fiberglass leaf springs:

My '88 Ranger has steel springs.

 

OK.....OK....man you guys are pushy!! j/k

Well, I have the flex-a-form springs and here's my experience with them so far....

The first pair I bought, the passenger side broke on a low 6 second pass at farmington dragstrip. I had made a couple of passes and noticed that the passenger side was sagging quite a bit.....after inspection, the spring had cracked where it is sandwiched between the rear end and the cal-trac mount. I loaded it up and came home not very impressed with the investment.

I immediately contacted George at Flex a Form and he informed me that he had been having health problems and the springs may have been made improperly by his mexican employee. At this point i'm just not too happy with the product overall and secong-guessing myself for buying them.

Since Flex a Form is located just down the road in SC, I hopped in the car and drove them down there to confront George with his faulty springs. We cut them up on the band saw and he informed me that the springs did now have the proper amount of fiberglass and that they were mostly resin......he blamed his employee for the crappy workmanship. George had a stroke, and in his absence had somebody else making his springs.

George made me up a new pair of springs, free of charge. The new springs had a much more noticeable amount of fiberglass in them. He uses fiberglass rope, not fibers or strands.

So at this point i'm wondering if I should even run them and after expressing this doubt to George, he assured me that the springs would function properly and outperform any steel spring on the market.

I ran them for two seasons with success and no signs of problems, best 60' on motor was a 1.42 and the best 60' on a 250 shot of juice was a 1.32......both on small tires. I don't have any hard data as to the actual reduction of 60' times, all I know is that my car launches hard and straight for the most part, with no body seperation. You can see how it launches in the video a posted recently. Not bad for a small tire car on little DOT tires. I'm still working out some bugs and the whole wheelie issue....

Take note that when I installed the springs I had to go back and check squareness in the rear subframe, where the springs mount. I actually took a note from Dave Morgans book "Doorslammers: The Chassis Book", and dropped plumb bobs from the center of each leaf spring mount in the frame. The mounts were way out of square.....so, with a little shimming here and there, I was able to square up the rear end quite nicely. Not to mention that I also added the qa1 adjustable shocks which were a great improvement.

So to sum up all this rambling, I think the biggest benefit of the fiberglass leaf is the reduction in dead and unsprung weight, as well as the fact that they are a mono-leaf design. They drop a TON of weight from the car!!

Did you guys know that Cadillacs new sports car, I think it's called the CTS (not sure) is suspended in the front with a SINGLE fiberglass leaf spring..........hmmmm

 

Just like a corvette

 

Except the vette's is in the back, isn't it?

 

First off, Thanks for the update. Sorry to hear the bad news ... but glad to hear he did you right in the end (did that come out right? ).

Now, I would like to address the satement, "A multi leaf spring will....cause the body to lift".

Isn't this a good thing?

Newton's Third Law of Motion: "For every action there is an equal and opposite reaction."

In other words, when one object exerts a force on another object, the second object exerts a force of equal strength in the opposite direction on the first object (ex: recoil of shotgun).

If weight of the rear of the car is lifting up during launch, an equal amount of weight is (ultimately) being planted to the ground through the tires.

Adjustable shocks and traction devices (bars) obviously play a big part in optimizing traction by means of weight transfer (another topic).

Related Evidence: My '90 Mustang had a stock suspension on it and "porpoised" at launch (the entire car looked like it was going to hop off the ground!). By chance, my low-dollar shocks combined with lowering (road racing) springs provided consistant low 1.5 sixty foots running only 7.2" @ 101mph in the 1/8th. My 60 foots were better than any of my friend's cars running higher mph's and/or same e.t.'s.

Anyway, I do not think that because the rear end is lifting upwards, that that is a bad thing.

(I think you know my statements are not meant to imply that I am a pro when it comes to optimizing a car's launch. They are merely my opinion based on those three factors; 1) Law of Motion; 2) My car's rear lifting at launch and; 3) getting consistant 1.5 sixty foots on a relatively slow car).

Maybe I should write a book and travel the globe giving seminars.

 

Do the pro stock cars "lift the body" when they launch?? Nope. On a leaf spring car, when the body seperates and lifts up off the supension, there is a loss of motion. This also means that, in most cases, the leafs in the springs are fighting each other.....I have video of my car doing this with the old multi-leaf springs. What happens is you end up "bouncing" up off the track and it unloads the tires......i'm speaking from experience and have the video to prove it.

I would suggest Dave Morgans book. It can explain it better than me....

 

Think about it this way Rick, what happens to the shocks when the body lifts up?? Would the body pull up on the shock if there was body lift?? What would that do to the rear-end??

 

bueler.......bueler...........bueler.......

 

Maybe I should also have stated that not ALL of the Rangers came from the factory with them. Just a model year span to look at. That's all.

 

The rear end "lifting" has more to do with the suspension geometry than the construction of the springs. Having said that, you're right, it's probably not the best. The best of everything would be if the suspension didn't move at all, but that's pretty hard to do. If you're hanging the front wheels at all, then it's ok if the rear lifts up a little. If you have a super sticky tire, you'll get faster weight transfer if the rear lifts a little. If you have little skinny hard tires, you're going to want the car to squat some, or you're just going to make a lot of smoke.

Back on topic. Mono-leafs out perform multi-leaf because the spring rate is much more smooth and linear. On a multi-leaf, every time a new leaf comes in contact, it changes the spring rate which will upset the car. Corvette has used a single composite transverse monoleaf since I can remember. Even the old swing axle cars were put together like that I think.

 

I think it's safe to say that different cars react differently at launch. My Mustang's suspension is (was ) no where near a Pro Stock's so I wouldn't expect it to mimic it.

The part about what happens to the car when the shocks rise is a good point, but I believe that only comes into play when the rear goes TOO high up (after initial launch) - unloading the tires like you said. Fortunately, my car didn't have the power to break the slicks loose when the car reached it's apex.

I too have a few videos I can show of the car's launch (while 'porpoising'). Now that I think about it, it did get loose on one particular run . I'll have to look for that one and post it.

Again, something was right with the suspension - getting 1.5 sixty foots in a heavy Mustang Vert running 7.2. I don't know that getting my car to 'sag' more would've improved the launch. It normally didn't spin.

 

Vette Springs

FYI - Corvettes have had fiberglass leaf springs since 1981.

 

Well, Ray! Your a day late & a dollar short (as usual). I just had my springs rearched & added a 4th leaf. I would've rather went with the fiberglass....

 

Rick, that is a good 60' for that cars weight and power.....in my mind, on a fox body mustang, I would want to see very little lift on the body since it is basically a 4-link car. Most of the 4-link cars i've seen don't lift very much if any. The problem i've seen with mustangs is the body "rolling over" on the chassis which acutally causes one side to lift and one side to squat. I think just about everyone offers an anti-roll device to cure that problem though.

Being that I had a bad experience with the fiberglass leafs, i'm not totally sold on them....I would like to give the Calvert Racing mon-leafs a try.

However, one thing I will say about the fiberglass leafs.....they REALLY smooth out the ride.....they seem to absorb more road vibration or something because I swear my little car rides like a cadillac on the road. I'm sure the soft setting on the Qa1's has something to do with it also!!

 

Well maybe a dollar short, but a day late?
That post is three years old tomorrow...
hehe