Question: Spring rates

[reflexuk]

Can't find much on the forum about your choice of spring rates. I'm trying to find out what will when I fit a pair of 80lb 12" 2.25dia competition coils to the front, I don't even know what the stock spring measures though!

Please post your spring rates and motorsport discipline. A comment on your opinion of their suitability would be nice too.

Thanks

 

[frank]

dont think i,ve ever seen anyone post springrates on here, there are some threads on cisco,s tho http://micra.com.au/community/message.php?messageid=18436

 

[reflexuk]

Yeah, seems that way. Good info there on Cisco's. Surprising how the 'community' are seemingly uninterested in some of the comparatively important facts. So long as your exhaust is oversized, your running low and wheels are wide it doesn't matter how well your car handles or hw safe and comfortable you are. Often get the same feeling when it comes to matters regarding uprated anti roll bars too.

 

[karlj]

I'm surprised Paul, Skinner or Low Rider haven't commented.

Ive got an email somewhere from Matt which has some info regarding spring rates

 

[frank]

Surprising how the 'community' are seemingly uninterested in some of the comparatively important facts. So long as your exhaust is oversized, your running low and wheels are wide it doesn't matter

we,ve all got pretty diverse goals for our cars tho eh some are into anything JDM, others euro, others bling, others performance.
i just like to get the maximum adrenalin with the minimum of dosh or effort

 

[Low Rider]

Yeah, seems that way. Good info there on Cisco's. Surprising how the 'community' are seemingly uninterested in some of the comparatively important facts. So long as your exhaust is oversized, your running low and wheels are wide it doesn't matter how well your car handles or hw safe and comfortable you are. Often get the same feeling when it comes to matters regarding uprated anti roll bars too.

I'm not going to say anything about spring rates.....any random spring that can be obtained from the scrappy for £5 seems to suffice

As for the above, aside from a few on here who setup their cars for a specific purpose, you're not far off. Looks certainly trump performance

 

[Skinner_87]

to be honest i dont know the rate of the springs but the 55mm tarmac rally springs from matt are very firm! My back & manx roads can prove that

For hillclimb and sprint i find them very good, very smooth & progressive but no comfort once the bumps start!

 

[pollyp]

i'm using whiteline 22mm front swaybar, 20mm rear swaybar, BC V1 coilovers full hard damper setting with originally 4kg front 3kg rear but currently running 6kg fronts to try reduce bodyroll but I think it might be affecting front grip.
only used on circuit tracks.

 

[reflexuk]

Looking at the numbers on Cisco's thread the uprated fronts start at around 125lbin ad go upto an astronomical 391lbin! The rears are always softer but there does seem to be some agreement around 123lbin even with your 391lbin up front!

Many of the road rallying fraternity that I have asked find that 'gravel spec' springs are absolutely as hard as you want to go, anything tarmac spec is just too uncomfortable and the navigator can't even see his map nevermind write on it!

Road rally cars don't tend to spend too much of their timee 'on the limit' unless something has gone wrong and you're faced with a sudden nasty surprise. Most of the other disciplines I partake in are low speed and require lots and lots of steering.

I underwent a certain amount of home grown suspension development with my first Micra but that didn't involve uprated dampers so there's only so far you can go before the springs and dampers no longer suit eachother anymore. Among the weapons to hand I have standard springs, chopped springs, lowering springs, standard A/R bars, modified A/R bars and the whiteline 22mm dia A/R bars.

I've just aquired a mix of bits which comprise uprated front (adjustable) and rear (fixed) dampers and a pair of 80lbin front springs. Now I need to find my uprated rear springs. It looks like I could do a lot worse than fit a 100-150ishlbin rear spring and switch front springs until I find the level of understeer I prefer.
Help!

 

[reflexuk]

i'm using whiteline 22mm front swaybar, 20mm rear swaybar, BC V1 coilovers full hard damper setting with originally 4kg front 3kg rear but currently running 6kg fronts to try reduce bodyroll but I think it might be affecting front grip.
only used on circuit tracks.

That's 170lbin rears and 224lbin fronts switched to 336lbin fronts. Why did you switch fronts Paul, was the bodyroll causing a front inside wheel to lift and spin up coming off the corner?

 

[pollyp]

i thought the whole body was leaning too much and ppl saying the rear inside wheel pops right up such as when i first did the handling course at japshow.

after i took it on track with 4/3kg f/r i noticed the front shock boot was pushed right down the shock body indicating it's been soft enough to hit the bumpstop so i stiffened the front to 6kg to see if it'll withstand the forces better within its dampening range and reduce the roll.

 

[Low Rider]

i thought the whole body was leaning too much and ppl saying the rear inside wheel pops right up such as when i first did the handling course at japshow.

after i took it on track with 4/3kg f/r i noticed the front shock boot was pushed right down the shock body indicating it's been soft enough to hit the bumpstop so i stiffened the front to 6kg to see if it'll withstand the forces better within its dampening range and reduce the roll.

Purely to you Paul, I will start off with 5kg/4kg split on the BC V1s and see how things go in testing. However we will also be undertaking a few necessary modifications to the suspension geometry to allow us to achieve what we want to. Consequently pure spring rates will only be part of the equation and wont be much use to Joe Bloggs. I fully expect things to get stiffer, especially since the car will not be setup for the road and will be running a semi-slick as a minimum and more likely a full slick for dry tarmac days.

 

[pollyp]

Purely to you Paul, I will start off with 5kg/4kg split on the BC V1s and see how things go in testing. However we will also be undertaking a few necessary modifications to the suspension geometry to allow us to achieve what we want to. Consequently pure spring rates will only be part of the equation and wont be much use to Joe Bloggs. I fully expect things to get stiffer, especially since the car will not be setup for the road and will be running a semi-slick as a minimum and more likely a full slick for dry tarmac days.

yep
with mine lowered by 50mm and the lower arm sitting level I have a feeling that it might be inducing +ve camber as that corner loads up and causing the outer sections of my front tyres to wear?

I'm guessing the pressure applied by the harder 6kg/mm spring on the tyres has a more sensitive working distance? say if part of the chassis rised few mm, the harder spring might not provide enough down pressure and it loses grip whereas the softer spring will still be apply some pressure and maintain some grip?

prob try going back to 4/3kg f/r to see if that improves the understeer

i think to lesson the bodyroll I should really be stiffering the front swaybar. but there's no stiffer bar I know of than whitelines 22mm bar.

 

[reflexuk]

i thought the whole body was leaning too much and ppl saying the rear inside wheel pops right up such as when i first did the handling course at japshow.

after i took it on track with 4/3kg f/r i noticed the front shock boot was pushed right down the shock body indicating it's been soft enough to hit the bumpstop so i stiffened the front to 6kg to see if it'll withstand the forces better within its dampening range and reduce the roll.

This information begs a plethora of new (off topic) questions? Perhaps a thread/convo on Chassis Setup is in order.

 

[pollyp]

This information begs a plethora of new (off topic) questions? Perhaps a thread/convo on Chassis Setup is in order.

yeah setup info need its own thread

 

[Low Rider]

yeah setup info need its own thread

+1

Someone can kick off and we can add as appropriate.

 

[reflexuk]

Here's the car on said 80lb front springs and whiteline 22mm bars front and rear. The 80lb spring is definately harder than stock, this I established when fitting to the car. The aforementioned popping of the inside rear wheel is prevalent as is some lift off oversteer. Interestingly its the left rear far more likely to lift than the right, perhaps this springs pair are not equal!? The oversteer is intended and is the reason 14in front tyres are mixed with 13in ones at the rear, tyre pressures are set to promote it too. Set this way the car was uber competitive setting test times beaten only by a modified Saxo VTR and a Corsa with a 2.0 16v red top conversion.
http://www.micra.org.uk/threads/micra-competing-in-autosolo.52480/

 

[Skinner_87]

Here's the car on said 80lb front springs and whiteline 22mm bars front and rear. The 80lb spring is definately harder than stock, this I established when fitting to the car. The aforementioned popping of the inside rear wheel is prevalent as is some lift off oversteer. Interestingly its the left rear far more likely to lift than the right, perhaps this springs pair are not equal!? The oversteer is intended and is the reason 14in front tyres are mixed with 13in ones at the rear, tyre pressures are set to promote it too. Set this way the car was uber competitive setting test times beaten only by a modified Saxo VTR and a Corsa with a 2.0 16v red top conversion.
http://www.micra.org.uk/threads/micra-competing-in-autosolo.52480/

I always get the nearside lifting more than the right as well reflex, i put this down to the rear panard rod arrangement (only a thought though)

 

[reflexuk]

Today I dissasembled and modified my Avo autograss adjustable struts. The 80lb spring gave me too little ground clearance and caused my gravel tyres to rub when cornering hard. So I was looking for a way to raise the ride height prefferably without fitting firmer springs. I drilled out the spring top cap so it could go further down the shock shaft and fitted a large diameter 3mm thick washer a 4mm thick stock plastic steering bush and a stack of washers to push the top cap further down the shaft. It was nearly impossible to rebuild the shock due to it being difficult to compress the spring as spring compressors don't fit between the coils. 7mm extra ride height just wasn't going to be enough so we turned to a pair of unknown brand blue coloured 140lb springs, removed the shim stack and rebuilt on those.

There is nearly an inch difference between my two 80lb springs free length! I commented earlier in the thread that I thought this might be the case and it turns out I was right.

The test drive was enough for me to decide that the ride quality is now too stiff. I could feel every bump in the road and the feeling of travel sickness wasn't far off as my cheeks bounced up and down, the facial ones of course . Initial turn in was crisp and responsive followed by a push understeer as the tyre walls started to bounce this was followed by a tendancy to turn into lift off oversteer as all the weight dumped on the rear outside corner suggesting to me there was too big a difference between front and rear springs. It might be alright on a smooth circuit (with a harder rear spring) but no good for me and road rallying.

 

[sterry9454]

We have run two sets of suspension on our rally car, ran some koni's which had spring rates of 180lbs i think and now we have bilsteins with 280lbs front springs which imo is too hard...... the spring ratio on bc suspension is either 225lb or 250lb i think which is better....