Choosing Spring Rates

[sburrell93]

Spring rates, talk to me! Currently the only thing I'm struggling with picking for getting new coilies. I realise it's a very personal thing but some opinions and ideas would be great to make sure I'm in the right ballpark with my figures.

Current plans are nothing too serious with the car as I'd rather have something I can have a bit of fun in on the road as well as track, compared with an all out track car with rock solid springs. I previously had Spax RSX coilies and they were 342lbs front and 228lbs coilover rears (according to Ktec's website). The rates on the Spax of 324/228 works out as the front being 1.5x stiffer than the rear, which would equate to 450/300 to maintain the same ratio, but that seems soft on the rear from everything I've read on here.

With that in mind, I'm thinking 400-450lbs front and probably 400lbs rear, but I'm interested to hear some opinions. Not sure if that's high enough on the rear but it's still a big jump up from before and I'm thinking the ARB on the rear should help achieve better roll resistance without going to a higher spring rate.

 

[sburrell93]

Any opinions on this before I go buy them?

 

[STEVE.M]

Any opinions on this before I go buy them?

400 lb rear seems way to hard.
The heavy front end of the car sits directly on the springs, whereas the lighter rear end is levered.
My GHA`s are 350 fr,225 rear, ok for road, though stronger than GAZ`s base settings, are much the same as the Spax rates.
I have considered something stronger for trackdays, but swapping springs over just for the day would be a lot of hassle.

With the value of hindsight, I wish I had gone for BC`s, as you can adjust the front ride height without affecting the spring preload.
Admittedly the rear BC`S are still separate shock & spring.

I have no idea what rear spring rate to suggest with a BC set up.
Perhaps someone else could advise?

 

[sburrell93]

400 lb rear seems way to hard.
The heavy front end of the car sits directly on the springs, whereas the lighter rear end is levered.
My GHA`s are 350 fr,225 rear, ok for road, though stronger than GAZ`s base settings, are much the same as the Spax rates.
I have considered something stronger for trackdays, but swapping springs over just for the day would be a lot of hassle.

With the value of hindsight, I wish I had gone for BC`s, as you can adjust the front ride height without affecting the spring preload.
Admittedly the rear BC`S are still separate shock & spring.

I have no idea what rear spring rate to suggest with a BC set up.
Perhaps someone else could advise?

Thanks for the input mate. I don't mind it being a bit harder on the road than usual, so long as it's still useable but performs well on track. Maybe be better going for 450/300 then to start with, and keeping the same ratio of spring rate front to rear that I was used to with the spax.

BC's were one set of coil overs I'd been looking it actually. The separate spring and shock on the rear is a deal breaker though as they only come in one spring rate and it's nearly impossible to find different springs for something like that if I wanted to change.

GAZ Gold's are the main contender for me just now. The rates are the only thing stopping me buying really!

 

[Sonic Boom]

Unfortunately you'll never get the answer you require as everyone has a different opinion on what makes a car handle.
Me personally I go for the big poundage springs at the rear and softer at the front (BC's standard kit is 4kg front and 8kg rear)
As with any FWD car you want to push all the available grip you have to the front wheels you can simply achieve this by making the rear not so grippy this in turn makes for a very nimble car with excellent change in direction characteristics, downside a lot of people don't like a happy rear end on their Clios, you do have to have a modicum of skill to drive with this setup and some people just prefer a "safe" setup where all that'll happen is you understeer.
I wait a flurry of racing drivers who say they run massive poundage front springs and much softer at the rear saying how quick they are and that's fine because if you have confidence in the car you can drive it very hard.

I use 500lb front and 650lb rears btw

Check out this video to see what heavier poundage rear to the front looks like, it looks very quick but it's also right on a knife edge of course these a 90's works car so obviously it has the best everything but you'll get the idea.



Ideally you'll want to drive your car and test out how different spring rates feel to you although this a very time consuming process.

Here's another video of a Clio 172 on the BC 4/8kg setup, it handkes very nicely:



Rich

 

[sburrell93]

Unfortunately you'll never get the answer you require as everyone has a different opinion on what makes a car handle.
Me personally I go for the big poundage springs at the rear and softer at the front (BC's standard kit is 4kg front and 8kg rear)
As with any FWD car you want to push all the available grip you have to the front wheels you can simply achieve this by making the rear not so grippy this in turn makes for a very nimble car with excellent change in direction characteristics, downside a lot of people don't like a happy rear end on their Clios, you do have to have a modicum of skill to drive with this setup and some people just prefer a "safe" setup where all that'll happen is you understeer.
I wait a flurry of racing drivers who say they run massive poundage front springs and much softer at the rear saying how quick they are and that's fine because if you have confidence in the car you can drive it very hard.

I use 500lb front and 650lb rears btw

Check out this video to see what heavier poundage rear to the front looks like, it looks very quick but it's also right on a knife edge of course these a 90's works car so obviously it has the best everything but you'll get the idea.



Ideally you'll want to drive your car and test out how different spring rates feel to you although this a very time consuming process.

Here's another video of a Clio 172 on the BC 4/8kg setup, it handkes very nicely:



Rich

Yeah I realise it's a very personal thing choosing spring rates. I guess what I'm trying to do is get a ballpark figure so if I do feel they need changed in future, say, upping the fronts 50lbs or something, I won't need to get the dampers revalved. If I end up miles out though and end up wanting to go up 100 or 150lbs in rates I'm most likely going to need the dampers revalved to suit.

Two very different answer between yourself and Steve above lol. I take it your car is full on track/race spec and not used on the road? I like the car a little tail happy but I'd rather achieve that with an ARB or upping rear pressures than going massively high with rear spring rates and having it uncomfortable on the road.

From my previous spax coilovers. I felt like the rear could've done with being a bit stiffer at times. I also know guys who get round my local track (knockhill) very quickly on 450lbs fronts. That's my basis on going 450 front and then slightly less on the rear. Whether or not my logic works though, I have no idea lol!

 

[STEVE.M]

[QUOTE="sburrell93, post: 11300437, member: 93445"

BC's were one set of coil overs I'd been looking it actually. The separate spring and shock on the rear is a deal breaker though as they only come in one spring rate and it's nearly impossible to find different springs for something like that if I wanted to change.

GAZ Gold's are the main contender for me just now. The rates are the only thing stopping me buying really![/QUOTE]

It is not possible to make a direct comparison between a true rear coilover and the OE set up of separate spring & damper spring rates, due to their different fitting position on the car.

BC do offer spring options according to this,
http://www.corbymotorsport.com/clio...lio-mk2-172-rs-9804-bc-coilover-kit-br-p-1206
but if not, you could use any make of spring of the required poundage, as they are in the OE mounting position.

If you go for GAZ,450/300 maybe 325 would be a good place to start, though you`ll need to be good on your pothole dodging skills on the road.
Also I found I needed the helper springs on the front to keep the springs located at a not particularly low ride height.
@Sonic Boom

 

[Fraser.J.]

I bought 550 front, 650 back for my AST [emoji849]

 

[STEVE.M]

I bought 550 front, 650 back for my AST [emoji849]

It`s a free country, sort of.
I assume you mean for your Ph1 172,and how did you get on?

 

[Fraser.J.]

It`s a free country, sort of.
I assume you mean for your Ph1 172,and how did you get on?

Find out in march when I first use them!

 

[vroomtshh]

I bought 550 front, 650 back for my AST [emoji849]

I've got 520 front, 450 rear on mine and it's almost undriveable with how stiff the rear is. Good luck with 650 rears :tongueout:

 

[NorthloopCup]

On my cup I had 450 fronts and 475 rears. You'll not go far wrong on those rates, but I'd possibly go with 500 fronts and 400 rears.

 

[sburrell93]

I bought 550 front, 650 back for my AST [emoji849]

Yeah f**k that [emoji23] pretty much track only though now I assume?

On my cup I had 450 fronts and 475 rears. You'll not go far wrong on those rates, but I'd possibly go with 500 fronts and 400 rears.

How was your cup on the roads? 500/400 sounds quite stiff! Lol

 

[NorthloopCup]

Yeah f**k that [emoji23] pretty much track only though now I assume?



How was your cup on the roads? 500/400 sounds quite stiff! Lol

It was alright tbh mate, but I think a lot of that comes down to the quality of the damper. I was running ast's.

 

[STEVE.M]

Y
How was your cup on the roads? 500/400 sounds quite stiff! Lol

If you remember, your original requirement was " Current plans are nothing too serious with the car as I'd rather have something I can have a bit of fun in on the road as well as track,"
Gaz`s Gold drive to track recommendation is 500 lb front,300 lb rear.
Why not start there?
AST do recommend some very high rear spring rates, but these are for a very specific track/race application, at a price that only the very committed will be prepared to pay.

 

[Fraser.J.]

Ye mines is complete track car now,

Pair of springs is only like £60 so if it's all wrong then it's easy to change

 

[sburrell93]

If you remember, your original requirement was " Current plans are nothing too serious with the car as I'd rather have something I can have a bit of fun in on the road as well as track,"
Gaz`s Gold drive to track recommendation is 500 lb front,300 lb rear.
Why not start there?
AST do recommend some very high rear spring rates, but these are for a very specific track/race application, at a price that only the very committed will be prepared to pay.

Had no idea they had recommendations like that, cheers mate. That's a good base to start with anyway, maybe bring the fronts down in hope of a little bit extra comfort and up the rears a little going on how my car performed in the past and the fact I prefer the rear to move around a bit.

 

[scotiamr2t]

Ye mines is complete track car now,

Pair of springs is only like £60 so if it's all wrong then it's easy to change

Where are you getting a pair of springs for £60 fraser? fronts yes as you can use faulkner, but what about the rears?

 

[Fraser.J.]

Where are you getting a pair of springs for £60 fraser? fronts yes as you can use faulkner, but what about the rears?

Why can't you get rears from there also [emoji848]

 

[scotiamr2t]

Why can't you get rears from there also [emoji848]

You can but the 1.9" they told me they can supply only go up to 450lbs, i want 550lbs to try as currently have 650lbs springs

 

[...]

It's also affected by rebound and bump settings

If not 2 or 3 way adjustable then the internal valving in the damper body needs to match appropriately

Body roll is also a consideration , that's affected by anti roll bar stiffness so there is alot to consider.

Lotus for example are renowned for softer sprung cars with stiffer arb's and appropriate bump and rebound settings meaning you can have a car that handles well without smashing your spine

 

[sburrell93]

You can but the 1.9" they told me they can supply only go up to 450lbs, i want 550lbs to try as currently have 650lbs springs

Just had a quick look there and found this website

http://www.shock-factory.co.uk/1.9-springs.html

Never heard of them before tbh, so no idea on quality but they do any spring rates and seem well priced!

 

[sburrell93]

Well, I ordered a set of Gaz Golds the other day and went for 450lbs front and 350lbs rear. So in true CS fashion, I've went ahead and listened to absolutely no one...almost 😂

Hopefully my logic in this works out but we'll see in about 6 weeks time when I get it out on track!

It's also affected by rebound and bump settings

If not 2 or 3 way adjustable then the internal valving in the damper body needs to match appropriately

Body roll is also a consideration , that's affected by anti roll bar stiffness so there is alot to consider.

Lotus for example are renowned for softer sprung cars with stiffer arb's and appropriate bump and rebound settings meaning you can have a car that handles well without smashing your spine

See, I'm half aware of everything involved as I've always been interested in how it all works, but don't know enough to start calculating or working things out accurately lol.

I did make sure the dampers would be valved to suit the spring rates though, as I knew that'd be an issue if they weren't.

 

[...]

Good man , have a look through books by Alan Staniforth


There are others that my help

It's all useful knowlage