Tyre scrubbing??

[AlanD]

Hi all,

Has any other MA/MB/MC owner experienced scrubbing of both front tyres on the inside corner of the tyres?

Went to get in the car today and discovered a flat tyre on the front. After removal it was clear that the tyre was sufferring from asymetrical wear across the tread with the greatest wear being on the inside. Checking the other front wheel was the same.

Clearly the car needs a wheel alignment, but with that kind of wear I'm wondering if the camber is wrongly set as well. Since it has had one alignment it is difficult to say if the odd wear pattern has been there from day 1.

New tyres in order I guess. 32, 000 on a set of Potenza RE050A Seems to me to be a bit on the low side as neither of us are press on drivers.

Cheers

[Allusion]

Mine are fine so far (potenza's on an MC at 45k) might be worth checking with the tyre guys when you get them replaced to make sure it's not something that might happen again.

[NZ XR6]

Alan, what sort of driving is the car used for? Have the tyres been rotated?

A decent alignment specialist should be able to diagnose what has caused the wear.

[AlanD]

Hi NZ, Allusion,

Normally a mixture of highway limit speed on smooth blacktop and some suburban low speed stuff.

We drove from Cooma to Orbost on the back road which is low speed and many bends in the latter half of the trip. Thre is about 20 km of gravel at the start of the "bendy" part. We've done that road going both ways.

The tyres have been rotated twice in the 30, 000+ km they have lasted and it has had one wheel alignment, from memory.

The manual says there is no ability to adjust camber or caster - so if the wheel alignment shows them out of spec, I guess I've got a real problem. I'm going to be interested in what the wheel alignment guys say about the readings they get "as is". If it isn't a camber problem (I really, really hope not) then I'm expecting a badly adjusted toe out condition, which, I suspect would have the inside edges scrubbing on both tyres. We will see later today.

One of the things I am noticeing is service centres encouraging un-necessary work. I get encouraged to get the Territory's wheel alignment checked constantly, but I point to the tread wear, which is flat and say, "You think so?"

The Mondeo will end up wearing Dunlop Rubber since there is a 20% discount offer on at the moment - and I want the car back on the road.

Guess I'll be able to report on the roadholding of a different tyre from the Brifgestones in due course. Looks to be pretty much the same tread pattern as the OE, Hopefully they wil last longer.

Cheers

[AlanD]

Should have left the original spelling error - "sprling" indeed

[AlanD]

And I can't misspell spelling twice the same way!!!

[AlanD]

Hi all,

Well I got the news back from the wheel alignment people and it was to the effect that the car had a "significant" degree of toe out on both front wheels slightly more on the drivers side than the passengers.

Every car I have owned with FWD has required some toe out for the normal alignment, as, so the argument goes, there is a tendency for the wheels to "pull" straight as power is applied. But this depends on the other alignment values, which in the case of the Mondeo demands a small degree of toe in. I've checked the specs and this is true according to the manual. The nominal setting is 12' of toe in. In our case the setting was about 60' or a degree of toe out.

I also checked the records and my memory was correct, there was an alignment done at the 15,000 service, so my conclusion is that the alignment was not properly done and I've paid the price for that 12 months later. I base this on my memory that the tread wear at 15,000 was pretty even and I ought to have followed my usual habit, which is to say no thanks to such an offer in the face of no abnormal wear and this together with the fact that both front wheels were showing a toe out condition which was, for practical purposes equal tends to cause me to believe it was due to a mis alignment or a rig out of calibration.

Whatever, the car feels better to drive, but that's totally subjective and might simply be due to the fact that I now have more rubber between me and the road (always a good thing to have rubber between you and potential danger!! ). I think the Dunlops are not quite so good from a roadholding perspective and the rubber seems to be harder, but that might mean better wear characteristics.

One thing is certain, I'll be watching the wear on them closely for a few months to make sure nothing is amiss

[svo supporter]

Originally Posted by AlanD

Hi all,


Every car I have owned with FWD has required some toe out for the normal alignment, as, so the argument goes, there is a tendency for the wheels to "pull" straight as power is applied.

When a car moves forward, the wheels push outwards. So setting the initial setting to toe out, is only going to cause the wheels to toe out some more. Doesn't matter if it's FWD, RWD,4WD or AWD, every car does it.

So leave it upto you to judge

[Allusion]

Sounds like good news for the long term Alan and something we can keep an eye on

[AlanD]

Hi Allusion,

Yep, The feedback about the state of the alignment would explain rapid wear where it occurred.

So the moral is be vigilant about the state of the tyres on a regular basis and take action early when things look to be abnormal. Problem is - how do you find someone who actually knows what to do to correct things and who has equipment that is regularly calibrated?

Cheers

[svo supporter]

Originally Posted by AlanD

Hi Allusion,

. Problem is - how do you find someone who actually knows what to do to correct things and who has equipment that is regularly calibrated?

Cheers

Word of mouth is the way and then try. Fair enough, someone might recommend someone highly and you'll be disappointed at their service, which means moving onto the next person.

Unfortunately that's the best advise I can give. So good luck

[NZ XR6]

Originally Posted by AlanD

Hi Allusion,

Yep, The feedback about the state of the alignment would explain rapid wear where it occurred.

So the moral is be vigilant about the state of the tyres on a regular basis and take action early when things look to be abnormal. Problem is - how do you find someone who actually knows what to do to correct things and who has equipment that is regularly calibrated?

Cheers

I usually go to a suspension/alignment specialist, my thinking being that they won't be in business long if they don't do a good job.

Like you, I don't get an alignment done if the tyres are wearing evenly and smoothly. I usually check mine every month or so - park the car in the drive with the front wheels on full lock, look at the tread wear and run your hand across the tyre to check for any "feathering".

Which Dunlops did you have fitted?

[AlanD]

Hi NZ,

Dunlop XL SP Sport 01

And I measured the tread depth as soon as I arrived home (I took the wheels to the tyre retailer in the Territory so the depths are without any use)

Full depth 7.5mm and to the wear bars 5.6mm. If the depth on the Bridgestones are similar when new, then I'm an upset motorist, because there was 2.5mm of depth to the wear indicators on the outer edge of the tyre - and that would translate to another 20000 km or so.

I agree with your comment about using a specialist, especially one who has no tyre sales franchise.

Anybody know of such a beast in the outer east of Melbourne? The car is getting checked after a couple of thousand ks or earlier if I detect any abnormal wear.

In contrast the Territory got 55,000 from the OE tyres (could have squeaked another 5000 but there was a 4 for 3 offer on). Replaced with the same tyre, and they are now up to 30,000 km with 50% tread left. - and that car has never had a wheel alignment. But I guess you can get a "rogue" car which is incorrectly set from the factory - I've been lucky.

Cheers

[sjb]

I've had a series of cars wear unevenly causing scrubbing as you describe and also terrible "harmonic renounce", which is that rhythmic thrumming a lot of tyres get as they age (I hate it and it totally destroys all the NVH work manufacturers put in when designing cars). This has even happened on a new Mercedes C-Class in the family, which is RWD and you'd think better set up than most...
I suspected a large, heavy and reasonably powerful car with large low profile tyres (Potenzas) like the Mondeo XR5 would be particularly at risk if suspension geometry is even a fraction out and I didn't want any harmonic resonance so I talked to a few tyre places and one local one recommended a rotate and balance (about $40) every 5,000kms and a four wheel alignment every 8,000km (about $60-70). Im now at 35,000 and the tyres are perfectly even and not a hint of thrumming.
Its quite frequent, but I think worth it - I learned my lesson when I once had a Mazda 3 SP23 with the same Potenzas which I didn't get regular rotate/balance/alignment on) and by 25,000km the tyre thrumming literally gave me a headache whenever I drove it! Plus the scrubbing meant new tyres at 30,000km.

[allanv6gt]

My MB XR5 is almost 30,000kms old, and front tyres will prob only last another 5,000. No rotation, and no thrumming. Just the expected level of wear from a set of tyres on a FWD car. 'Exercised' driving without pushing too hard, mostly around town (ho hum....).
Continental Conti-Sport Contact 2 (or something like that) - won't be buying them again at nearly $400 each and horrible in the wet (since new).

[sjb]

Lucky man - Ive looked into it and the uneven wear and "feathering" (when one edge of each tread wears more quickly than the rest of the tread) seem to be pretty common, especially on softer, lower profile tyres like the XR5s. Ive been in a friends older TDCI Mondeo and it made a lot of thrumming from the rear tries oddly enough. Whatever you're doing, keep doing it!
The Contis are known to be grippy (at least in the dry?) but very poor wearing and expensive! When I change, I really like the look of the new Michelin Sports Pilot 3 - its won a bunch of tests by convincing margins for each criterion, especially wet braking and slalom, and they are around $265 each - I'd have a look at them but check out whether they are available in the right configuration - the MB XR5 has a very high load and speed rating for a passenger car (95Y or something like that), and many tyres are not available in that spec at 235 wide - apparently this can cause insurance worries if anything ever happens.

[svo supporter]

Originally Posted by sjb

Lucky man - Ive looked into it and the uneven wear and "feathering" (when one edge of each tread wears more quickly than the rest of the tread) seem to be pretty common, especially on softer, lower profile tyres like the XR5s.

Love to know where you've looked, to make these comments. Tyre profile has nothing to do with the wear patterns you describe. It's all in the suspension geometry settings, coupled with the driving habits of the individual and the roads the particular individual travels on.

My comments come from looking at numerous cars and their tyres and using common sense to adjust the settings accordingly. So I wait to hear where yours come from.

[svo supporter]

Originally Posted by sjb

Ive been in a friends older TDCI Mondeo and it made a lot of thrumming from the rear tries oddly enough. Whatever you're doing, keep doing it!

This "thrumming" noise, you describe, is typical of a FWD vehicle,if the tyres aren't rotated reguarly.

The rears on these types of cars,(ie FWD cars) are there just to keep the rear of the car dragging on the ground. Becuase there is no weight (to speak of) in the rear of these types of cars, the rears have a tendency to "skip" over bumps, rather than "ride" over them.

With the constant skipping over bumps, with the rear, they tend to develop high and low spots over the whole tread face. By avoiding rotations, these high and lows become more prevelant, and eventually the "thrumming" noise gets unbearable. (Another common description for this, is a noise very similar to a worn wheel bearing) Yes, you could attempt to place the rears on the front, to flatten the tread out, once these highs and lows become more prevelant, however you'll then experience massive steering wheel rocking, at all speeds.

As for you're comments regarding Mercedes vehicles. These cars are the Australian equivant of a Commodore or Falcon. As common as dirt in Germany. This means, they are massed produced, therefore the suspension geometry settings are a quick set and they're booted off to the dealership to be sold.

So hopefully this gives more of an inside about things

[svo supporter]

On the subject of Mondeos and camber. If my memory serves me correctly, these cars had rather agressive camber from the factory. ie, over 1 degree negative, to enable them to handle around corners.

With such aggressive cambers, it is advised to reguarly rotate the tyres and keep a close eye on inside edge wear.

I will admit, it has been about 2 years since I have aligned one of these cars, so memory wise regarding camber is a little hazy. However I am reasonably confident about my posting about it.

One last thing. I work in a tyre franchise, so of course it's terrific to see people tarnishing all tyre franchises with the same brush. The market is so competative, within this industry, constant bad reports will see these shops go out of business very quick.

So I'll leave it upto people to make their own minds up.

[sjb]

Originally Posted by svo supporter

This "thrumming" noise, you describe, is typical of a FWD vehicle,if the tyres aren't rotated reguarly.

The rears on these types of cars,(ie FWD cars) are there just to keep the rear of the car dragging on the ground. Becuase there is no weight (to speak of) in the rear of these types of cars, the rears have a tendency to "skip" over bumps, rather than "ride" over them.

With the constant skipping over bumps, with the rear, they tend to develop high and low spots over the whole tread face. By avoiding rotations, these high and lows become more prevelant, and eventually the "thrumming" noise gets unbearable. (Another common description for this, is a noise very similar to a worn wheel bearing) Yes, you could attempt to place the rears on the front, to flatten the tread out, once these highs and lows become more prevelant, however you'll then experience massive steering wheel rocking, at all speeds.

As for you're comments regarding Mercedes vehicles. These cars are the Australian equivant of a Commodore or Falcon. As common as dirt in Germany. This means, they are massed produced, therefore the suspension geometry settings are a quick set and they're booted off to the dealership to be sold.

So hopefully this gives more of an inside about things

SVO I have no idea about the details - I dont work in the tyre industry and therefore have to pay someone else to sort it out! From a layman’s perspective, its hard to make sense of what you’re told by the various franchises, which is often contradictory, unfortunately.
Completely agree as you say that any wear issues are ultimately to be traced back to suspension geometry - I was pointing out as I was told, that if this is the case, "sports" tyres will wear more quickly because they are usual softer. Is this not correct?
I probably wasn't clear about the thrumming issue - not saying its related to profile so much as tread pattern – again, so I've been told by tyre store experts-slash-hacks (it’s a lottery which of those you get). I agree with you and did mention in my original post that large FWD cars can be the worst offenders for tyre dramas, but I also do note that this occurs on other cars – the C Class for example – e.g. you see (or rather “hear”!) it on heaps of commercial vans, Landcrusiers etc which are neither FWD nor wearing sporty tyres??!?
You’d know better than me, but having experienced it on the Mazda (FWD small) and a Subaru (AWD medium), I figured I didn’t want the large FWD Mondeo to go down the same track because I cant stand the sound of it! Whatever my tyre store are doing, it seems to be working so far, touch wood!
PS Disagree slightly about Mercs – sure they are far from perfect and perhaps not quite what they used to be, but having lived several years in Germany recently, I can assure you that – although often used as taxis - they are NOT the German equivalent of Commafore/Falcon…that would be more like VW Passat…and Mondeo!! Mercs even in Germany are still broadly considered more upmarket and (by reputation at least) of having higher levels of engineering, mass-produced though they may be…

[allanv6gt]

MB XR5 has 235/40x18 Y rated - not many options. Was considering Yokohamas (good run with brand on prev cars), Michelins (luv'd the MXLs), and interested top hear comments re Bridgestones et al.
But Y-rated is a real pain, even W-rated is easier.
And....Many more options on 17" rims.......

Would concur with svo_supporter (he who fixes Fords' F-ups). Feathering is wheel alignment or driver over-exuberation beyond limits of steering geometery....

[sjb]

Originally Posted by allanv6gt

MB XR5 has 235/40x18 Y rated - not many options. Was considering Yokohamas (good run with brand on prev cars), Michelins (luv'd the MXLs), and interested top hear comments re Bridgestones et al.
But Y-rated is a real pain, even W-rated is easier.
And....Many more options on 17" rims.......

Would concur with svo_supporter (he who fixes Fords' F-ups). Feathering is wheel alignment or driver over-exuberation beyond limits of steering geometery....

I hear you - the Y rating is tough on 18" rims for some reason. The Bridgestone Potenza REO50's (came on the car ex factory) are brilliant, but I think hideously expensive to replace. Potenza Adrenalins are much cheaper and the consensus seems to be not quite s good as the 50s, but still up there. These Michelin Sport Pilot 3 just read brilliantly in the reviews - they are available at 245/40x18 Y rated, but I'm not sure if this extra 10mm is too wide?
I like the look of some of the Yokohamas too.

[NZ XR6]

Originally Posted by sjb

I hear you - the Y rating is tough on 18" rims for some reason. The Bridgestone Potenza REO50's (came on the car ex factory) are brilliant, but I think hideously expensive to replace. Potenza Adrenalins are much cheaper and the consensus seems to be not quite s good as the 50s, but still up there. These Michelin Sport Pilot 3 just read brilliantly in the reviews - they are available at 245/40x18 Y rated, but I'm not sure if this extra 10mm is too wide?
I like the look of some of the Yokohamas too.

Falken F K 452. They are Y rated in the 235/45-18 size and are excellent tyres, although being directional can be noisier than ribbed tyres.

The Adrenalins have great grip but are a bit lacking in wet traction. The F K 452 is much better in this regard.

[NZ XR6]

The Mondeo runs slight negative camber (-0.35°), which is certainly not "aggressive". BTW, the alignment specs are in the sticky at the start of the Mondeo forum.

My petrol Mondeo actually wore the rears just as fast as the front tyres, which would suggest that they did a little more than "keeping the rear of the car from dragging on the ground." You can feel the weight transfer to the rear when cornering hard, which may be one of the reasons why there is little understeer.

The diesel certainly wears the fronts faster though due to the much greater engine torque.

[svo supporter]

Originally Posted by NZ XR6

The Mondeo runs slight negative camber (-0.35°), which is certainly not "aggressive". BTW, the alignment specs are in the sticky at the start of the Mondeo forum.

My petrol Mondeo actually wore the rears just as fast as the front tyres, which would suggest that they did a little more than "keeping the rear of the car from dragging on the ground." You can feel the weight transfer to the rear when cornering hard, which may be one of the reasons why there is little understeer.

The diesel certainly wears the fronts faster though due to the much greater engine torque.

The fronts on all front wheel drive cars wear quicker, as they drive the car, steer the car, as well as the majority of the braking.

I would hesistate to say, if the rears on yours wore as quick as the front, you've got some problems with the car.

As for weight transfer. Maybe you could explain why FWD cars when tyres aren't rotated, end up with scalloped rear tyres then? Not being a smart alex, but I would be interested to hear an explanation for this occurance, seeing the rears do a little more than hold the bum off the road.

[AlanD]

Hi all,

NZ is correct with the figure provided. But the figures in the chart (see sticky) have some inconsistencies, particularly in relation to Camber angles. because the decimal figures do not agree with the degree/minute figures. Assuming the degree/minute figures are correct then the decimal figures oughty to be -0.59 degrees. There is also a discrepancy in the tolerance range column that is clear as the -(1degree 51 minute) translates to -2.10 degrees and, of course, the 1-51 figure must yeild a decimal value less than 2 (its -1.85). So I guess you believe whichever figure you prefer. But when wheel aligning I suspect it will be a function of the alignment rig. If it gives its readout in decimal figures then those readings will determine which set of figures get used, if in degrees/minutes then those.

But on the MA/MB/MC vehicles, unless there has been a suspension manufacturing change after the MA there is no adjustment capability for camber and caster unless an after market kit has been fitted.

And after some thought, I suspect the combination of negative camber and slight toe in figures allows for even wear across the tyre face in that negative camber will tend to wear the inside corner faster but toe in will wear the outside corner more, so things tend to even up. In my case the combination of toe out coupled with negative camber aggravated the inside corner wear with the results I have witnessed.

But if there is a professionaly qualified suspension person reading the forum, I'll be pleased to get an alternative opinion.

Cheers and a merry Christmas to all - I don't plan on driving today or tomorrow, but if you are driving please take care - but then I know everyone here does.

[NZ XR6]

Alan, you are absolutely correct. The setting is -0°35' which is 0.58° decimal according to my calculator.

svo_supporter, there were no problems with the car. I had an alignment check done when I bought the car at 14,000 kms as the rears had actually worn more than the fronts and had never been rotated. (I checked.) The rear wheel alignment was fine but they had to adjust the front toe slightly. And after that, all 4 tyres wore at about the same rate.

I will freely admit to some"brisk" driving on back roads from time to time but my usual driving style is to minimise hard acceleration or braking. If you drive a late model Mondeo, you should notice what I mean by the weight transfer to the rear when cornering. Not sure how they do that, but I understand that the control blade rear axle is a clever bit of engineering.

[svo supporter]

The current alignment machines I have used (Beissbarth and Hunter) all show camber and caster in degrees and minutes. The only change is toe. it's either degrees and minutes, or millimetres.

Yes, adding more toe in, does help wear the tyres more evenly, when there is large negative cambers.

As for qualified suspension people. I thought you would have got the hint, regardless of working with tyres. Never mind

[NZ XR6]

Originally Posted by svo supporter

Yes, adding more toe in, does help wear the tyres more evenly, when there is large negative cambers.

As for qualified suspension people. I thought you would have got the hint, regardless of working with tyres. Never mind

Isn't it toe out for negative camber?

Merry Christmas everyone!

[svo supporter]

Originally Posted by NZ XR6

Isn't it toe out for negative camber?

Merry Christmas everyone!

No mate. Toeing it out, means more of the inside edge of the tyre will be contacting the road, therefore causing the tyres to wear quicker on that edge.

So if you've got bigger negative cambers, you toe it in more, to have more outside edge contacting the road surface, which in turn helps wear the tyre more evenly across the tread face.



The art form of aligning comes from reading tyre wear on a car ie what the cambers are, and adjusting the toe to help the tyre wear become more even.

This only applies to normal street driving. When it comes to circuit or hill climb cars, this goes out the window. But that's a topic for another day.


Merry Xmas to every one too. Don't get too drunk