WARNING TO CLS OWNERS!!! 8000 mile tyres!

[Number_Cruncher]

Be careful if reducing the rear tyre pressure against the front ones as that will alter the slip angle so will give the car a tendency to over-steer, as opposed to the safer design specification of gradual under-steer.

Hurrah!

As you know I've been banging this particular drum for a long while, and it's really heartening to read someone else writing it up.

I fully agree that the difference in pressures on car tyre pressure specs is very important, and it should not be erroded.

If the car's wheels are all the same size, the correct way on MBs to avoid the problem is to rotate the tyres. The fronts will tend to wear their edges, and the rear tyres their centres - swap them over every now and again, and the wear will be shared out, and you'll get longer total tyre life. Tyre rotation is a part of the MB service schedule that seems to be missed out or disregarded for some reason.

 

[Alex M Grieve]

Hurrah!

As you know I've been banging this particular drum for a long while, and it's really heartening to read someone else writing it up.

I fully agree that the difference in pressures on car tyre pressure specs is very important, and it should not be erroded.

If the car's wheels are all the same size, the correct way on MBs to avoid the problem is to rotate the tyres. The fronts will tend to wear their edges, and the rear tyres their centres - swap them over every now and again, and the wear will be shared out, and you'll get longer total tyre life. Tyre rotation is a part of the MB service schedule that seems to be missed out or disregarded for some reason.

I used to do front to rear swaps on a Volvo Diesel I had - serviced every 10,000 miles and the original tyres were good to 70,000 miles. Their replacements were still on the car when I parted with it at 125,000.

Rotating the wheels certainly enabled balanced tyre wear. That was a front wheel drive car and the regular service intervals were probably crucial, catching the more worn tyres and "resting them" on the rear before they wore too much.

 

[television]

Changing the tyre pressure within the stated figures cannot affect the car by much in the way that it drives.

For a start how many check the tyres when cold.

Where do you find petrol stations that all give the same reading.

I think that if you are driving in such a way that the pressures if somewhere near correct can cause instability then you should not be driving.

Again I run my car within the stated pressures and adjust to balance out wear that takes place on the edges or in the center, all within the limits,, I would rather have tyres with an even tread wear across the whole width then tryes with only ½ the correct width of tread, non of it is rocket science, the whole thing allows for little old ladies to do the tyre pressure checks

 

[Alex M Grieve]

Changing the tyre pressure within the stated figures cannot affect the car by much in the way that it drives.

For a start how many check the tyres when cold.

Where do you find petrol stations that all give the same reading.

I think that if you are driving in such a way that the pressures if somewhere near correct can cause instability then you should not be driving.

Again I run my car within the stated pressures and adjust to balance out wear that takes place on the edges or in the center, all within the limits,, I would rather have tyres with an even tread wear across the whole width then tyres with only ½ the correct width of tread, non of it is rocket science, the whole thing allows for little old ladies to do the tyre pressure checks

Very true Malcolm. The whole car compensates for changes in pressure. I have experience two extremes,

On the Rover P4 105S I had in the 1960s, I felt the rear of the car "floating" a bit one day and suspected a tyre pressure problem. Back right tyre had lost no more than 4 lbs psi - but the effect was significant.

Some years later I had a complete deflation of a rear tyre on a S**B 99 and the only evidence I had was the noise of the slapping of the tyre carcass - there was no discernible effect on the steering at all.

I suspect that most MBs would be in the latter, rather than the former category.

 

[parthiban]

If the car's wheels are all the same size, the correct way on MBs to avoid the problem is to rotate the tyres. The fronts will tend to wear their edges, and the rear tyres their centres - swap them over every now and again, and the wear will be shared out, and you'll get longer total tyre life. Tyre rotation is a part of the MB service schedule that seems to be missed out or disregarded for some reason.

I was told by Tony at WIM that rotating tyres isn't the best idea as it actually accelerates tyre wear.

 

[television]

I was told by Tony at WIM that rotating tyres isn't the best idea as it actually accelerates tyre wear.

I have heard this too, as the tread settles, you reverse the thrust and the tread hes to wear down to a new level

 

[parthiban]

I have heard this too, as the tread settles, you reverse the thrust and the tread hes to wear down to a new level

Yep exactly that, the most effective way to moderate tyre wear is to monitor tyre pressures and make sure the geo is well calibrated.

 

[television]

Yep exactly that, the most effective way to moderate tyre wear is to monitor tyre pressures and make sure the geo is well calibrated.

Yes I agree, getting two gauges to read the same would be a good start

 

[Omega]

Years ago it was just one of the things you always did - rotate yer wheels, and in a specific order.

Whilst it must have seemed logical - at the time, the change in both the thinking and the compounds have made a difference.

I never thought that I'd hear my old dad change his mind,,,, but as an ex mechanic he would always tell people to rotate,,,, but in the end, he too stopped doing it.

I suppose if you don't rotate, you'll probably need to replace the rears & fronts at slightly different times ?!

I'm just looking into Marangoni tyres. The write-ups so far seem very encouraging.

 

[parthiban]

Is the rotating thing something that changed due to lower profile tyres or was it something that was just wrong from the beginning?

Been thinking about getting one of those aftermarket tyre pressure monitors (don't have the factory fit system) - does anyone have any experience with them? Are they any good?

 

[television]

The one built into the wheels known as direct monitoring made by Buru are awfull with constant wrong info, the only other ones were the valve caps that told you the set pressure was wrong,,have not seen those for ages now.

The indirect system use the wheel sensors, but the tyre would have to be a long way out before you knew

 

[parthiban]

So the systems like http://www.tyresave.co.uk/smartire.html aren't too reliable then?

 

[Omega]

Is the rotating thing something that changed due to lower profile tyres or was it something that was just wrong from the beginning?

In my opinion - it was dead right - at the beginning. But don't forget that apart from almost solid and cross-ply tyres back then, most family cars wouldn't be scorching away from the lights etc,,, it was a different ball game.

Been thinking about getting one of those aftermarket tyre pressure monitors (don't have the factory fit system) - does anyone have any experience with them? Are they any good?

Not heard of them. My car also dosn't have a built-in one,,,, but then again,,,, as an Executive,,, it came with bugger all as standard.

There are several Valve / dust cap monitors on the market,,,, but i've resisted so far. Far too pretty for the Robin Chav.

 

[Diver233]

I have a E220 CDI and ave just got 27000 on the original set of Good years.

 

[Omega]

When researching for tyres for my last car, I came across a list on the interweb of Wear Rate for about the top 20 brands/models.

I was serious in my quest, so I wouldn't have taken notice of Company/Brand orientated lists, 3rd party reviews or hear’say reports.

I wanted to quote a couple of things from it, but want to confirm them before I do, but as Sods law prevails, I can't find it now.

Has anyone come across a similar thing ?

 

[buster651]

92 500sl 235/45/zr17 & 265/40/zr17 only 6000mls last year on mich trying pirelli this year ive seen posted that the 129 with wide tyres eat them and at near £800 a time am thinking of changing the rims

 

[Number_Cruncher]

I was told by Tony at WIM that rotating tyres isn't the best idea as it actually accelerates tyre wear.

Rotation is part of the MB service schedule for many of their cars.

 

[television]

NC a question for you,, I have heard it said before,, on the new S class to come it states that bigger wheels use more fuel, even wheels of the same width, how can this be

 

[Number_Cruncher]

I'm not sure, but, two possibilities spring to mind Malcolm;

- the larger wheel has larger inertia, and so, the "effective" mass of the car is higher

- the larger wheel produces more aerodynamic drag

 

[parthiban]

NC a question for you,, I have heard it said before,, on the new S class to come it states that bigger wheels use more fuel, even wheels of the same width, how can this be

I think it's also to do with rolling resistance, bigger wheels and lower profile tyres should have a higher rolling resistance due to a better contact patch and less compliance with the road surface.