Agggh! The endless track coilover and spring rate debate!! Help!

[cbmotorsport]

Sorry to go over old ground. I have spent about 2 weeks reading and reading on here, and the difference of opinion is vast.

I'm in the process of turning a rather tired 172 Cup into a track tool and want to change the current standard suspension for a set of coilovers.

The car will be 70% track biased with the 30% road use being the driving to circuits, trailer may follow at a later date.

I've looked at AST, 1's and 2's, and note that their 'track' setup spring rates are 450lb front and 450lb rear. Fair enough.

i've copnsidered the more mainstream kits, B14's etc, but worry that I will end up buying twice as they're not really a track setup.

I've also been in contact with AVO who suggested 300lbs front and 175lbs rear for a track setup??? Seems awfully soft at the rear to me...understeer aplenty?

I'm struggling to justify the £1600+vat for AST 2's, as in reality the car will probably only see 4 or 5 track days a year. Seems like overkill.

I could go for AST 1's but I'm drawn to the AVO's (similar design to AST 2's - inverted monotube etc) and considering having them revalved to AST's track spring rates 450lb/450lb.

I have a few questions, if not these, what spring rates should I consider? What do you run? - do the AST track setup spring rates work well? Anybody have experience of them off the shelf? Should I go softer and compromise a bit due to driving the car to the circuit? Any other manufacturers to consider? They will need to offer the option of revalving to suit. I don't want a 'fast road' setup. I'd like to spend around £1000.

I've raced Alfa Romeos at club level in the past, and we used to run them bloody hard at the back 700lb and around 400lb at the front to dial out understeer and promote a bit of drift through the corners, but I'm a bit clueless as to a clio.

Thanks folks.

 

[vecbtb]

I imagine AVO suggested that setup as that's what I decided to go with from them a couple of months ago. My discipline is hill climbing so not quite the same demands as track days. I am tempted to up the rear spring rate to 225 and try that, although I can't say that I've notice much under steer so far - but I haven't really driven it in anger yet. The car is with Fred at the moment and I'll be interested in his thoughts when I pick it up this weekend.

 

[Steven103]

There was a very good thread a few weeks ago full of spring rate info between the options without much opinion. Which is refreshing.

Ultimately this is just going to be another thread that comes down to "averaging" a bunch of different opinions. Not so much because of the old "there's no right answer" but more because everyone wants a different blend of price and track/road focus.

• Dampers are a case of you get what you pay for, hence everyone is going to say AST, Bilstein etc. People on CS seem to get tied up in wanting all the bells and whistles.
  
• Spring choice is influenced far more by tyre choice and sprung/unsprung mass than anyone gives them credit for. So this is a really good area to be looking at other people's cars (slicks, stripped, half hearted cage or a proper thing that really stiffens the shell up)

 

[Coops Mk1]

as above, I have tried to research this a bit as well but seems to be no hard and fast rules.

mines a bit more of a quandary too as I cant easily adjust the rears as its torsion bar. so I'm unsure at to optimum spring rates really.

will watch this with interest

 

[Steven103]

Brilliant thread, spring rates for all the popular coilover options: http://www.cliosport.net/forum/show...er-kits-spring-rates!&p=10309585#post10309585

Thread is so interesting because it reveals a lot about what each kit is intended for.

 

[mark123]

Brilliant thread, spring rates for all the popular coilover options: http://www.cliosport.net/forum/show...er-kits-spring-rates!&p=10309585#post10309585

Thread is so interesting because it reveals a lot about what each kit is intended for.

Did you post the right link? Not much info in there really.

I have AST 1 450/400 front/rear. It is driveable on the road but is very stiff. Too stiff to enjoy on road really, OK for driving to tracks.

I'll go stiffer still next time, but my car 100% motorsport use.

 

[Steven103]

Did you post the right link? Not much info in there really.

Thanks, just double checked but that is the link I had in mind. Not Chip/Northloops musings, but the spring rates for 5 or 6 brands of coilover all in one place for comparison.


I know you're only looking at full coilovers but don't forget about motion ratios when listening to what other people are using. The rear of a Clio has a motion ratio of about 1 for a full coilover and about 0.5 for an inboard spring (making the spring effectively twice as soft if you use the standard spring position). I'm sure you realise the handling balance implications of halving a rear spring rate! Likewise fitting big old 25mm spacers upfront will effectively make the spring and anti roll bar softer (which partly reverses a benefit of fitting spacers lol)

 

[cbmotorsport]

Mark,

What are the handling characteristics? Does this give a slightly loose rear end, or planted? Does it dial out understeer or is it more prone to that than oversteer.

Thanks

Did you post the right link? Not much info in there really.

I have AST 1 450/400 front/rear. It is driveable on the road but is very stiff. Too stiff to enjoy on road really, OK for driving to tracks.

I'll go stiffer still next time, but my car 100% motorsport use.

 

[mark123]

Mark,

What are the handling characteristics? Does this give a slightly loose rear end, or planted? Does it dial out understeer or is it more prone to that than oversteer.

Thanks

I'd say it is pretty well balanced, with a slight bias for oversteer.

 

[cbmotorsport]

Thanks Mark. This is really the sort of characteristics I'm after for track days. Looks like AST's 450/450 track combo might be a good starting point.

 

[vecbtb]

I found some figures a while ago for a standard cup - to use as a reference point; 3.25 front / 5.7 kg/mm rear. Using an online converter I made that 182 / 319 lb/in. The rear spring is in-board so would I be correct in thinking that you have to use a 2:1 conversion on that figure to take into account leverage? So a standard cup is 182 front and 160 rear in old money if swapping to a full coilover rear and keeping standard spring rates?

 

[cbmotorsport]

Makes sense to me.

 

[Steven103]

I found some figures a while ago for a standard cup - to use as a reference point; 3.25 front / 5.7 kg/mm rear. Using an online converter I made that 182 / 319 lb/in. The rear spring is in-board so would I be correct in thinking that you have to use a 2:1 conversion on that figure to take into account leverage? So a standard cup is 182 front and 160 rear in old money if swapping to a full coilover rear and keeping standard spring rates?

Correct, but the springs are progressive and not linear like the springs you'd find on coilovers so you can't compare numbers with much confidence at all. The 3.25/5.7 might be an average, might be an average over an arbitrarily defined working rage, code be a modal value etc.

But you're spot on regarding using the motion ratio to calculate a wheel rate to get your "old money."

 

[Chip-mk1]

I found some figures a while ago for a standard cup - to use as a reference point; 3.25 front / 5.7 kg/mm rear. Using an online converter I made that 182 / 319 lb/in. The rear spring is in-board so would I be correct in thinking that you have to use a 2:1 conversion on that figure to take into account leverage? So a standard cup is 182 front and 160 rear in old money if swapping to a full coilover rear and keeping standard spring rates?

Those figures sound like the sort of ballpark I was expecting, although Steven103 makes some great points as to why its not quite that simple.

 

[vecbtb]

Thanks.

 

[Ricardos]

Mentions spring rates regarding the Spax full coilover setup, how would this hold up on the odd track day?

http://www.k-tecracing.com/show_product.asp?id=4510

 

[Steven103]

There's 3 or 4 reasons why those spring rates shout "road" and not track focused IMO. On the flip side the adjustable 2-way damping (if the adjustment is big enough) might make them a perfect compromise for a daily driver.

It's not just the overall number, it's things like the front/rear ratio is very similar to OEM. This suggests it will keep a similar (safe & progressive) balance to the OEM setup rather than an ultimately faster but neutral/oversteery balance of more track focused kits like the AST. Other things as well like the softer springs would be well matched to road tyres, but you might find excessive body roll if you step up to semi slicks.


I'll be the first to admit I haven't used/been in anything with Spax springs & so would be very interesting to hear opinions of those who have owned the Spax and something more track focused to see if it backs up what the spring rates suggest.

It's also a lot of money to be spending on "occasional" track use.

 

[mark123]

Mentions spring rates regarding the Spax full coilover setup, how would this hold up on the odd track day?

http://www.k-tecracing.com/show_product.asp?id=4510

I'd suggest you searched on the forum to see how people who've bought spax have gotten on with them... There have been some quality control issues...

 

[NorthloopCup]

Did you post the right link? Not much info in there really.

I have AST 1 450/400 front/rear. It is driveable on the road but is very stiff. Too stiff to enjoy on road really, OK for driving to tracks.

I'll go stiffer still next time, but my car 100% motorsport use.

That tells me there's a difference in the damper settings then as I run the sportline 2's with 450 front and 475 rear. Yeah it's stiff but I can still push on on the roads with confidence. It's surprisingly comfortable when set on full soft tbh.

 

[Ricardos]

I'd suggest you searched on the forum to see how people who've bought spax have gotten on with them... There have been some quality control issues...

I have the Spax full coilover setup and well aware of the product problems. Maybe I should rephrase the question to try and get a simple lamens terms answer (if possible)

Regardless of damper make and damper stiffness, what poundage spring would be close for spirited drives and the odd trackday. What's regarded as too harsh for road but ok for track? I know there's potentially many scenarios to throw into the hat but a start off point would be helpful, like with the Spax poundage mentioned in the K Tec advert, how would they fair on track.

I don't know everything but willing to have a better understanding of how the products fitted to my Clio work.

 

[NorthloopCup]

I have the Spax full coilover setup and well aware of the product problems. Maybe I should rephrase the question to try and get a simple lamens terms answer (if possible)

Regardless of damper make and damper stiffness, what poundage spring would be close for spirited drives and the odd trackday. What's regarded as too harsh for road but ok for track? I know there's potentially many scenarios to throw into the hat but a start off point would be helpful, like with the Spax poundage mentioned in the K Tec advert, how would they fair on track.

I don't know everything but willing to have a better understanding of how the products fitted to my Clio work.

If it was me I'd be going with a 350-400lb front and a 250lb rear mate. My kw v2's were 336 front and around 225 rear (that's taking the motion ratio into account for having the original inboard location) and the car was sublime on the road and bumpy lanes and alright on track. Always did well for itself.

Cheeky edit! The spring rates on the k-tec page wouldn't be to bad as an all round package, although personally i'd up the rears to 250 or possibly 275. It just helps to reduce the understeer.

 

[Ricardos]

Thank you, really appreciate the reply. So with that in mind having the Spax setup would I have to contact them direct to see whether they offer something different?

I thought I'd post this as I remember them offering a bespoke service

http://www.dfaulknersprings.com/

 

[NorthloopCup]

Thank you, really appreciate the reply. So with that in mind having the Spax setup would I have to contact them direct to see whether they offer something different?

I thought I'd post this as I remember them offering a bespoke service

http://www.dfaulknersprings.com/

No worries mate. Do you know what your spax setup is? As in current rates? You can usually get away with altering the rates by around 25-50% either way of what they currently are you see. Also you need to know what size the rear spring id is. The ast's are 51mm or 1.9" in old money and to get them in the correct length means getting them custom made.

 

[Ricardos]

Copy and pasted from the K Tec website which is where my Spax kit came from

http://www.k-tecracing.com/show_product.asp?id=4510

Front 342lbs
Rear 228lbs

New rear units delivered to me this week

. by Ricard o1, on Flickr

 

[NorthloopCup]

Copy and pasted from the K Tec website which is where my Spax kit came from

http://www.k-tecracing.com/show_product.asp?id=4510

Front 342lbs
Rear 228lbs

New rear units delivered to me this week

. by Ricard o1, on Flickr

I'd contact spax and see if they offer any stiffer springs for the rear mate.

 

[Ricardos]

I'll give them a call on Monday, if they do I'll get a price on 250lbs springs. Thanks again for the advice

 

[NorthloopCup]

I'll give them a call on Monday, if they do I'll get a price on 250lbs springs. Thanks again for the advice

No worries mate. Happy to help.

 

[Ricardos]

No worries mate. Happy to help.

I've just had a look on the Faulkner website and they have any combination of spring length and poundage to suit.

These are the 250lbs springs, £31 each
http://www.dfaulknersprings.com/acatalog/1.9-Inch-ID-11-Inch-Free-Length-Standard-Spring.html

 

[NorthloopCup]

I've just had a look on the Faulkner website and they have any combination of spring length and poundage to suit.

These are the 250lbs springs, £31 each
http://www.dfaulknersprings.com/acatalog/1.9-Inch-ID-11-Inch-Free-Length-Standard-Spring.html

Yeah they're bang on mate! Didn't know that they did them that long now either tbh!

 

[Ricardos]

Yeah they're bang on mate! Didn't know that they did them that long now either tbh!

Result, I'll be making a call to them instead

 

[Ricardos]

One way of measuring the likes of Eibachs and Cooksport springs, group test?

http://www.dfaulknersprings.com/acatalog/Spring-Testing.html

 

[bozothenutter]

interesting ...might order some too.
might not go the whole 450 though as mine is a daily.
400 seems a good comprise

 

[mark123]

interesting ...might order some too.
might not go the whole 450 though as mine is a daily.
400 seems a good comprise

I really think 400 would be a bit harsh for a daily.

 

[Tony Hunter]

450 though as mine is a daily.
400 seems a good comprise

you really believe that 50 is going to make that much difference, Mark is right.

 

[bozothenutter]

I have no idea really.
that's why i rely on much more experienced heads like yours.....
just want to learn..

 

[bozothenutter]

To me the rates are just numbers.
At I'm on 60/40 N/mm.
It seems the go to setting is equal rates all round (what AST do for example)
I have ordered the roll centre correction kit from Mark.
What would be wise?
Going for 60 all round? As 80 might be too harsh for a daily?
Don't mind a bit of discomfort.

 

[mark123]

60 N/mm = 343 lb/in
40 N/mm = 228 lb/in

So you're already pretty stiff for a daily IMO, but you know what you can cope with - all depends on what you do daily I guess.

I'd say see how you get on with the roll centre correction kit first. It should give you less body roll and more front grip so will change the balance anyway.

What do you want to achieve? Apologies if I've missed it.

 

[NorthloopCup]

To me the rates are just numbers.
At I'm on 60/40 N/mm.
It seems the go to setting is equal rates all round (what AST do for example)
I have ordered the roll centre correction kit from Mark.
What would be wise?
Going for 60 all round? As 80 might be too harsh for a daily?
Don't mind a bit of discomfort.

I run 450 fronts and 475 rears. It's not horrendous on the road but I'm not convinced I'd put up with it if it was a road car. You will always have to run a compromised setup when using the car on the road, there's just no getting away from it. The 60/40 combo you've currently got is imo, bang on for road use, and the only possible change I'd make would be to go with 400lb fronts (70N). Leave the rears on 40N.
What are the roads like in the Netherlands? If they're full of w**k pothole repairs like the uk ones I'd definitely stick to your current setup.
It is of course all personal preference, but combine the setup I've mentioned above with the roll centre kit and you'll soon find yourself with a very capable little car.

 

[CamMoreRon]

I'm going for AST 5100 with "track" set-up, so 80N/mm (456lb/in) front and 90N/mm (513lb/in) rear. I'll let you know what that's like on the road.. probably "FIRM".

A low roll centre isn't the terrible thing that the internet makes it out to be.. sometimes it can be a very very nice thing to have, especially at the front end. It reduces load transfer (which improves grip) at the expense of body control, but if you're putting whacking great springs on and shifting your roll stiffness bias rearwards (fitting an ARB for example) then that extra control isn't needed anyway. I would be much more concerned about correcting bump steer and ensuring you have adequate suspension travel.

 

[mark123]

I'm going for AST 5100 with "track" set-up, so 80N/mm (456lb/in) front and 90N/mm (513lb/in) rear. I'll let you know what that's like on the road.. probably "FIRM".

A low roll centre isn't the terrible thing that the internet makes it out to be.. sometimes it can be a very very nice thing to have, especially at the front end. It reduces load transfer (which improves grip) at the expense of body control, but if you're putting whacking great springs on and shifting your roll stiffness bias rearwards (fitting an ARB for example) then that extra control isn't needed anyway. I would be much more concerned about correcting bump steer and ensuring you have adequate suspension travel.

Correcting the roll centre reduces load transfer.