Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: Topcat999 on June 22, 2016, 05:17:26 PM

Title: CUTTING COIL SPRINGS- effects?
Post by: Topcat999 on June 22, 2016, 05:17:26 PM
does cutting a coil spring harden the spring rate?
Title: Re: CUTTING COIL SPRINGS- effects?
Post by: Dave69 on June 22, 2016, 06:40:26 PM
Shouldn't do since your only changing the spring length
Title: Re: CUTTING COIL SPRINGS- effects?
Post by: The Smiths on June 22, 2016, 06:58:02 PM
should only drop the height
Title: Re: CUTTING COIL SPRINGS- effects?
Post by: isle of man on June 22, 2016, 07:53:03 PM
Tim it's a MOFOing science.... Pay someone to do it for you !!
Title: Re: CUTTING COIL SPRINGS- effects?
Post by: jay140285 on June 22, 2016, 09:45:33 PM
Why do you want to cut a spring?


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Title: Re: CUTTING COIL SPRINGS- effects?
Post by: Delk on June 22, 2016, 10:01:04 PM
Rate will not change. They will still be x amount per x amount of travel. You will just have lesss travel.

 Springs get old and are cheap considering they are the heart of suspension.

100lbs spring will travel 1 inch for every 100lbs.
Title: Re: CUTTING COIL SPRINGS- effects?
Post by: Topcat999 on June 23, 2016, 09:05:12 AM
many thanks for the input

this is for my race Camaro

the corner weights have gone all wrong- the front too soft and the back too hard (hence oversteer) I have stiffer spare front springs that raise car too much
we have taken out 1x leaf from rear

so we are trying some options

My shocks are 10 years old- Protech adjustables- we are going to try Quantum doubles

lots to do before next event being Chateau Impney 10 July.............
Title: Re: CUTTING COIL SPRINGS- effects?
Post by: LairdScooby on June 25, 2016, 07:58:33 PM
Tim it's a MOFOing science.... Pay someone to do it for you !!

 :iagree:

Cutting a coil (or two) off a coil spring can introduce all kinds of stress fractures throughout the remains of the spring, causing premature (and often drastic) failure. Last thing you'll want on a race car heading up to a corner at xyz mph. IT can also "mess" with the overall spring rate,reducing the progressiveness and other unexpected effects.
What little i know of cutting coil springs is they need to be de-tempered, cut, heat treated then re-tempered after. That may or may not be exactly right but it's seriously unwise to just get your angle grinder/disc cutter out and lop a coil or two off each spring.

Anyway, i thought Camaros always over-steered when they're being driven properly?  :icon_winkle: :icon_biggrin:
Title: Re: CUTTING COIL SPRINGS- effects?
Post by: johnnyboy on June 28, 2016, 01:09:03 PM

From my fading memories of cutting springs om MG midgets in the 1970's, beware that the "progressiveness" (is there such a word?)  goes wrong.

A coil spring is a curled up torsion bar. If you shorten the bar it might try to deform by the same amount overall initially (as described in an earlier post...) but each inch of bar will be twisting more than it did before, and this twisting normally gets more difficult as the degree of twist increases, so the overall spring rate increases faster than it would with a longer bar.

So we found that in practice cutting them DID seem to increase stiffness.
Title: Re: CUTTING COIL SPRINGS- effects?
Post by: LairdScooby on June 28, 2016, 01:33:55 PM

 beware that the "progressiveness" (is there such a word?) 

http://www.thefreedictionary.com/progressiveness

Title: Re: CUTTING COIL SPRINGS- effects?
Post by: johnnyboy on June 29, 2016, 10:56:09 AM

 beware that the "progressiveness" (is there such a word?) 

http://www.thefreedictionary.com/progressiveness

It was a lucky guess. Unfortunately it appears to be an American dictionary so I am not sure that counts.... :icon_toilet:
Title: Re: CUTTING COIL SPRINGS- effects?
Post by: LairdScooby on June 29, 2016, 11:39:05 AM

 beware that the "progressiveness" (is there such a word?) 

http://www.thefreedictionary.com/progressiveness

It was a lucky guess. Unfortunately it appears to be an American dictionary so I am not sure that counts.... :icon_toilet:

You're bisecting follicles now!  :icon_winkle: :icon_rolleyes: :hysterical:
Try this one for size then :

http://www.oxforddictionaries.com/definition/english/progressive?q=progressiveness#progressive__21

It does exist both sides of the pond but as we were talking about Camaro springs and Camaros are American the first one would probably suffice!  :icon_biggrin:

In fairness you made me think and double-check about progressiveness though!