question about altering leaf springs

I was discussing this on Facebook's ford ranger fanatics, but the guy I was discussing it with was just getting pissy and not explaining why it wouldn't work. Apparently I don't know anything about suspension. So I would like some insight if anyone would be able to explain it to me.

with a set of chevy leaf springs from a 1990 chevy 1500 they should give about 2.5"-3" lift over stock height. You would have to move the front hangars forward to make them fit.

So I was thinking, what if you didn't move the front hangars forward, what if you managed to give them more of an arch and force them into the stock location? Wouldn't it give you more height and a firmer/stiffer ride? I realize they're longer and don't mount up in the stock spots, I realize that maybe the hangars wouldn't be able to handle the force exerted by the springs if they were forced into an arch to fit in the stock spot.

So what about applying enough heat to give them more of an arch to fit in the stock spot? Heating them up just enough and bending them, then cool them down once you get the distance you want from front to rear hangars.

Only negative thing I think could be is heating the leafs hot enough to give them more of an arch may weaken the integrity of the metal. That and maybe it would be too firm of a ride. In theory it should work. But I don't believe the hangars could handle the amount of stress from just arching them enough to mount in stock location. So that why I figure heat them to the point you would be able to give them the degree of arch needed to mount in stock location. But not sure if the metal would weaken from heat stress. And how the resistance of the springs would change from the heating and reposition. I would expect an increase In lift and firmer ride but not sure if it would compromise the integrity of the springs.

Like I said the guy said I Clearly know nothing about suspension, when I asked him to explain it to me, he just said it wont work, there, explained

So if anyone is willing to explain it to me or give me your thoughts on this I would really appreciate it.

I'll try.
When the longer leafs are forced into the same spot as the stock ones, there isn't room for the leaves to straighten out. The leaves would bind once the shackle had moved as much as it can. This would lead to broken parts or your truck acting like a pogo stick.

Take a look at the spring shackle on your truck. When there is a lot of weight on the truck the leaves will straighten out forcing the shackle to move towards the bumper. A longer spring will bind once the shackle has reached its farthest position.

Two slightly different explanations, hope one makes sense.

Richard

Ok thanks. That makes sense. Wonder why the other guy couldn't tell me that. I was thinking along the line of coil springs. With them ou can get a taller spring and have more height. But with leaf springs you can't do that. You can't arch them and make them taller. I understand now


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rdm21740:

I'm going to be lazy and use some approximations (springs are curved, ranger axle isn't in middle of spring, etc. - I'm going to assume straight) I'm also way from my engineering text books so I can't give you the new spring rates. If you need more detail, I will be able to on weekend.

Ranger spring is ~56.75" mount to mount with ~6" arch = ~57" steel (Pythagorean theorem). by same method, Chevy C1500 spring is ~64" mount to mount with ~7.5" arch ~ 64.5" steel. To fit 64.5" of steel between mounts 56.75" apart, you would need ~31" of arch.

Probably a little more lift than you were looking for! (Note because the bolt which locates the leaves together isn't centered on Ranger, you wouldn't have this much lift, but rather spring would be closer to 1/4 circle and provide very little compliance.)

Also, the steel in the leaves is "spring" steel because of the tempering (quenching) done to it. Heating to deform would remove the tempering and the steel would no longer have the properties to return back to original position (spring).

Hope this answered your question.

Don

Ah yes, I forgot about the heating of springs. As don says, heating without quenching will ruin the "springiness" of the spring. It'll bend but not "spring" back into original shape. And quenching is a long learning process, almost art. But you can re-arch springs without heat. I've done it twice...no, three times. Once by accident when I used a forking lift truck to move a b-2. After seeing that ... Two attempts on purpose using a 12 ton press. Make sure you have a cage around the press as spring steel will snap [break] and shoot out at very high velocities. I didn't get hurt...I was lucky. The third time was the charm and I was able to bend both ends into a reverse arch for a project.

Richard

Thank you all for the input. That's what I was looking for. Y'all are excellent


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rdm21740:

Re-reading your comment to alwaysFlOoReD; you are confusing 2 items: longer springs and springs with more arch. While they often go together, it is not a requirement.

I can take my existing springs with ~6" arch to local spring shop and have them re-arched to 8" arch (allowing fit larger tires and not use blocks; shop has 'safer/more controlled' equipment than I do...). As the 1st leaf is still the same length (measured on curve, not eyelet to eyelet) I can reinstall on the original shackles and be good to go. So, I can arch springs and make them taller.*

What I can't do is install longer springs with either moving front mount (keeps rear axle in correct place too) or installing MUCH longer rear shackle (capable of handling the springs eye - 2 - eye distance when axle hits bumps stops).

*There is a limit to how much arch you can put on stock springs as you want to ensure the rear shackle doesn't "over center" as a result of shortened eye - 2 - eye distance. Over centering does real bad things to suspension...

Make sense?