PDA

View Full Version : Car slightly pulls to the left



FastFwd
09-07-2009, 12:19 PM
Ok so i recently had an issue with my front lower ACL bushing which failed and at that time my car would pull to the left and i thought replacing that bushing would fix it but it hasnt. Then i just ruled it out as torque steer but this morning on the way to work i was testing it and i was holding my steering wheel dead still in a straight line and when i would put the foot down it would veer off to the left quite alot.

I've checked all major bushing etc and all seem to be fully intact.

Would a wheel alignment fix this?

FastFwd
09-07-2009, 07:18 PM
bump!

SHOGUNOVDDRK
09-07-2009, 07:33 PM
Check:

Tyre Pressure.
Wheel Alignment
Tyre Wear
ETC

Then come back.

OMG.JAI xD
09-07-2009, 07:56 PM
LSD box?

If not. Definately torque steer.
If yes. Im guessing it would be helical (the type that doesnt need the special fluid). Check that it is working correctly.

JohnL
09-07-2009, 10:06 PM
Check:

Tyre Pressure.
Wheel Alignment
Tyre Wear
ETC

Then come back.

Also you might try swapping the front wheels side to side. If that changes nothing, try swapping the rear wheels to the front. This is of course looking to see if the problem might be tyre related.

Note that the only alignment settings that might affect whether the car pulls to the side will be (assuming a straight chassis with equal side to side wheelbase); front camber and caster, rear camber and individual rear toe. Of these only the rear toe is easily adjustable using the adjustments provided by Honda.

Make sure that you're checking for steering pull on road that doesn't have left leaning road crown, i.e. on a properly flat road surface.

vtesh
09-07-2009, 11:12 PM
get it on a hoist it you can, or bring it to a front end specialist, swap tyres over, see if problem still occurs, also check tyre pressure, do a full visual inspection on the suspension system and components, any accidents happen lately? or smacked a curb? check for signs of wear and tear, especially shocks, springs, struts, lower control arms, sway bars, hubs,

hotdc2
10-07-2009, 04:00 AM
is it consistantly occuring or only when you put the foot down. maybe the actual steering wheel needs to be aligned? Whenever i get my wheels aligned they always take it around the block to make sure it's all aligned.

FastFwd
13-07-2009, 08:15 AM
Check:

ETC

Then come back.


Tyre Pressure: 43 All round, recently checked
Wheel Alignment: Do need one but it only happens when applying gas.
Tyre Wear: Even, checked yesterday when i was replacing brake.


LSD box?

If not. Definately torque steer.
If yes. Im guessing it would be helical (the type that doesnt need the special fluid). Check that it is working correctly.

Nah I have a MFactory LSD. this was happening before i put the LSD in so i dont think it would be that.


Also you might try swapping the front wheels side to side. If that changes nothing, try swapping the rear wheels to the front. This is of course looking to see if the problem might be tyre related.

Note that the only alignment settings that might affect whether the car pulls to the side will be (assuming a straight chassis with equal side to side wheelbase); front camber and caster, rear camber and individual rear toe. Of these only the rear toe is easily adjustable using the adjustments provided by Honda.

Make sure that you're checking for steering pull on road that doesn't have left leaning road crown, i.e. on a properly flat road surface.

My problem only occurs when accelerating so if it was a camber wear issue or alignment issue it would be happening all the time right?


get it on a hoist it you can, or bring it to a front end specialist, swap tyres over, see if problem still occurs, also check tyre pressure, do a full visual inspection on the suspension system and components, any accidents happen lately? or smacked a curb? check for signs of wear and tear, especially shocks, springs, struts, lower control arms, sway bars, hubs,

No accidents, no curb smacks, no unusual tire wear, shocks have done 15,000, just replaced LCA bushings, Just put in brand new sways. But remember this issue was occuring before i did all this.


is it consistantly occuring or only when you put the foot down. maybe the actual steering wheel needs to be aligned? Whenever i get my wheels aligned they always take it around the block to make sure it's all aligned.

Yeah its only happening when i put my foot down, and it doesnt have to be alot just a little will still cause it to happen thats why im sorta ruling out torque steer.

I havent had it aligned in a while so i mean i can try that but it just feels a little different to that. Dunno.

riruiz_88
13-07-2009, 12:45 PM
check the condition of you rear trailing arm bush (big bush). could be the problem

FastFwd
13-07-2009, 12:47 PM
check the condition of you rear trailing arm bush (big bush). could be the problem

Will do cheers...

string
13-07-2009, 01:47 PM
Each tyre will influence the yaw of the vehicle. Since the rear tyres are a long way from the centre of gravity, the slightest toe change creates a substantial torque on chassis.

A wheel alignment might show your rear thrust angle as straight but this is only under the static load of the car. Add some more load through forward acceleration and one side might move more than the other if you have worn bushes somewhere.

Summary: Any bushing, front or rear can profoundly affect stability, balance and control.

FastFwd
13-07-2009, 02:14 PM
Each tyre will influence the yaw of the vehicle. Since the rear tyres are a long way from the centre of gravity, the slightest toe change creates a substantial torque on chassis.

A wheel alignment might show your rear thrust angle as straight but this is only under the static load of the car. Add some more load through forward acceleration and one side might move more than the other if you have worn bushes somewhere.

Summary: Any bushing, front or rear can profoundly affect stability, balance and control.

What if the camber on the rear isnt the same? or maybe on the front. Or ride height?

Is the somewhere i can take my car to and get all of my adjustments setup? I got scunk2 camber kit for front and rear, and G4 coilovers, Whiteline Xtra Heavy Sway bars and Generic front and rear Strut braces. Ohh and MPR Rear LCA's

Limbo
13-07-2009, 02:20 PM
any noise? a wheel bearing going perhaps?

SHOGUNOVDDRK
13-07-2009, 07:30 PM
any noise? a wheel bearing going perhaps?

That my friend is something I didn't think of.

This also should be in the check list.

Ally Angel
14-07-2009, 01:43 PM
I actually have a simular problem myself with my car, i know its not alignment.., rear bushes have just been replaced a few weeks ago. but mine does it also when i brake and when driving. Sometimes its there real bad and sometimes its not. But im getting new 17'' wheels put on in a about a month so see what happening if its still doing it then.

But sounds like a real simular problem, ive had for a about a year and only gotten worse

FastFwd
14-07-2009, 03:12 PM
I actually have a simular problem myself with my car, i know its not alignment.., rear bushes have just been replaced a few weeks ago. but mine does it also when i brake and when driving. Sometimes its there real bad and sometimes its not. But im getting new 17'' wheels put on in a about a month so see what happening if its still doing it then.

But sounds like a real simular problem, ive had for a about a year and only gotten worse

Yes exactly...its when braking and accelerating. some times its worse and sometimes its not to bad. Occasionally gives a really loose steering wheel feeling.

And when under boost, im holding my steering wheel steady and strong straight it feels like i keep having to re-correct the car when im just going straight. It will pull to the left then i have to turn the wheel left a little. Mixing this with torque steer, LSD and 230hp occasionally doesnt feel so good.

Car feels like it wants to take off without me in different directions.

string
14-07-2009, 03:36 PM
When your tyres generate a forward or backwards force from acceleration or braking it attempts to rotate the upright around the steering axis. The further the centre of the contact patch from the intersection of the steering axis and the road (the scrub radius) the greater the magnitude of this force.

RWD vehicles experience the exact same force, except obviously only when braking.

This is all well and good when the tyre forces are equal (and the scrub radii are equal left and right) because one side pushes on the rack and the other pushes back and the forces balance and you get zero net force. At any time when the tyre forces are NOT equal, you get unbalanced forces, and as a result you get steering pulls (and they are real forces: you have to counter them entirely or else the steering will change directions).

A helical LSD does not always put the same torque through both wheels therefore under heavy acceleration you might be getting more steering kickback from one wheel than the other. The same applies for braking on an uneven surface.

When one wheel is providing more torque than the other, it is likely deforming the bushings more than the other causing a greater change in geometry and a further imbalance.

Further more, you likely have near stock ratio spring rates front:rear meaning the front track is doing the majority of the yawing work. This means that toe changes to the front axle will greatly affect the yaw of the vehicle. The first thing I noticed when changing from a front stiff to a rear stiff setup was that the front end has a much harder time yawing the vehicle on it's own - i.e. torque steer is near gone.

FastFwd
15-07-2009, 08:21 AM
When your tyres generate a forward or backwards force from acceleration or braking it attempts to rotate the upright around the steering axis. The further the centre of the contact patch from the intersection of the steering axis and the road (the scrub radius) the greater the magnitude of this force.

RWD vehicles experience the exact same force, except obviously only when braking.

This is all well and good when the tyre forces are equal (and the scrub radii are equal left and right) because one side pushes on the rack and the other pushes back and the forces balance and you get zero net force. At any time when the tyre forces are NOT equal, you get unbalanced forces, and as a result you get steering pulls (and they are real forces: you have to counter them entirely or else the steering will change directions).

A helical LSD does not always put the same torque through both wheels therefore under heavy acceleration you might be getting more steering kickback from one wheel than the other. The same applies for braking on an uneven surface.

When one wheel is providing more torque than the other, it is likely deforming the bushings more than the other causing a greater change in geometry and a further imbalance.

Further more, you likely have near stock ratio spring rates front:rear meaning the front track is doing the majority of the yawing work. This means that toe changes to the front axle will greatly affect the yaw of the vehicle. The first thing I noticed when changing from a front stiff to a rear stiff setup was that the front end has a much harder time yawing the vehicle on it's own - i.e. torque steer is near gone.

Cheers for that string good info...

Ive got installed:

scunk2 camber kit Front
scunk2 camber kit Rear
G4 36 point adjustable coilovers
Whiteline Xtra Heavy Duty Sway Rear 28mm
Whiteline Heavy Duty Sway Front 22mm
Generic front and rear Strut braces.
MPR Rear LCA's

New Front LCD Bushings

I was thinkin about purchasing a poly urethane bushing kit soon also.

One thing i did notice yesterday was i was running 21psi on my rear tyres and 40 on my fronts...i changed the rear to 40 also and that cleaned up the ride a little but im thinking its what you said. I setup the camber myself and it was fairly half assed when i did it, i had no measuring tools or nothing. Just all by eye sight and the front or the rear could be in a difference of 2 degree's or so and that would be effecting the scrub as you would say.

Might take it to a suspension joint and get them to calibrate it all.

Ally Angel
15-07-2009, 09:45 AM
I had my rear trailing arm bushes replaced with the poly urethane ones, did make a big difference to me.. but thats what im doing next going to a pedders and getting them to check it out when i get new tyres put on in about month..

Thanks guys i been trying to work this shit out for ages, its annoying and rather dangerous

hotdc2
15-07-2009, 10:08 AM
my friend has G4 coilovers on her silvia and they're the worst thing she has ever done to it.. With all the money you've spent on the rest of your car i'm suprised you shorted yourself in the sussy department hey...

FastFwd
15-07-2009, 10:12 AM
my friend has G4 coilovers on her silvia and they're the worst thing she has ever done to it.. With all the money you've spent on the rest of your car i'm suprised you shorted yourself in the sussy department hey...

I love em tbh.

I've had two sets of d2's in two s15's also and i loved them.

I like a really stiff ride, and thats what they give. I've not had one issue with them and ive been running them for 2 years. I was going to get other brands but you need to spend at least 3-4g to get the compression and stiffness i wanted. G4's give that.

They typical cheap drift/race setup suspension. Dont really recommend them for the daily driver. But it doesnt bother me.

Ally Angel
15-07-2009, 11:11 AM
Yeh ive defently noticed it stiffen up but that was the whole point of it... its your own personal choice really what u like.. ive only got that on that rear tho at the moment just cos they needed replacing but when the fronts need doing then ill do the same

JohnL
15-07-2009, 11:53 AM
When your tyres generate a forward or backwards force from acceleration or braking it attempts to rotate the upright around the steering axis. The further the centre of the contact patch from the intersection of the steering axis and the road (the scrub radius) the greater the magnitude of this force.

String is talking about 'scrub radius' here, i.e. the nominal lateral distance from the nominal centre of the contact patch, to the point at which the steering axis intersects the ground.

(note: positive SR = when the steering axis intersects the ground to the inside of the nominal contact patch centre, negative SR = when the SA intersects the ground to the outside of the nominal contact patch centre)

Notice that I deliberately used the word "nominal", which is because on the drawing board we assume that the centre of the contact patch is on the centreline of the tyre, but in reality it in effect usually isn't since the wheel is usually always cambered to some degree.

Camber affects ‘real’ (or ‘effective’) SR because when we have substantial negative camber it's reasonably obvious that the outside of the tread is often not even on the ground, so can't be part of the actual contact patch. Thus, if the nominal (positive) SR were X, then the 'effective' SR must be X- (or the effective SR might even be negative, i.e. instead of some degree of positive SR there could be some degree of negative SR).

Even if the full width of tread is actually touching on the ground, but more heavily loaded on the inner edge than then outer edge, this will still affect the effective SR in the same way as if tread were so unevenly loaded that it was only resting on it's inner edge, the only difference is in degree. Whenever part of the contact patch is more heavily loaded than another part, the ‘effective centre’ of the contact patch moves toward the more heavily laden part of the contact patch.

Now, 'effective SR' is influenced by camber angle and tyre pressure because both camber and pressure affect the location of the ‘effective centre’ of the contact patch.

For example, if you had X negative camber at Y tyre pressure, then the effective centre of the contact patch will be offset to the inside of the tyre centreline (increasing effective pos SR over the nominal pos SR). If we now increase the camber, then the outside of the tread will become more lightly loaded and the inside become more heavily loaded and the effective SR will increase further. If we significantly increase tyre pressure then the loading across the width of the contact patch will change, and the affect of any camber will increase, i.e. with existing X neg camber the inside of the tread will become more heavily loaded and the outside less heavily loaded (with pressure increase), resulting in a change in location of the effective centre of the contact patch toward the inner edge of the tread and thus an increase in effective SR.

So what?

If the static camber is unequal side to side (especially with high tyre pressure), then the effective SR will be unequal side to side, and this will tend to cause a steering pull when accelerating, and an opposite pull when braking.

This is because the SR is in effect a 'lever arm' through which forces generated within the contact patches are 'leveraged' into the steering axis on each side, and forces leveraged into the steering axis through a lever arm generate a torque force around the SA that is felt by the driver as a steering pull, but only when these are unequal side to side.


When you accelerate you create a force that tries to ‘pull’ the contact patch forward, and there are two ways in which it can go forward: by turning around the steering axis, or by moving forward in a straight line if it is not allowed to turn. When you brake you create an identical dynamic but in reverse.

Any difference side to side will result in the driver feeling a pull. Note that the effective SR changes every time the dynamic camber changes, i.e. any time a wheel rises or falls relative to the chassis (causing dynamic camber change), whenever the contact patch encounters a change in road camber or the effective centre of loading traverses across the face of the contact patch.

This is the case even when the nominal SR is zero, i.e. the effective SR rarely - if ever - actually is zero unless the car is travelling on a dead flat perfectly smooth road with zero wheel camber angle (obviously a situation that almost never actually occurs in the real world).

Just to make things very confusing, camber also causes a tendency to pull that is related to the manner in which a rolling ‘cone’ tends to roll in a curved line (a leaning / rolling coin being an easily visualised example). This has nothing to do with any pull caused by effective SR, and may even be a counteracting or an additional factor re any other pull, and one cause of pull may overwhelm another cause of an opposite pull some of the time, yet add to it at other times.


RWD vehicles experience the exact same force, except obviously only when braking.

This is all well and good when the tyre forces are equal (and the scrub radii are equal left and right) because one side pushes on the rack and the other pushes back and the forces balance and you get zero net force. At any time when the tyre forces are NOT equal, you get unbalanced forces, and as a result you get steering pulls (and they are real forces: you have to counter them entirely or else the steering will change directions). .


Agreed (of course), and this is all part of what the driver interprets as steering ‘feel’. The other part of the ‘feel’ equation is the forces generated by the ‘trail’, which in principle is similar to SR except that the distance of the SA ground intersection point from the nominal centre of the contact patch is longitudinal not lateral (note that trail too can have nominal and effective values, as does SR).


Further more, you likely have near stock ratio spring rates front:rear meaning the front track is doing the majority of the yawing work. This means that toe changes to the front axle will greatly affect the yaw of the vehicle. The first thing I noticed when changing from a front stiff to a rear stiff setup was that the front end has a much harder time yawing the vehicle on it's own - i.e. torque steer is near gone.

You’ve lost me here, I don’t follow what you’re trying to say (but, I suspect I might disagree if I understood you clearly…).

Ally Angel
15-07-2009, 12:57 PM
Awesome, so mine could be simply my tyres then i think... mines front wheel drive but had new tyres put on the front when i got it but not the back cos they were alright and the pulling wasnt that bad and wasnt wheel alignment... but since then its gotten worse and my back tyres are now pretty ****ed.. would that effect it even tho my car is front wheel drive and its the back tyres that are ****ed?

Either way im getting a full new set going up to 17'' so hopefully that sounds like it will fix it?

string
15-07-2009, 02:50 PM
You’ve lost me here, I don’t follow what you’re trying to say (but, I suspect I might disagree if I understood you clearly…).

The effect is similar to that of a car in a cross-wind (i.e. an applied lateral force at the centre of gravity). Our example car is traveling down a flat road with a wind blowing from right to left.

The more understeer a chassis is, the more it will yaw to the left in the cross wind. An oversteer chassis will yaw to the right in the wind, and a neutral steer chassis will not yaw at all.

If you take an understeer chassis and instead apply a lateral force further towards the rear of the CG, it will yaw less than if the force was applied at the CG. If you go far back enough you will reach a point where you get zero yaw.

If you instead apply the force ahead of the CG, the chassis will yaw even more to the left than the first example. Go far enough forward that you are now at the front track and imagine that instead of the cross-wind applying a force, the front tyres do due to geometry changes under power application. The greater the car is understeer, the greater the yaw (felt as torque steer) from the tyre force.

If you modify your understeering FWD's suspension such that the rear track's slip angles are greater per unit of lateral acceleration, and the front track's slip angles are less per unit of lateral acceleration*, the point at which a side applied force gives zero yaw (the neutral steer point) is moved forward towards the CG. To get the same yaw to the left as the understeer example, you need to apply the force much further forwards towards the front of the vehicle - the same lateral tyre force at the front track results in less lateral acceleration and less yaw. Forces at the front track have a harder time upsetting the vehicle in this configuration.

Summary: The more understeer your chassis, the more torque steer.

I hope I've made myself more clear. Feel free to pick up my mistakes. Automotive dynamics is not my direct field of study, simply a hobby.

* There are many ways to do this. It is not impossible, or even difficult to produce a neutral steer chassis with a forward CG - this configuration does not have to mean perpetural understeer.

JohnL
16-07-2009, 11:02 AM
Awesome, so mine could be simply my tyres then i think... mines front wheel drive but had new tyres put on the front when i got it but not the back cos they were alright and the pulling wasnt that bad and wasnt wheel alignment... but since then its gotten worse and my back tyres are now pretty ****ed.. would that effect it even tho my car is front wheel drive and its the back tyres that are ****ed?


You say your steering pulls left under accelerative forces, and pulls right under braking forces. This doesn't sound to me like the problem is at the rear end. It does very much sound like it is a front end problem. If it were a rear end problem then there would be no difference between coasting (no acceleration or braking) and accelerating. Braking could cause a rear end problem to cause a steering pull if the braking force caused some part of the rear suspension to dynamically misalign (which would be caused by a worn bush or bushes).

Note too that a pull such as you describe might be caused by worn suspension articulations in the front end.

If your front camber is significantly unequal then this could cause the effective scrub radius to be different enough that the tractive forces at the contact patches would be leveraged differently enough that you might feel a steering pull when accelerating and an opposite directioned pull when braking.

If I'm barking up the right tree, then in your case (with a left pull under accceleration and a right pull when braking) I would expect to find that the left side had more neg camber than the right, and as a result the left front would have greater effective scrub radius then the right side. Note that this would be negative scrub radius, not the more usual positive SR. Note too that even if the nominal SR is positive, the effective SR can easily be negative (especially when more neg camber is used), but also that the effective SR can fluctuate substantially and rapidly, and more so the wider the tyre's tread is (and the stiffer the tyre casing, the higher the tyre pressure, and the more uneven the road surface, which is why wide stiff sidewalled tyres at a higher pressure on a rough road cause a lot of very variable forces to be felt at the steering wheel).

Note also that the wider the tread and the stiffer the tyre casing etc, the more sensitive the car is likely to be to unequal camber angle.

Lets imagine a car with an extreme case of this same unequal front camber on each side. For ease of visualisation lets assume very high tyre pressures (that disallow any significant vertical tyre flexure with loading), and let's also assume that the right side has zero camber and SR (in theory creating zero steering pulls related to SR).

In this case the right side will be carrying it's load across the full width of the contact patch and on very smooth surfaces no tractive forces would be leveraged into the steering axis on that side (i.e. acceleration and braking pulls would be zero on that side).

If however the left front has substantial neg camber then it will be carrying most of it's load on the inner edge of the tread, and will have an effective SR equal to nearly half the tread width (extreme hypothetical case).

In this case an accelerative tractive force will cause the centre of the contact patch (this centre being a point defining the average centre of contact patch grip, as well as loading) to attempt to rotate around the steering axis, which it can only do by attempting to move forward in an arc centred on the steering axis.

This will be felt by the driver as a pull to the left under acceleration because it isn't being countered by an equal but opposite 'pull moment' from the right side (which remember has an actual and effective SR of zero). The affect is the same but opposite under brakes, i.e. no affect at the right side but a right pull moment from the left side as the contact patch tries to move backward in an arc centred on the steering axis.

Now, the neg camber on the left side will also create a seperate tendency to pull to the right because of the 'rolling cone' effect. This pull will be a constant, i.e. it will be there all the time regardless of tractive force direction (forward or backward or zero) with any other pull moments being overlayed upon it.

A car that pulls left when accelerating and right under brakes because of unequal camber (creating unequal efffective SR), is not unlikely to have at least a slight pull to the right (from the rolling cone camber effect) when not accelerating or braking. Note that even just travelling at a constant speed requires engine power that might be enough to cause some left pull (through unequal effectiveb SR) that might or might not be enough overcome a tendency to pull right due to the rolling cone effect...

Now, this is all theoretical, it should hold true in practice but the real world is a complex place. Keep in mind that I've been using extreme examples to illustrate the principles involved, examples where we have zero affects on one side and simple strong clear affects on the other. In the real world we will have constantly fluctuating forces acting on both sides, any predominant pulling affects as felt at the steering wheel being created by inequalities in these forces left vs right.

JohnL
16-07-2009, 12:01 PM
Awesome, so mine could be simply my tyres then i think... mines front wheel drive but had new tyres put on the front when i got it but not the back cos they were alright and the pulling wasnt that bad and wasnt wheel alignment

Swap front tyres side to side to see if this makes any difference. Don't worry if you cause directional tyres to rotate 'backwards' as this is only an experiment and you can change them back if it makes no difference (but if it does make a difference then the pull could be related to uneven front tyre wear).

Note that bias steer seems to get worse the more the tyres wear (bias steer being to do with how the steel belts are laid up in the tyre).


... but since then its gotten worse and my back tyres are now pretty ****ed.. would that effect it even tho my car is front wheel drive and its the back tyres that are ****ed?

A rear problem is I suspect more likely to cause the car to 'crab' as it travels in a straight line, more than it's likely to cause a pull (not meaning to implyn that it can't cause a pull). I would expect any pull caused by the rear end to be potentially not as strong as a front problem, and to be a farly constant thing, not particularly changeable with acceleration / braking.

Try swapping rear tyres side to side. Try swapping front to rear and rear to front...


Either way im getting a full new set going up to 17'' so hopefully that sounds like it will fix it?

Personally I think 17" is too big. Not so much that the wheel is too big, but the tyres that are likely to be fitted to them will probably be too low in profile (i.e. not enough sidewall). Too much sidewall is not a good thing, but this does not necessarily mean that as little as possible is...

Keep in mind that If my speculation related to uneven camber and effective SR is correct (if you even have uneven camber / ESR...), then a very low profile tyre will have limited sidewall flexure that may well make the problem worse than it is already is...?

For a road car (and most race cars), I personally think that tyre profiles less than 50 are not a very good idea...

FastFwd
17-07-2009, 08:20 AM
crap i really need to get mine looked at hey...going onto the freeway this morning applied some boost got upto speed and then let off the gass and the car felt like it wanted to turn a heavy right on me all of a sudden while it was wet/raining and im doing 100-105.

And on certain roads when they are extemely wet it feels like the front end is just sliding...as if your aqua planing.

JohnL
17-07-2009, 09:52 AM
crap i really need to get mine looked at hey...going onto the freeway this morning applied some boost got upto speed and then let off the gass and the car felt like it wanted to turn a heavy right on me all of a sudden while it was wet/raining and im doing 100-105.

Wide tyres? High psi? Stiff / low profile casing? Uneven tyre wear? Slight camber inequality? Uneven road sufaces? Predominant left inclined road camber? A soft bushing (etc)? All factors that might be causing problems for you.


And on certain roads when they are extemely wet it feels like the front end is just sliding...as if your aqua planing.

You might well be...

FastFwd
17-07-2009, 09:56 AM
Yes Wide tyres, Yess High PSI, Yes extremely stiff suspension, Not that much uneven tyre wear, yes slight camber, yes uneven road, No left incline road camber, yes maybe soft bushings.

But there has to be a way to get my setup to feel like its ok to put the foot down and it doesnt want to go off into different directions.

Will i be able to achieve this with my setup? or will i always have an issue due to stiff suspension, wide tyres, camber etc.

string
17-07-2009, 11:14 AM
What are your spring rates?

JohnL
17-07-2009, 04:12 PM
Yes Wide tyres, Yess High PSI, Yes extremely stiff suspension, ................... yes slight camber,

Slight neg camber is a good thing, but not too much for a road car, especially if you're using wider tyres. Mac Strut suspended cars tend to require quite a lot of neg camber, but Hondas with SLA suspension don't (IMO it's counter productive to use substantial static neg camber angles with Honda SLA suspensions, far better to use lots of caster angle, e.g. my Accord has -1° static camber and 6+° caster).

But, what you really need to know is whether or not the camber is equal side to side (or at least very close to it), to know this you need the numbers an alignment will give you, but before you align the steering and suspension angles you need to replace any suspect bushes or joints (otherwise there is no point).

I strongly suspect that a car with wide tyres with stiff casings (sidewalls in particular) at high pressure will tend to be more sensitive to unequal (side to side) alignment settings than narrower tyres with softer cases at lower pressures. Stiff spring and damper rates are not unlikely to add to this sensitivity.

Have you increased the caster angle? I also suspect that greater caster angle also tends to make the car more sensitive to unequal alignmnet settings.

(Note that an increase in caster angle is very likely to introduce significant to substantial bump steer that should be rectified because it causes 'roll oversteer', which makes the car unstable from turn-in to mid corner, at least it did with my CB7 until I corrected the bump steer.)


yes uneven road, No left incline road camber, yes maybe soft bushings.

When you pay attention to it, you'd be surprised how often the road is at least slightly inclined to the left. You need to replace any suspect suspenion components. You shouldn't really be complaining about steering pulls etc unless you are sure that your suspension is in good order re bushes etc.


But there has to be a way to get my setup to feel like its ok to put the foot down and it doesnt want to go off into different directions.

See above...


Will i be able to achieve this with my setup? or will i always have an issue due to stiff suspension, wide tyres, camber etc.

You should be able to, but you need to know that the basics are good before you start trying to fix a problem that might be caused by something rather simple. Make sure all your articulations are good and know your alignment numbers, then get back to us if the problem still exists...

string
17-07-2009, 04:21 PM
Caster comes at the cost of steering feedback. With 6 degrees can you even feel what your tyres are doing?

JohnL
18-07-2009, 11:36 AM
Caster comes at the cost of steering feedback. With 6 degrees can you even feel what your tyres are doing?

Yes, I find very much so compared to the 'feedback' I had at a much lesser caster angle.

Caster creates steering feel in it's own right, but it does tend to overwhelm another source of steering feel. This other source is the reduction in steering 'weight' that occurs as the front tyre nears it's limit of lateral adhesion, this loss of 'weight' being caused by a reduction in 'pneumatic trail' as the grip falls away.

"Pneumatic' trail is created by rolling tyre deformation, whereby the contact patch actually moves backward relative to the wheel (and the rest of the tyre) in elastic response to the rolling resistance inherant in the tyre. Note that this reduction in pneumatic trail is less significant with stiffer tyre casings (lower profile / stiffer sidewalls) or wider treads (because a wider contact patch will be a shorter contact patch), or at higher pressures (which effectively increases casing stiffness).

Pneumatic trail is very significant with cross-ply tyres because their tread isn't very stiff (and has high rolling resistance), but much less significant with radial tyres because their tread is so much stiffer (with much lower rolling resistance). This is why old cars originally designed to use cross ply tyres typically require a significant increase in 'mechanical trail' when fitted with radial tyres (achieved with a caster angle increase), otherwise the steering tends to be vague and wandery because total trail (i.e. pneumatic + mechanical) is insufficient for steering stability (due to the lesser rolling deformation of the radial tyre).

Anyway, this 'at the limit' steering feel is caused by an effective reduction in pneumatic trail as the tyre starts to lose grip, and it's 'trail' that is the operative word here. This kind of feel occurs at / near the limit of adhesion, but the steering has feel / feedback / communication well below this and this is where the feel created by the trail associated with caster largely occurs.

Note that the feel created by caster angle is actually (mostly) to do with the 'mechanical trail' that is created by caster angle. Trail is in effect a lever arm that feeds the lateral forces generated at the contact patch into the steering axis (as a 'torque' around the steering axis), and vice versa.

When the driver steers the car he/she is in effect pushing against the contact patches through the 'lever arm' of trail, and this causes the contact patch to move in an arc around the steering axis (which it wouldn't do if trail were zero), which is resisted through the trail and thus creates 'weight' in the steering that is felt as the tendency to 'self-centre'. (steering 'weight' is also created by caster angle causing the car mass to be lifted above ride height with any steering input, but this is a more or less seperate thing).

So now, when trail exists and more so with greater trail, because it's the contact patch that has the grip, steering inputs alone (i.e. lateral accelerations created by force and inertia are not yet heavily involved) cause a lateral force to act upon the chassis (i.e. causes the contact patch to exert a lateral force against the chassis through the trail), and the front of the chassis will then move inward in the steered dirction (this action actually sharpens up steering response with higher caster / trail). Then, in response to the onset of lateral acceleration (i.e. lateral 'G force') the inertia of the car mass then 'pushes' back against the contact patch through the trail lever arm, and the more lateral accelerartion there is the heavier the steering will become, until we approach and then exceed the limits of lateral adhesion (these effects are stronger with greater trail).

Now, when we reach / begin to exceed the limit's of adhesion the grip starts to diminish, and so too does the lateral acceleration. This means that the steering will start to lighten up (because the force being fed into the steering axis is reducing), providing some degree of 'on the limit' steering feel, i.e. the driver detects a lightening of the steering that is interpreted as increasing grip loss, in much the same manner as the driver interprets lightening of the steering due to reducing pneumatic trail as increasing grip loss.

Note that this effect operates with a fixed trail and a change in the force leveraged through that trail, whereas the pneumatic steering feel operates through a changing effective trail value as well as a change in contact patch force as leveraged through that changing trail.

So, we have (at least) two sources of steering feel here. At higher levels of trail the 'mechanical feel' is stronger and tends to dominate the pneumatic feel, making subtle changes in the steering weight caused by changes in pneumatic trail harder for the driver to detect.

In some instances the mechanical feel may be quite good so it may be no great loss to lose much of the pneumatic feel (i.e. 'lost' in the stronger background feel coming from high levels of mechanical trail). In other instances the mechanical feel may not be so good (i.e. might be too abrupt), so losing the pneumatic feel may cause the steering to become too un-communicative approaching the limit of adhesion.

Steering feel is a hugely complex interplay of forces / resistances, and a very great deal of what any change in the geometry might have will depend on the tyres that are being used....

string
18-07-2009, 05:58 PM
Now, when we reach / begin to exceed the limit's of adhesion the grip starts to diminish, and so too does the lateral acceleration. This means that the steering will start to lighten up (because the force being fed into the steering axis is reducing), providing some degree of 'on the limit' steering feel, i.e. the driver detects a lightening of the steering that is interpreted as increasing grip loss, in much the same manner as the driver interprets lightening of the steering due to reducing pneumatic trail as increasing grip loss.


The tyre aligning torque from pneumatic trail peaks well before the maximum lateral grip does - with pneumatic trail the driver can know about the grip limit well before he or she exceeds it.

JohnL
19-07-2009, 12:10 PM
The tyre aligning torque from pneumatic trail peaks well before the maximum lateral grip does - with pneumatic trail the driver can know about the grip limit well before he or she exceeds it.

Yes, so assuming that you do have tyres that create a significant degree of pneumatic trail as they roll, then they should give plenty of user freindly warning of impending grip loss. Such a tyre would tend to have a softer casing, be run at lower psi, and have a wider but longer contact patch.

This isn't to imply that a tyre with a stiffer casing, higher pressure and a wider but shorter contact patch won't exhibit pneumaitc trail characteristics, but they would be significantly less. Note that it's typical for high performance and racing tyres to provide substantially less 'warning' to the driver than 'low' performance tyres.

Keep in mind that with increased caster angle (i.e. increased mechanical trail), any pneumatic trail affects don't actually disappear (or even lessen in absolute terms), they just become less pronounced to the driver against the larger unchanging constant of the mechanical trail. The driver may need to be more sensitive / attuned to feel the less pronounced loss of steering 'weight' from the lessening pneumatic trail approaching the limit, but it's still there and still useful to the driver.

A great many racing cars use substantially high caster angle because of the desirable steered camber changes it provides, and the improved steering response. I've heard figures quoted (bandied about?) of up to 20° caster for some V8 Supercars. Though I'm not certain as the veracity of this number, these cars do use a spool differential and so may need huge caster angle to assist in jacking the inside rear tyre, like a kart does (if so then this is outside the scope of this dicussion). The cars are however still driveable on the limit, so must retain adequate steering feel despite the huge caster angle (a lot less than 20° is still huge...).

Note that while my car now has 6° of caster angle, despite this being nearly 3X the stock caster it isn't really a great deal relative to some cars (10° isn't unknown). Golf GTIs and Porsche 911s have about 7° from memory. I find my car's increased caster angle has substantially improved steering feel / communication at sane cornering speeds (i.e. not at the limit of adhesion), as well as on centre feel and steering response. On the limit the feel is fine, though it's hard to say if it's any better or worse than it was at the stock caster angle (I don't spend much time at 10/10ths...).

Ally Angel
23-07-2009, 02:36 PM
Got my car booked in at Peddars on Monday, so see what they find and ill let yous know

FastFwd
27-07-2009, 01:16 PM
Got my car booked in at Peddars on Monday, so see what they find and ill let yous know

Booking mine into WA Suspension soon also. Brand new tyres wore out in 3-4 months. I mean i get wheel spin but not that much.

Ally Angel
28-07-2009, 11:47 AM
OK results.. Peddars found $2000 worth of stuff to fix on it :(

I can give u a full list later on when i get the time if u like. Its shit from Suspension to steering wheel being off centre to the left...theres heaps of shit. they reckon all can be the cause of it. cant remember from the top of my head

FastFwd
28-07-2009, 11:50 AM
Did you get them to do one of there 1 million point checks? or did you tell them your issue and get them to try and find the source of the problem?

Maybe i should go to pedders also? I kinda just found them a little Generic, for the run of the mill daily cars etc, Not for full custom setups.

Ally Angel
28-07-2009, 01:51 PM
hmm not sure what a 1 million point check is.. but they gave me a full list, suspension check as well, gave me their print out of it. Only cost $14 for them to do it and they found a fair bit.. Ill try and type out the list for ya when i get home.

FastFwd
28-07-2009, 05:03 PM
Yeh thats the check i meant about...."1 million point check" is just an exaggeration dude. I meant that they do a Huge check on the complete suspension setup.

I would like to know what they check so that would be great if you cos scan it or type it out if you can be bothered.

Ally Angel
29-07-2009, 06:37 PM
Ok the list

Front

Shocks - Failed shock test poor control
Radias Rod and bushes on front - Excess movement under brakes, NA LH oil soaked
Steering Damper - Steering gear off centre -Rectify at time of wheel alignment
CV Joints - LH Outer corner boot split
Engine mounts - LH torn, front and RH mount excess moevment
Bump Stops - not visable inspect when apart
Upper control arm & inner bushes - May require alignment kits, re-check after repairs

Rear

Fail Shock test very poor control
Bumps Stops - not visable - inspect when apart

and my back tyres need replacing which i already knew that

hotdc2
30-07-2009, 01:02 AM
i'm no expert on the matter but that doesn;t sound like $2000 worth of gear. But then again a place like that would only use brand new and genuine OEM parts

sorry but just noticed your name and wondered if you are female? get your boyfriend or dad or someone who knows cars to take care of it for you if you are. not trying to come across sexist or anything but if the workshop thinks you have no idea what they're talking about and will give them money saying "just fix it" then they will milk it for all it's worth. Even if you are male..

Ally Angel
30-07-2009, 09:46 AM
Yes i am female and im definetly not just giving them the money to fix it cos one i dont have the money and two, i always look at different prices first and get parts from somewhere else sometimes if its cheaper... im concidering selling the car, not sure what to do with it... both my dad and bf are helping me out with that.. but i am slowly learning about things

FastFwd
30-07-2009, 11:28 AM
I'm thinking about getting the same check done...how long did it take?

sounds pretty extensive. I wonder how they test it

Ally Angel
30-07-2009, 04:58 PM
It was only $14 to do i dropped my car off at 10 and they rang me at like 12 so roughly 2 hours, he said they were busy thats why i left it there

FastFwd
01-08-2009, 12:07 PM
So i couldnt get my car onto the tester at pedders, car was to low. its actually not that low atm you just need to be a truck to get onto it.

The guy did a manual check of my car though and his conclusion was that even tho some of my bushing maybe looks ok on the outside they could have crapped themselves where you cant see it and he said because it being the age of the car and had done 270,000kms on the chassis the bushing that havent been replace with most defiantly need replacing. He suggested a urethane complete kit, i almost bought one a while back but bailed on it, should of got it.

Soo im gonna buy the energy polyurethane kit and install what i can myself and the parts that i cant im gonna take it to a suspension joint to install...

He also said there could be some play in my tearing rack. I had the joints replace not long ago but he said that actual rack might be stuffed.

FastFwd
01-08-2009, 05:23 PM
Ok so i got this today...

https://pontiworld.com.au/energysusp/product_info.php?cPath=56&products_id=226&osCsid=50eefb7e1c5c7de0b1e4dcbdb1f53da3

Doesnt look like it has all the rear bushings tho?

Who got this kit? Does it come with everything i need?

vinnY
01-08-2009, 10:56 PM
afaik those master kits are usually missing the rear lca bushes and the trailing arm bushes

Ally Angel
03-08-2009, 09:18 AM
i only got the kit for rear bushes so i dont know.. but yeh i got the urethrane ones however u spell it

dinorider
05-08-2009, 06:13 PM
It was only $14 to do i dropped my car off at 10 and they rang me at like 12 so roughly 2 hours, he said they were busy thats why i left it there

I'd suggest you take the car to a more specialised suspension shop. Pedders is too generic and from my past experience don't always give the right, nor good, advice. Unless of course you've come across a really good one.

Don't be intimidated by the specialist performance shops. If you know what you want, and how much you can afford, they'll usually give much better advice than a generic Pedders place that deals with Falcons and Camrys and commodores all day.

nigs
05-08-2009, 07:10 PM
lol Pedders, nicely played.

Ally Angel
06-08-2009, 10:03 AM
I'd suggest you take the car to a more specialised suspension shop. Pedders is too generic and from my past experience don't always give the right, nor good, advice. Unless of course you've come across a really good one.

Don't be intimidated by the specialist performance shops. If you know what you want, and how much you can afford, they'll usually give much better advice than a generic Pedders place that deals with Falcons and Camrys and commodores all day.

Yeh im photocopying the statement they gave me and giving it to someone else my bf knows and see what they say.. no idea where they work tho

FastFwd
02-10-2009, 02:28 PM
Ok sorry to bring up my old thread but i still need a little help with this...

I've replaced almost every bushing on my car now, these are the ones ive replaced...

ES - Front Coil Spring Isolators
ES - Rear Coil Spring Isolators
ES - Tie Rod Dust Boots
ES - Front Sway Bar End Links
MPR - Lower control arms
Whiteline - Rear sway bar end links
Skunk2 - Front upper ball joint
ES - Front Shock Mount
ES - Shifter Stabilizer
Skunk2 - Rear Upper Control Arm
Skunk2 - front uppder control arm
ES - Steering Rack Bushings - Power Steering
ES - Front Control Arm Set
ES - Rear Control Arm Set
ES - Ball Joint Dust Boots
ES - Rear Trailing Arm Bushings
ES - Rear Compensator Arm Bushings
ES - Front Control Arm Bushings
ES - Front Sway Bar Bushings
ES - Steering Rack Bushings
ES - Ball Joint Dust Boots

I'm still getting a little issue with my steering, now its not pulling to the left but it feel a little unstable in my hands. when pushing it it feels like it either ready to go left or right and i have to hold the wheel tight.

is it maybe im being paranoid and thats just the way a front wheel drive car drives with 250hp+ atw's

My civic has always had aroudn 200-250hp atw's for over 3 years but just recently since i put new rims, more camber etc its been a little different. Feels a little the car just wants to go wild and let loose out of my hands

vinnY
02-10-2009, 02:37 PM
probably just the new alignment settings
speaking of which what are you alignment settings?

FastFwd
02-10-2009, 02:45 PM
lol dunno! thats one thing i need badly...an alignment because ive done so much work on the susp, it would be totally out.

should i get that done first and then see?

vinnY
02-10-2009, 02:48 PM
well that's probably why it's pulling like a mofo and feels insteady

aaronng
02-10-2009, 03:40 PM
lol dunno! thats one thing i need badly...an alignment because ive done so much work on the susp, it would be totally out.

should i get that done first and then see?

You must do a front and rear wheel alignment again after replacing the bushes. Remember to get a printout of the settings as well. If you know what settings you want, then let the tyre place know beforehand.

FastFwd
02-10-2009, 03:49 PM
You must do a front and rear wheel alignment again after replacing the bushes. Remember to get a printout of the settings as well. If you know what settings you want, then let the tyre place know beforehand.

Wheel alignments is something i have no idea about. how do i know what settings i want and how is it measured?

aaronng
02-10-2009, 04:14 PM
Wheel alignments is something i have no idea about. how do i know what settings i want and how is it measured?

Then you should stick to the stock settings that the tyre place will use based on a database of car models. That is the safest. Otherwise, you can read this first to get an idea: http://www.familycar.com/Alignment.htm. The advanced section in the bottom half of that page has good info.

In the front, there is camber, toe and caster.
In the rear, there is camber and toe.

Camber and caster is measured in degrees and toe in millimeters. The tyre shop should use a laser wheel alignment system which tells them the amount of each setting as they adjust the suspension components. On most cars camber and caster are not adjustable without the use of aftermarket control arms or A-arms.

FastFwd
02-10-2009, 04:17 PM
Then you should stick to the stock settings that the tyre place will use based on a database of car models. That is the safest. Otherwise, you can read this first to get an idea: http://www.familycar.com/Alignment.htm

In the front, there is camber, toe and caster.
In the rear, there is camber and toe.

Camber and caster is measured in degrees and toe in millimeters. The tyre shop should use a laser wheel alignment system which tells them the amount of each setting as they adjust the suspension components. On most cars camber and caster are not adjustable without the use of aftermarket control arms or A-arms.

I've got the skunk2 camber kit for the front and rear on my eg. How much does it usually cost for a full alignment on all four?

If i get them to use stock setting then wont the put my Camber setup back to 0? i want to keep my camber setup as it is. just get it dialed in on all 4

Ally Angel
02-10-2009, 04:39 PM
Ive noticed that when i got my new back tyres on mine, it fixed it a little its not as bad as it was but yeh still pulls to the left, i dont have the money to sort it out right now.

Man you have done so much to try and fix ur problem, lucky u got money

aaronng
02-10-2009, 04:46 PM
I've got the skunk2 camber kit for the front and rear on my eg. How much does it usually cost for a full alignment on all four?

If i get them to use stock setting then wont the put my Camber setup back to 0? i want to keep my camber setup as it is. just get it dialed in on all 4

Let the tyre place know that you have adjustable front and rear camber kits. They can adjust the rear with no problems, but the front can be a challenge if there is not enough space to get to the bolts holding down the A-arm ball joint. Otherwise, if you are happy with the current camber settings, tell them that you want to keep the current camber, but just want to make sure that they are even for left and right sides.

Tell them what setting you want beforehand and they won't set your camber back to 0. :)

FastFwd
02-10-2009, 04:58 PM
Cheers man!!

FastFwd
02-10-2009, 05:02 PM
Ive noticed that when i got my new back tyres on mine, it fixed it a little its not as bad as it was but yeh still pulls to the left, i dont have the money to sort it out right now.

Man you have done so much to try and fix ur problem, lucky u got money

Well not really. I needed to do all of this anyways but i wanted to rule out all options so i purchased every bushing on the car and replaced them to my sure i was 100% it wasnt that. In doing it i found my two rear Trailing arm bushings were a little soft and worn and my front right lower LCA was stuffed completely plus the two front LCA bushings where it bolt onto the coilovers at the bottom were also a little worn out. So the pulling to the left is now sorted which had to be the LCA's, trailing arms etc. Now i just need to get a nice wheel alightment and i should be set for a perfect Track ride.