Spring Rates - Standard vs. Aftermarket

[Tav]

One thing I've noticed over the years is that it seems very difficult to come across information on spring rates when looking to buy new suspension.

I was looking at the car the other day and I'll admit, a little ride height reduction would make the 182 look a bit better. Eibach seem to be a good shout as I don't want to go down the coilover route...yet...

The only problem is, other than the reputable name, you don't actually know what you are buying? I would like to know what the standard Clio 182/182 Cup/Trophy spring rates are and how these compare to the after market options. Are the standards springs progressive rate or not?

It seems to be a lot easier to find this information for Japanese car. A quick search on the net and you can find out exactly what the spring rate of a 1998 Civic EK9 Type R is in kg/mm. A friend of mine changed the suspension on his Integra and know he went from say 5kg/mm to 7kg/mm at the front and 4kg/mm to 6kg/mm rear. This would at least give him an idea of the potential handling characteristics.

Any thoughts?

 

[Fred@BTM]

to my knowledge renault have never released that info but i maybe wrong, its safe going with eibach though, they did the springs for the trophy (amongst others) so i'm sure they'll know the rates and whats going on

 

[clioalesi]

Interesting question there Tav. I'll eagerly wait for the answers.

 

[ben_r1]

Eibach springs are much stiffer than OEM, i can offer you that much info

 

[Inferno]

I asked the experts ages ago on the RenaultSport forum (expert panel - think the guy's name is Allen Collen?), they gave me the answer, but I can't remember what it was! Ask the question again on there.

Edit - don't bother, I've just asked again. Will post up when I have the answer.

 

[Justin]

Tav, just wait and get coilover's.. I done the springs first, then quickly changed to H&R's on my 182

 

[Tav]

I won't be able to afford coilovers for ages it's going to take a me months to save up for the cambelt/auxbelt change : ( Plus springs might do all I want with it being a road car, I had an H&R spring and shock kit on my Polo and it was really good.

 

[Justin]

Yeah true. Coilover's are probably a bit overkill for just road.

 

[Tav]

Does anyone have a definitive price for trophy front dampers? Are they available from Renault or direct from Sachs?

Yeah true. Coilover's are probably a bit overkill for just road.

Overkill unless your car is pap as standard or you got on LOTS of track days/compete.

 

[ForceIndia]

Roughly £1200 a piece. I disagree on coilovers being overkill. My Kw's ride and handle better than my 182 on sportlines.

 

[Justin]

Roughly £1200 a piece. I disagree on coilovers being overkill. My Kw's ride and handle better than my 182 on sportlines.

Depends on whether you can afford/justify/need them. If I bought another 182 I probably wouldn't bother.

 

[Tav]

Depends on whether you can afford/justify/need them. If I bought another 182 I probably wouldn't bother.

I think for most people it's afford...followed by justify...and lastly need

 

[JasonA]

I decided to fit the eibach sportlines after i found out how much i was going to be to replace my broken front spring.
A full set of springs from Ktec was about 155 compared to the 126 Renault wanted for the one spring, made sense really, i wasnt going to entertain coilovers as wasnt prepared to pay for them when i was rarely using the car on the track, which after all is what they are really meant for.

 

[Inferno]

I asked the experts ages ago on the RenaultSport forum (expert panel - think the guy's name is Allen Collen?), they gave me the answer, but I can't remember what it was! Ask the question again on there.

Edit - don't bother, I've just asked again. Will post up when I have the answer.

Took their time!

182: 2.43/5.04 daNM/mm F/R
182 Cup: 3.19/5.65 daNM/mm F/R
182 Trophy: 3.19/5.65daNM/mm F/R

 

[SymonSi84]

Took their time!

182: 2.43/5.04 daNM/mm F/R
182 Cup: 3.19/5.65 daNM/mm F/R
182 Trophy: 3.19/5.65daNM/mm F/R

Hmmm so basicly spring rate of 182 CUP and Trophy are same?

Sorry for digging up old thread.

 

[Matthew]

2 year mega bump. BOOM! lol

 

[Tav]

And here is me coming to check answer, lol

 

[ripp]

so the front springs on a cup are softer than the rears?

 

[Alex Conway]

so the front springs on a cup are softer than the rears?

When I read stuff like that it reminds me why I leave the VD to my mate and dabble in everything else!

I'm thinking a combination of squat, boot load and other stuff have led to it. But then you get stuff like rear wheel frequencies being faster to allow it catch up with the front. Then it's a beam axle too which will have something to do with it. Eurgh I hate VD.

Edit:

Sorry had a bit of a moment there.

 

[MG cup]

There going to harder most likely due to their position, the axle has a lot of leverage on them. Front/rear spring comparisons don't become relevant until the car has independent coilovers all round.

 

[Alex Conway]

There going to harder most likely due to their position, the axle has a lot of leverage on them. Front/rear spring comparisons don't become relevant until the car has independent coilovers all round.

Sounds right, it's all about wheel rate rather than spring rate.

 

[Steven103]

wheel rate

We have a winner.

Installation ratio of the rear beam of a Clio is about twice that of the front of a Clio so the springs would have to be twice as stiff to give the same wheel rate. That explains why it looks unusually high (you'd expect a FWD car to have stiffer springs at the front to "support" the weight of the engine & transmission) and then the exact spring stiffness is dictated by the desired handling characteristics (desired level of body roll, anti squat & overall oversteer/understeer balance)

Also being a nit-picking cnut "daNm/mm" is really annoying me. Should be "daN/mm."

 

[Alex Conway]

Also being a nit-picking cnut "daNm/mm" is really annoying me. Should be "daN/mm."

I also hold the opinion that the DaN is a sinful thing.

 

[CamMoreRon]

3-year bump!

DaN/mm sucks because it looks confusing as hell, but it means "Decanewton per millimetre" so it's just 10N/mm (3.19DaN/mm * 10 = 31.9N/mm).

For anyone who wants to convert to lb/in, just multiply N/mm by 5.71 (or DaN/mm by 50.71)

31.9N/mm * 5.71 = 182lb/in for the Front
56.5N/mm * 5.71 = 323lb/in for the Rear

Also I'm sure this has been covered a million times over the past 3 years, but for anyone (like me) who is Googling "Clio Cup standard spring rate" and finds this thread, a quick comment on why the rear spring rate is higher than the front: the installation ratio (ratio of wheel travel to spring travel) is a factor, but it is mostly due to the way FWD cars need to be set up. For a FWD car to handle well, the rear roll stiffness - a combination of spring rate and ARB rate - needs to be a lot higher than the front.

 

[allanallen]

I'd be curious to know what the actual wheel rates are rather than the spring rate. The standard rear spring is mounted part way up the arm rather than at the wheel centre so it will be considerably less than the 323lb spring would suggest.

 

[CamMoreRon]

Rough estimate made from eyeballing a beam is an installation ratio of 1.25 (spring roughly 4/5ths distance of the axle to the pivot)

To find wheel rate [k(w)] from spring rate [k(s)] and installation ratio [IR], use: k(w) = k(s) / IR^2

If IR(F) is around 1.05 (about right for a McPherson Strut) and IR(R) is around 1.25 then:

31.9 / 1.05^2 = 28.9N/mm (or 165lb/in) for the Front
56.5 / 1.25^2 = 36.2N/mm (or 207lb/in) for the Rear

I'll measure up my suspension today and post something a bit more accurate if you're interested.

 

[CamMoreRon]

I ran out of time yesterday, but as promised here's something a bit more accurate.

It was tough to measure, but the IR for the rear spring is more like 1.44 (390mm to wheel vs. 270mm to spring) so we get:

31.9 / 1.05^2 = 28.9N/mm (or 165lb/in) for the Front
56.5 / 1.44^2 = 27.2N/mm (or 156lb/in) for the Rear

So I was a bit off with my original Google-based eyeballing oo:

For an interesting comparison, my 172 Cup has AST "track spec" coilovers which puts the rear IR at pretty much 1:

80.0 / 1.05^2 = 72.6N/mm (or 414lb/in) for the Front
90.0 / 1.44^2 = 90.0N/mm (or 514lb/in) for the Rear :fearscream:

I'd actually expected the standard Cup to be a bit stiffer at the rear, but I suppose they had to compromise somewhere with how comfortable it would be. Also not accounted for here is the ARB & twist beam stiffnesses, which will make a big difference in terms of roll stiffness. What I can say is the AST's make my 172 handle beautifully, albeit at the expense of my spine! :grin:

 

[CamMoreRon]

Thought I'd add ride frequency while I had Excel open..

Standard: 1.05Hz Front, 1.43Hz Rear
AST: 1.66Hz Front, 2.60Hz Rear :astonished:

 

[allanallen]

It shocked me that the rear rate would be so high for a road car so that makes a bit more sense, still way higher rate at the rear compared to most other stuff

 

[bozothenutter]

Usefull thread this.....bookmarked!
So basically the ast tracksetup for the front is about the same as B14's....and they are considered too soft by most.....could the too soft stm from the rear rates of the billies?

 

[MiniCooper1380]

Thought I'd add ride frequency while I had Excel open..

Standard: 1.05Hz Front, 1.43Hz Rear
AST: 1.66Hz Front, 2.60Hz Rear :astonished:

Hello,
what sprung mass and tyre vertical stiffness have you used to obtain these results?

 

[CamMoreRon]

Hello,
what sprung mass and tyre vertical stiffness have you used to obtain these results?

Bonjour!
I used corner weights from a standard 172 Cup (thread found on here) and a stiffness of 400N/mm.

 

[MiniCooper1380]

Bonjour!
I used corner weights from a standard 172 Cup (thread found on here) and a stiffness of 400N/mm.

Hello,
isn't 400N/mm too high value for street tyres?
If you used corner weights you have considered sprung mass + unsprung mass!

 

[CamMoreRon]

Probably, but it was a rough hand calculation to give a comparison of front & rear rates. If I wanted to be super accurate I wouldn't have measured by crawling under the car with a tape measure, either. 😅

 

[TheStub]

I should open up old discussion as in our market (Latvian) many original spare parts are no more available from dealership. In that category falls springs for 172/182
In this case does someone knows what producer was for springs for non-CUP version? Eibach was for CUP version, that is for sure.

 

[flebay]

Eibach was for CUP version, that is for sure.

No nobody knows who makes them,apart from the clio trophy fronts that have Eibach printed on the spring.

 

[Kev@KAM]

Easy enough to get made based off an original spring. Not sure there is the interest. I could get them done (if someone could supply a set to copy) but I would have to make 25 sets to keep the price down. I'm not sure theres the interest...

 

[JB21]

Probably whoever put in the cheapest tender price at the time, could be 1 of 20 manufacturers but you'd never know as they'd be Renault stamped.

Just purchase a set of performance after market springs as they'd be cheaper than an OE blueprint set.

 

[alexandre.]

I can help with infos about the front springs, but i need know the color indetification of the spring, maybe i can get info about the rear too

 

[Grey2231]

Sorry but I will be awakening this thread once more. But I figured it's still better than starting a new one.

I am looking to get better springs for my 1.4 16v since it will be getting a new turbo 1.6 next year and I drive this thing like I stole it in the city (So damn fun!).

I want stiffer better springs but I don't want to lower it. I live in Germany and the only aftermarket springs I find from Eibach or Bilstein are lowered.
I currently have a set of stock replacement Bilsteins mounted.

I will be doing a Poly Bushing kit at the same time so I am also looking for a good shock set to go with it all.

Any good ideas?