S1 front spring specifications

[Fulvia-hf]

Hello,
my S1a is steadily coming together. I've managed to source a set of NOS Koni front dampers. They are for 1.9" ID springs. Can anyone tell me the specifications for the front springs? uncompressed length, number of coils and strength? If possible also if the OEM specifications need to be changed for modern usage.
Cheers,
william

[bjthomp]

Spring specifications are detailed on Page 15 of the Technical Data Section of the Workshop Manual. Whether they apply to an S1A is another matter, since the book was published after the introduction of the S2.

[Bryan Boyle]

Probably not enough for you, but, the online parts manual has the following.  Specific details are missing since they weren't necessarily published or tracked:

S1 prior to chassis number 480
No. of Coils      15 (measured from 460355)
Diameter, outside   6.6cm (2.59375")
?

S1/S2 fom chassis number 480 to 2383
No. of Coils      14 ?
Diameter, outside   4.8cm (1.875")?
?

S2 after chassis number 2584 to September 1971
No. of Coils      17
Wire diameter      8.83mm (0.348”)
Length, free      32.38cm (12.75”)
Length, fitted      19.68cm (7.75”)
Rate         1.15kg.m (100 lbs.in)
Load, fitted      227.3kg (500 lbs)
Diameter, outside   6.4cm (2.5")

S2 after September, 1971
No. of Coils       14.75
Wire diameter      10.16mm (0.400")
Length, free      34.90cm (13.75")
Length, fitted      ?.??"
Rate          lbs/in
Load, fitted       lbs

TC/TCS
No. of Coils      13.5
Wire diameter      10.16mm (0.4”)
Length, free      31.77cm (12.51”)
Length, fitted      20.01cm (7.88”)
Rate         1.33kg.m (116 lbs.in)
Load, fitted      224.5kg (537.08 lbs) 

[Fulvia-hf]

Thanks for these answers but unfortunately I cannot order a set of the correct springs with this data. I hope there is someone who has solved this problem and has fitted good 1.9"ID springs to his S1 or early S2 front shocks.
Thanks in advance!
William

[Fulvia-hf]

It has taken a while but I've made progress. Unfortunately it was not possible to find a usable 1.9" ID spring for my professionaly modified KONI dampers. Therefor I've bitten the bullit and bought a set of brand new Protech shocks with springs. The modified KONI's are now useless to me but will be perfect for later cars with the larger ID springs. I only have to make a set of slightly larger spring seats on the lathe. But therefor I need the exact ID of the larger springs as used on the later S2 cars. I think they are slightly smaller than 2.5".
Can anyone with a later S2 spring in their parts collection and a vernier caliper confirm the ID of those springs?

Very much appreciated!

W

[kram350kram]

Try Merlin Motorsports in Britain. They have 1.9 springs;   www.merlinmotorsport.co.uk

[Clifton]

All of these springs, adapters, and spacers are off the shelf.  I'm running 2.25" springs on 1.9" shocks with adapters and some 1" spacers. This is on an early 54 S2. I wouldn't run a 2.5" spring unless you really had too. It's a big and heavy spring. I went with 2.25 as 1.9 spring rates didn't go high enough for me.

Measuring some springs I have

QA1 1.9"         1.965" ID
Eibach 2.25"    2.283" ID
Hypercoil  2.5" 2.585" ID

[Fulvia-hf]

@Clifton,
Thanks for this info. Are those 2.25ID springs readily available? Are they sold as Lotus Europa springs or are they motorcycle springs? What rate and free lenght did you go for?  The available free lenght on my modified shocks is 32cm max with the adjustable springseat on its lowest setting. To still have some adjustment I would say I have 31 cm. Stroke of the shock is 6cm.
Cheers,
William

[Clifton]

@Clifton,
Thanks for this info. Are those 2.25ID springs readily available? Are they sold as Lotus Europa springs or are they motorcycle springs? What rate and free lenght did you go for?  The available free lenght on my modified shocks is 32cm max with the adjustable springseat on its lowest setting. To still have some adjustment I would say I have 31 cm. Stroke of the shock is 6cm.
Cheers,
William

They are all off the shelf coil over, non specific springs. The ones in the pic are 650lb 6" long. Eibach does length, ID, rate, 600.225.650. I was running 8", 1.9" ID springs, 250lb, then 350lb, then 400lb. You don't want that stiff unless you are competing.  Being that you are not in the US, QA1 will probably not be a less expensive an option but Eibach is in Europe. Most single shocked motorcycles do run a 2.25" rear spring but they may not be the rate or length you want. FWIW, Some makers list 1.9" springs as 1.88".

https://www.demon-tweeks.com/eibach-competition-springs-1-9-internal-diameter-2002517/