[DeTomaso] Resetting Ride Height With Stiffer Coils - the sequel

Ken Green kenn_green at yahoo.com
Fri Sep 24 19:38:04 EDT 2010 

Mike,
 
If you raise the bottom spring perch you will raise the car.  It's a little counter intuitive, but the end result is that the spring will be compressed by the car's weight to the same compressed length before and after adjusting the spring perch.  The spring may start out shorter if you raise the bottom perch, but it then will be compressed less by the weight of the car when you remove the jack.
 
If you imagine the compressed spring under the car's weight having a fixed length, when you lower the bottom perch, the result is that the top shock mount moves down with the spring and the car is lowered.
 
Ken

--- On Fri, 9/24/10, Mike Thomas <mbefthomas at comcast.net> wrote:


From: Mike Thomas <mbefthomas at comcast.net>
Subject: Re: [DeTomaso] Resetting Ride Height With Stiffer Coils - the sequel
To: "'Julian Kift'" <julian_kift at hotmail.com>, davidabell at worldnet.att.net, "'De Tomaso List'" <detomaso at realbig.com>
Date: Friday, September 24, 2010, 3:29 PM


OK, slight script change here.  The new springs were 10", the ones I pulled
off the car, after sitting for a day to relax, were at 9.5".  I had called
Aldan to ask about spring heights, and they said only come in 1" increments,
so I can only guess that my fronts sagged 1/2" over 5 years (doesn't seem
right), or they were slightly short to start with.

After a short drive, I've dropped about 3/16", so am still an inch higher
than before.  If my suspicion is correct, I need to compress the springs by
at least an inch on the shocks to get back to my original height.


Mike

  _____  

From: Julian Kift [mailto:julian_kift at hotmail.com] 
Sent: Friday, September 24, 2010 3:15 PM
To: mbefthomas at comcast.net; davidabell at worldnet.att.net; De Tomaso List
Subject: RE: [DeTomaso] Resetting Ride Height With Stiffer Coils - the
sequel


Did you measure the length of the springs you removed?

Julian

> From: mbefthomas at comcast.net
> To: davidabell at worldnet.att.net; detomaso at realbig.com
> Date: Fri, 24 Sep 2010 14:59:59 -0700
> Subject: Re: [DeTomaso] Resetting Ride Height With Stiffer Coils - the
sequel
> 
> As with most sequels, this was not as good as the original . . .
> 
> So I finally got the new springs on the car, and I believe Dave Bell wins
> the Christmas Turkey (see his last post below).
> 
> In our last episode . . .
> 
> Ordered new 450lb 10" springs from Aldan. They were actually closer to
> 10.5". Replacing 350s.
> 
> When I took the old Aldans off the car, I measured the number of threads
> below the collar. Summing up the various inputs I received from a bunch of
> helpful folks, I adjusted the original change in spec from ~.4" to
slightly
> ~.33" lower on the spring perch to compensate for less compression from a
> stiffer spring and the angle of the coil/shock assembly when installed on
> the car.
> 
> .33" converted to ~5 threads on the shock body, so when I installed the
new
> 450 lb springs on the shocks, I reduced the number of threads on each side
> by 5, and reinstalled the assemblies.
> 
> WTF!!
> 
> Where my fender lip was ~25.75" above the ground, now it's ~27"! Lowering
> the spring perch .33", and the .5" longer springs have somehow combined to
> raise the car 1.25"!
> 
> OK, so I haven't driven it yet (don't really want to look like Jesse James
> going down the street), but I've given both fenders a good bounce after
> rolling the car back and forth and bouncing it again to settle things as
> much as I can in the shop, and no change to the height. Will take it
around
> the 'hood to hit the brakes a few times to see if it changes anything. If
> no changes, I'm wondering:
> 
> A - send the springs back to Aldan for some really-o truly-o 10" long 10"
> springs.
> B - go back to he previous thread count and go the other direction.
> Both A and B
> None of the above
> Open a beer and wait for the replies to come pouring in.
> 
> . . . Hey, it's Friday, the latter is a given.
> 
> Thanks again!
> Mike Thomas
> Keeping my tips up in Seattle
> 
> 
> -----Original Message-----
> From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com]
On
> Behalf Of David & Marilyn Bell
> Sent: Tuesday, August 24, 2010 9:25 PM
> To: David & Marilyn Bell; detomaso at realbig.com
> Subject: Re: [DeTomaso] Resetting Ride Height With Stiffer Coils
> 
> I guess I either write or think (or both) upside down. The new springs
> should put the tire 1/2 inch further away from the fender, not closer.
> 
> Dave Bell
> 
> -----Original Message-----
> From: detomaso-bounces at realbig.com
> [mailto:detomaso-bounces at realbig.com]On Behalf Of David & Marilyn Bell
> Sent: Tuesday, August 24, 2010 6:11 PM
> To: detomaso at realbig.com
> Subject: Re: [DeTomaso] Resetting Ride Height With Stiffer Coils
> 
> 
> OK - I purposely mentioned 'roughly' and 'approximately' to indicate this
> was a purely bubba type estimate, though probably I shouldn't have used
any
> decimal places that may have added some artificial precision.
> 
> So, I've got 20 bucks that says the top of the front tire will be about
1/2
> inch (plus or minus 1/4 inch) closer to the fender lip with the new 450#
> springs than with the previous 350# springs (obviously before moving the
> spring perches up or down).
> 
> Who's in?
> 
> Also be sure to drive the car around to settle the suspension before
> measuring the fender to tire gap.
> 
> 
> Dave Bell (don't need no stinkin corner weights to go around corners fast)
> 
> 
> -----Original Message-----
> From: detomaso-bounces at realbig.com
> [mailto:detomaso-bounces at realbig.com]On Behalf Of Paul - Home
> Sent: Tuesday, August 24, 2010 9:47 AM
> To: unlisted-recipients:; no To-header on input
> Cc: detomaso at realbig.com
> Subject: Re: [DeTomaso] Resetting Ride Height With Stiffer Coils
> 
> 
> Goran is of course correct and the reason is that springs are not
installed
> vertically, they are at an angle.
> 
> Paul
> #9270
> 
> Pantdino wrote:
> > It will be interesting to see if that is the case.
> > Goran sent me some information regarding suspension systems once that 
> > was
> over my head, but I do remember that the force felt by the spring is not
the
> same as the weight on the wheel. Therefore the change in spring
compression
> may not be 0.4"
> >
> >
> > Jim
> >
> >
> > -----Original Message-----
> > From: David & Marilyn Bell <davidabell at worldnet.att.net>
> > To: Mike Thomas <mbefthomas at comcast.net>; 'Tony DiGiovanna'
> <tonydigi at optonline.net>; detomaso at realbig.com
> > Sent: Mon, Aug 23, 2010 10:23 pm
> > Subject: Re: [DeTomaso] Resetting Ride Height With Stiffer Coils
> >
> >
> > Mike,
> > If your car weighs roughly 3200 lb and the weight distribution is 
> > roughly 0/60 front to rear, then the weight on the front is 1280 lb so 
> > each front pring must support 640 lb. A 350 lb/inch spring will 
> > deflect 1.8" under han load while a 450 lb/inch spring will deflect 
> > only 1.4". So you need
> to
> > rop your front spring perches by approximately 0.4" to maintain the 
> > same ide height.
> > Dave Bell
> >
> > ----Original Message-----
> > rom: detomaso-bounces at realbig.com
> > mailto:detomaso-bounces at realbig.com]On Behalf Of Mike Thomas
> > ent: Monday, August 23, 2010 7:44 PM
> > o: 'Tony DiGiovanna'; detomaso at realbig.com
> > ubject: Re: [DeTomaso] Resetting Ride Height With Stiffer Coils
> >
> > hanks. Should have added that both new and old springs are 10" Aldan 
> > oils, so the free height is the same on both rates.
> > Mike
> > -----Original Message-----
> > rom: Tony DiGiovanna [mailto:tonydigi at optonline.net]
> > ent: Monday, August 23, 2010 5:23 PM
> > o: 'Mike Thomas'; detomaso at realbig.com
> > ubject: RE: [DeTomaso] Resetting Ride Height With Stiffer Coils Don't 
> > assume the new springs will have the same free height.
> > hink you are best served to measure the ride height of the car 
> > relative to he ground with the old springs, then change springs and 
> > adjust back to hose settings.
> > -----Original Message-----
> > rom: detomaso-bounces at realbig.com 
> > [mailto:detomaso-bounces at realbig.com] On ehalf Of Mike Thomas
> > ent: Monday, August 23, 2010 8:11 PM
> > o: detomaso at realbig.com
> > ubject: [DeTomaso] Resetting Ride Height With Stiffer Coils OK, time 
> > for the math wizards to have a head shed . . .
> > I'm swapping out my front springs from 350 lbs to 450 lbs, and want to 
> > chieve the same ride height. Since I won't (I assume) get as much 
> > spring ompression with the 450's, I'll need to revise the spring 
> > perches on my ldan shocks. I'm guessing I'll need to compress them 
> > slightly more on the hock (the collar height up the shock body) since 
> > the springs won't drop as uch when I let the car back down and the 
> > springs settle in. My car is tock up front with the addition of an 
> > aluminum radiator, so probably close o stock weight on the front wheels.
> > Any thought on how much more to compress, or notes form someone whose 
> > been here, would be helpful. Pulling and readjusting or trying to 
> > adjust the ront on the car are both a much bigger PITA than the rears. 
> > I'd like to ave to do it as few times as possible.
> > Thanks in advance for your sage advice.
> > Mike Thomas
> > ellow '74 L #6328
> > _______________________________________________
> > Detomaso Forum Managed by POCA
> > Archive Search Engine Now Available at 
> > http://www.realbig.com/detomaso/ DeTomaso mailing list 
> > eTomaso at list.realbig.com 
> > ttp://list.realbig.com/mailman/listinfo/detomaso
> >
> > ______________________________________________
> > Detomaso Forum Managed by POCA
> > Archive Search Engine Now Available at 
> > http://www.realbig.com/detomaso/ DeTomaso mailing list 
> > eTomaso at list.realbig.com 
> > ttp://list.realbig.com/mailman/listinfo/detomaso
> > _______________________________________________
> > Detomaso Forum Managed by POCA
> > Archive Search Engine Now Available at 
> > http://www.realbig.com/detomaso/ DeTomaso mailing list 
> > eTomaso at list.realbig.com 
> > ttp://list.realbig.com/mailman/listinfo/detomaso
> >
> > _______________________________________________
> >
> > Detomaso Forum Managed by POCA
> >
> > Archive Search Engine Now Available at 
> > http://www.realbig.com/detomaso/
> >
> > DeTomaso mailing list
> > DeTomaso at list.realbig.com
> > http://list.realbig.com/mailman/listinfo/detomaso
> >
> >
> _______________________________________________
> 
> Detomaso Forum Managed by POCA
> 
> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
> 
> DeTomaso mailing list
> DeTomaso at list.realbig.com
> http://list.realbig.com/mailman/listinfo/detomaso
> 
> _______________________________________________
> 
> Detomaso Forum Managed by POCA
> 
> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
> 
> DeTomaso mailing list
> DeTomaso at list.realbig.com
> http://list.realbig.com/mailman/listinfo/detomaso
> 
> _______________________________________________
> 
> Detomaso Forum Managed by POCA
> 
> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
> 
> DeTomaso mailing list
> DeTomaso at list.realbig.com
> http://list.realbig.com/mailman/listinfo/detomaso
> 
> _______________________________________________
> 
> Detomaso Forum Managed by POCA
> 
> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
> 
> DeTomaso mailing list
> DeTomaso at list.realbig.com
> http://list.realbig.com/mailman/listinfo/detomaso

_______________________________________________

Detomaso Forum Managed by POCA

Archive Search Engine Now Available at http://www.realbig.com/detomaso/

DeTomaso mailing list
DeTomaso at list.realbig.com
http://list.realbig.com/mailman/listinfo/detomaso

More information about the DeTomaso mailing list