Track car coilover spring rates......

[DCELEC 182]

Bought a clio 182 before last summer and built it into a reasonable spec track car to have some fun in, but unsure as to specs etc have had to learn along the way! Did 5 days over the summer at castle combe (my local track), and whilst having a lot of fun have found the weaknesses now so looking to make a few improvements over the winter for next year and hopefully some trips further afield.
I bought coilovers pretty much straight away and after a minefield of options went down a semi budget route and bought BC's with their track spec springs. Really impressed with the build quality/fitment etc but spring rates in hindsight are too low and once I started pushing on with track tyres have found the limits and realise stiffer springs are definitely needed.......but what to go for, real dilemma!
They are also inboard springs so that will change what rates to go for on the back.
Any feedback welcome, I'd rather persevere with the suspension I've got at least for now, than fork out £1600 on AST's but I'm not adverse to spending money in the right places on the right things!

 

[JamesBryan]

What have you got at the minute? Is it 7kg?

 

[DCELEC 182]

Front 5kg/rear 8kg. Front is way too soft, on hard cornering it's pitching over loads and bottoming out the suspension....wheel tucks up so hard it hits the inside of the arch (not the liner)!

 

[JamesBryan]

I'd go with 7 or even 9 on the front.

 

[DCELEC 182]

Funnily enough I had thought about going up to 9/10kg up front.....not too sure what to do with the rear, whether to double that as well inline with the fronts?
What suspension do you run (track car?)

 

[JamesBryan]

I'm on H&R's which are too soft as well, but been advised on here previously that 8/8 is a good starting setup.

I believe a 8kg front / 11kg rear is an AST track equivilant.

 

[DCELEC 182]

Ahh right, ok great cheers.....I've sent Mick at KPM a message regarding changing the rates on my BC's so I'll see what he comes back with as to how easy it is to get hold of springs and any revalving that may be needed!
I'd said 9/12kg so not a bad guess. A friend has had Gaz Golds built with 650/450 rates and I can't help thinking they're a tad too stiff if I'm honest, I do like to use the curbs lol.

 

[JamesBryan]

Yeah that is stiff, the AST are around 450/450.

 

[NorthloopCup]

I run Ast sportline 2's or 5100's as they're now know and I'm on 450 fronts and 475 rears. It's a tad to soft on the fronts now, but it's nothing awful. I'm actually considering upping the fronts and dropping the rears slightly. Not decided 100% yet though.

 

[DCELEC 182]

I run Ast sportline 2's or 5100's as they're now know and I'm on 450 fronts and 475 rears. It's a tad to soft on the fronts now, but it's nothing awful. I'm actually considering upping the fronts and dropping the rears slightly. Not decided 100% yet though.

I'm not sure going stupidly stiff on the back offers better handling for the average joe....my friends car with the 650/450 springs and pms strengthened beam etc doesn't seem to get round any quicker but might be harder to drive quickly?!
I'm happy to experiment with springs it's just getting the dampers in place where there is allowance to do so.....

 

[NorthloopCup]

I'm not sure going stupidly stiff on the back offers better handling for the average joe....my friends car with the 650/450 springs and pms strengthened beam etc doesn't seem to get round any quicker but might be harder to drive quickly?!
I'm happy to experiment with springs it's just getting the dampers in place where there is allowance to do so.....

The rear needs compliance mate. That's the simple truth.

 

[DCELEC 182]

That's the way I see it.....but people seem to think harder means quicker, and race car setups certainly tend to go along with that? I know they like the cars to move around a lot under braking etc.
Without anyone giving me setup tips etc of course it's only trial and error but mine on a softer setup seems to go really well at combe where the track isn't dead smooth, but I can tell from driving it there's so much more to come with stiffer springs on the front....don't want to jack up front and rear rates to a silly level and make the car hard to drive fast on the edge (I'm guessing that will miss out on ultimate performance)??
Sent mick at kpm a message but can't get reply so I may have to sack off upgrading the bc's

 

[JamesBryan]

@MicKPM

 

[olly-r]

I got spax k tec 750 mc spec coil overs they are awesomely stiff but normally run rear on softest damper settings save any 1st lap spins on cold tyres lol

 

[ripp]

I run Ast sportline 2's or 5100's as they're now know and I'm on 450 fronts and 475 rears. It's a tad to soft on the fronts now, but it's nothing awful. I'm actually considering upping the fronts and dropping the rears slightly. Not decided 100% yet though.

Isn't the front supposed to be stiffer, as the weight ballance is mostly on the front axis?

 

[NorthloopCup]

Isn't the front supposed to be stiffer, as the weight ballance is mostly on the front axis?

The majority, if not all the Clio racers on here run with a stiffer rear spring mate. It's all to do with insufficient roll control, so you cheat and use stiffer springs instead. On a fwd car, the rear controls what the front end does.

 

[Sonic Boom]

I run 500lb up front and 650lb on the rear, and everyone says that must be so twitchy and horrible to drive, I can assure you it isn't and handles great.

Rich

 

[Tony Hunter]

I think mine are, rear 400 and front 850. But there again I'm slow.

 

[NorthloopCup]

I think mine are, rear 400 and front 850. But there again I'm slow. :wink:

And old. :up:

 

[Tony Hunter]

Hi

 

[Martin.]

I think mine are, rear 400 and front 850. But there again I'm slow. :wink:

Reading fail x

 

[Tony Hunter]

?

 

[getikte]

My BCs are 10kg front and 8kg rear, just done knockhill on michelin slicks and the suspension felt fantastic

 

[LeeRS]

Bumping this old thread!

Looking at getting some BC BR for track only 172.

After reading many threads, I’m still none the wiser what to go for.

Some say stiff front, softer rear, others say the opposite.

I’m no track hero but want to be able to push on so wondering what people are using now.

I was thinking 8k front, 8kg rear but told this may be to soft?

 

[R3k1355]

You could always buy some extra springs?

That way you can try a stiffer spring and see if it suits you.

 

[JamesBryan]

Bumping this old thread!

Looking at getting some BC BR for track only 172.

After reading many threads, I’m still none the wiser what to go for.

Some say stiff front, softer rear, others say the opposite.

I’m no track hero but want to be able to push on so wondering what people are using now.

I was thinking 8k front, 8kg rear but told this may be to soft?

Get the BC DS with solid top mounts from KAM Racing.

I run 8/8kg on mine on the road. I'd go for 9 or even 10 on the front on yours as it's just for track.

8kg rear is the most they do for these, but don't forget it's a separate spring and shock, and the spring being positioned where it is makes it act more like a 4kg.

 

[LeeRS]

Get the BC DS with solid top mounts from KAM Racing.

I run 8/8kg on mine on the road. I'd go for 9 or even 10 on the front on yours as it's just for track.

8kg rear is the most they do for these, but don't forget it's a separate spring and shock, and the spring being positioned where it is makes it act more like a 4kg.

Checked on kam racing and they offer more than 8kg on the rear so confused by you saying they only offer 8kg?

 

[JamesBryan]

Checked on kam racing and they offer more than 8kg on the rear so confused by you saying they only offer 8kg?

8 used to be the max.

Maybe there's more now.

 

[LeeRS]

8 used to be the max.

Maybe there's more now.

So do you reckon I should be looking more at 10/10kg if possible?

 

[JamesBryan]

So do you reckon I should be looking more at 10/10kg if possible?

Yeah I would.

Mine was scrubbing under hard cornering on the front at Oulton yesterday, so a stiffer spring would help that.

 

[Anakin]

I run 9/8 BC DS on my track car, they are a little harsh on the road but mega on track.

 

[JamesBryan]

I run 9/8 BC DS on my track car, they are a little harsh on the road but mega on track.

Mine is mostly road use but I might stick a 9kg on the front next year.

 

[Anakin]

Mine is mostly road use but I might stick a 9kg on the front next year.

it's very crashy on the road even with the dampers on full soft, I wouldn't! Mine doesn't see the road really, I excercise it everynow and then. I've just bedded a clutch in for 500 miles of cheshire B roads and it's not as fun as it would be with some softer suspension.
Ruined for the road...

 

[Anakin]

P.S your welcome to come have a go in mine, I'm only down the road in Middlewich.

 

[JamesBryan]

it's very crashy on the road even with the dampers on full soft, I wouldn't! Mine doesn't see the road really, I excercise it everynow and then. I've just bedded a clutch in for 500 miles of cheshire B roads and it's not as fun as it would be with some softer suspension.
Ruined for the road...

I'm already running 8/8kg, so 9kg on the front shouldn't be too bad.

 

[Waitey]

Why are everyone's spring rate so high?

There's no aero loads to support so there can't be much need to be over 300lb/in 5.3kg/mm in a Clio!

 

[JamesBryan]

Why are everyone's spring rate so high?

There's no aero loads to support so there can't be much need to be over 300lb/in 5.3kg/mm in a Clio!

That's probably not far off stock spring rate 😅

It's all to combat roll and to make it more stable.

It's nothing compared to what the EP3 Civic boys use, like 14kg front/16kg rear 😂

 

[Waitey]

That's probably not far off stock spring rate 😅

It's all to combat roll and to make it more stable.

It's nothing compared to what the EP3 Civic boys use, like 14kg front/16kg rear 😂

Yes but a springs purpose is just to keep the body off the floor. So you find the softest spring and length combo that will do that.

Roll is sorted with ARB's.

14kg is akin to what a GT2 car with full aero package would run. Which is handling the 1500kg of the car and a further load of about 800/1000kg from downforce.

After reading this, it really highlights how backward we (in the tuning sense) are when it comes to understanding suspension.

 

[PhillipM]

'cause most people aren't running enough droop and are too low for anything outside an aero car.

 

[JamesBryan]

Yes but a springs purpose is just to keep the body off the floor. So you find the softest spring and length combo that will do that.

Roll is sorted with ARB's.

14kg is akin to what a GT2 car with full aero package would run. Which is handling the 1500kg of the car and a further load of about 800/1000kg from downforce.

After reading this, it really highlights how backward we (in the tuning sense) are when it comes to understanding suspension.

View attachment 1670778

There isn't really anything out there for ARB/roll control upgrades apart from roll centre kits.

We also lower the cars which makes it worse, so it's substituted with stiffer springs.