Wheel Alignment the big con!

[KenONeill]

I'd be interested, but it'll be a couple of weeks before I'll even see the paper, much less read and understand it.

One of the few times I've ever seen anything similar it was caused by a slightly out of round tyre car carcase leading to the tyre wearing down more quickly at one TWI than the other 5, and eventually to a rhythmic droning caused by the effective tread depth getting shallower every few feet along the road.

[wheels-inmotion]

KenONeill[/left]']I'd be interested, but it'll be a couple of weeks before I'll even see the paper, much less read and understand it.

One of the few times I've ever seen anything similar it was caused by a slightly out of round tyre car carcase leading to the tyre wearing down more quickly at one TWI than the other 5, and eventually to a rhythmic droning caused by the effective tread depth getting shallower every few feet along the road.

Here you go>

........................................

I will summarize the two papers, if you overlap your car and problem we can

mediate between the two most likely possibility's.

1: P1:Compression: Tread pattern:

The tyre tread in essence is without structure and subject to compression

between the road and the constructive casing, the "rolling" influence

concludes that the tyre tread will have an "compression" on and "release"

off, so in effect "pinch" the rubber, the ratio is higher on the back edge

of the tread bar since this will be the initial point that receives the

vehicles weight and subject to a higher wear ratio.

1.2: All tyres are subjected to the same force but show different levels of

resistance, so an habitual trait between tyre tread pattern can be assumed,

study shows.

1: Directional tyres low resistance

2: asymmetrical tyres moderate resistance

3: symmetrical tyres high resistance

1.3: explanation: Taken that the pattern of wear is due to "compression" and

"release" then the tyre be it front or rear is also subject to the point of

load "camber" this will conclude that the "heel and toe" pattern will not

cover the whole tyre width.

2:P2: Suspension:Drive:

The relationship between the vehicles parallelograms is through the

suspension, on cornering the weight transfer will unload the inner

transverse wheels and is subject to "Damper" over coil control, if this

relationship is unbalanced then the coil spring will unload and generate a

"driver" area pattern of wear, this "pulse" will favour certain areas of the

tyre tread since no part of any tyre is symmetrical.

2.2: Study has shown that the "damper" theory is consistent with the

countries road lay out, passenger side wear/ drivers side wear, suggesting

that the lack of damper control and "heel and toe" is global

2.3: Type of drive: resistance to "heel and toe" has an evident scale over

drive.

1: Front wheel drive: under braking has a low resistance on the rear dampers

2: Rear wheel drive ( UK ) has a low resistance on the front inner tyre on a

turn

3: 4WD: assuming independent suspension has high resistance due to the

uniform thrust.

................................................

There is some technical stuff as well but it's a nose bleed of a read....

[afcb ian]

I have a 58 plate Octavia TDi vRS hatch which has been lowered by Skoda.

The car is less than 6 months old and has covered approx 12k miles.

There has been a slight hum from the tyres since we bought it a few weeks ago and on a trip to Scotland at the weekend I noticed the hum became louder and there was slight vibration through the seats. In addition the steering is a bit twitchy at high motorway speeds.

When I got back yesterday I checked the rear tyres and they are noticably worn on the inside edges.

As you run your hand round the outer edges of each rear tyre the tread blocks are evenly worn and the tyre feels smooth.

As you run your hand round the inside edges of each rear tyre the tread blocks are unevenly worn. Every other tread block is worn excessively giving a lipped/stepped effect.

The tyres are Dunlop Sport Maxx directional.

Is this simply a case of the rear camber needing adjustment ? The only trouble I can see is that because it's lowered the standard settings no longer apply.

[wheels-inmotion]

You are absolutely correct... The lowering has generated more compression on the tyres inner edge, plus you probably have some toe issues as well.

Normally OEM lowering coils allow the Geometric change to fall within the OEM Geometric checking range? if this were the case then there shouldn't be any wear? it might be wise to contact your installer on this topic.

If the chassis is adjustable then this should have been dealt with after the coils were installed.... once again the installer needs to address this.

[afcb ian]

You are absolutely correct... The lowering has generated more compression on the tyres inner edge, plus you probably have some toe issues as well.

Normally OEM lowering coils allow the Geometric change to fall within the OEM Geometric checking range? if this were the case then there shouldn't be any wear? it might be wise to contact your installer on this topic.

If the chassis is adjustable then this should have been dealt with after the coils were installed.... once again the installer needs to address this.

Many thanks

[KenONeill]

You are absolutely correct... The lowering has generated more compression on the tyres inner edge, plus you probably have some toe issues as well.

Normally OEM lowering coils allow the Geometric change to fall within the OEM Geometric checking range? if this were the case then there shouldn't be any wear? it might be wise to contact your installer on this topic.

If the chassis is adjustable then this should have been dealt with after the coils were installed.... once again the installer needs to address this.

I believe that's correct, but the mere fact that there is a range implies that a specific car could be right on the (mathematically) lower bound of that range, so lowering springs could put that car running too much negative.

I'd agree that that the installer should fix this, since it seems to imply that they failed to check the geometry after installation.

[wheels-inmotion]

An industry wide confusion is the ranges.... we have

1: Checking range

2: Tolerance range

3: Disparity range

4: Dynamic range

OEM lowering coils should fall within the checking range but not neccacarily the dynamic range... Oh dear so how do we math this?

It's very easy to simulate dynamics static by adding compression (pull down) then lifting (droop) the suspension, allowing the operator to visualise the dynamic tendency's of the suspensions articulation, then adjust accordingly.

[KenONeill]

Please, don't introduce the subject of dynamic geometry changes! There have been whole books written on that subject!

[wheels-inmotion]

Please, don't introduce the subject of dynamic geometry changes! There have been whole books written on that subject!

I know, oh boy do i know......

Obviously these topics are dependant on the type of car and club but chassis dynamics, suspension dynamics and aerodynamics's apply to all cars with varying attentiveness.

I think you will agree most literature is relevant to the 70's, 80's and falls into insignificance by comparison to the modern car. I feel an "overview" in chassis dynamics alone would be impossible today.

[bazwaterboy]

I`m confused now reading this thread.

My Fabia has just hads its annual service and I had advisorys on my wheel alignment as my tyres are wearing on the outside quite badly.

I need rear tyres urgently but will a basic £26 electronic alignment do the job and solve the wear?

I have only just lowered the car onto Eibach pro springs and to be honest getting it aligned didnt cross my mind.

[wheels-inmotion]

I`m confused now reading this thread.

My Fabia has just hads its annual service and I had advisorys on my wheel alignment as my tyres are wearing on the outside quite badly.

I need rear tyres urgently but will a basic £26 electronic alignment do the job and solve the wear?

I have only just lowered the car onto Eibach pro springs and to be honest getting it aligned didnt cross my mind.

If the wear is on the outside then reluctantly i say yes to basic laser alignment.

[KenONeill]

I'm not entirely certain; Is the wear saw-toothing, with the high edge on the trailing edge of the block in normal driving? If so, do you habitually push hard enough through roundabouts and the like to encounter scrubby front end understeer?

[andy2407]

I've just read this whole thread - and its been very informative, even if I didn't understand large parts of it.

Thanks in particular to WIM and Ken - some interesting debate.

Anyway a question - I've just had Koni FSDs and Eibach lowering springs fitted to my Fabia vRS. Should I go for basic laser alignment and just monitor tyre wear to look for any problem areas that might warrant a full geometry check, or should I really go for a full geo straight away?

[KenONeill]

With a ride height change (either way), I'd always go for a full geometry, because you could have moved just about everything.

[bazwaterboy]

Cheers Ken you got me

I do now and again "drive" my car around roundabouts for a thrill. Not very often as I`ve only had this car whilst my missus has been pregnant and now my little`n rides in the back with her.

But booked in for 2 new tyers and 4 wheel align for £120 all in. Had to go for cheap tyres unfortunatly due to the pitter patter of a little drain on my resources

[KenONeill]

Cheers Ken you got me

I do now and again "drive" my car around roundabouts for a thrill.

Been there, done that etc. I've proved that FWD cars do that wear pattern if you get enthusiastic enough, even with correctly set toe angles (joys of having an enthusiastic mate who worked in a small garage that the owner of would lend us after hours).

[cjb]

Been there, done that etc. I've proved that FWD cars do that wear pattern if you get enthusiastic enough, even with correctly set toe angles (joys of having an enthusiastic mate who worked in a small garage that the owner of would lend us after hours).

Yep, I've had that too.

[wheels-inmotion]

I've just read this whole thread - and its been very informative, even if I didn't understand large parts of it.

Thanks in particular to WIM and Ken - some interesting debate.

Anyway a question - I've just had Koni FSDs and Eibach lowering springs fitted to my Fabia vRS. Should I go for basic laser alignment and just monitor tyre wear to look for any problem areas that might warrant a full geometry check, or should I really go for a full geo straight away?

I would go for the full image, that way if there's any camber issues you have the option to deal with that before the tyres wear out.

[boris74669]

Biggest con I've come across when having my car set up that the mechanic sets the front suspension alignment to "toe" in rather than "toe" out.

Looks right on the print out, drives ok too, if a bit "light " and vague on the steering but it wears the inside of your tyres out pretty quickly which is all money for them when you go more often for new tyres.

These cars are front wheel drive , the front wheels drag the car forward and in so doing trying to pivot in an arc against the steering arm and wishbone bushes.

So, to counter this they should have a slight amount of toe out so that when they do swing in against the suspension bushes they end up pointing in a straight line and run parallel to each other.

Result is taught steering bushes, more responsive steering, more feedback, less drift and because the tyres are pointing in the same direction as the car, less wear and more fuel economy.

[Bodge]

This thread is scary! But hoping for some advice...

My suspension history: Had a front nearside spring snap a few weeks back, so Skoda replaced the one spring with a new one to get me back on the road, while I sourced a set of coilovers to fit myself. After they replaced the spring, the car wandered slightly to the left, and the steering wheel was off centre, a few degrees to the left. I assumed this was due to the spring imbalance, and would be cured when I fitted the coilovers over the weekend.

Alas, the car still wanders slightly to the nearside, and the wheel is slightly off-centre. The thing that confuses me is that nothing has been touched steering-wise! The subframe, rack, rod ends, wishbones, balljoints are all in the same place and are all in good condition. I don't get it. The rear nearside brake caliper does drag more than the offside (think I need a new caliper there as it's just not returning properly), but it always has, and never caused this before.

Tyre wear seems perfectly even. One thing I've noticed is that I seem to have more Ackermann (I might be wrong, forgive my basic knowledge!). With the car parked, if I set the offside wheel dead straight, the nearside wheel is turning out slightly, and the steering wheel is off-centre to the left. Do I have too much toe out? How has this happened?! I've only dropped the suspension by 5mm from original.

The car turns in very well, and has good stability in a straight line. It's just not perfect!

I'm based in Huddersfield, so if anyone knows of a good geometry place please let me know.

Thanks in advance

[wheels-inmotion]

This thread is scary! But hoping for some advice...

My suspension history: Had a front nearside spring snap a few weeks back, so Skoda replaced the one spring with a new one to get me back on the road, while I sourced a set of coilovers to fit myself. After they replaced the spring, the car wandered slightly to the left, and the steering wheel was off centre, a few degrees to the left. I assumed this was due to the spring imbalance, and would be cured when I fitted the coilovers over the weekend.

Alas, the car still wanders slightly to the nearside, and the wheel is slightly off-centre. The thing that confuses me is that nothing has been touched steering-wise! The subframe, rack, rod ends, wishbones, balljoints are all in the same place and are all in good condition. I don't get it. The rear nearside brake caliper does drag more than the offside (think I need a new caliper there as it's just not returning properly), but it always has, and never caused this before.

Tyre wear seems perfectly even. One thing I've noticed is that I seem to have more Ackermann (I might be wrong, forgive my basic knowledge!). With the car parked, if I set the offside wheel dead straight, the nearside wheel is turning out slightly, and the steering wheel is off-centre to the left. Do I have too much toe out? How has this happened?! I've only dropped the suspension by 5mm from original.

The car turns in very well, and has good stability in a straight line. It's just not perfect!

I'm based in Huddersfield, so if anyone knows of a good geometry place please let me know.

Thanks in advance

Odd one.... Unless the new coil had the wrong rate i:e to low compared to the OSF then it shouldn't pull left, if anything a "new-V-old" would pull right.

Can we clarify things

* When driving straight the steering position is left hand down

* If you relax the steering does the car drift left?

* If it's a pull do you have to resist the pull

* Did the dealer align the car after the coil install.... this is common practice.

[Bodge]

Odd one.... Unless the new coil had the wrong rate i:e to low compared to the OSF then it shouldn't pull left, if anything a "new-V-old" would pull right.

Can we clarify things

* When driving straight the steering position is left hand down

* If you relax the steering does the car drift left?

* If it's a pull do you have to resist the pull

* Did the dealer align the car after the coil install.... this is common practice.

Thanks for replying. Yeah this is a confusing one for me! My answers:

*To hold the car in a straight line, I need to have the wheel turned right hand down (clockwise from central) by a few degrees.

*If I release the wheel, the car drifts to the left gradually, and continues to drift left on a constant turn.

*I wouldn't say I have to really resist it, I can just dangle a little finger on the steering wheel to hold the car straight. I don't have to fight any high forces. But if I let go of the wheel, the car just goes into a nice consistant left turn!

*I have no idea if they aligned it after changing the one coil. No one mentioned it to me, so I assumed they wouldn't bother. But I'm guessing they must have, since that's the start point of the issue.

When I park the car, with the steering wheel dead straight, the front offside wheel looks like it's pointing straight ahead, while the nearside wheel looks to be pointing out slightly. Is that even possible, or am I seeing things? Or could this be a camber imbalance?

As I see it they could have moved 2 things. Balljoint to wishbone bracket (slight camber adjustment), or tie rod end.

To get the ball rolling I'm taking the car to the best tyre place in town over lunch (It's run by one guy, and he's really switched on and honest). He's going to give it a once over and see If I've missed something. He only has 4-wheel laser alignment equipment, but I'm more after his opinion on it.

Thanks again for your help on this.

[ultra_joel88]

Problems:

- When letting go of the steering wheel, car pulls left strongly, and steering wheel sits left-of-centre

- I can feel it pulling when driving normally - sometimes it will "crab" to the left fairly violently

- N/S Rear tyre "feathering" with patches of increased wear on N/S edge

- N/S Front tyre wearing faster on the outside edge (however only by around 1mm)

Recent work:

- New solid console bushes fitted in Feb - consoles were removed from car

- Coilover suspension fitted in Feb

- 4 wheel laser alignment carried out by AA Tyres in Cardiff - Toe was adjusted to OE Spec.

None of the above problems existed BEFORE this work was done

Any ideas?

Print off below:

Edited 23 July, 2009 by ultra_joel88

[Bodge]

Right it appears to be sorted.... well it goes straight now, and the wheel is straight when going straight, so I'm happy so far!

I stood with the guy when he did it, and he laughed when he saw how much toe out I had! 19mm apparently, whatever that relates too. He said he couldn't understand how it got so far off, but he's set it parallel now.

I've never bothered to have alignment done on a car before, so was interesting to see!

I drove up on two freely rotating platforms, then he locked the steering wheel straight in the car. Then attached 2 big laser things to either front wheel. With laser beams pointing at eachother, and beams pointing back. Then he connected things to the rear wheels with measurement boards on, to pick up the rear facing lasers. I assume the two measurements allow you to align the front wheels in relation to the rear. After adjusting both tie rod ends, both sides matched up on the rear measurement board things, and the front wheels were parallel to eachother.

He said he doesn't have the equipment to measure castor, camber etc., so if this doesn't work there's not much else he can do, and he wasn't sure of a place nearby with that capability. Oh well..... I'll see how I get on. I would like to get a full geometry printout at some point though, just out of interest.

For £15.99 I can't complain though.

Edited 23 July, 2009 by Bodge
Spelling!

[wheels-inmotion]

Right it appears to be sorted.... well it goes straight now, and the wheel is straight when going straight, so I'm happy so far!

I stood with the guy when he did it, and he laughed when he saw how much toe out I had! 19mm apparently, whatever that relates too. He said he couldn't understand how it got so far off, but he's set it parallel now.

I've never bothered to have alignment done on a car before, so was interesting to see!

I drove up on two freely rotating platforms, then he locked the steering wheel straight in the car. Then attached 2 big laser things to either front wheel. With laser beams pointing at eachother, and beams pointing back. Then he connected things to the rear wheels with measurement boards on, to pick up the rear facing lasers. I assume the two measurements allow you to align the front wheels in relation to the rear. After adjusting both tie rod ends, both sides matched up on the rear measurement board things, and the front wheels were parallel to eachother.

He said he doesn't have the equipment to measure castor, camber etc., so if this doesn't work there's not much else he can do, and he wasn't sure of a place nearby with that capability. Oh well..... I'll see how I get on. I would like to get a full geometry printout at some point though, just out of interest.

For £15.99 I can't complain though.

At 19mm it's hardly worth the expense of further measurements since this was clearly the problem..... Makes you wonder though, how the hell can they get it 19mm wrong?