Hyperco composite leaf spring question?

[Brads70]

Hello all!
I've installed Hyperco composite leaf springs 175# rate in my 1970 Challenger. They are too soft, car bottoms out on the pinion snubber to easy and if I put passengers in the rear it sits on the pinion snubber. So I ordered 225# rate and just got them yesterday. Using a vernier I measured them and found they measure exactly the same as the 175# ones! I figured someone at Hyperco screwed up and put the wrong decal on them. So I phone Hyperco and explain the situation to them. They quickly replied that yes they all measure the same but it's the material in the composite that gives the different rates? He also told me they ID the spring rates by a colored square molded into the spring. Sure enough it is there , the 175# had a green square, the 225# has a blue one.
Anyone use Hyperco springs and try different rates? I'm no scientist but not quite sure I believe the "different composite" story. I'm planning on taking one of the 175# off the car, flipping in over arc side up, standing on it and measuring the drop between the 2 rates? Sound like a plausible plan?
Anyone have experience with this?
Thanks Brad

[Bryce]

composite strength and stiffness comes from the material and the direction the material is laid. Makes sense to me. Sounds like they do some engineering, Im impressed.

Uni-directional tape is only stiff in one direction.

[SLO_Z28]

Measuring them seems like a no brainier, but I think their story is plausible. You did get the right "Chrysler" spring right? Its a little longer.

[Brads70]

Measuring them seems like a no brainier, but I think their story is plausible. You did get the right "Chrysler" spring right? Its a little longer.

Thanks for the replies guys. Yes I did get the Chrysler springs . They are the same as the Chevy spring , they just trim them slightly shorter for Chrysler applications , and move the mounting pad to suit the shorter front segment Mopars have. Here is a few pictures of what I had to do to make them fit.
http://www.hypercoils.com/mph/tech-t...ing-dimensions

[David Pozzi]

On a multi-leaf, you have to load the spring like it is loaded in the car to measure rate. I didn't think it was necessary for Composite leaf springs, but it looks like it is.

[Brads70]

On a multi-leaf, you have to load the spring like it is loaded in the car to measure rate. I didn't think it was necessary for Composite leaf springs, but it looks like it is.

Can you explain that a little for me? Somewhat of a newbie to this? So how would I measure the rate?
Thanks Brad

[Brads70]

Finally got them installed and even though the roads around her still have some salt on them I couldn't resist and took her out for a rip around the block. I did not ride rough/ harsh at all. In fact I'd say the family Suburban rides much rougher than the Challenger.

[Bryce]

Finally got them installed and even though the roads around her still have some salt on them I couldn't resist and took her out for a rip around the block. I did not ride rough/ harsh at all. In fact I'd say the family Suburban rides much rougher than the Challenger.

congrats

[David Pozzi]

Here is a photo of how I tested a leaf spring. It is inverted, placed on turntables, the bottle jack is over the center bolt & has a hydraulic valve spring tester on top to measure applied load. The jack is under my car trailer hitch & applying 700 lbs load. My trailer has 900 lbs tongue weight.
Applied load is half the rear unsprung weight of the car.
David

[rustomatic]

You have my apologies, but this has long been my answer to such a conundrum: back seat delete. Passengers (in the rear, anyway) and "fun" suspension/driving do not mix.

[Brads70]

Here is a photo of how I tested a leaf spring. It is inverted, placed on turntables, the bottle jack is over the center bolt & has a hydraulic valve spring tester on top to measure applied load. The jack is under my car trailer hitch & applying 700 lbs load. My trailer has 900 lbs tongue weight.
Applied load is half the rear unsprung weight of the car.
David

Thanks for the reply!

[Brads70]

You have my apologies, but this has long been my answer to such a conundrum: back seat delete. Passengers (in the rear, anyway) and "fun" suspension/driving do not mix.

? Wrong post?