Camber intrigue

[tinywillyuk]

Chaps

I've noticed recently - notably since replacing dampers at the rear - that my handling has not been quite as sure footed - even a catseye on a bend at speed is making the car squirm.

So this weekend I started looking at the geometry - the first thing my eye being drawn to was my camber.

To cut a long story short, my car is showing very visible negative camber (tilting in at the top) and a measurement shows the rear camber at 8.7 degrees on one side and 9 on the other and front camber to be 7 degrees either side.

A skim of the service notes would indicate this is massively out of spec - 1 deg being about right iirc without digging it out..

So I thought I'd throw this one out for an opinion - how many of you have wheels so near straight you cant see it and how many have visible amounts of camber?

I realise that its easily solved - but what implications have any of you found to your camber settings or having it changed?

2p anyone?

ps - the camber was previously reset with the knackered dampers in place and the fronts will be replaced over during my upcoming winter "deep maintenance" program.

I still have castor and toe in or out to check.. but one thing at a time eh!

[CarlC]

... 2p anyone?

<{POST_SNAPBACK}>

2p, thats about all I can offer . . .

I've had my camber adjusted as there was signifcant wear on the inside of both my rear directional tyres. The outside of the tyres looked nearly new but the insides where nearly bald. So I got new tyres put on and had the camber adjusted to the correct one degree setting. And your right I cant see the 1 degree angle it just looks vertical.

Im no expert on the matter but IMO the ten degrees your talking about does sound very excessive and will obviously have a negative effect on grip especially as time goes on.

IIRC, I read that the origonally Lotus spec'd tyres for the S4 had wet weather tread on the inside part of the tyre. If I had taken my car out in the wet with the tyres in the condition I found them in I would have had nearly no wet weather tread at all. Just a thought.

[Guest teigan]

got 2p, but it's the older style. what point of reference are you measuring degrees of camber from?

[Jonathan]

Small amounts of negative camber is used to give extra grip when cornering, as the car rolls around on the suspension the angle of the angle of wheel to the road changes, negative camber ensures that at a specific cornering load the maximum tyre spread is in contact with the road.

Service manual has all the settings, the fronts should be set by the camber plates (see the LEW guide I did on changing suspension) so in theorey they shouldnt be far out if the suspension is mechanically sound.

The S4s is the same as the GT3, front is 0.9 degrees - Rear is 1 degree which is measured with 1/2 tank and laden with 1 driver / 1 passenger in the car to give it a mid-laden stance. Just looked at mine and the negative camber is visable....just...remember when the car is laden the negative camber increases (ie the tops of the tyres will point in towards the car).

The rear is adjusted by a tie rod and winding the threads in and out to adjust it's length and how much it pushes/pulls the wheel hub.

Incorrect camber setting will present un-even tyre wear and unstability of the car in acceleration (due to loss of grip) and cornering. You find people who ower the car also get camber issues, if yours has that much camber there's something very wrong imo and I'd get it sorted ASAP or you might find trye wear the least of your problems !

Has the car been used on a track ?

[tinywillyuk]

No track use - not that brave! Suprisingly the wear is almost uniform though tyres dont last very long.

The camber measurement was taken in reference to a known vertical with as close to mid laden as defined in the book (170mm under rear hoop etc). It is hugely visible and I've ignored it - one of those things to do later, but now having replaced the rear dampers I suspect the whole geometry has altered and no needs that attention.

The sad bit is as soon as I ease my mighty mass into the drivers seat its going to get worse!

As said, something isnt right and its now on the agenda of things to do ..soon.

Unusually an easy (and cheap) job to get done.

Jonathan - read your excellent write up - we mustve been doing virtually identical work in tandem - although in my pics everything looks so much more beaten up than yours! I also note from the pics I couldnt see the rubber seats the springs sit on (on the S4 at least) on the rears?

[Jonathan]

The more the suspension travels the more negative camber you get. There should be a rubber insulator on the upper cup of both chassis mounts for the spring to ride on, some people take them out to lower the car somewhat.

If they're out that mcuh I really would get the car's geo sorted asap becuase you're really compramising the car's handling issues, losing grip at the front isn't too bad cus the car will understeer but at the back it'll go nuts on acceleration - you wouldnt wanna do a Jono now and lose the back end all over the place !

Rears I can understand, what worries me is the fronts, the camber plates must be missing in order to get that much camber - for ref I can take photos tomorrow of my car and highlight the camber.

[DAVES_GT3]

The more the suspension travels the more negative camber you get.  There should be a rubber insulator on the upper cup of both chassis mounts for the spring to ride on, some people take them out to lower the car somewhat.

If they're out that mcuh I really would get the car's geo sorted asap becuase you're really compramising the car's handling issues, losing grip at the front isn't too bad cus the car will understeer but at the back it'll go nuts on acceleration - you wouldnt wanna do a Jono now and lose the back end all over the place !

Rears I can understand, what worries me is the fronts, the camber plates must be missing in order to get that much camber - for ref I can take photos tomorrow of my car and highlight the camber.

<{POST_SNAPBACK}>

id be interested in seeing pics jon as i know my camber is out on the front because the inside of my tyres are worn badly. was going to wait until i re tyred before i got the geo set up. would that make sense or not make any difference? was just thinking if it was set up with the current tyres it may be over adjusted to compensate for the wear on the inside edge. or am i talking crap ?

dave

[tinywillyuk]

Pics would be good - an excellent comparison.

I agree totally with the need to fix it. As you say its so far out that either theres something wrong, badly set - or the camber measurement was inaccurate. That said you can see it - so pics of yours to illustrate the difference would be excellent.

Coming up is the replacement of front dampers and removal of steering rack for refurb - its leaking from the top u/j - so the geo is on the list once the wheels are back on the wagon with all new bits back in place.

Its interesting to note that after a run at even 30mph (honest officer) the tyres are very warm.

Talking Daves inner wear (Im not getting that) isnt that toe adjustment needed - esp if its uniform inside of both tyres?

Simon

[Jonathan]

OK I get pictures tomorrow if I can illustrate it correctly.

Toes is another factor in tyre wear as well which is something I was going to suggest to you Simon if your tyres are getting that hot. Might be over reacting but I would get your cars looked at - tyres are not something to be over looked on a supercar.

All geometry has a small tolerance, the readings are taken off the wheel hub iirc so it shouldn't matter on the tyre as long as it's the same dimensions.

With the front the only way the camber can be adjusted significantly is with different shim plates. This allows the upper ball joint to effectivly me moved along the upper wishbone and hence change camber - if thats OK you need to check toe and castor angle.

[Jonathan]

Couple of pictures - don't know if that's gonna help much.

There is negative (in at the top) camber on all wheels at about the same angles, the car is 1/2 laden with fuel but no crew....again the more you load it the more it'll go negative.

Note the tyre wear, the outside of the tyre is important as you can see the whole of the tread is getting grip, same on the inside (have to take my word).

The last pic is probably the best, very hard to see but you can notice them pointing in very slightly.

Edited September 21, 2005 by Jonathan

[tinywillyuk]

Excellent pics Jon!

I wont be able to photo in daylight until Sunday - so will see what I can do in order to offer a comparison.

As you say - its a supercar and the only thing between you and the road are those little but vital rubber bands! If they aren't all doing the right stuff in the right way you could end up travelling in random directions through hedges, over kerbs.. all sorts!