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Input on Centerline Springs, Koni Reds & OEM Swaybars

12K views 43 replies 24 participants last post by  Dklassen1! 
#1 · (Edited)
I am planning a new suspension for my 74 GTV. I am looking for something that is "better" than stock, but something that is tried & true by many. My requirements: nice street performance, reasonable ride, ride height that won't scrape my sump guard on street dips and a reliably "good stance" without a bunch of spring spacer trial and error.

I've read through a fair number of threads...seems to get complex quickly with spring coil counts, rebound rates, etc. I just want something tried and true that I can install and be happy without a lot of tinkering. I'll be running 65 or 60 profile tires.

To that end it seems a pretty standard setup is:
  • Centerline springs
  • Koni Reds in front
  • Koni Yellow in back
  • OEM sway bars

Is anyone running this suspension? Do you think it meets my criteria above?

Thanks!
 
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#31 ·
I had Centerline springs and found them too stiff. They are reported as 1100lbs. Same as the old IAP springs. Alfaholics are reported as 600lbs and over there they don't like them as stiff as we do here, so I decided to go softer and got some Eibach 700lbs, 11" springs. When you buy them as circle track springs you pay about $60 each(I found them on sale at Speedway for $40 each), so that was pretty easy.

Alfaholics and Centerline seem tight lipped about their spring rates so some AlfaBB members had to measure them to catalog that, but Eibachs are sold by the rate. You can chose anything from about 400lbs to 1600lbs, so I would hope Classic Alfa would reveal that. For example, mine were #: 1100.550.0700. (Length.Dia.Rate)

I am much happier getting rid of the Centerline springs. My thoughts for street use is you should chose somewhere between 600 and 900lbs. I use Koni reds at maybe 1/2 stiff front, and 1/4 stiff in the back.
 
#36 ·
I know a lot of people want a “ plug and play” solution. But you can calculate the rate of your current springs easily based on dimensions and then pick from a wide variety of “circle” track options.
 
#38 ·
No, yes, yes.

All steels have the same modulus (same force per elongation, basically) in elastic deformation. Wire diameter is involved; thicker wire = harder spring. Length is also a parameter; a longer spring (more coils) is softer.

The actual math involved isn't that hard, actually.
 
#40 ·
No they are not, and they exist in dynamic relationship with tyres, wheels, shocks and bushes.



What a great segue! I have much more experience going fast on bikes than cars.
A bike frame is part spring but that spring is not just vertical (tension). It also has to manage the torsional loads of pedalling and turning. There's a reason Titanium frames are the "holy grail" and, prior to Carbon Fibre (which is not what it is claimed to be as it deteriorates quickly), the columbia (?) steel from Italy was the bee's knees.

Cycling taught me that, if you are time trialling over varied terrain other than dead flat perfect tarmac, then "give" is crucial. Stiff frame, wheels, tyres over 100psi is significantly slower than an "absorbent" frame, wheels with long strong spokes and tyres that have a "cushion" built in.

I found that a Ti frame that was 500g heavier than the Carbon equivalent made up in performance what it gave up in weight.

There's a kind of voodoo in all of this...
 
#41 ·
Good post, thanks!

I have a Reynolds 531 steel race frame from the early 70s - fantastic feel and control, but even I with my smaller build can twist the bottom bracket standing up in a big gear and make the derailleur drag the chain.

I've ridden a couple of carbon frames and they seemed sort of dead - no give, no life.

I rode a TI frame long ago and it was pretty whippy. I was surprised at how soft. Now it may have been a soft touring frame, I don't know.

My forever bike is a 2006 Colnago Master Light in Columbus steel. Fantastic bike. Light, stiff, lively and responsive. Super thin tubes are shaped sort of like an Alfa 4-leaf clover for extra stiffness!

Hood Office supplies Rectangle Bumper Rim
 
#42 ·
The early Ti frames were bitterly expensive and not real strong. My "forever" bike is a Lynskey Pro Ti. It is every bit as fast as the GT Team Pro, a Tour bike with a mega spec.
Because we all use the internet and iPhones we think that the big leaps in the past 30 years are IT related, and they are, but materials tech has moved on spectacularly too.
Brake pads, disc rotors, tyres!!!, glues that hold cars together, silicon rubber in the brake and clutch parts, silicone bushes and so on...
 
#43 ·
I'll be running a fast road stage 1 from Arese Trade in the Netherlands. This is on my Italian delivered Euro 71 GT. I'll put feedback after it's installed.
rear suspension 1.
2 x 2 bush Montreal quality
2 x 3 bush Montreal
2 x 9 rubber Montreal
2 x 12 rubber
2 x 14 bump stop
2 x 19 limit staps
4 x 20 plates for limit straps

rear suspension 2.
2 x 1 Koni red
2 x 3 plate
2 x 5 rubber

front suspension 1
2 x Koni Sport
4 x 3 plate
4 x 4 rubber
2 x 8 rubber
4 x 13 complete with bushes

front arms and bushings
2 x 1 tie rod joint
2 x 3 bush
4 x 4 plate
2 x 5 top suspension arm (you don't need #3) we also have them adjustable
4 x 7 dust cap
4 x 9 bush
2 x 13 bump stop
2 x 14 bump stop
2 x 18 lower joint
Shelf Shelving Automotive tire Automotive design Electrical wiring
 
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