Dangerous tyre wear on inside shoulder

[skomaz]

If you don't understand the basics look at this for a basic guide. 

 

https://www.motor.com/magazine-summary/mastering-the-basics-wheel-alignment/

 

The issues that those above are pointing out are not the camber values but the rear individual toe values that are way out., especially the left, meaning the thrust angle is wrong and you car is trying to steer from the back. 

 

In general toe values should be positive such that the wheels point inwards slightly. As, once driving and play in the suspension is taken up then point forwards. 

 

Yours are pointing outwards and the left quite significantly this means the tyres are being dragged sideways slightly as they roll wearing the inner edges. 

 

Now given one wheels is worse than the other you'd expect one wheel to wear more than the other but it doesn't as, being on the rear, the back of the car will, instead, naturally crab along sideways slightly to even things out and both tyres will wear thier inner edges. 

 

What is causing this appears, as Pete and Jr have said is likely to be a bent axle in the horizontal plane.  Jr is right in that it MAY be possible to correct some of the issue and even the thrust angle out by adjusting the axle on its mountings if there is enough play in them but that won't fix the underlying problem.  And neither will changing suspension components like springs and dampers. 

 

As to how it has occurred we'll probably never know but an accident, clipping a kerb badly, or even just a big pothole could have caused it, as could, say, garage damage such as when on a lift.  Either way the damage may not be visible but the resulting toe out issue is. 

 

Does that help explain?

[AndyM20]

3 minutes ago, skomaz said:

If you don't understand the basics look at this for a basic guide. 

 

https://www.motor.com/magazine-summary/mastering-the-basics-wheel-alignment/

 

The issues that those above are pointing out are not the camber values but the rear individual toe values that are way out., especially the left, meaning the thrust angle is wrong and you car is trying to steer from the back. 

 

In general toe values should be positive such that the wheels point inwards slightly. As, once driving and play in the suspension is taken up then point forwards. 

 

Yours are pointing outwards and the left quite significantly this means the tyres are being dragged sideways slightly as they roll wearing the inner edges. 

 

Now given one wheels is worse than the other you'd expect one wheel to wear more than the other but it doesn't as, being on the rear, the back of the car will, instead, naturally crab along sideways slightly to even things out and both tyres will wear thier inner edges. 

 

What is causing this appears, as Pete and Jr have said is likely to be a bent axle in the horizontal plane.  Jr is right in that it MAY be possible to correct some of the issue and even the thrust angle out by adjusting the axle on its mountings if there is enough play in them but that won't fix the underlying problem.  And neither will changing suspension components like springs and dampers. 

 

As to how it has occurred we'll probably never know but an accident, clipping a kerb badly, or even just a big pothole could have caused it, as could, say, garage damage such as when on a lift.  Either way the damage may not be visible but the resulting toe out issue is. 

 

Does that help explain?

Thank you and yes it does explain. Will a new axle solve the issue? Excellent explanation! Thanks for taking the time to write! 

[J.R.]

36 minutes ago, skomaz said:

In general toe values should be positive such that the wheels point inwards slightly. As, once driving and play in the suspension is taken up then point forwards. 

 

But isn't that negative toe? Toe in equals a negative value?

 

Or am I getting my knickers in a twist, normally I would be very positive in my knowledge but I am very under the weather with what could turn out to be my 2nd dose of Covid.

 

Driven axles often have a small amount of toe out, usually zero to very little, the torque reaction from putting power through the driven wheels will counter the natural toe out forces.

 

Rear driven axles have toe values approaching zero but not toe out on a road vehicle to my knowledge or maybe my frazzled brain is playing tricks with me.

 

I will read your article to seek clarification regarding the +ve or -ve nomenclature.

[J.R.]

Yes my brain is frazzled, toe in measurements are indeed positive.

 

I retract what I said about the report although the specified toe angle does seem large.

 

I also got whether toe out would scrub the inside or outside edge backwards in my head.

 

Time for bed, if only it were cool enough yet.

[AndyM20]

Time for a new axle I guess. If you mentioned a pothole could have caused that then yes I hit a pothole on the A1 back in Jan. still waiting for NH to reimburse me. Squashed the NSF wheel and punctured both near side tyres. That could be the culprit. 

Edited 28 April, 2023 by AndyM20

[varooom]

2 hours ago, Breezy_Pete said:

 

I don't think I have the relevant erWin documents for this model.

The wonderfully helpful fella that is @varooom may have?

D4B802B4ACF-Axles__steering.pdf

 

This is the name of the file for the Ocatavia III (I think this is the motor you were asking for)

Let me know if you are needing values still for something.

[Breezy_Pete]

Thanks but already resolved I think. 🙂

[skomaz]

1 hour ago, J.R. said:

Yes my brain is frazzled, toe in measurements are indeed positive.

 

 

Yep toe in positive. The other bits of your earlier post sounded about right thoug

 

2 hours ago, AndyM20 said:

Thank you and yes it does explain. Will a new axle solve the issue? Excellent explanation! Thanks for taking the time to write! 

 

No problem - we sometimes forget others aren't quite as up to speed with interpreting techie stuff so I figured a basic explanation might help.  In terms of whether it will fix it...   It should do provided the replacement is straight and there are no other issues. 

[Breezy_Pete]

I took a quick look at both our Polo and Fabia an hour or two ago, both of which are in spec as far as I know, for their respective rear ends.

The toe in is quite visible even at a casual glance, so nearly 2 degrees of toe out on Andy's car's nearside rear must stick out like a sore thumb, I'd think?

Edited 28 April, 2023 by Breezy_Pete

[skomaz]

Yes it should be easily visible by sighting down the side of the car from the back.  And I guess a big pothole hit as described could cause it (I notice the camber is out on that side as well?). 

 

I'd love to know where its bent though (I'm also trying to think if there is anything else that could cause those readings - like a bent hub for example) and I can only imagine it's close to the hub so difficult to see any dmamge from underneath. 

Edited 28 April, 2023 by skomaz

[Breezy_Pete]

6 hours ago, skomaz said:

Yes it should be easily visible by sighting down the side of the car from the back.  And I guess a big pothole hit as described could cause it (I notice the camber is out on that side as well?). 

 

I'd love to know where its bent though (I'm also trying to think if there is anything else that could cause those readings - like a bent hub for example) and I can only imagine it's close to the hub so difficult to see any dmamge from underneath. 

 

I woke up wondering the same, it could be a much cheaper and easier repair if it were just the hub assembly, rather than the beam.

Looking at the pictures in this ebay listing here, particularly the second to last one, makes me think that the bearing would surely be audibly and functionally destroyed ahead of that structure getting bent? 

Thoughts @skomaz, @J.R., @bentrearhubassemblyexpert?

[skomaz]

4 hours ago, Breezy_Pete said:

 

I woke up wondering the same, it could be a much cheaper and easier repair if it were just the hub assembly, rather than the beam.

Looking at the pictures in this ebay listing here, particularly the second to last one, makes me think that the bearing would surely be audibly and functionally destroyed ahead of that structure getting bent? 

Thoughts @skomaz, @J.R., @bentrearhubassemblyexpert?

 

I can't see that casting bending but could imagine it fracturing under a big 'hit'??  Like you I'd expect the bearing to be making a noise though as well if that were the case as I'd expect that would be damaged too. 

 

More likely in my mind to have bent is the part of the axle that that assembly bolts to as it won't be as 'solid' or rigid in terms of structure. 

 

Having sais all that it really needs someone to strip it down and have a proper look before committing to a new axle? 

Edited 29 April, 2023 by skomaz

[J.R.]

No I dont think so, bearings can transfer an immense transient load.

 

Its a shame the OP neglected to mention this minor (to him) pothole event that destroyed 2 tyres and an alloy wheel even when I asked if there was any evidence of damaged or replaced alloy wheels, it would have saved a lot of speculation.

 

I had a similar shunt when recovering from my first detached retina, a width restriction kerb that was on the trajectory for a left turn & which had been hit many times & continues to do so, it was also dark, enough of my excuses, both front and rear wheels went over it throwing the car up like a bucking bronco twice, front tyre wrecked rear tyre ok, neither alloy broken, just scuffed.

 

The impact bent the steering arm like a banana and also bent the track rod end and skewed the ball of the inner joint, all were replaced in time but straightened initially.

 

The wheel bearings were unaffected and were still silent when the car was scrapped a decade later at 32500 miles.

 

I have never seen a torsion beam axle, do they have seperate bolt in hub shafts like a trailer suspension unit? If so then it makes sense that these will be designed to be the weak link in an impact, if the part is available then just replacing that will be a lot cheaper and  reckon bring it back into spec, someone earlier explained how the consequent crabbing would wear both rear tyres even though the static toe in on the other side is correct.

 

Assuming the OP is paying to have the work done I would recommend having the stub axle alone replaced initially if the part is available, if not but the old one can be removed then it can be clocked in a lathe which will show any bend.

 

If its bent then it will have been removed to check, if a new part does not exist then I would buy the cheapest second hand axle and just use the stub axle from it to repair the vehicle.

 

AndyM20, did you really not consider that the pothole that wrecked one wheel and 2 tyres only 3 or 4 months ago would have been the cause of your subsequent tyre wear? Did none of the garages ask you the question?

[J.R.]

Looking at the photos on the Ebay listing that Pete kindly linked to the shaft diameter inside the rear bearing (or is it a single double row bearing?) is about 1", I reckon that would give before the trailing arm of the torsion beam, the fixings are spread over a wide area and the rear face machined, I think it is designed to be a very strong joint to the very strong trailing arm  of the torsion beam and the removable hub assembly being the sacrificial part in the event of a significant impact.

 

Garages will always diagnose and propose the repair that makes them the most money on parts and labour and in fairness to them the one that has the least doubt of success, I would swap the hub first.

 

Its the shame that the hub looks both handed and the fixings polarised, otherwise they could be swapped side to side to prove that the axle is not bent or it could be rotated 90° so that the camber and not the toe in would be affected again proving the axle to be straight.

[Breezy_Pete]

If Andy would like to message me with his VIN I can look up hub part number for his car and price.

[Ootohere]

When looking at replacement rear axles for Disc Brake conversions on Mk2 Fabia there are plenty that will have been bent in accidents before being sold as spares, 

but ones on cars can be bent from being lifted probably with a single trolley jack.

Edited 29 April, 2023 by toot

[J.R.]

With all due respect Root, if you think a moment about what you say you would realise that it cannot be so.

 

The load on a stub axle through raising a vehicle by lifting under it (which could only be achieved with the wheel removed and very difficult with the disc and caliper in place) is no higher than the wheel riding over a bump like a sleeping Policemen.

 

Reading it again I think you mean the torsion beam axle bending and not the stub axle, nonetheless the exact same comments apply.

 

Ok reading it again (I am woozy with Covid) you probably mean bent by lifting the rear of the car by jacking on the centre of the torsion beam, yes it could well be that it does not have the resistance in bending to cope with that, its deliberately weak to twist in torsion.

Edited 29 April, 2023 by J.R.

[Ootohere]

@J.R.With all due respect, if you look see at Fabia rear axles they can bend with someone putting a jack in the middle and lifting the car. 

 

EDIT.

#memories.

http://briskoda.net/forums/topic/486539-rear-axle-alignment

 

Edited 29 April, 2023 by toot

[J.R.]

Yes indeed, I had editted my post when I thought of that, the postings overlapped.

 

My apologies for misinterpreting what you meant, I am quite woozy and the wording was ambiguous, I see you have since editted out the "to" which further confused me.

Edited 29 April, 2023 by J.R.

[AndyM20]

On 28/04/2023 at 17:40, Breezy_Pete said:

See if this helps. Why do you not believe the rear beam has a problem (e.g. being bent)? Have you inspected thoroughly from underneath yourself?

Probably needs to be on an overhead ramp/lift to see clearly.

 

 

8 hours ago, J.R. said:

No I dont think so, bearings can transfer an immense transient load.

 

Its a shame the OP neglected to mention this minor (to him) pothole event that destroyed 2 tyres and an alloy wheel even when I asked if there was any evidence of damaged or replaced alloy wheels, it would have saved a lot of speculation.

 

I had a similar shunt when recovering from my first detached retina, a width restriction kerb that was on the trajectory for a left turn & which had been hit many times & continues to do so, it was also dark, enough of my excuses, both front and rear wheels went over it throwing the car up like a bucking bronco twice, front tyre wrecked rear tyre ok, neither alloy broken, just scuffed.

 

The impact bent the steering arm like a banana and also bent the track rod end and skewed the ball of the inner joint, all were replaced in time but straightened initially.

 

The wheel bearings were unaffected and were still silent when the car was scrapped a decade later at 32500 miles.

 

I have never seen a torsion beam axle, do they have seperate bolt in hub shafts like a trailer suspension unit? If so then it makes sense that these will be designed to be the weak link in an impact, if the part is available then just replacing that will be a lot cheaper and  reckon bring it back into spec, someone earlier explained how the consequent crabbing would wear both rear tyres even though the static toe in on the other side is correct.

 

Assuming the OP is paying to have the work done I would recommend having the stub axle alone replaced initially if the part is available, if not but the old one can be removed then it can be clocked in a lathe which will show any bend.

 

If its bent then it will have been removed to check, if a new part does not exist then I would buy the cheapest second hand axle and just use the stub axle from it to repair the vehicle.

 

AndyM20, did you really not consider that the pothole that wrecked one wheel and 2 tyres only 3 or 4 months ago would have been the cause of your subsequent tyre wear? Did none of the garages ask you the question?

 

6 hours ago, Breezy_Pete said:

If Andy would like to message me with his VIN I can look up hub part number for his car and price.

Hi Breezy

 

let me have an email address please. Thanks

[AndyM20]

J.R,

 

you are absolutely right never thought a pothole can do such damage. Yes it was a hard one and did a lot of damage to my wheels but never thought the axle would be damaged. 
 

I will buy a second hand and get someone to replace it for me and take it from there. It seems that everyone thinks the pothole created all this. Here is the pothole I hit. 
 

also attached is the axle I will buy and have installed. 

[KenONeill]

39 minutes ago, AndyM20 said:

let me have an email address please. Thanks

He doesn't need to; use the Briskoda Private Message system. Hover on his profile picture, and press "Message" bottom left on the info/buttons shown.

[Breezy_Pete]

22 hours ago, J.R. said:

Looking at the photos on the Ebay listing that Pete kindly linked to the shaft diameter inside the rear bearing (or is it a single double row bearing?) is about 1", I reckon that would give before the trailing arm of the torsion beam, the fixings are spread over a wide area and the rear face machined, I think it is designed to be a very strong joint to the very strong trailing arm  of the torsion beam and the removable hub assembly being the sacrificial part in the event of a significant impact.

 

I tend to disagree, having looked a the stub axle itself (item 11), which has a tight M16 bolt through the middle of it holding the bearing when in service. doesn't look at all likely to bend, according to my amateur structural engineer's gut.

 

 

 

 

This is one such piccy. There's an M16 bolt up the middle of it holding the bearing on, just seems really hefty as an overall chunk, but possibly still worth checking before going for full rear beam swapout:

[J.R.]

I never got to contribute any more to this thread because unbeknown to me the 2nd dose of Covid I thought I was suffering from turned out to be a massive bacterial infection to the head which put me in intensive care for a week.

[Donweather]

So getting back to the original post of this thread has anyone got a solution to the dreaded inside tyre wear?  I’ve got it albeit it’s only occurred since lowering my car on eibachs but I’m going to have to bite the bullet on new tyres and want to ensure these tyres don’t get eaten out on the inside edges also and hence waste $1500 on early replacement of inside feathered edges tyres. I’ve already upped the tyre pressure to the max recommended. Should I get a good tyre alignment place to reduce the camber fronts and rears?  Noting camber does look a lot more currently on rears but inside edge wear seems to be occurring on all four tyres?