Standard RS2 Front Springs / S2 springs (not A/C)

[S2central.net]

Well there's 13 spring types at the front for the ACOQ from 1989 thru 1996.

I have them all in a spreadsheet which I'll post later today.

[mcandmar]

13 LOL, that should keep you busy for a while Andy

I think we could safely ignore all the cq20v and below spings, a stock CQ handles like a boat so i cant see anybody wanting to use those springs in anything, they also ride slightly higher than S2's. First change i made to mine was a set of ABY springs and it took about half an inch off the ride height, and felt about 20-30% firmer. Rather subtle the difference, but going from those to H&R's was a big difference.

[Paulgo]

First change i made to mine was a set of ABY springs and it took about half an inch off the ride height, and felt about 20-30% firmer. Rather subtle the difference, but going from those to H&R's was a big difference.

I did the same to my cq20v and felt exactly the same - a subtle but highly effective improvement with ABY springs and dampers! Just renewned a lot of the S2 front suspension components (bushes, top mounts, droplinks, RS2 dampers, track rod ends) but still a bit disappointed at what seems a little too much body roll for my liking, even tho its tight as hell cornering. Got an RS2 Farb on already so I reckon a Whiteline on the back is the way to go next - but often wondered about the effect of upgrading from the stock springs Im currently riding with, even on standard shocks (tho id love Konis if I had the dosh!)

cheers

Paul

[S2central.net]

Well there's 13 spring types at the front for the ACOQ from 1989 thru 1996.

I have them all in a spreadsheet which I'll post later today.

Here's the spreadsheet for starters on ACOQ fronts only. There's 20 combinations listed in the family album which boils down to 13 actual spring types at the front.

Some are common to the 2WD Coupe / Cabrio and probably 80 sedan/avant also

I'll try and add to this since I've started it now, but I'll happily take contributed additions from any other family album jockeys out there.

Paul

[Rusty]

Thanks Paul, that'll save me having to go through EKTA.

Just have to get the normal and AC spring side by side and try and come up with a suitable way of measuring the rates etc. Then I need the spring rates of the H&Rs rears to make an educated guess as to a suitable OE spring to match the H&R fronts.

Hand waving arguement:-

From memory the S2 is a 60:40 front weight distribution so it's not going to be too far away from a 50% stronger spring on the front than the back, give or take a bit of chassis tuning (!?!) by Audi. Therefore, assuming that the H&R is somewhere near 50% stiffer, a front spring on the rear would be 50% stiffer and so should give the same balance.

Any thoughts on where to get real numbers for this one? Might just buy a set of H&R fronts and have a play... this is getting costly now! It always does though!

[pastures16]

i bid on these when i was pissed cost a tenner but what are they for theyre discribed as rs2 front and rear but the seller never gave me any part numbers do i refuse to as there not rs2 as discribed

[Rusty]

BUMP

Cheers to Jamo for a set of rears and a few other toys!

Still looking for a set of front springs (non A/C).

David, please PM me about your (A/C) springs that I politely declined originally!

[Rusty]

Looking like I have a set of A/C springs but still after a set of OE front springs for non A/C car. If anyone has some taking up space then please let me know as I'd be interested to see if there is a difference in spring rate and I'd like slightly sofer springs (I assume) on the rear. I'll report on my findings as and when I fit them but hoping to have my rear sorted by the end of the year!

[s2driveruk]

should be on the way to you shortly.....

[Rusty]

Bonus! Should be interesting if nothing else!

[Rusty]

Most confused. The rear springs seem to be made from a thicker material fronts... Hmmmm.

[s2driveruk]

to carry the extra weight on an original 5 spoke spare alloy???

[Rusty]

Indeed...

The number of coils and the helix OD are the same so it's all quite confusing! Uncompressed height is greater on the front springs so they will be under more pre-load and therefore will require more force to compress when pre-loaded. I'll try and measure the sag on the spring and calculate the relative spring rates from the spring dimensions, helix angle etc.

Will swap them over and see what I think, if they're made from a different material then that would make a difference too but it's unlikely.

[Rusty]

Right then, I've done a bit of measuring and have come up with the following numbers:-

Front
D = Outside Diameter = 139mm
d = Wire Diameter = 14.1mm

Rear
D = Outside Diameter = 145mm
d = Wire Diameter = 14.7mm

Now then, here's the science bit as I see it,

Assumptions:-

• The OEM springs are not variable rate
• The OEM springs are made from the same material
• Both front and rear springs have equal numbers of coils (I've counted them and this is true).

The spring rate of a helical spring is proportional to d^4/D^3 using the assumptions above and that they have the same number of the coils. Using this formula, the rear springs have a spring constant approximately 4% stiffer than the fronts! However, the front is 50% heavier (60:40 weight distribution) and so there is 50% more preload on the spring (so it sags more). The increased preload on the front moves the operating region of the spring up the force vs. deflection curve and so the spring requires more force to achieve the same deflection as the rear under static loading conditions. Dynamically the mass means that the increased force is proportional to the increased mass and that's where my knowledge begins to fail me!

Therefore, it looks as though my idea of fitting front springs on the rear really shouldn't make much difference with standard springs! Might just do it anyway if I'm bored and see if there really is no noticable difference other than a possible change in rideheight.