Anyone heard of "Tyre Run Out". ?

[Bam Bam]

I've always suspected that something has never been quite right about the front end of my 99 CLK W208.
The car was fitted with 18" aftermarket alloys with 225/40 tyres when I bought it and for the short time I ran the car with those wheels it always had some slight problems, since upgrading to 19" AMG's with 235/35 tyres fitted on the front I hoped the problem would go away but it never did and I've always noticed a slight whirring noise which comes on at 20mph and goes away at 25mph, also the car has never driven as I would have liked it at speed, at approx 60mph onwards it has always suffered from slight wheel wobble and also the feeling that something is loose at the front, after rechecking the balance of the front wheels and all the obvious stuff that could work loose everything was ok so no improvement was gained.

I went along to my local Merc Dealer and asked for advice, a mate of mine works there in the Parts Dept. so he arranged one of their older more experienced guys who took the car out for a short drive, he immediately mentioned "tyre run out" and to be quite honest I dismissed his explanation of what the problem could be straight away thinking he didn't know and was just clutching at straws and guessing what the problem could be.

In short I was wrong to dismiss him and he was right but I'm interested to know if anyone has ever heard of tyre run out before, I've been driving for over 35 years, all sports or high performance cars that have had an upgrade to the wheels and tyres, if the car has had standard rims when I've got it I've always upgraded myself as it's the first thing I do and in all that time I've never heard of or come across tyre run out. Is it a problem that has occured more recently or have I been lucky and it's something I've got away with for so long.

I'll give you the explanation of what it is and the diagnosis of how to check to see if you have it later but I'm just interested to see how many of us older middle aged drivers like myself who think they have come across every problem have suffered from it or have even heard of it.

What do you think it could be. ?

Jim. ;-)

 

[Richard Moakes]

What about the coloured stripes in the tread?

Often when you buy tyres, there will be a coloured band or stripe running around the tyre inside the tread. These can be any colour and can be placed laterally almost anyhwere across the tread. Some are on the tread blocks whilst others are on the tyre carcass. For ages I thought this was a uniformity check - a painted mark used to check the "roundness" of the tyre. But I had a tyre dealer contact me with a far more feasible answer. The same tyre is often made with slightly tweaked specifications for different vehicles. To easily identify these same labelled tyres when they are warehoused or in storage, different markings and stripes are used. Sometimes stripes are added for huge bulk orders to various manufactures. Eg All the red outside stripes are for Toyota next week. This gives anyone in the warehouse a very quick visual check of the different types of tyres without needing to pull them all down and read the sidewall on each one.
As well as the colour, the actual position of the lines is something to take note of too. They're a measure of something called runout. Depending on how the belts are laid on the tyre during manufacturing, they can cause the tire to "run out" - to not track perfectly straight, but pull to the left or right. The closer to the centre of the tyre that these lines are, the less runout the tyre has and the straighter it will track when mounted on your car. So for example, if you were looking at your car from the front and you saw the coloured striped running around the right side of both your front tyres, the car would likely have a tendency to pull to that side. The best thing is to have the coloured stripes on opposite sides of the tyres for opposite sides of the car, so that the runout on each side will counteract the other and help maintain a good straight running. This is something that not many tyre fitting places know about or take any notice of. The obvious solution to having the stripes both on one side is to flip one of the tyres around, but that will only work if they're not unidirectional tyres. If they are unidirectional (and thus must be mounted to rotate a specific way) then you should try to find another tyre from the same batch with the stripe on the opposite side.
runout stripes

 

[Richard Moakes]

All of the previous post and more at http://www.carbibles.com/tyre_bible.html

 

[Blackbird]

I worked in the tyre trade many years ago but never came across that term. I would have to guess that he was talking about toe-out which relates to the front wheel alignment. Rear wheel drive cars generally have zero or a tiny amount of toe-in alignment. Running with toe-out will scrub the inner edges of the front tyres and if particularly excessive may cause wallowing in a straight line.
I eagerly await the correct answer?
Regards, Blackbird

 

[Blackbird]

An excellent response from Richard and what a good link! A day without learning is a day wasted?
Regards, Blackbird

 

[Chas]

All of the previous post and more at http://www.carbibles.com/tyre_bible.html

Just for info which isn't included in the aquaplaning paragraph.

Tyres aquaplane at 9 x sq. root of tyre pressure.

eg

a tyre with pressure 36 psi will aquaplane at 54mph

So generally speaking look out for aquaplane at about 50mph for most cars or approx. 135 knots on your aeroplane

 

[Bam Bam]

....good one Richard, you nailed it when you mentioned the "roundness" of the tyre, I already have the Carbibles link and have used and referred to it many times but didn't think it would be included there as I thought it a fairly recent problem.

So to give you the benefit of what has actually plagued me for the last 4 months, cost me 2 sets of front wheel bearings (1 aftermarket set which I thought were inferior and then 1 genuine Merc set which were still no better) removal of both front Axles to check for damage and excess wear etc, a lot of hard work out in the snow some days (snow actually laying on my back and fingers like icicles) I'm told it could well be tyre run out. !!!! :-(

To check for this you simply run your hand around the treaded area of the tyre quite quickly and feel for any slight peaks or troughs as you go, my tyres are Pirelli PZero Rosso's so it can happen to any of the best branded tyres on the market, don't know why it's happened but the inner edge of the treaded area has 2 or 3 slight peaks to them, the Merc guy spotted them and I agreed with him as I could feel them too but I didn't think they were significant, my mistake. With it being the inner edge I'm thinking it could be related to the camber set up of the front wheels, maybe delamination (?) I don't drive the car hard or corner hard to have caused this.

So I'd like to think that this post may in the future save someone a whole lot of the same trouble I've been through for the past 3-4 months, I'm off now to check on Carbibles to see if I may have saved myself all that bother.

Jim.

 

[Bam Bam]

....Well it does get a brief mention but no explanation of what causes it.

Quote.

"Problem, Spot Wear. A part or parts of the circumference of the tread that are wearing faster than other parts.
Solution, Excessive runout of tyre/rim assembly."

Apart from the obvious of wheel spinning and braking to a skid, it's mainly connected to front steering and suspension goemetry, toe-in, toe-out, positive/negative camber etc causing the flat spots, no presice explanation of what causes it considering a balanced wheel should turn evenly. ?
Hope Blackbird is satisfied. ;-)

Jim.

 

[Rory]

I bought a couple of Michelin tyres the other day from Costco for our Jazz and both tyres had two runout bands around them - one yellow and one white, if I recall correctly. They were in exactly the same position on both tyres - about 1/3 in from the edge. As the tyres were going on opposite side that seemed fine.
I asked the fitter what the bands meant and he had no idea.


I have a W203 with a bad case of drifting left. There is a Mercedes bulletin that tells the dealers to first try swopping the wheels diagonally to see if that helps, and it also suggests pressing the tyre off the rim and ensuring that it's fitted centrally and evenly.

I can't swop my wheels diagonally as I have different sizes front/rear, but swopping the fronts made quite a bit of difference, although that may just be the scuffed outer edge that was on the NS tyre helping now that it's on the OS.

 

[Bolide]

Runout described the amount of wobble in a rotating part. Brake discs may have a couple of thou runout at the edge and you can somethimes feel this as a pulse through the brake pedal as the disc pushes the brake pistons in & out

There could be runout in the tyre if it's out-of-tolerance and wobbles when it spins. Otherwise I'd look at bent or badly-manufactured wheels, loose wheel bearings and bent hubs for sources of runout and also at worn suspension bushes which might exacerbate the effect

Nick Froome
www.w124.co.uk

 

[davidsl500]

Swapping tyres diagonally is not a good idea if you have directional tyres of course !