what spring rates do people run?

what spring rates do people run?

What do you run front/rear and what weight is your vehicle?

Anyone have corner weight info and distribution?

cheers
bill

 

generally 600-650 at the front, 800-850 at the rear

corner weights being done over christmas

tt

 

Hi Bill,
I run 350 front and 400 rear for mostly track use and 275 front and 200 rear for more road/ring use.

Thats on the mk1 which weighs approx 750-800kgs (????),
Ian.

 

CRIKEY! for track use that is i take it?!

 

I use 350lbs front and 280lbs rear. Its a compromise setup that is just about useable on the road. A bit stuff for high speed bumps though. The car weighs about 900kgs.


For a good track setup you should be aiming for 90 - 110 cycles per minute. This can be worked out if you know your wheel weights etc. A good book that'll tell you how to do it is the Race and Rally Source Book. Its a Haynes series I think.

 

Bill, will you still have the car road legal and want to use it to drive to events etc, or is she going to be a trailer queen from now on?

 

hells bells..
you ever driven around castle combe? be like a pogo stick.. wow .. well 'ard rates..

 

It will be road legal, and spring to suit castle combe (bumpy) so really hard rates is'nt likely to work well in the traction department. did a TTOC track day a couple of weekends ago and bumps vs loosing traction is a serious consideration. Road spring rates & damping as I ran it, seemed to cope pretty well... so trying to choose a setup which will work there specifically.

it will remain road legal but in combe saloon car class b spec.

 

only driven donny and cadwell. was running 450 f and 650 r but was too soft at cadwell. certainly makes it 'lively' but Keith Smith will tell you the difference it made going much harder on his mk1

tt

 

You want similar rates to me then. These rates have given a good balance to the car. I can drastically affect the amount of oversteer by changing the rear anti-roll bar - it has three settings. Car can go from understeery to oversteery. If I had more rate at the back then the car would become too oversteery. More in the front - too much understeer. So I reckon the 350 / 280 balance is about right.

 

wow jump from 450f to 600f? one heck of a leap.
I am too scared to try that on mine... pogo's on bumps on 400lb's

 

I run softer front than rear, but bigish arb's both ends.. when I ran 400lb front and 300lb rears is understeered like a biatch... dropped to 280 fronts and left 300 rears added my arb's both ends and it went to near neutral.
thinking going more rear than front, but up on rates both ends, as I need to keep wheel on ground round combe as its struggling to put power down. dont want to cock up my nice balance I have, but other mods in the wheel and tyre size combo and caster may well change things (for good or ill time and testing will tell)

 

Eh ? Bumpy .... which bit ?

600lb rr 500lb frts

 

all of it..
I had'nt really considered combe that bumpy previously, but trying to apply full power round there now is showing it all up... well bumpy.
I guess its a case of power to track and the differences.

 

i guess we'd have to soften the car at combe from what you say - never driven there though. the rates were based on andy's (tracksport) mk1 race car and the mk2 track car he hired out to people at cadwell and donny.
we only went for that big a jump as they were the only stiffer springs we had

tt

 

Its a learning experience for me.. track specific setup.. not ever changed things other than damping, but the new motor spec has provoked other changes.. power and only fwd at combe has exposed bumps I had not previously noticed. Sure notice them now. (higher speed & more power)
Donny is smooth as a... by comparison, Cadwell was'nt bumpy either as I remember.
Combe's Folly is difficult to take flat now, combination of bumps and speed under power... give it a sphincter factor of 8/10 thru there.
Also coming out of bobbies-westway-dean straight is also unloading the driven wheels over bumps..
My dampers are more than l ikely past their best which I have to factor in at some point when allow. 5 year old PSS9's
http://www.castlecombecircuit.co.uk/circuitmap.htm

Wider/bigger wheels and tyres to go on shortly so this will again change it all.

Lots of testing to do me thinks.

 

it's certainly something I'd like to look at in more detail myself, but with racing the single seater as well [which takes priority] I just don't have time to commit.

I'll certainly be corner-weighting the car over Christmas so I'll post-up the results

tt

 

I would think anything over 550 would be too hard for most UK tracks. The wheels would be off the ground most of the time. The rebound damping required by that spring rate would almost impossible to match.

Rollbars rather than high spring rates are prefered on most UK tracks as they are far from smooth. As you know they will transfer the load across the car still give an amount of wheel travel helping the rebound of the wheel to give traction.

I looked after a ex DTM M3 during a domestic/endurance race series a few years back. This shell was built by Matter and had in-car adjustable rollbars. Ideal not hard to engineer either. Very good if it started to rain during the race.

Spring rates similar to "I V - mk1 16v" suggestion would be better.

 

The combe day I recently did had another ibiza (more powerful than mine I think) with ~350lbft front springs on it.. and it struggled applying power, skipping (revs jumping) over the bumps.. Mine was borderline skipping underpower by comparison running 280lbft fronts but 25mm front ARB

I am not too sure 350lb springs on the front of mine will make it worse or better.
Got some new springs arrived today in various rates to try, but I am thinking conservatively and worst case for bumps at the mo.

Spring rates seem to jump up in 50lb rates but I would like 25lb increments really. Oh well

going to try initially 300lb front and 350 or 400lb rears and see what its like.

I like th eidea of adjustable in-car arbs if the regs allow me to do so, and I can figure out how to do this on an ibiza

thanks for all the info so far chaps.
cheers

 

if you found you needed a 25lb increment I'm sure someone like Faulkner Springs bwould he happy to wind them up
I'm sure they could also make recommendations if you took your corner weight info to them and told them your requiremets in relation to road use

tt