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live axle striker spring rates
bigfoot4616 - 30/6/14 at 08:19 PM

i'm wanting to try some stiffer rear springs on the rear of my striker. its on 130lb at the moment.
i want to try and cut down the roll and unloading of the the inside front wheel hopefully cutting out a bit of understeer.

i've got some 180lb springs in the garage, are these going to be to stiff? if i had to buy some to try i was going to go for 160lb.

cheers

JAG - 30/6/14 at 08:55 PM

I don't have a Striker but I do have a live-axle Seven style car.

I have 150lb spring rates on my car.

bigfoot4616 - 30/6/14 at 09:25 PM

thats the thing though, the striker(and think fury also) have a different setup for the axle than other sevens and generally run softer springs than others.

should of added its for hard track use on slicks. it gets much more track use than road use nowadays. i'd be surprised if it does over 300 road miles a year.

ian locostzx9rc2 - 30/6/14 at 09:31 PM

If you have them in your garage it maybe worth trying them but it is quiet a large step up 150 or 160s maybe better?

TimC - 30/6/14 at 09:45 PM

Would an ARB not be a better solution?

bigfoot4616 - 30/6/14 at 09:47 PM

the large step up is what concerned me. if i don't get much response to this i'll try them at rockingham in a few weeks, shouldn't take to long to swap back if they are to stiff on the day.

bigfoot4616 - 30/6/14 at 09:53 PM

quote:
Originally posted by TimC
Would an ARB not be a better solution?


not on the rear of a live axle'd striker apparently, anyway i've always thought an ARB is for fine tuning once you have the correct spring rates.

jeffw - 1/7/14 at 04:51 AM

I run 220lb fronts and 180lb rears on my Live axle Phoenix.

Sam_68 - 1/7/14 at 06:27 AM

quote:
Originally posted by jeffw
I run 220lb fronts and 180lb rears on my Live axle Phoenix.


There's the rub.

I assume you're thinking of changing just the rear springs; in which case the key factor is the ratio of spring stiffness front:rear ... So we'd need to know what front springs you're running too. Also your total weight and weight distribution may big sufficiently different to Jeff's to distort direct comparison.

You've said that one of your objectives is to kill a bit of understeer, in which case a bit more rear spring stiffness might not harm (but where in the corner are you understeering and would it be better managed with the dampers?).

I'm guessing though (because they are standard spring rates used by many Strikers) that you may currently be running 180lb fronts with your 130lb rears, in which case 180lb rears (ie. the same spring stiffness front:rear) would be a step too far.

If you are on 180lb fronts then that means you're currently about 38% stiffer at the front than at the rear (neglecting leverages). Jeff is about 22% stiffer at the front (again neglecting leverages), so to get an equivalent ratio you'd be looking at 180lb fronts and 150lb rears. You might want to be a bit more scientific about it and calculate the actual wheel rates, though, before making the comparison.

FWIIW, my Sylva, set up for racing, ran the same spring rates as Jeff when I bought it (and was much lighter than Jeff's car, and probably less nose-heavy). It was too stiffly sprung for my personal tastes on the street, so I reverted to 180F/130R.

Andy D - 1/7/14 at 09:49 AM

Having run behind this Striker on track, I must say it doesn't look particularly understeery? I didn't see you on track at Anglesey Rich, but elsewhere it's allways looked very "pointy" in the corners. I'm guessing it's understeering as you power out of the corner?

For what it's worth, I recently came down from 160 to 150lbs on the rear of my live axled Westy, and felt it was a step in the right direction. Totally different beast mind... my Pinto v your R1

I tried some stiffer rears on mine a few years back.. 180 or 200.. can't remember, but it wasn't good.

bigfoot4616 - 1/7/14 at 05:45 PM

quote:
Originally posted by Sam_68
quote:
Originally posted by jeffw
I run 220lb fronts and 180lb rears on my Live axle Phoenix.


There's the rub.

I assume you're thinking of changing just the rear springs; in which case the key factor is the ratio of spring stiffness front:rear ... So we'd need to know what front springs you're running too. Also your total weight and weight distribution may big sufficiently different to Jeff's to distort direct comparison.

You've said that one of your objectives is to kill a bit of understeer, in which case a bit more rear spring stiffness might not harm (but where in the corner are you understeering and would it be better managed with the dampers?).

I'm guessing though (because they are standard spring rates used by many Strikers) that you may currently be running 180lb fronts with your 130lb rears, in which case 180lb rears (ie. the same spring stiffness front:rear) would be a step too far.

If you are on 180lb fronts then that means you're currently about 38% stiffer at the front than at the rear (neglecting leverages). Jeff is about 22% stiffer at the front (again neglecting leverages), so to get an equivalent ratio you'd be looking at 180lb fronts and 150lb rears. You might want to be a bit more scientific about it and calculate the actual wheel rates, though, before making the comparison.

FWIIW, my Sylva, set up for racing, ran the same spring rates as Jeff when I bought it (and was much lighter than Jeff's car, and probably less nose-heavy). It was too stiffly sprung for my personal tastes on the street, so I reverted to 180F/130R.



front springs are 200lb. total weight including me is 520kg, its a bike engine so there's not that much weight up front.
the understeer tends to be from the center to exit so as i'm powering out. i know the LSD wont help but it would be nice to improve it a little.
i did go up on the damper settings with a slight improvement on saturday but i'm already way past the settings i was recommended to run the dampers at when the car was last setup.

i'm also thinking 180lb will be to stiff but i've got them so may be worth trying at rockingham, its not a big job to swap back if needed.
not sure whether to use the 180's for a big swing at it then go back down until i'm happy or try somewhere in the middle straight of and see how that goes.

either way there's no harm in trying things to look for improvements on something as easy to swap back as springs.


andy,
its not bad but its there more so than it used to be. as you say powering out. i didn't notice any at knockhill, croft was to wet to make a judgement but at anglesey i had some. i seem to remember cadwell has a couple of corners where i get a bit as well.
have you still got the 160's? and what size if you have, i need 8" x 2.25"

Andy D - 2/7/14 at 11:23 AM

I do still have the 160s but they're 9" and 1.9dia.