Rear Springs

[Colin Byrne]

Hi Tim
All depends if your going for looks, performance or ride quality.   Putting spacers in will lower the ride height (there are also 3 different height spring pans available for 105) without effecting the spring rate.  If you've already installed 'Sports' springs (and by 'sports' I'm assuming higher spring rate) then by not increasing the front spring rate, you will have increased the vehicles tendency to over-steer, in a car that has snap over-steer characteristics to begin with (pretty scary in the wet particularly). If I where you I would defiantly go down the higher front spring rate option.

[Tim Jobson]

Thanks for that Colin, the King Springs I put in the rear I believe are a higher spring rate than origional (they were certainly shorter), so I will take your suggestion on fitting  similar Sport new front springs so that it will be safer as a good road car.

I hope to enjoy driving the car this year before Phase 2 which will be a new paint job to replace the current spray can patch up job!

Cheers

Tim

[monoman]

Bum down attitude is good because rear roll centre is too high already.  Mine car rides 610mm front, 580mm rear at the highest point of the wheel arches unloaded.  While you're down there, discard the rear ARB as not needed.

Heed Colin's advice about stiffer front springs, or go back to standard springs all round. 

Shortening a spring will increase spring rate.  The following are only rough calculations as they do not take into account the actual material your springs are made from and any loss on springability? The standard rears from my 1750 GTV (7 active coils, 4.59" outside diameter coil, .434" wire = 101Lb/in.  Cutting off 1 coil will increase rate by 18% to 118Lb/in.  Cutting off 2 coils = 42% increase over stock, 142Lb/In.

Standard fronts are   (4 active coils, 5.35" outside diameter coil, .662" wire = 669Lb/in.  Cutting off 1 coil will increase rate to 893Lb/in - which is about right with Koni yellows. 

BTW.  My Koni yellows had about 2.5 turns of adjustment.  With 800Lb/in front springs, 2.25 turns of rebound damping was too much although turn-in was sharp.  Over consecutive bumps like a rail crossing, the car would almost bottom out because it was too much rebound for the spring rate.  The shocks weren't fully rebounding before the next bump, so would compact down.  At least a quarter turn too stiff.  Your mileage may vary. 

The King Springs you have, KARS-04 are 150Lb/in - .492" wire.  Should match up well to 1 coil shortened standard fronts.  Adjust height using standard spacers to get the ride height you want.  Bum down!  See pic of mine attached.  Mine's running Alfaholics stuff.

I've not tried it, but as a guess I'd say 2 coils off the back, and 1 off the front would probably result in about an inch or so lower ride height.

Cheers
George

[Tim Jobson]

Thanks for the very informative spring rate info George.    I do now want to increase the front spring rate as well as lower the front down about an inch, I am happy with the rear ride height.

As you suggested, chopping about an inch from my stock front springs should give me a higher spring rate to better match my King Spring rears, however would this also lower the car by more than an inch?
I would not want to have to put a heap of spacers back under the front springs to raise it up again.

From the picture of your car, which looks fantastic by the way, your road stance does not look bum heavy, it even looks a tad front lower.     I am using the crease line that runs the length of the car as a datum to get the car to sit level or just slightly rear lower, what are your measurements from ground to crease line above each wheel?

I had read some articles regarding problems with chopping off springs and there by giving adverse spring rates......will need to learn some more on this before I take action.

Thanks

Tim

[monoman]

There are many things to consider here. 

1. Shortening a spring will always make it stiffer.  Keep cutting down a spring and it gets exponentially stiffer as it approaches infinite stiffness at zero coils.
2. Because the front springs are mounted half way along the lower wishbone, removing  a 7mm spacer (common factory fitted alloy spacer) will lower front by 14mm.  Shortening the spring by 1" will not lower the car 2" because the shorter spring is now stiffer so it will compress less. 
3. There are more than one spring pans (ebspares list a shallow and a deep pan), and a variety of spacers and seats (both above and below the spring).  Which are in your car is anyone's guess.

Back to my ride height.  The photo is deceptive because the car is not sitting on level ground.  Now, front is 697mm to the crease line, rear is 682mm to crease line, making my rear 15mm lower than the front.  The photo is from when I was running the Alfaholics "C" kit with Koni yellows.  Since then have changed fronts to Alfaholics 2 1/4" springs with their geometry kit and Bilsteins all round.  These 2 changes alone took 4 attempts to get front ride height correct - the Bilsteins were fitted later.  1st set of 2 1/4 spings were either too short or did not suit my spring pans.  Second set eventually needed 2 x 5mm spacers to get the ride back to were it was in the attached photo.  Ride height went up by 10mm all around just by changing from Koni yellows to Bilsteins. 

So if  you are going to chop the front springs, it will have to be by trial and error.  Start with 1" and go from there.  Also, don't forget to drive the car  after each change (around the block will do) so that it will settle down on the springs before you measure it.

Cheers
George

[Tim Jobson]

Thanks again George, the thought of removing the front springs a number of times to get it right does not appeal to me much as I have a deep respect for springs under tension.

Tim

[monoman]

No need to compress the springs on the front.  Just make yourself some of these spring removal tools from allthread and a few nuts.  See http://www.alfaholics.com/new_products/document_727_121.php .  Simply replace the bolts holding up the spring pans one at a time, and wind the spring pans down.

Easy Peasy, and safe too.

Harder to describe than do.

[Tim Jobson]

Thanks for the tip George on using threaded rod to remove the front springs, and yes it was much easier and safer than expected.     I purchased all the bits from bunnings, namely three 3/8 threaded rods cut to about 270mm each, 9x 3/8 nuts and washers and I used 12mm nuts as spacers so that they provide clearance to swing the spanner on the lower 3/8 nut......great idea!

Taking the springs out revealed very rusty spring pans, I hope to reuse these, the lower spring rubber and seat are R/S.     Also noted the A arm ball joints and bushes look to be worn as well.   The bushes on the A arm look tricky to remove, I have attemped to remove the end caps, I stopped before destroying them.....may need to take it to an alfa shop to get these fitted.

When it is ready to put back together I will then probably chop an inch (in height) from my front springs as you suggested....hopefully this will lower the car by about 25-30mm.

Regards
Tim

[Tim Jobson]

After much info collecting on the best way to level my ride height, I decided to bit the bullet and purchase a new set of "Fast Road" front springs for my 105 from pace Engineering.

I also purchased new spring pans and rubber supports as the origionals were too far gone.    The thought of removing springs in and out to experiment with ride height was not really appealing.

Any way I was delighted to see the car have a fairly level stance with a firmer than standard set up yet still plenty of ground clearance for daily driving which is what I wanted.

Thanks everyone for your suggestions and advice that made the task alot easier.    I will have to wait awhile until I strip her down for a new paint job, in the mean time I will finally get around to checking her valve clearances and timing.

Tim