Anyone used 20/25mm spacers on rear???

[kneesparks]

Hi guys, I keep looking at the rear of my Williams and no matter how much I look the rear end is just too narrow. As in the rear wheels need to be closer to the arches like the front. Why didn't Renault widen the rear track as well as the front??
I'm going to add some wheel spacers around 20-25mm so the rear track looks wider. May help with lift off oversteer also? What do you all thing? AnyOne else done this???

[kneesparks]

Anyone??? Has no one else thought of this?

[16v_paddy]

I think the track on the williams is also wider at the rear over the valver :?:

[MatBrown]

Only from the wider wheels.

[Evogone]

Coops runs spacers on the rear i think...

[lloydvalver]

i have thought about it a few times and the only issue i can see it having is a slight bit more stress on the wheel bearings other than that i think it is a good idea

[Geronimo]

The rear track isnt wider because the handling is related to the track ratio front to rear.

If you add 20 mm spacers to the back you will get more understeer.

It will also lighten the steering and reduce sharpness.

Renault obviously didnt want this effect, as its the antithesis of everything the Williams is.

[robi1000]

This is correct. :goodposting:

[16v_paddy]

Only from the wider wheels.

Pretty sure I read somewhere that Gaz (cliolord) actually measured a valver & willy rear beam & said the track width was wider on the willy beam :?

[chip]

Ive got 15mm spacers on the rear of mine, I think you will have to start cutting the arches if you run 25mm.

Saying that they promote understeer is kind of misleading, as although its sort of true, IMHO the standard bias with the williams widetrack is towards oversteer anyway (great for rallying but not so great on trackdays) so the slightly wider rear track brings it more towards neutral than towards understeer I find.

Try it and see though, not exactly a big investment required to find out if you like it or not.

[Geronimo]

Ive got 15mm spacers on the rear of mine, I think you will have to start cutting the arches if you run 25mm.

Saying that they promote understeer is kind of misleading, as although its sort of true, IMHO the standard bias with the williams widetrack is towards oversteer anyway (great for rallying but not so great on trackdays) so the slightly wider rear track brings it more towards neutral than towards understeer I find.

Try it and see though, not exactly a big investment required to find out if you like it or not.

I dont agree, if you find a big carpark and turn the wheel left and hold it there and slowly increase power, what happens? Eventaully the front washes out with understeer.

To say the williams is biased towards oversteer is just wrong imo. All manufacturers of FWD cars bias their cars towarfds understeer for stafety.

[cliokiz]

I've had 20mm spacers on mine previously, with 195/50/15 tyres on valver/clover alloys.

It was at standard ride height, but with people in the back it used to scrub over bumps. I think 10-15mm will be your limit if the car is lowered.

Mine is so low on the back the rim of the Williams alloy is level with the top of the rear arch, and there's not very much clearance between the tyre and the arch (and thats before I attempt to fit 10mm spacers either side!)

I'll report back when i've tried 10mm to see if they'll fit.

[Wobba]

10mm on each side will fit np.

15mm fits too.

20mm may fit but may scrub a bit on bumps.

It increases understeer. It enhances straight line stability (or thats how it felt to me).

[snowman]

Only from the wider wheels.

Pretty sure I read somewhere that Gaz (cliolord) actually measured a valver & willy rear beam & said the track width was wider on the willy beam :?

It was Flan

[MatBrown]

Only from the wider wheels.

Pretty sure I read somewhere that Gaz (cliolord) actually measured a valver & willy rear beam & said the track width was wider on the willy beam :?

It was Flan

And it could have been an Rsi beam.

[chip]

Ive got 15mm spacers on the rear of mine, I think you will have to start cutting the arches if you run 25mm.

Saying that they promote understeer is kind of misleading, as although its sort of true, IMHO the standard bias with the williams widetrack is towards oversteer anyway (great for rallying but not so great on trackdays) so the slightly wider rear track brings it more towards neutral than towards understeer I find.

Try it and see though, not exactly a big investment required to find out if you like it or not.

I dont agree, if you find a big carpark and turn the wheel left and hold it there and slowly increase power, what happens? Eventaully the front washes out with understeer.

To say the williams is biased towards oversteer is just wrong imo. All manufacturers of FWD cars bias their cars towarfds understeer for stafety.


If that is how you drive on track then its YOU that is biased towards understeer not oversteer, pretty much ANY fwd car driven that badly will wash out.
And are you still on factory toe settings cause I sure as hell am not.

Little bit more toe out than standard helps with the turn in no end IME, but a side effect of this is the rear being much more likely to come around under trail braking, a bit of that is good, but if you have the car stripped out (we're talking trackday handling here so seems a safe assumption) it can be more than is ideal, so a little wider track on the back can help it be that little bit easier to work with without it oversteering too much.

But we all drive cars differently at the end of the day, handling is a personal preference, so like I said, he should just try it on track with and without spacers and see which he prefers, personally I prefer it with, but he might not.

[Geronimo]

If that is how you drive on track then its YOU that is biased towards understeer not oversteer, pretty much ANY fwd car driven that badly will wash out.
And are you still on factory toe settings cause I sure as hell am not.

Sorry, when i mentioned 'Williams' i assume everyone would realise that i was talking about a standard Williams, but i guess unless i S P E L L I T O U T, there will always be someone who twists the discussion to fit their own highly modified car.


Little bit more toe out than standard helps with the turn in no end IME, but a side effect of this is the rear being much more likely to come around under trail braking, a bit of that is good, but if you have the car stripped out (we're talking trackday handling here so seems a safe assumption) it can be more than is ideal, so a little wider track on the back can help it be that little bit easier to work with without it oversteering too much.

What has this go to do with widening the rear track causing understeer? Now you are talking about toe in / toe out. Is this deliberate obfusaction? Throw enough technical terms about and hope no one will notice you got it wrong?


But we all drive cars differently at the end of the day, handling is a personal preference, so like I said, he should just try it on track with and without spacers and see which he prefers, personally I prefer it with, but he might not.

We do all drive cars differently yes, but it doesnt hide the fact that widening the rear of the car will induce more understeer and decrease sharpness to the steering. Just like i said. It also doesnt hide the fact that factory standard Williams come with slight U N D E R S T E E R because ALL fwd cars do, as a safety feature to prevent people spinning into trees.

I am sure you will now attack me personally, call for me to be banned, or just make a joke of it,. just like most people do when they post shite and i pull them up on it.

[chip]

If you look at his original post he said:


Hi guys, I keep looking at the rear of my Williams and no matter how much I look the rear end is just too narrow. As in the rear wheels need to be closer to the arches like the front. Why didn't Renault widen the rear track as well as the front??
I'm going to add some wheel spacers around 20-25mm so the rear track looks wider. May help with L I F T O F F O V E R S T E E R also? What do you all thing? AnyOne else done this???

So why you keep banging on and on about P O W E R O N U N D E R S T E E R is beyond me?


If you want to talk about power on understeer then im sure others will be interested so start a thread about it but this thread is V E R Y C L E A R L Y about L I F T O F F O V E R S T E E R


And nothing in my posts is wrong at all, its all an accurate description of the effects I have felt on my own car as he was specifically after the opinions of people who have tried this modification which I have.
By definition that rules out S T A N D A R D williams as you keep banging on about as if it was standard it wouldnt have spacers now would it?


I was talking about toe in and toe out as it is so relevent to any discussion about a car oversteering or understeering when you lift off, if the thread starter hasnt considered the effects of it then I was prompting him to do so, if he has considered it then I was putting my findings based on trying the spacers (he wanted to know about people who actually have tried the spacers) in terms of the other mod on the car that would greatly effect this aspect of handling, if I didnt mention that, then somebody would assume I was refering to a standard car perhaps to which my results wouldnt be as directly relevant ;)

Ie I was putting my own tests into context for him so he can decide if they are relevant to him or not, and if the arent to him then they may be to others.

[Geronimo]

You were doing what many so called 'experts' do on forums wich is hiding your lack of knowledge on a subject with deliberate obfuscation and misleading ambiguity.

The fact reamins that fitting wider rear track to a fwd car will induce understeer. It really cant be any clearer that that can it?

If you want to induce lift off oversteer there is a far easier way. Just fit harder less grippy tyre to the rear.

[chip]

You were doing what many so called 'experts' do on forums wich is hiding your lack of knowledge on a subject with deliberate obfuscation and misleading ambiguity.

Absolutely not, you have misinterpreted what I was saying.
And furthermore it is YOU that seem to have a lack of knowledge on the subject as you seem to have read somewhere that a wider track "induces understeer" and you just keep repeating it for every scenario wether it is appropriate or not, where as in my case I am talking specifically aboutthe context in which he is asking the question and my answer is based on experience of developing various cars during 15 years of trackdays, and a fairly good grounding in suspension geometry theory (I have been professionally published on the subject, so certainly am more than an average layperson although I wouldnt claim to actually be an expert)



The fact reamins that fitting wider rear track to a fwd car will induce understeer. It really cant be any clearer that that can it?

Actually thats not correct, what you are doing is changing the balance of the car, it will make the car more likely to understeer than before if you widen the rear track (on any car) and it will make it less likely to oversteer if you widen the rear track, but wether that changing in balance actually goes as far as to induce understeer or wether it just lessens oversteer is entirely dependant on the application in terms of the car itself and what you are doing with it at the time.

In this case he was SPECFICALLY talking about how the car behaves when he lifts off the throttle on turn in and it currently oversteers in that situation.
And the reality is that if he fits the spacers, it will STILL oversteer in that situation, but just slightly less so.
So in fact it will NOT "induce understeer" for the specific application he is referring to it will merely damp out some of the oversteer.



If you want to induce lift off oversteer there is a far easier way. Just fit harder less grippy tyre to the rear.
He doesnt want to induce lift off oversteer, he wants to lessen lift off oversteer and an easy way to do that is to widen the rear track like he is suggesting!

[MAXIBOY]

somebody ban the queen stromba again..

every time i can spot his crap..

[chip]

somebody ban the queen Robert Barrington again..

every time i can spot his crap..


I dont think that being short of knowledge should be a bannable offence personally.

Ok so he got the wrong end of the stick, but at least his posts then prompted further response from those of us with actual first hand experience so the net effect is a positive one.


But obviously if he is a previously banned user its different, I wouldnt know about that as not been here very long yet myself.

[16v_paddy]

But obviously if he is a previously banned user its different, I wouldnt know about that as not been here very long yet myself.

I think he's been banned at least twice since you've been on here, weapons grade troll

[chip]

But obviously if he is a previously banned user its different, I wouldnt know about that as not been here very long yet myself.

I think he's been banned at least twice since you've been on here, weapons grade troll

Oh right, I dont take any notice of forum politics, im just here to learn about cars and to help others learn about cars, so I havent noticed that.

My opinion in general is that banning people is a bad thing, I run a couple of forums and only ever ban accounts if they are spambots or someone who really is just deliberately posting utter crap, if people are posting stuff like this fool simply cause they dont understand it, I think its better to try and educate them than ban them if possible.

[16v_paddy]

The problem with him is that he posts mainly to cause an argument & belittle people that don't have the same amount of knowledge/experience.

He's thoroughly poisonous :evil:

[chip]

The problem with him is that he posts mainly to cause an argument & belittle people that don't have the same amount of knowledge/experience.

Well he seems to have picked on the wrong person this time if he is going to try and talk down to me, lol

[schakal]

Its the roids !! :D

[chip]

Its the roids !! :D

Oh, I didnt realise he suffers with heameroids, poor fella :(

Still no excuse for him pretending he has a clue what he is on about when he doesnt though, lol

[16v_paddy]

The problem with him is that he posts mainly to cause an argument & belittle people that don't have the same amount of knowledge/experience.

Well he seems to have picked on the wrong person this time if he is going to try and talk down to me, lol

I do recall that you slapped him down on a few occasions on c16v as well

[zmaster2k]

Ditto the above!

[-jo-]

got 30 mm spacers :oops:

[Geronimo]

lateral load transfer (lb) = Lateral acceleration (g) x weight x centre of gravity height / track width

Put some arbitrary figures in the equation. Lets say we pull 2.5 g, in a 990 kg Williams, and have a centre of gravity height of 20 inches with a track width of 60 inches.

lateral load transfer (lb) = 2.5 (g) x 990 x 20 / 60 = 825

Now lets keep everything the same but change the rear track by adding a 1 inch spacer an each side taking total track width to 62 inches.

lateral load transfer (lb) = 2.5 (g) x 990 x 20 / 62 = 798.4

So increasing the rear track with a spacer gives you less lateral load transfer. Less lateral load transfer will increase the grip. If you increase the grip at the rear, guess what happens to the front. UNDERSTEER.

[chip]

[quote="Geronimo"If you increase the grip at the rear, guess what happens to the front. UNDERSTEER.[/quote]

What actually happens, as I have already explained, is that the balance of the car will shift towards understeer.

So if you were in a situation where the car oversteered a lot, then it will now oversteer less, if you had a pefect neutral turn before it would now understeer slightly etc.

You keep making this sweeping statement about understeer and in doing so keep demonstrating your total inability to understand the very basic point that the car isnt perfectly neutral to start with in lots of situations.

[Geronimo]

Its ok mate, you keep talking in riddles for your internet fluffers. Im sure they will be along in a minute to show their appreciation.

Anyone with google can see that i am right. Rear spacers will cause increased understeer.

[chip]

Its ok mate, you keep talking in riddles for your internet fluffers. Im sure they will be along in a minute to show their appreciation.

Anyone with google can see that i am right. Rear spacers will cause increased understeer.

Rear spacers will change the balance of the car towards understeer.

You seem to be finally getting slightly closer to understanding this simple fact that I have been saying from the beginning now that you are saying "increased understeer".

So lets try and take your understanding just a little further, lets quantify it for you, lets say they case 5 degrees more understeer in a partcuar circumstance.
If you had 10 degrees of oversteer to begin with, and you added 5 degrees of understeer, what do you now have? ;)

[jock]

An accident ?

[chip]

An accident ?

LOL

[Geronimo]

Its ok mate, you keep talking in riddles for your internet fluffers. Im sure they will be along in a minute to show their appreciation.

Anyone with google can see that i am right. Rear spacers will cause increased understeer.

Rear spacers will change the balance of the car towards understeer.

You seem to be finally getting slightly closer to understanding this simple fact that I have been saying from the beginning now that you are saying "increased understeer".

So lets try and take your understanding just a little further, lets quantify it for you, lets say they case 5 degrees more understeer in a partcuar circumstance.
If you had 10 degrees of oversteer to begin with, and you added 5 degrees of understeer, what do you now have? ;)

Tha balance of the car is already understeer. All FWD cars will have understeer for safety reasons. No manufacturer will deliberately create a fwd car with oversteer.

To get any oversteer in a williams you have to shift weight by lifting off mid turn. In a standard, completely mechanically sound williams, you wont get oversteer any other way.

So adding spacers to the rear increases the tendedncy to understeer even more than normal.

Please dont post up some boring riddle about toe and camber to make it sound like you are some kind of expert. Im bored of reading your convoluted reasoning.

[Geronimo]

Also, maybe you could post up the details of all the bog standard williams that you have owned? I would be interested to hear you experience of ownership.

[Geronimo]

He's thoroughly poisonous :evil:

What a silly little cry baby you appear to be. Grow up.

[chip]

Its ok mate, you keep talking in riddles for your internet fluffers. Im sure they will be along in a minute to show their appreciation.

Anyone with google can see that i am right. Rear spacers will cause increased understeer.

Rear spacers will change the balance of the car towards understeer.

You seem to be finally getting slightly closer to understanding this simple fact that I have been saying from the beginning now that you are saying "increased understeer".

So lets try and take your understanding just a little further, lets quantify it for you, lets say they case 5 degrees more understeer in a partcuar circumstance.
If you had 10 degrees of oversteer to begin with, and you added 5 degrees of understeer, what do you now have? ;)

Tha balance of the car is already understeer. All FWD cars will have understeer for safety reasons. No manufacturer will deliberately create a fwd car with oversteer.

To get any oversteer in a williams you have to shift weight by lifting off mid turn. In a standard, completely mechanically sound williams, you wont get oversteer any other way.

So adding spacers to the rear increases the tendedncy to understeer even more than normal.

Please dont post up some boring riddle about toe and camber to make it sound like you are some kind of expert. Im bored of reading your convoluted reasoning.

aha, finally you are getting there at last!

This feels like real progress!

The situation the thread starter is looking to control his oversteer in his the following:

May help with lift off oversteer also?

The very situation that you finally seemed to have grasped that even a standard williams (with its factory safe toe and camber settings) oversteers in, is the very one that he is looking to reduce that oversteer with the addition of rear spacers.


So hopefully (at last) you can finally see why it wont "understeer" in that situation, it will merely oversteer less!

In other situations, where it already understeers, it will get worse, in situations were its currently neutral, it will understeer slightly, in situations where it currently oversteers slightly it will become neutral.

Its a VERY simple concept, oversteer and understeer arent black and whites, its a shades of grey thing and altering one end or other of the car will generally more you along that scale a shade or two.

[Geronimo]

Just to remind people what you said to start with:


Saying that they promote understeer is kind of misleading, as although its sort of true, IMHO the standard bias with the williams widetrack is towards oversteer anyway

And how over a series of posts you have changed what you said to make out you were right all along. You clearly said the bias on a standard williams was towards oversteer. Anyone who has owned one will know this is bollocks.

Also waiting for your previous ownership of standard williams. I notie you keep avoiding this question, presuably because you have never owned one and so next to **** all about them.

[chip]

Just to remind people what you said to start with:


Saying that they promote understeer is kind of misleading, as although its sort of true, IMHO the standard bias with the williams widetrack is towards oversteer anyway

And how over a series of posts you have changed what you said to make out you were right all along. You clearly said the bias on a standard williams was towards oversteer. Anyone who has owned one will know this is bollocks.

Also waiting for your previous ownership of standard williams. I notie you keep avoiding this question, presuably because you have never owned one and so next to f**k all about them.

Indeed I did say that about the williams front suspension changes from the valver, for the simple reason that it is/was/always be of course a very true statement about the effects of the changes to the williams front track.
It gives the car more bias to oversteer as a result.

The way that the williams track has been changed to have a widened track more at the front than the rear (front and rear both altered slightly by wheel offset but front also altered by wider bottom arm width) gives it a bias towards oversteer compared to the standard valver which doesnt have the extra width at the front as the front outer gains more grip compared to the rear as a result during roll.

So adding some width to the rear as well, simply brings the bias more back inline with the standard valver.

Thats how it works:
widen the front = alter bias towards oversteer.
widen the back = alter bias towards understeer.

Thats how it worked for my first reply, thats how it has worked for every single reply I have made since, what I am saying hasnt changed at all.


So, as I said before its the changes to the front track to create the williams model that has made it even more likely to lift off oversteer than the standard valver.
And likewise the proposed changes to do the same to the rear as was done to the front on the williams model, will of course have the opposite effect on the bias.

Standard valver -> williams front track = increased oversteer bias
williams rear track -> wider rear track = increased understeer bias

As for owning a standard williams, I have never owned a standard one, but have driven them, and its driving them that we are talking about not owning them, you seem to prove very well yourself its perfectly possible to own something and know nothing about it, and I prove the opposite, as TBH even if I had NEVER driven a clio at all (let alone the reality which is I have spent years doing trackdays in them including continual suspension alterations that has actually taught me a lot about the platform and how changes effect it in the real world versus my already fairly good theoretical knowledge carried over from practical experience on other cars) I could tell you the same thing about the fact that widening the front track will give it a bias towards oversteer compared to the unwidened car simply because that is always the case, its very basic car suspension fundamentals.

[kneesparks]

Wow, I did not know that asking this question would cause such a debate ;)
Chip thank you for your continued replys in my question of helping with lift off oversteer. You gave me the answer I was looking for in detail, I'm unsure why we have the haters banging on about understeer when that was not my question in the 1st place. Maybe you could help me set up my skyline some time :p

[chip]

No problem mate, and its not haterS its just the one numpty, lol

[robi1000]

Chip, there's one good side to this. You thoroughly explained for everyone basic suspension foundamentals.

I would also like to add, that I changed the oversteering tendency to more neutral on my AX with wider tires at the back (more specific 175 front and 185 rear). However I don't think that's road legal. But on trackdays I don't think anyone cares. If you can, try 185 on the fron and 195 on the back.

You can also do a bit of fine tuning with tire pressure.

[chip]

Chip, there's one good side to this. You thoroughly explained for everyone basic suspension foundamentals.

I would also like to add, that I changed the oversteering tendency to more neutral on my AX with wider tires at the back (more specific 175 front and 185 rear). However I don't think that's road legal. But on trackdays I don't think anyone cares. If you can, try 185 on the fron and 195 on the back.

You can also do a bit of fine tuning with tire pressure.

Perfectly legal to put wider wheels on the back, no problem at all with that.

In fact an M3 has that as standard.

Tyre pressures in some motorsport are absolutely vital, and as you say in all instances are a good place to do some fine tuning.

[zmaster2k]

You would expect wider tyres on a rwd car though surely?

How much benefit would their be to fitting 205 tyres over 195?


Love this thread

[robi1000]

From my experiance I'd say that in terms of cornering speed it's not a really a massive difference between one tire size and next size up. It's more noticable in terms how responsive is the car on throttle changes mid corner. Wider tires give a more safe feeling but less response. Really depends on what you want. It also depends on the rims you use. Fitting wide tires on rims that are too narrow for that size can make things worse (and vice versa of course). It changes turn-in and mid-corner grip characteristics.

Regarding different sizes on the front and rear... I know there's abundance of cars with different sizes front/rear, but it's homologated that way from the factory. So in general it's allowed, just probably not on a Citroen AX (at least not in my country). :lol:

[robi1000]

Fitting wide tires on rims that are too narrow for that size can make things worse (and vice versa of course).

This came out wrong. What I meant was that you can make them too wide, or go for "zee German style" and fit narrow tires on a wide rim. Both extremes change handling.

[chip]

You would expect wider tyres on a rwd car though surely?

Yes of course, but it was just illustrating that a variation in tyre size isnt a reason for the car to be illegal.

As Robi mentions though, it might be just on the basis of deviation from type approved values, but in the UK that isnt something the police care much about yet (starting to though!)


How much benefit would their be to fitting 205 tyres over 195?

You will have to try it with your preferred brand of tyre and see how it feels to you, there really arent a lot of generalisations you can make with tyre widths really.

Bear in mind that wider means less pressure for each inch of width as the weight is spread over a larger footprint though, so if you have a high grip tyre this is probably of benefit and on a low grip tyre probably a hinderance.
during tight cornering a wider tyre will lose grip as a result of the inside and outside moving in different size circles.

Its one of these bell curves though for any given car and tyre compound, so it depends if you are just to the left or just to the right of optimum if going wider helps or hinders for any given corner.
You'll find typically that in a very tight corner you want narrower tyres, as the effects of the different circles the inner and outer edges of the tyre are moving in are more pronounced and it makes direction changes easier (tight chicane for example) but on a looser bend you will want a wider tyre.

Personally I havent been able to really feel a big difference when going from 195 to 205 and back on my clio, so maybe the best width on a clio is 200, lol, but on the other hand (as you'll probably know as I think I took you out in my car once) I tend to drive past the limit of traction quite often with the car sliding about, and the negative side of going wider is less noticeable when you are breaking traction anyway with a fairly aggressive driving style, it would be more noticeable to someone who likes to drive purely within the grip limits of the vehicle.

[zmaster2k]

Cheers chip V informative! :-)