Front Coil Springs Question

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Jun 4, 2014 | 09:14 AM

rotolock

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Front Coil Springs Question

I have a 1968 corvette that I was having all the front rubber bushings replaced. While the front a arms were off decided to replace the front coil springs. The old springs free stand about 15 1/2 inches high. The new springs free stand about 12 1/2 inches tall. It has a 327 without ac. From what I can determine the 12 1/2" height is correct for stock replacement springs. Anyone know why the difference in height? Thanks for any information .

Jun 4, 2014 | 09:18 AM

wombvette

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From: New Hill NC

Quote:

Originally Posted by rotolock

Reproduction (replacement) Springs.

Jun 4, 2014 | 10:54 AM

gkull

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From: Reno Nevada

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Is there a reason why you want stock springs? To answer your question the shorter spring would have stiffer coils to have the same ride height as the longer

Jun 4, 2014 | 12:20 PM

bashcraft

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From: Butler Pa

Quote:

Originally Posted by rotolock

The old springs free stand about 15 1/2 inches high. The new springs free stand about 12 1/2 inches tall.

You're replacing stock springs with 550 lb springs. The wire diameter on the new ones is bigger so they'll be much stiffer.

Jun 4, 2014 | 03:40 PM

wombvette

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From: New Hill NC

Quote:

Originally Posted by restoman1

Yes, because when coil springs wear out, they expand, not contract. I know this is contrary to what you would think, but that's the way it is.

Ed

Would you care to explain that one?

Jun 4, 2014 | 04:46 PM

7t9l82

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From: melbourne florida

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not sure i buy into that in an automotive application. but i have seen worn out springs that were almost exactly the same length as the identical replacement indicating they didn't compress.

Jun 4, 2014 | 05:48 PM

rotolock

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Thanks again for all the info. I will install them and see how the car sits height wise.

Jun 4, 2014 | 06:16 PM

wombvette

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From: New Hill NC

Quote:

Originally Posted by restoman1

I wish I could, but I'm not a mechanical engineer. I had a mechanical engineer friend try to explain it to me once, but it was so over my head that he gave up and said just take my word for it!! But, here's the formula if you're interested

http://www.eng-tips.com/viewthread.cfm?qid=60441

Ed

That formula is for the diametrical expansion and has nothing to do with the height. I can tell you that I have never seen a front auto coil spring get taller with wear. I can also guarantee that a coil spring will not start out at 12 inches and end up at 15. It just aint going to happen. The reason his spring is shorter is that it is a replacement non spec. spring, period.

Last edited by wombvette; Jun 4, 2014 at 06:18 PM.