setting up suspension.

[redmire]

My Caterham has Eibach springs and nitron Shocks.
When i bought the car, the owner had 'Softened up' the Suspension a bit, as he felt that the previous owner had set up too hard!

Not having driven Caterhams before, i was a little surprised just how hard the ride was!
I wasn't so much interested in comfort as handling, it was quite a handful, it was VERY Skittish around our, lets face it, Bumpy country roads, almost to the point of being dangerous.

Well i backed off the springs a little (about 10mm)and the difference is very obvious, handles much better...(haven't given it a good country test yet)...it doesn't tend to understeer anymore either...almost 'Too eager' to turn in!

Much better!
The question i have is, can i 'play' with the camber, toe and castor, to see if i can improve further?
What i mean is, how do i make sure the wheels are the same toe or camber forinstance?...can i use a laser (i use one for work)...If so or does anyone else have any other ideas?
I know i could get it set how i want in the garage but then i can't experiment!
Any thoughts welcomed!
Mike.

[mickrick]

Get yourself "Competition Car Suspension" "A Practical Handbook" By Allan Staniforth. ISBN798 1 84425 328 9

Then take it to bed with a nice single malt.

[pikeyboy]

mickrick said:

Get yourself "Competition Car Suspension" "A Practical Handbook" By Allan Staniforth. ISBN798 1 84425 328 9

Then take it to bed with a nice single malt.

Day two, find some fishing line and a tape measure and then the fun begins.

[redmire]

I shall give the Malt a miss but i will take all the above advice!...

I am guessing that the fishing line is my straight line...maybe raised and lowered on two 'plumb' uprights, to measure camber and toe?

You gonna keep me guessing?..

Will get the missus to look in our local book store.

Cheers chaps
Mike.

[mickrick]

http://www.amazon.co.uk/Competition-Car-Suspension...

[redmire]

Thanks Mick!

[BertBert]

redmire said:

Well i backed off the springs a little (about 10mm)

What does that mean? If you changed the ride height by 10mm, that is one effect. If that effectively reduced the stiffness then that means it was very bad and actually coil-bound.

Bert

[pikeyboy]

redmire said:

I shall give the Malt a miss but i will take all the above advice!...

I am guessing that the fishing line is my straight line...maybe raised and lowered on two 'plumb' uprights, to measure camber and toe?

You gonna keep me guessing?..

Will get the missus to look in our local book store.

Cheers chaps
Mike.

Use the fishing line as a plumb line along the side of the car. Start by finsding the center of the car then measure out from this a known distance. You know have a known datum for setting your toe in out. Just had mine corner weighted etc and the front running radical team who did it for me use this method and find it comprable to a laser alignment. Plus or minus 0.5 mm wont be felt through the steering so dont worry too much about accuracy.

[redmire]

BertBert said:

redmire said:

Well i backed off the springs a little (about 10mm)

What does that mean? If you changed the ride height by 10mm, that is one effect. If that effectively reduced the stiffness then that means it was very bad and actually coil-bound.

Bert

Yes, i loosened the top retaining nut, the one that compresses the spring, to make the suspension a little softer, hoping this would cure the 'Skittish' action of the car.
It certainly made for a nicer ride and definately appears less skittish!
Not sure that i have gone about it the correct way or not??
the previous owner had already 'softened it up a little' he told me....
Isn't it 'coil bound' if it is stiffened up too much, or just compresses to the max?

Interested to hear what your take is on it, or how you would adjust to reduce this reaction to our typically bumpy country roads?
Any pointers on reducing understeer would be appreciated as well.. (though i shall read up as well, when my missus picks up my book for me!)
Thanks Bert,
Mike.

[redmire]

pikeyboy said:

redmire said:

I shall give the Malt a miss but i will take all the above advice!...

I am guessing that the fishing line is my straight line...maybe raised and lowered on two 'plumb' uprights, to measure camber and toe?

You gonna keep me guessing?..

Will get the missus to look in our local book store.

Cheers chaps
Mike.

Use the fishing line as a plumb line along the side of the car. Start by finsding the center of the car then measure out from this a known distance. You know have a known datum for setting your toe in out. Just had mine corner weighted etc and the front running radical team who did it for me use this method and find it comprable to a laser alignment. Plus or minus 0.5 mm wont be felt through the steering so dont worry too much about accuracy.

mmm! thought it was something similar!...
Just need to learn what to adjust, without upsetting the car completely
I have a couple of ideas, i always take notes as well, so i can 'undo' anything that feels wrong...(guess the centre measurement of car is a good way to record the current settings as well!)
Thanks again!
Mike.

[Dave J]

in adjusting the top collar youhave lowered the ride height

with the nitrons you have adjustable damping rates through 24 clicks of adjustment using the knurled adjuster at the lower end of the damper

the adjuster has a plus or minus sign

turn the adjuster In the minus direction and the damper will become softer

try the maximum and minimum settings and see how it feels

leave the ride height as it is for now

check out the nitron website for some more info

as for tracking , the rear is not really adjustable . but get a garage to set the front to 20 minutes toe out or parallel

what tyres are you using ?

lowering the ride height won't change the ride quality - this is down to spring rate , damper setting and tyre pressures

dave

[pikeyboy]

Dave J said:

in adjusting the top collar youhave lowered the ride height

with the nitrons you have adjustable damping rates through 24 clicks of adjustment using the knurled adjuster at the lower end of the damper

the adjuster has a plus or minus sign

turn the adjuster In the minus direction and the damper will become softer

try the maximum and minimum settings and see how it feels

leave the ride height as it is for now

check out the nitron website for some more info

as for tracking , the rear is not really adjustable . but get a garage to set the front to 20 minutes toe out or parallel

what tyres are you using ?

lowering the ride height won't change the ride quality - this is down to spring rate , damper setting and tyre pressures

dave

Spot on Dave,

By adjusting the spring collar he's altered the rake of the car and also probabrly upset any previous corner weighting. However, how relevant that is depends on his weight relative to the previous owners. I doubt anyone would fit nitrons etc and then not have this done.

[Dave J]

the corner weights won't have been upset if the rear was adjusted equally both sides

the rake would have been altered and biased towards more understeer

[PapaHotel]

My Roadsport behaved as described by redmire. After changing the 15” wheels against 13” it was a different car. Now you can corner fast even on bumpy roads.
But this is only a solution if redmire has 15” on his Caterham.

PapaHotel

[redmire]

pikeyboy said:

Dave J said:

in adjusting the top collar youhave lowered the ride height

with the nitrons you have adjustable damping rates through 24 clicks of adjustment using the knurled adjuster at the lower end of the damper

the adjuster has a plus or minus sign

turn the adjuster In the minus direction and the damper will become softer

try the maximum and minimum settings and see how it feels

leave the ride height as it is for now

check out the nitron website for some more info

as for tracking , the rear is not really adjustable . but get a garage to set the front to 20 minutes toe out or parallel

what tyres are you using ?

lowering the ride height won't change the ride quality - this is down to spring rate , damper setting and tyre pressures

dave

_______________________________________________________________
Thanks for that Dave, can't quite understand why the ride wouldn't be a little softer, with less 'pre-load' on the springs? (certainly take your word for it though! )
I shall try the softest setting on the dampers...silly really, as i asked someone if adjusting them would help make a slightly softer ride and they said no...i was a tad surprised.
I nearly always drive with my missus, so not sure any prepared 'driver weight' would make much odds?
I have made a note of ALL adjustments...even the previous owners and can return to 'original' very easily!
Not sure what tyres they are but they are 13" wheels to answer the other suggestion.
I shall see how it all goes on the weekend (if i get time..very busy) and report back...
Thankyou for your input!!
_______________________________________________________________
Spot on Dave,

By adjusting the spring collar he's altered the rake of the car and also probabrly upset any previous corner weighting. However, how relevant that is depends on his weight relative to the previous owners. I doubt anyone would fit nitrons etc and then not have this done.

Guess i have cancelled out any 'Flat Flooring' that has been set up but as i am normally two up, it probably makes little odds...i guess??
Thanks for your help my friend,
Mike.

Edited by redmire on Thursday 22 July 22:40

[Dave J]

would be good to check the tyre pressures too before you go out

what tyres are you using ?

the r888's and cr500's generally run around 15-18 psi although I have dropped down to 14 psi for trackdays where I have got plenty of heat into the tyres . aiming for circa 21 psi hot

dj

[redmire]

Will check that tonight!
Only 1 click left on the dampers at the front!
5 left on rear, which i have softened fully....see what occurs!
Thanks all again,
Mike.

[Dave J]

be carefully with one click from soft on the front

that's how I ttted my sump - I normally run 8 from soft on the front

dj

[redmire]

Sounds savage!....don't want none of that!!
Down to Zero clicks now, brought the back up another 5 clicks (after taking it down 8)...It loves the smooth roads, doesn't like the bumps much still...although i would say it is better!
Think i might bring the ride height on the springs up 'mid way', don't really want to bottom out!

The tyres are 215's rear and 175's front...none of the above names..can't remember what they are called!!
I shall check the pressures when i get a chance, getting a little more used to the car now, maybe i should stop farting around and drive....

So addictive, soon as i am indoors i want to play again...!!

Mike.

[EFA]

Dave, surely your sump would be knacked if the damping was too severe, preventing ride height from being restored on rebound? This was a problme many a corssflow with Spax Adj. sufferred from years ago.

Dampers being too soft should not be an issue.