Camber/tracking settings?

[Brummmie]

Can anyone tell me what they should be as i'm going to give her the once over.

[sonnylad]

Scroll down in link as there's some here as used by Ireland http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[HarryW]

I put a little more camber on my fronts than shown on Irelands list. Can't remember the rest of the settings tbh.

[Ireland]

My car was set up recently by Eoin Corrigan and the guys at Munster Motorsport ( www.munstermotorsport.com ) and they gave me some extra negative camber as well and it's made a big difference to the car's handling.

It may be worth talking to them to get their input as they have worked on a couple of Cerbs over here and have successfully set them up for even the crap roads we have.

Tell them I sent you.

[Ab Shocks]

Just remember guys that the front toe will need to be varied depending on rack levels.
The easy answer is to get the aligner shop to do a pull down test and see what happens in bump, early cars may toe in, 99ish cars may bump steer, 2000ish cars may have no toe movement at all.
BTW
Factory settings on the last Cerbs were
Front
0.5 to 0.75 neg camber
1.5mm(12minutes)toe in overall
Rear
1.4 degrees neg camber
3mm(24minutes)toe in.

I don't mind the rear factory settings but personally prefer more front camber and less toe on my car but that's the point, you can make the front end more or less pointy to suit individual driving styles.
There is no such thing as a setting to suit all, the relationship between the driver and alinment shop to get the optimum handling package is paramount.

[trackcar]

crikey youve changed your tune derek. before it was all : you must have this height, you must have arms parallel with ground you must run that setting, now it's : generic settings are bad and you have to tune to individual tastes, it's almost as if you've had a sneak look at my next Sprint magazine article. You'll be visiting my barber and tailor, and undertaker for my coffin size next

My advice on suspension is you won't go far wrong with about a degree of camber front and back and about 30mins toe in rear 20 mins toe in front and tune from there. It'll be safe, predictable and easy on your tyres, though to be fair you can be a way out and still have a nice car, they're not as sensitive to set-up as you may think. for instance do you think you could tell if a car was set up with exactly 12 mins toe in as opposed to say 20mins? I'm damn sure I can't ..

[julian64]

Won't somebody think about the castor?

I have it on very good authority that the Cerb is very sensitive to castor changes and a lot of the tramlining problems in a Cerb are due to it.

None of you experts ever mention the castor.

Last time I was trying to make my shopping trolley hug the corner of the pavement after a long downhill section I started to think it handled rather like the Cerb. They're not called castors for nothing y'know.

[trackcar]

The caster on the cerb is set by the length of the drag strut, there were supposed to be different lengths of those to correct caster problems but I don't know if they ever got used. I never even bother checking caster because there's no way to change it other than making your own drag struts (ok you can move the top ball joint fore and aft but you lose the ability to change to large negative cambers because the ball won't go between the arm any more if offset).

There are trade offs on caster (and it's not strictly the castor that's having the influence, it's the change in trail that does that, you can increase the trail and increase the self-centre effect by fitting larger diameter tyres without ever touching the caster itself) and you have to make quite large changes to caster/trail to make an impact on the stability of the car, but you can trim any veering to one side or the other on relative small caster changes.

Also every time you increase caster/trail to increase stability you dull steering response and increase the turning circle so I think all-told nobody bothers with it, there's so much to lose and so little to gain.

I explain caster to people in relation to wheeling a wheelbarrow .. keep the handles low and you have a large caster angle and consequently a very long trail, the wheelbarrow is stable and direction changes are slow .. Now tilt the handles up a long way say to shoulder height .. the caster angle is steep, the trail is very short and the wheelbarow responds quickly to direction change inputs at the handles, you can turn it in a smaller space (turning circle) but is now directionally unstable.

If you ever play around with your own car though Julian i'd be interested to hear the results

Edited by trackcar on Monday 26th May 18:30

[Ab Shocks]

I don't mention caster for the resons given by TC but I aways carry out a caster swing to ensure that both sides are within tolerances.
I'll read your article with interest TC, Mandy did ask me for a contribution but I'm afraid I'm a bit too busy to get involved
Off to work again, 7 day weeks at the moment.
BTW Joo, Racing Reds arived over the weekend.I'll call you.

Edited by Ab Shocks on Monday 26th May 07:34

[Brummmie]

How about raising the rack with some packing washers, does this improve the stability on bumpy roads?

[Nefarious]

I think I'd better check my front campber. Car feels fine (better than fine, actually), but the wear rate on the inner fifth on the front tyres is simply shocking - two thirds of the tread left on the majority of the tyre, inner edge pretty much down to the canvas.

[Ab Shocks]

Brummmie said:

How about raising the rack with some packing washers, does this improve the stability on bumpy roads?

I wouldn't pack out the rack until I knew what the car was doing in bump.

[Brummmie]

Track rods are at quite an angle when sat in the resting position, the further the angle the worse the bump effect will be? i would have thought you would want to start from a completely neutral angle? Just thinking if i'm going to give the front end a check over this will be a good time to sort this, i'm having the engine out in the near future so going the whole hog. ( i know do the angles with engine in!)

[trackcar]

Brummmie said:

Track rods are at quite an angle when sat in the resting position, the further the angle the worse the bump effect will be? i would have thought you would want to start from a completely neutral angle? Just thinking if i'm going to give the front end a check over this will be a good time to sort this, i'm having the engine out in the near future so going the whole hog. ( i know do the angles with engine in!)

You can't really tell just by looking, and every cerb chassised car i've seen that needed bump steer changes to introduce a desirable steer effect needed the rack lowering not raising, which can't be done easily. The only car i've ever had to raise a rack on was fitted with longer steering arms which moved the track rod end upwards, but i could even have left that alone as it brought in neutral bump steer/bump toe-in so increasing stability on the brakes.

Essentially you need the track rod to describe an arc the radius of which meets the intersection of the upper and lower wishbones so that the track rod end is never pushed in or out relative to the hub, so no steering effect takes place for no bump steer. Usually this only happens over a tiny proportion of the suspension movement anyway but is acceptable over a fair range so you would set it for near zero bump steer at the normal ride height and accept it would be slightly out at the extremes of suspension movement.

However some bump-steer can be beneficial for instance adding bump toe-in can make the car more stable on the brakes, adding bump toe out can make turn-in on the brakes very reactive for instance to tame a car which is a natural turn-in understeer car on track ,but there are stability draw-backs of course and exagerrated inner edge tyre wear under braking. It all depends what you want to achieve.

I have to say in 99% of suspension set-ups i never touch the rack. I haven't even touched the rack on our T350 race car. I think they are slightly high as std so I don't understand why people are moving them even higher.. we know the std cars have bump toe-out .. you can see this yourself as the front springs sag the cars start to have much exagerrated inner tyre wear. It's not the gain in camber that's the primary cause, it's the toe-out introduced as the car goes into an effective suspension-compression situation, the toe-out occurring drags the inner edge of the tyre down the road so increasing it's wear rate. I say raise the rack only if you understand the considerable downsides and are willing to live with those compromises.

i've just done this test for you on C1RVY which is in at the moment:

I've taken camber and toe reading at full droop, full bump and the std ride height.

camber:
droop +0.75
std -1.00
bump -3.25

so you can see the change into negative camber as the car goes into bump at the front.

toe readings rack std height:
droop 10mins toe out
std 30mins toe in
bump 10 mins toe in
so from full droop to std ride height it gains 40mins toe in
from std ride height to full bump it gains 20mins of toe OUT. Had this car been set parallel at std ride height it would have lost all it's toe in on bump and gone into toe out.

Rack rasied 10mm (far more than you would go usually but i wanted to get a big swing to make the point):
droop 15mins toe out
std 10mins toe out
bump 1degree10mins toe out

here you can see that from full droop to std height the change is only 5mins and it's a change towards toe in which is nice, however once you get past the mid point into bump it gains a whopping 1 degree of to out. If you imagine a car with softish road springs, set up with parallel stering at std ride height hard on the brakes and with a raised steering rack you can see that at it's bump stops it would have -3.25degrees camber and maybe up to 1 degree of toe out! the inner edges of the tyrs would be destroyed in no time at all, and teh handling on heavy braking would be atrocious.

I hope this has shown how the last thing these cars require is a rack any higher than std ..

[trackcar]

Ab Shocks said:

I don't mention caster for the resons given by TC but I aways carry out a caster swing to ensure that both sides are within tolerances.
I'll read your article with interest TC, Mandy did ask me for a contribution but I'm afraid I'm a bit too busy to get involved
Off to work again, 7 day weeks at the moment.
BTW Joo, Racing Reds arived over the weekend.I'll call you.

Edited by Ab Shocks on Monday 26th May 07:34

It's just a short paragraph at the end of an article i've done about my dislike for generic suspension settings derek, but has sparked me into writing something at the moment specifically suspension based which might be of interest to a few people. In the meantime i've got an engine to change and it's bank holiday monday

[JensenA]

Interesting read TC and Derek. I've always struggled a bit to get my head around Toe-in, Camber, Castor etc etc. but you described it brilliantly TC, my head was beginning to hurt when you started explaining Castor, but your Wheelbarrow analogy has made me understand it perfectly for the first time in my life