Rear camber shims make the rear seem lively at normal speeds?

[Chip-mk1]

Much toe out on the rear will make it monstrously lively on turn in, to the extent of feeling very unstable at high speeds even on straight roads when you are changing lane etc.

Toe in on the back will promote understeer and make the car much more stable at speed.


Personally I quote like the rear of a car to be parellel or quite close to it, which yours already is.

 

[Space Cadet]

Thanks Chip. That makes sense.

On the basis that my last readings are the same then I'll leave it alone.

Sorry, so is Toe-in a positive figure and the wheels are pointing inwards?

​What kind of Toe readings should I want on the front?

 

[Sam@NP]

Fact of the day, FWD touring cars run so much negative rear camber to reduce low speed grip.

When I was tracking my Trophy at no point did I feel it needed more rear camber, but then I was driving pretty slowly in it

 

[...]

For anyone who wants to start to understand the science , and i mean start as the reality is that what should work on paper is not what works in reality all the time

order and read

http://www.amazon.co.uk/Competition-Car-Suspension-Practical-Handbook/dp/1844253287/ref=dp_ob_title_bk


and


[URL]http://www.amazon.co.uk/dp/185960644X/?tag=cliospnet01-21[/URL]

 

[Chip-mk1]

Thanks Chip. That makes sense.

On the basis that my last readings are the same then I'll leave it alone.

I'd certianly not go making dramatic changes.

Sorry, so is Toe-in a positive figure and the wheels are pointing inwards?

People dont seem to agree on this, I totally avoid talking about positive and negative toe and stick to talking about toe in or toe out instead, as Ive seen machines label it both ways!


​

What kind of Toe readings should I want on the front?

Depends how you want the car to drive, toe in and it will understeer but be very stable.
Toe out and it will be much keener to turn in and very unlikely to understeer but be less table.

Personally I like high powered FWD cars to be parellel, but with a lower power one where I am more likely to be enjoying chucking it around tight corners at low speeds I like a couple of degrees toe out.

 

[...]

Tbh unless your taking tyre temp readings its pretty pointless adding more camber as there's no way you will know if you've made any improvements.
How is the car behaving? Are you suffering from understeer? What toe settings are you running front/rear? I'm just trying to get an idea of where your coming from and what you are aiming to achieve.

the biggest single problem with people trying to set things up is actually understanding what's happening , and then even harder why.

 

[Sam@NP]

For anyone who wants to start to understand the science , and i mean start as the reality is that what should work on paper is not what works in reality all the time

order and read

http://www.amazon.co.uk/Competition-Car-Suspension-Practical-Handbook/dp/1844253287/ref=dp_ob_title_bk


and


http://www.amazon.co.uk/dp/185960644X/?tag=cliospnet01-21

Good for the basics however this was my bible during my dissertation writing.

http://books.google.com/books/about/Race_car_vehicle_dynamics_Hauptbd.html?id=opgHfQzlnLEC

 

[...]

I'd certianly not go making dramatic changes.



People dont seem to agree on this, I totally avoid talking about positive and negative toe and stick to talking about toe in or toe out instead, as Ive seen machines label it both ways!


​
Depends how you want the car to drive, toe in and it will understeer but be very stable.
Toe out and it will be much keener to turn in and very unlikely to understeer but be less table.

Personally I like high powered FWD cars to be parellel, but with a lower power one where I am more likely to be enjoying chucking it around tight corners at low speeds I like a couple of degrees toe out.

​also altering toe and camber can (i did say can) have an effect on castor and that will alter turn in and mid corner again .

 

[Chip-mk1]

​also altering toe and camber can (i did say can) have an effect on castor and that will alter turn in and mid corner again .

On a clio I dont beleive that to be true TBH, certainly not to an significant extent.

Caster is about the centre line of the wheels vertical position relative to the centreline of the top mount bearing, changing the camber or toe is unlikely to effect that unless you do so by altering the top mounts to eccentric ones, but then you are very clearly altering caster and camber together anyway, its not a side effect its simply allowing you to adjust both.

Setting individual corner ride heights is the thing most likely to alter castor, lowering the back will increase it, lowering the front will decrease it.

 

[...]

your completely correct and i was thinking using top mount adjusters as thats how i have always done it , ever noticed the rake on a R5 cup car ?

 

[Space Cadet]

Thanks guys. I've spoken with Simon at Track-Group and he's going to send me over the last geo print-out.

He explained in layman's terms why my car had been set up as it had. i.e a bit of toe-out on the front to aid change of direction, but a touch of toe-in on the rear to help with straight-line stability and quite a bit of camber on the front to help with cornering. He actually said that reducing the rear camber would help with the understear as it would make the rear tyres less grippy when cornering and therefore promote oversteer.

I mentioned that "Touring cars have lots of rear camber" and he said yes but that they're another 300kg more than my car and have much better weight distribution and run bigger slick tyres.

​Anyway, just waiting on the geo-print-out and we can take it from there.

 

[Cup_Phil]

Positive toe means the wheels are pointing inwards.. Good for high speed stability but not great for turn in

I've read several people (including the burspeed lads) recommend running rear shims to get zero toe on the back

I'm running 1.5mm of toe out on the front (not sure what minutes/degrees that equates too) to help turn in - but back is standard (should be same as yours)

 

[Cup_Phil]

He actually said that reducing the rear camber would help with the understear as it would make the rear tyres less grippy when cornering and therefore promote oversteer.

Don't agree with that at all - they will have more grip when you start to turn in and the front will have less as they have more camber, so the car will initially understeer. Then as the front rolls over the front will gain grip and the back will lose grip so you'll have oversteer mid corner.

Not to my taste

More camber on the rear means you'll have less rear grip at the initial turn in point, so a bit of oversteer, then as the car rolls onto it's tyres you'll have more grip throughout the corner and exit.

 

[Chip-mk1]

You cant apply a "more does this and less does that" rule of thumb to all cases, its very application specific and even down to driving styles, some people turn in more aggressively than others so a setting that for someone very smooth would cause understeer will cause oversteer instead with someone more aggressive.

The only way to set your car up for your driving style is trial and error, you are already in a sensible ballpark and no one just looking at bits of paper can get you closer than that reliably IMHO

 

[...]

You cant apply a "more does this and less does that" rule of thumb to all cases, its very application specific and even down to driving styles, some people turn in more aggressively than others so a setting that for someone very smooth would cause understeer will cause oversteer instead with someone more aggressive.

The only way to set your car up for your driving style is trial and error, you are already in a sensible ballpark and no one just looking at bits of paper can get you closer than that reliably IMHO

Thats why setups that do certain things become paddock secrets ... as theory and reality rarely match

 

[Space Cadet]

Don't agree with that at all - they will have more grip when you start to turn in and the front will have less as they have more camber, so the car will initially understeer. Then as the front rolls over the front will gain grip and the back will lose grip so you'll have oversteer mid corner.

Not to my taste

More camber on the rear means you'll have less rear grip at the initial turn in point, so a bit of oversteer, then as the car rolls onto it's tyres you'll have more grip throughout the corner and exit.

I think then actually it may help me, turn-in is no problem, its actually mid-end of the corner that i see understeer.

Thanks for everyone's help.

 

[Chip-mk1]

I think then actually it may help me, turn-in is no problem, its actually mid-end of the corner that i see understeer.

Thanks for everyone's help.

Are you sure you arent just turning in too soon?
As that sort of understeer on the way out is more likely to be the wrong line than a suspension setting IME

 

[Cup_Phil]

I was gonna say - I've never experience any mid-corner understeer unless applying too much power with lock still on or taking the wrong line into the corner.

 

[Chip-mk1]

I was gonna say - I've never experience any mid-corner understeer unless applying too much power with lock still on or taking the wrong line into the corner.

A diff helps a lot when people are making those sort of mistakes as it changes the turn in point slightly and how soon you can get back on the power.

 

[Space Cadet]

Are you sure you arent just turning in too soon?
As that sort of understeer on the way out is more likely to be the wrong line than a suspension setting IME

​I don’t think so, I mostly drive the Brands Indy circuit and have had enough instruction to remember where to turn in but you of course may be correct. Next Thursday is the full GP circuit which I haven't driven before (have been a passenger) so I'll be getting some instruction anyway, will brush up on my turn in skills then.

 

[Chip-mk1]

​I don’t think so, I mostly drive the Brands Indy circuit and have had enough instruction to remember where to turn in but you of course may be correct. Next Thursday is the full GP circuit which I haven't driven before (have been a passenger) so I'll be getting some instruction anyway, will brush up on my turn in skills then.

Has the car changed at all since instruction?
As every car (and weather condition) changes the point slightly.

As Phil mentions how soon (and how hard) you get on the power after the apex has an effect too.

I know from getting it wrong so often myself, FLOL. I can build an engine a lot better than drive a car!

 

[...]

​I don’t think so, I mostly drive the Brands Indy circuit and have had enough instruction to remember where to turn in but you of course may be correct. Next Thursday is the full GP circuit which I haven't driven before (have been a passenger) so I'll be getting some instruction anyway, will brush up on my turn in skills then.

Your problem won't always be turn in related , the most comon mistake for people in FWD on track is not unwinding lock as they apply power , if you hand onto the lock to long when going to full throttle it will wash out badly

 

[Tony Hunter]

It's taken nearly 3yrs to get the race car to where it is now. But if somebody else drove it, they would probably spin on the first corner.
Learning how to drive with what you've got will do much more than just guessing at a set up.

Sam, Harv and a few others on here I guess would agree, I could and have jumped in a car, and after a couple of laps, have taken in what it feels like, then just drive to that.

 

[Chip-mk1]

It's taken nearly 3yrs to get the race car to where it is now. But if somebody else drove it, they would probably spin on the first corner.
Learning how to drive with what you've got will do much more than just guessing at a set up.

Sam, Harv and a few others on here I guess would agree, I could and have jumped in a car, and after a couple of laps, have taken in what it feels like, then just drive to that.

These things tend to evolve over time too, generally people get more and more lively with their settings as they keep getting used to the car and gaining in confindence and ability with it specifically.

So even you yourself might have disliked how it is now if you drove it like that 3 years ago. (or poss not in your case as a seasoned racer, but certianly the case for most people doing trackdays compared to the same person a few years down the line now with a lot more practice)

 

[Space Cadet]

Thanks guys, sounds like I need some instruction anyway just to see if its me that's causing the understeering or the car.

I've had a later geo print-out sent through, but not what I believe to be the latest and the settings are worse than those I listed before, it was set up by Al at TDF using Track-Group's ramps and the front camber is -2.45 / -2.04 which is a bit alarming. (No comments from the anti TDF brigade!).

I might try and book a geo session this Saturday just to be safe before I'm out next Thursday.

 

[Chip-mk1]

Over half a degree out is a bit much TBH, might be worth getting it set again.

 

[McGherkin]

Isn't that .4 degrees?

 

[Chip-mk1]

Isn't that .4 degrees?

Its in minutes:

so 2.60 = 3

So 0.41 is just over 2/3rds of a degree

 

[Tony Hunter]

These things tend to evolve over time too, generally people get more and more lively with their settings as they keep getting used to the car and gaining in confindence and ability with it specifically.

So even you yourself might have disliked how it is now if you drove it like that 3 years ago. (or poss not in your case as a seasoned racer, but certianly the case for most people doing trackdays compared to the same person a few years down the line now with a lot more practice)

Our old track was the same, Danny Sideways drove at Bedford, span it on the 2nd corner lol.

 

[mikes86]

Guys i'm running 3 degrees on the rear and 1.2 degrees on the front (max i could get with standard) and while i am extremely happy with initial turn in and mid corner, im having great trouble coming off the apex/out of corners. It turns in very well with a lovely bit of oversteer, just enough to help the car round the corner, but then it will understeer quite bad and even sometimes spin the wheels on really tight corners (you can also feel the front skipping to the side on very fast corners). Am i needing more camber on the front, or caster/toe??

Camber working its magic

 

[...]

Guys i'm running 3 degrees on the rear and 1.2 degrees on the front (max i could get with standard) and while i am extremely happy with initial turn in and mid corner, im having great trouble coming off the apex/out of corners. It turns in very well with a lovely bit of oversteer, just enough to help the car round the corner, but then it will understeer quite bad and even sometimes spin the wheels on really tight corners (you can also feel the front skipping to the side on very fast corners). Am i needing more camber on the front, or caster/toe??

Camber working its magic

How did you deduce that was a good setup .... sounds undrivable and without wishing to sound patronising your understanding of things is way off .

Wheelspin out of tight corners will be down to no lsd and a very strange setup ...... in fact it must be bloody awful .a standard car would handle way better ... you sure thats what you have

 

[Tony Hunter]

3 deg does sound a lot.

 

[...]

3 deg does sound a lot.

With negligable on the front it would behave weirdly

 

[mikes86]

Don't worry about sounding patronising, i'll be the first to admit i know very little about car setup, its mostly trial and error for myself If im right, the rear has 1 degree standard and i have 2degree shims in. I have camber bolts in the front, but according to my last geo its only 1.2 degrees (i did ask for the max negative). Odd setup maybe, but i certainly prefer the way the car drives since adding camber to the rear, it turns in far better now. The problem being is its a bit of a pig coming out of corners. I can't imagine a near standard engine and 595rsr tyres would warrant an LSD to the extent that im getting wheel spin (im feeding the steering and progressive throttle). Could this be down to the geo im running?

 

[...]

If your running camber bolts then this all sounds weird ... and yes a standard 1*2 would always benifit an lsd but you have to change how you drive ..... seriously 3 degrees on the rear sounds odd and would make it turn in better as the contact patch on the rear at turn in would be very small .... I would expect it almost to go strsight into oversteer

 

[dmallett]

Considering adding half a degree rear to mine, its running 2.5degrees up front. Will it make a noticeable difference?

 

[...]

Considering adding half a degree rear to mine, its running 2.5degrees up front. Will it make a noticeable difference?

What does the car do now ? ... all this chuck this on do that is ok if you understand what you have , what your driving style is , how accomplished you are behind the wheel etc .
You may find the rear more lively and help turn in initially but there would be a mid corner trade off how much only testing with tyre probe and a stop watch would really tell

 

[Tony Hunter]

TBQH you just have to try it and see. There are so many other parameters, and no magic answers.

 

[mikes86]

The rear is a little lively in the wet and you have to be pretty careful with coming off the throttle (at all), but in the dry you can properly throw the car in (when messing around) and the rear only gives a tiny little flick out and helps pull the car round. It's on the long fast corners where i can feel the front push out mid to corner exit. I'm running the PMS front strut and topmount kit and have a whiteline rear ARB set to the hardest setting, running with slight positive rake (about an inch higher at the rear) and running shitty ktec coilovers 59n/mm & 46n/mm (front/rear) with terrible dampening

 

[dmallett]

What does the car do now ? ... all this chuck this on do that is ok if you understand what you have , what your driving style is , how accomplished you are behind the wheel etc .
You may find the rear more lively and help turn in initially but there would be a mid corner trade off how much only testing with tyre probe and a stop watch would really tell

IT handles very well at current i find, took me a few days of tweaking and driving it on our ring trip to get it how i wanted. Im confident driving it in the way It is now and wasnt planning on changing it but was on ebay and a set of camber shims came up for not alot of money near me so was thinking it might be worth a try for the small amount of money.

Dont get me wrong im not a decent driver and i dont actually drive the clio that much, it was just the ease of these being so cheap and close that made me think of it lol.