Re: Cutting springs and defending Joel.. then I'll shut up.

["Mark Battley" <m.battley@xxxxxxxxxx>]

Firstly, my apologies to Joel, I didn't mean to be as rude as I was. Sorry
if I offended you or anybody else. Normally I try to avoid posting when I'm
in a grumpy mood....

Ultimately the best solution for most people is likely to be a set a set of
well designed and manufactured aftermarket springs. What the consumer has to
do is somehow decide which product best suits their particular car and
driving requirements/style. For that reason I'd be very interested in
knowing more about the characteristics of the products from different
suppliers: for someone who likes to see numbers I find some of the
catalogues a bit lacking in detail (I can understand that there are IP
issues though). I've collected some data (e.g. dimensions, claimed rates,
resulting ride heights) from a couple of people who are using Shankle and
Ward and Deane springs, but not for any others yet. And as with any product
I'm sure that some springs are better quality than others.

Still there will always be some of us who are happy to fiddle and
experiment, and take our (calculated) chances where we end up. Those who are
not interested in this thread, just hit the page down key....    Otherwise
humour me for a few more lines:

>Ride quality would likely suffer since you
>have lost some effective spring rate due to
>one fewer coil. 
Because there is less length of spring to "twist" the rate actually
increases (the spring gets stiffer) as you reduce the length. But perhaps
this is what you mean by ride quality: the car will ride "harder"?

>And all of this is assuming that the spring's
>temper isn't played with by the cutting and
>bending process.  Heck, I guess it would be
>conceivable to 'harden' the cut coils to increase
>the spring rate.  Is this possible?
Afraid not: heat treatment of steels changes the (yield and ultimate)
strength, but not the stiffness.  Someone posted an excellent overview of
this recently on the AD. While I can appreciate why it would be good to
reshape the ends I'm nervous about suggestions that I have seen to locally
heat and bend the ends. It seems to me that (unless followed by a correct
heat treatment cycle) this is very likely to anneal the region where it is
bent, which will reduce the yield stress, with the result that ultimately
the spring may suffer permanent deformation at the point that was heated and
"sag". 

Boing, boing, boinging away.

Mark Battley
Auckland, New Zealand.

1974 Alfa Romeo 2000 GTV
1989 Fiat Croma

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