Coilover Spring Rates (Fast Road/Track)

Niall · Jun 12, 2017

Looking to buy some BC DR series coilovers at the end of the month, and I'm not sure what spring rates to go for. BC offer custom spring rates free of charge so it's just a case of meeting my needs. I've been told these new DR series BC's are a lot more compliant and comfortable too, then of course there's the adjustable damping to give some more adjustability with hardness etc.

The car is predominantly a road car, and I do use it for track, I'll be wanting to increase the amount of track work I do in future once I've bought more things for the car etc. I don't mind it being a bit hard for the road, I know a lot of people on here like to make a mountain out of a molehill when it comes to comfort in cars, so I'm not going to be getting rid of them after a week if they're anything other than a Rolls Royce.

They start at a 4/8kg setup, up to 10/8kg. I was thinking perhaps 6/8kg could be a good middle ground? I was hoping somebody could tell me from experience what each is like. I suppose you have to bear in mind that you have the adjustable damping to make the car harder softer too.

Any ideas/experiences?

Christopher · Jun 12, 2017

@NorthloopCup
I'd guess the same as you mate, around 6kg. You don't want to make it unusable on the road, like you say.

Niall · Jun 12, 2017

Christopher said:
@NorthloopCup
I'd guess the same as you mate, around 6kg. You don't want to make it unusable on the road, like you say.

Yeah I thought it seemed like a good compromise. I'm hoping at that rate the damping should be good enough so it's not harsh, then I can turn it to max and it will be as hard as I need for track days.

NorthloopCup · Jun 12, 2017

What's those kg rates in lbs?

JB21 · Jun 12, 2017

I'll be going 8kg/8kg on mine Niall, mines the opposite with use though so mostly track, minimal road.

Niall · Jun 12, 2017

NorthloopCup said:
What's those kg rates in lbs?

@JamesBryan?

Niall · Jun 12, 2017

JB21 said:
I'll be going 8kg/8kg on mine Niall, mines the opposite with use though so mostly track, minimal road.

Yeah I'm hoping with the dampers on hard it should be hard enough anyway really, just about having enough softness when on soft. We'll see!

JamesBryan · Jun 13, 2017

Niall said:
@JamesBryan?

Times the kg rating by 56 to get the figure in lbs.

Niall · Jun 13, 2017

So that'll be 336lbs @NorthloopCup.

NorthloopCup · Jun 13, 2017

Niall said:
So that'll be 336lbs @NorthloopCup.

That's a similar setup to what I had on my cup originally when I was running kw v2's. Worked well tbf.

Niall · Jun 13, 2017

NorthloopCup said:
That's a similar setup to what I had on my cup originally when I was running kw v2's. Worked well tbf.

Ah good stuff. How was it on the road?

NorthloopCup · Jun 13, 2017

Niall said:
Ah good stuff. How was it on the road?

Excellent mate. Nice and compliant on the road. Was a bit soft on the track, but it was a very good compromise.

Niall · Jun 13, 2017

NorthloopCup said:
Excellent mate. Nice and compliant on the road. Was a bit soft on the track, but it was a very good compromise.

Yeah fair enough, sounds great then. Not terribly bothered about it being that soft on track within reason, at least not for the moment. Will still be a damn lot stiffer than my current sportlines which I didn't have any major issues with on track.

NorthloopCup · Jun 13, 2017

Niall said:
Yeah fair enough, sounds great then. Not terribly bothered about it being that soft on track within reason, at least not for the moment. Will still be a damn lot stiffer than my current sportlines which I didn't have any major issues with on track.

For track, go full stiff on the rear dampers and go half way on the fronts. Then dial the fronts in to suit.

JB21 · Jun 13, 2017

I'll be going 9kg/8kg (504/448 lbs) bet it'll be horrendous on the road, should be good on track though.

Niall · Jun 13, 2017

NorthloopCup said:
For track, go full stiff on the rear dampers and go half way on the fronts. Then dial the fronts in to suit.

Is that with a RARB too? I'll be getting a Whiteline you see.

Niall · Jun 13, 2017

JB21 said:
I'll be going 9kg/8kg (504/448 lbs) bet it'll be horrendous on the road, should be good on track though.

Yeah will be ace for track, classic horses for courses situation really isn't it!

NorthloopCup · Jun 13, 2017

Niall said:
Is that with a RARB too? I'll be getting a Whiteline you see.

In that case, full stiff rear, half way on the fronts and then dial both ends in to suit. If it's too stiff at the rear and a bit flighty, turn the damper down one click.

JB21 · Jun 13, 2017

Niall said:
Yeah will be ace for track, classic horses for courses situation really isn't it!

Yeah mate, can't wait to get a set now. When is your next track day after fitting them?

Niall · Jun 13, 2017

NorthloopCup said:
In that case, full stiff rear, half way on the fronts and then dial both ends in to suit. If it's too stiff at the rear and a bit flighty, turn the damper down one click.

Ah awesome, cheers for that! Looking forward to having an experiment with it when I get them on.

JB21 said:
Yeah mate, can't wait to get a set now. When is your next track day after fitting them?

Not sure, was playing with the idea of one at Oulton in late summer, maybe towards the end of August. Would depend if anyone I knew was game really, doing track days on your own takes half the fun away for me tbh! @Christopher was considering it too.

JB21 · Jun 13, 2017

Niall said:
Ah awesome, cheers for that! Looking forward to having an experiment with it when I get them on.

Not sure, was playing with the idea of one at Oulton in late summer, maybe towards the end of August. Would depend if anyone I knew was game really, doing track days on your own takes half the fun away for me tbh! @Christopher was considering it too.

Fully agree, done a few on my own. Not fancy Aintree end of September?

Niall · Jun 13, 2017

JB21 said:
Fully agree, done a few on my own. Not fancy Aintree end of September?

Hmm, I am tempted, Aintree looks awesome. What's the price?

JB21 · Jun 13, 2017

Niall said:
Hmm, I am tempted, Aintree looks awesome. What's the price?

£120 with free instruction.

Niall · Jun 13, 2017

JB21 said:
£120 with free instruction.

Cheap too, will have a think about that one then!

DCELEC 182 · Jun 13, 2017

I run 8/8kg with the bc's on a track only car....ran the 5kg springs up front first off which were ok but found them too soft pretty quickly. Both rates are fine on the road with the dampers turned down, the 5kg in particular were really quite compliant on the road!
I'll go for heavier spring rates again if I upgrade to ast's, I do run a Pms rear anti roll bar and roll centre correction kit up front as well as a gripper diff.

Niall · Jun 14, 2017

DCELEC 182 said:
I run 8/8kg with the bc's on a track only car....ran the 5kg springs up front first off which were ok but found them too soft pretty quickly. Both rates are fine on the road with the dampers turned down, the 5kg in particular were really quite compliant on the road!
I'll go for heavier spring rates again if I upgrade to ast's, I do run a Pms rear anti roll bar and roll centre correction kit up front as well as a gripper diff.

That must go well with all of that! But that's interesting. May find somebody with coilovers they know the spring rate of and get them to take me out.

DCELEC 182 · Jun 14, 2017

Niall said:
That must go well with all of that! But that's interesting. May find somebody with coilovers they know the spring rate of and get them to take me out.

It's only standard power but does lap well with all the handling mods!
How many trackdays are you likely to do in reality compared with road driving?
Personally I wouldn't get too hung up on going to crazy with spring rates if you're realistically doing a couple of days a year.
The 5kg fronts I had first would be a great compromise as it drove lovely on the road, really not crashy at all.
A mate had 650/450kg springs (gaz golds) and was horrific on the road!!

Christopher · Jun 14, 2017

Niall said:
Ah awesome, cheers for that! Looking forward to having an experiment with it when I get them on.

Not sure, was playing with the idea of one at Oulton in late summer, maybe towards the end of August. Would depend if anyone I knew was game really, doing track days on your own takes half the fun away for me tbh! @Christopher was considering it too.

The Oulton date in August I think mate. 23rd, it's a Wednesday

eon172 · Jun 16, 2017

Are the BC's rear coilovers or separate spring? Got a link to a recommended seller?

Niall · Jun 16, 2017

eon172 said:
Are the BC's rear coilovers or separate spring? Got a link to a recommended seller?

Separate spring. I'll be getting mine from Kam Racing, if you google search BC Coilovers Clio 172/182 Kam Racing you'll find them, there are two versions, the BR and DR.

eon172 · Jun 16, 2017

Thanks, read up on the differences and also Kams Facebook page, seems the DRs are most suitable for track and only available via them anyway.

Niall · Jun 16, 2017

eon172 said:
Thanks, read up on the differences and also Kams Facebook page, seems the DRs are most suitable for track and only available via them anyway.

Yeah yeah. They have a better ride though which means they would be better for road too with the digressive valves.

eon172 · Jun 24, 2017

@Niall @JB21 did you pull the trigger on the BC's? Getting close to it myself now but considering spring rates for a track/sprint/hillclimb only setup. Good to read your view on your setup @DCELEC 182 , l'll have a similar setup with the diff following at a later date. I assume the BCs are valved according to the springs you order with them? Cheers.

[Edit: @Niall just seen your other thread, I see you haven't as yet]

JB21 · Jun 25, 2017

No not yet for me, going to be next year now. I'll be going 9kg/8kg maybe even 10kg/8kg....

eon172 · Jun 25, 2017

JB21 said:
No not yet for me, going to be next year now. I'll be going 9kg/8kg maybe even 10kg/8kg....

Yeah, I was thinking those rates too

JKING3008 · Jun 25, 2017

Sorry to hijack the thread

I have the Clio 182 cup control suspension (Spax, 750lb front/ 450lb rears) currently got mine set halfway Front and rear.
Would it be better to set the rears to full stuff aswell?

JamesBryan · Jun 25, 2017

JKING3008 said:
Sorry to hijack the thread

I have the Clio 182 cup control suspension (Spax, 750lb front/ 450lb rears) currently got mine set halfway Front and rear.
Would it be better to set the rears to full stuff aswell?

In the dry, yeah run the rears full hard.

Greeny. · Jun 25, 2017

FYI I have these coilovers with their standard 'track rates' and they are far to soft, apart from that no complaints from the kit, love it.

eon172 · Jun 26, 2017

DCELEC 182 said:
I run 8/8kg with the bc's on a track only car....ran the 5kg springs up front first off which were ok but found them too soft pretty quickly. Both rates are fine on the road with the dampers turned down, the 5kg in particular were really quite compliant on the road!
I'll go for heavier spring rates again if I upgrade to ast's, I do run a Pms rear anti roll bar and roll centre correction kit up front as well as a gripper diff.

What's the front end body roll now like on cornering with those 8/8kg? do you have any track videos you could share? Cheers

JB21 · Sep 9, 2017

Thought I'd revive this rather than start a new thread.

Managed to get hold of a used set of AST 4100 Coilovers and they come with 50/30nm & 90/110nm springs. Has anyone any experience with AST spring rates? As I only really know rates in KG, so not a clue in nm. Got a feeling the 90/110 will be to hard for road and the 50/30 to soft for track? Car is only used on road to drive to and from track, with the odd road blast.

Coilover Spring Rates (Fast Road/Track)

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