spring questions

[jason81k20]

My leafs are broke and I'm buying a shackle flip to get rid of the blocks. I have some springs I was told are for my truck(81 k20 56"springs. They still have the stickers on them that say triangle spring or something like that part #22-440. I measured them and everything seems to match up but when I looked up the part number it said they were chevy front springs. They have 8 leaves, were they actually used on the front of a Chevy? They're 2.5" wide same as the rear ones now..I'm curious. They've never been on anything just been sitting for along time.

 

[bucket]

I would disregard the part number because it might apply to something else too. Your measurements and description say they are rear springs.

 

[bucket]

Nevermind, I tried to steer you wrong. Like was brought up in your other thread, they are for a P30. Rear 56's have the center pin offset with the long side to the rear.

BUT, you still might be able to use them. When you do a shackle flip, the springs are at a different angle and the axle ends up getting moved forward, then a "zero rate" is needed to relocate the axle rearward a bit. Your springs that you have could work in your favor, if they have enough arch. You still might have to relocate the axle with a zero rate, or you could also drill new center pin holes in the spring perches (if you have stamped perches).

 

[jason81k20]

I would disregard the part number because it might apply to something else too. Your measurements and description say they are rear springs.

A fella on my build thread said he found the measurements and they're 29x29 I'm gonna measure again with the arch to make sure

 

[jason81k20]

I think I'll give it a try once my shackle flip arrives..worst comes to worst I'll have to buy new springs to

 

[chevyk10]

If they are the measurements I told you on the other thread then under no circumstance would you want to run them on the rear. The flipped shackles have nothing to do with the distance from the front hanger to the center bolt. The arch of a spring is generally concentrated more to the rear. Moving the rear end back 3 inches is a long way. Even if you think it will work when you load the truck the rear end will push more to the rear. Front springs off. 2 wheel drive will have a different arch pattern than a rear spring. Think about how the hangers and shackles are arranged with the rear higher than the front. This is generally not the case on the front.


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[jason81k20]

Yeah the more I thought about it the more I figured on not trying to use em I want everything to be right

 

[bucket]

If they are the measurements I told you on the other thread then under no circumstance would you want to run them on the rear. The flipped shackles have nothing to do with the distance from the front hanger to the center bolt. The arch of a spring is generally concentrated more to the rear. Moving the rear end back 3 inches is a long way. Even if you think it will work when you load the truck the rear end will push more to the rear. Front springs off. 2 wheel drive will have a different arch pattern than a rear spring. Think about how the hangers and shackles are arranged with the rear higher than the front. This is generally not the case on the front.


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Excuse me for being blunt, but some of that info is false. Doing a 4 inch lift shackle flip DOES move the axle forward 1 to 1.5 inches forward. So the center pin being 2 inches further back COULD help the situation. Also, it is very common for guys to run stock Chevy REAR springs on the FRONT for more flex and a softer ride. A lot of it just depends and it's an experiment every time, the outcome is never certain until you give it a shot.

So IF the P30 springs have a similar arch to them, it might be worth the time mocking them up since the OP already has them. Sure, it might ride too stiff/soft/high/low... whatever, but it could work out great. For all anyone knows, they might function just like the correct rear springs, only difference being the center pin location. Which again, could work out in the OP's favor.

 

[chevyk10]

It's 3 inches longer on the front. It will move some but not as much as he needs. You will be adding a much stronger spring and the truck will be very stiff. Plus you are adding 4 inches. Overall probably raise the truck 8 inches pretty easy with those shackles. I only did suspension work for 20 years and just trying to help.


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[bucket]

It's 3 inches longer on the front. It will move some but not as much as he needs. You will be adding a much stronger spring and the truck will be very stiff. Plus you are adding 4 inches. Overall probably raise the truck 8 inches pretty easy with those shackles. I only did suspension work for 20 years and just trying to help.


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But we don't know if it is a much stiffer spring, there are just too many variables. The shackle flip will gain about 4 inches, but that does nothing really for the spring rate. If the leaf width and thickness, amount of arch, and number of leaves are all similar to stock rear 56's, it's worth trying IMHO. The center pin really is not a factor in this case because of the flip. Worst case, zero rates are needed to relocate the axle a bit, but that is normally needed with a flip anyway. Like I said before, it's all just a crap shoot until you try it. Even the custom spring manufactures often don't get it right in the first couple tries. All we have to go on is similar experiences and educated guesses.

 

[chevyk10]

All you can do is try it. It just depends on how much lift you want


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[bucket]

Sorry, left out a key word in my last post about the custom springs, "often" is now in there.

 

[jason81k20]

So you guys think its worth a try? I sat them beside the springs on my truck now and they're basically exactly the same...the 440's have a little more arch but if figured with the weight of the truck on them they would squish down that little bit...they both have the same number of leaves...the only visible difference is how the springs meet at the eyes the 440's have a slight bend on the main leaf whereas the original ones have no bend

 

[chevyk10]

That's called a Berlin eye. Do they have the same bushings? Where is the center bolt in comparison? If there is 3 inches difference then I would be Very careful before I would use them.


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[chevyk10]

Yours should have come stock with I believe RB117's. Not sure what's in the 440's


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