My ast springs query. Rally boys helpfull

[ScottRallye]

Hello all.. I'm currently prepping my 172 to do some single venue rallies so due to buying the car with the suspension fitted already I was unsure on what springs were fitted as they are very stiff!

Turns out I have these.. On the front

These on the rear along with a whiteline arb.

So I think the fronts are HR springs
But only 285lb/in??? They're solid!

Rears eibach ast's 230lb/in which do feel abit softer..

So Im wondering what a good starting point would be regarding the springs, also running a 9inch spring instead of the 7's currently fitted would be a good move as the current ones have marks of binding..

Cheers for any help.

 

[itsjamz]

I've got 550lbs all round ATM... I'm only on circuit though. I've also got some 700lbs rears and 450lbs fronts.

 

[EVOgone]

Rally wise my Reigers are 60nm and 30nm but think rear may need to be 40nm. This is approx 370 front and 185 rear but the 40nm would be 245ish.

 

[ScottRallye]

Interesting, any idea why the front is solid? As is, open door.. Stand on the sill and bounce and the only movement is in the tyre walls? I got a feeling the springs are too short. Will try some 9" springs instead of the 7"s currently fitted on the front

 

[EVOgone]

They may be 180nm..!!! 1000lbs a la cup racer

 

[ScottRallye]

Hmm I doubt it but it feels like it! My toyo r888 tyre walls have more movement than the springs.

 

[bozothenutter]

Well the number does start with 180......

 

[ScottRallye]

It does yes but that refers to the length of the spring followed by the rate in NM

 

[bozothenutter]

You sure about that?
I have 60/40 Nmm F/R which isn't that stiff

could it be stiffness/diameter/???

 

[ScottRallye]

99% sure yeah, diameter is 2.25" which is 57mm

 

[sprintcup]

I'm not sure if this helps but if they are Eibach springs I think the 180 is the spring compressed in kg per mm 180 would = 18.0 x 55.88 which would convert to 1001lbs, the lads at Blink told me this when they were working out the numbers on my rear Bilstein coils for me.
The 55-88 converts kg to lbs if I remember correctly, the 50 may be the internal spring diameter.
Regards Russ.......

 

[ScottRallye]

Hmm would help if I knew exactly what make they were and not guess at HR.. They certainly do feel like 1000lb springs

 

[BIGASH]

They won't be 1000ib front springs if the rears are only 250ib

From my experience the first number is the spring length, second number is the rate in nm/mm and the 3rd number is internal diameter of the spring Can't see a 3rd number though for the front springs?

 

[ScottRallye]

Still none the wiser, all I know is the back feels decent, the front is ridiculous for road/rally, I imagine very good for track, just dont want to buy some circa 275lb 9/10 inch springs to find out its still stiff but surely it shouldnt be. Il take the risk

 

[EVOgone]

To match 250lbs rear springs get 60nm or 350/375lbs up front (you will not need any stiffer for a Rallycar), i do think they are 1000lbs (same a cup racer which i have driven on the road and would feedback exactly the same as you have). Only way is to buy some and try and get them rate tested.

 

[Tony Hunter]

Plus they would be useless, unless the shocks have been valved for them.

 

[ScottRallye]

To match 250lbs rear springs get 60nm or 350/375lbs up front (you will not need any stiffer for a Rallycar), i do think they are 1000lbs (same a cup racer which i have driven on the road and would feedback exactly the same as you have). Only way is to buy some and try and get them rate tested.

I thought the given idea on clios was to have stiffer springs on the rear? Such as perhaps 400lb rear with 325lb ish fronts?

 

[EVOgone]

I thought the given idea on clios was to have stiffer springs on the rear? Such as perhaps 400lb rear with 325lb ish fronts?

Depends on preference but the rule of thumb generally to have a neutral handling car is to match weight distribution front to rear. Car with 50/50 weight distribution should in theory have same weight springs all round if like a clio its 60/40 then thats what you should be looking at. Cup cars are 1000lbs front and 400lbs rear so follow this principle. For Rallying the renaultsport recommendation follow the same rule with 350lbs front and similar rear but the rears is near 2-1 ratio.

Hope that makes sense but this is how the top companies work it Reiger / Ohlins etc

I asume you mean rear lbs is std position so need to apply 2.1 ratio, so 325 front and 200 rear. Sounds about right to start. If shocks location are 1.1 ratio then 400 rear is cup racer hard and a no no for rallying.

 

[sam JFM]

Depends on preference but the rule of thumb generally to have a neutral handling car is to match weight distribution front to rear. Car with 50/50 weight distribution should in theory have same weight springs all round if like a clio its 60/40 then thats what you should be looking at. Cup cars are 1000lbs front and 400lbs rear so follow this principle. For Rallying the renaultsport recommendation follow the same rule with 350lbs front and similar rear but the rears is near 2-1 ratio.

Hope that makes sense but this is how the top companies work it Reiger / Ohlins etc

I asume you mean rear lbs is std position so need to apply 2.1 ratio, so 325 front and 200 rear. Sounds about right to start. If shocks location are 1.1 ratio then 400 rear is cup racer hard and a no no for rallying.

Is that asphalt spec?

 

[ScottRallye]

Depends on preference but the rule of thumb generally to have a neutral handling car is to match weight distribution front to rear. Car with 50/50 weight distribution should in theory have same weight springs all round if like a clio its 60/40 then thats what you should be looking at. Cup cars are 1000lbs front and 400lbs rear so follow this principle. For Rallying the renaultsport recommendation follow the same rule with 350lbs front and similar rear but the rears is near 2-1 ratio.

Hope that makes sense but this is how the top companies work it Reiger / Ohlins etc

I asume you mean rear lbs is std position so need to apply 2.1 ratio, so 325 front and 200 rear. Sounds about right to start. If shocks location are 1.1 ratio then 400 rear is cup racer hard and a no no for rallying.

Good read, the rears are together with the dampers, 1:1 ratio 230lb so thats fairly stiff.

 

[EVOgone]

Is that asphalt spec?

Yes tarmac

 

[EVOgone]

Good read, the rears are together with the dampers, 1:1 ratio 230lb so thats fairly stiff.

230lbs rear and 375lbs front would be were i would start but certainly no higher.