when I had the extra six batteries in there.

Looking under the car, the rear coil springs appear to have an interior diameter of pretty close to 4 inches. Hard to say exactly, just because it's hard to get a clean measurement with the swing arm, wheel and tire, and everything else in the way.

The length of the rear coil spring appears to be about 7.5 inches right now, loaded with the 72V system.

On the door frame, it lists vehicle weight information.

GVW=2590lbs/1175KG
GAWR FRT=1399lbs/635KG
GAWR RR=1234lbs/560KG

Max load = 688 lbs occupants and cargo

Overall, the car feels low in its suspension. It rattles a bit going over bumps, smooth roads are just fine.

The front end of the car has a bit more bounce to it than the rear.

I don't know how I would add another set of springs in the rear. There just isn't any room for something like that.

I found a web page that had pairs of basic air bags that go inside the rear springs, for what didn't sound like a lot of money.
Air Lift Air Suspension For Chevy And Chevrolet Passenger Cars
The kit is $85, but I haven't found one listed for the Metro.

I am sure I could figure out how to install these things in the springs.

[TestDrive]

Originally Posted by bennelson

I found a web page that had pairs of basic air bags that go inside the rear springs, for what didn't sound like a lot of money.
Air Lift Air Suspension For Chevy And Chevrolet Passenger Cars
The kit is $85, but I haven't found one listed for the Metro.

Do the shock absorbers on the Metro run through the centers of the coil springs (a strut assembly) or are they mounted outside the coil springs? I think all of the cars listed in the link you supplied follow the later design.

[bennelson]

The fronts are MacPherson struts.

The rear is a separate shock absorber and spring independent of each other.

[MazdaMatt]

looks like a pretty sweet option