Tyre Size/brand Advice Needed

[Kenic]

Hi all. I've recently got a Ml270 (my first Merc) and I'm a little disappointed with the general ride quality. The suspension and steering has been given the once over and all seems OK so I'm wondering if a change of tyre make and/or size could improve things and would appreciate some opinions.
Currently it has 275x55x17's fitted with Dunlops on the rear and Hankook Ventus ST's on the front. Besides the usual day to day driving I also tow a caravan and would lean towards comfort rather than performance with the ability to cope with the odd muddy camp site.

 

[G.P]

Mich., Conti. and Toyo all have butter soft walls..

 

[Dee James]

Hi all. I've recently got a Ml270 (my first Merc) and I'm a little disappointed with the general ride quality. The suspension and steering has been given the once over and all seems OK so I'm wondering if a change of tyre make and/or size could improve things and would appreciate some opinions.
Currently it has 275x55x17's fitted with Dunlops on the rear and Hankook Ventus ST's on the front. Besides the usual day to day driving I also tow a caravan and would lean towards comfort rather than performance with the ability to cope with the odd muddy camp site.

I had exactly the same issue and found there are two different wheel widths on the ML270, 8 and 8.5 inch the factory tire size being 255 and 275 respectively. Post a picture of your wheel and I will tell you what you have, you may have the wrong tires on.

I had 275`s on my 8 inch wheels for a week (based on a garages advise) and it felt terrible so I went back to the garage told them they had fitted the wrong tires and did what a lot of people do, went down to 235/65/17 which totally transformed the feel - much better than the 255`s it had when I bought it.

 

[Kenic]

I'm Struggling to add a pic of my rims for some reason (may be as I'm a new member). So I've added a link to a page with a picture on it (bottom left). "Dee James", if my current rims are the correct one's for 275's, do you think the ride quality improvement gained by going to 235's would warrant the cost of getting some 8" rims.

The links not working so here's the url.
http://www.luxuryautosac.com/parts-cars/004985-mercedes-ml430-suv-w163-2001.html

 

[Dee James]

i think yours are the earlier style 8.5" but i`m not 100% sure so i would wait for someone else to confirm . . .

this is the 8"currently i have 235/65/17`s on and i have found them a huge improvement over the standard size. I`ve not driven a ML with 275`s on the correct 8.5" rim but i would probably go for a 255

 

[Dee James]

i think yours are the earlier style 8.5" but i`m not 100% sure so i would wait for someone else to confirm . . .

this is the 8"currently i have 235/65/17`s on and i have found them a huge improvement over the standard size so depending on how much you could sell yours for and how much 8" wheels would cost you it may well be worth doing, especially taking into account the difference in tire prices

 

[BlackC55]

Don't discount the shock absorbers to be worn too.

 

[bolide]

I think the wheel width is a red herring. The tyre construction determines its stiffness and a 65 profile tyre will have much taller, and likely much softer, sidewalls than a 55 profile

There will be differences between manufacturers, tyre models and tyre profiles. By & large the premium tyre manufacturers' products will ride better

Nick Froome

 

[G.P]

Don't discount the shock absorbers to be worn too.

Whenever I've driven a vehicle with worn shocks it's always provided a softer ride..

 

[Kenic]

I've had a good look at the shocks and they seem to be in OK nick, there's no leaks or obvious corrosion but I know that does not necessarily mean they are not past their best. Is there a reliable way they can be accurately tested?.
I was wondering if I should swap to 255x65x17 but wonder if the increased side wall size would make that much difference? I have found that my local ring road, parts of which new and still have a decent smooth surface (difficult to find I know) the ride is not too bad. But on any other roads with a surface less than "billiard table" flat the ride quality seems poor at best.

 

[F1BHP]

a 275/55 has a 151mm sidewall and a 235/65 has just under 153mm sidewall so the difference is tiny. It is the type of tyre that will determine the softness of the sidewalls not necessarily the width.

 

[Dee James]

I've had a good look at the shocks and they seem to be in OK nick, there's no leaks or obvious corrosion but I know that does not necessarily mean they are not past their best. Is there a reliable way they can be accurately tested?.
I was wondering if I should swap to 255x65x17 but wonder if the increased side wall size would make that much difference? I have found that my local ring road, parts of which new and still have a decent smooth surface (difficult to find I know) the ride is not too bad. But on any other roads with a surface less than "billiard table" flat the ride quality seems poor at best.

if you are at all unsure about the shocks have them looked at, they will make a big difference to the ride quality.

When you say the ride is n`t great what do you mean, just over bumps or tram-lining steering response etc.?

 

[Dee James]

a 275/55 has a 151mm sidewall and a 235/65 has just under 153mm sidewall so the difference is tiny. It is the type of tyre that will determine the softness of the sidewalls not necessarily the width.

unless, like me, you had 275/55 on a 8" wheel - it felt like there was just too much tire like they were flat almost, turn in response was slow it tram lined something awful and the road noise was much worse than it is now.

 

[Kenic]

For me the problem is mainly with bumps and potholes, as well as too much road noise. I would describe the ride as harsh and jarring.
At the moment my realistic options seem to be a change of tyres to four of the same size as the current ones but with softer side walls. I don't see changing wheels with a view to changing tyre size is likely to give me enough of an improvement to justify the expense.

And further investigation into the state of the current shocks.
Does anyone know if there is anyway to actually test the shocks to get a clear idea as to their condition. As things stand it's a fair bet they are original so must have done 111,000 miles and while they look OK the mileage alone suggests they could be past their best. But it's a fair chunk of money to pay out in the hope of a worthwhile improvement.

 

[G.P]

a 275/55 has a 151mm sidewall and a 235/65 has just under 153mm sidewall so the difference is tiny.

The outside rolling circumference has to be within 3% or the original size..

 

[Kenic]

I've been reading up a bit more on this and it seems there is some widely differing opinions on the ride quality of the Ml in general. Some say it's poor at best while others are quite happy with theirs. One person commenting in 2004, when his vehicle was only about a year old, was very disappointed and his description of the ride appears to mirror my findings in my 11 year old one. Taking this into consideration and the fact that this is my first 4x4 (so I don't have any previous experience of the type to draw on) I'm wondering if it's more me than anything particularly wrong with the car. I think I need to find someone local with some experience who can give me a second opinion.

 

[gIzzE]

I went from 255.60.17 Contis to 235.65.17s Michelin Latitude Tour HPs and the difference was very impressive.
Less tramlining, less crashy over potholes and ironworks etc.

Then swapped for new Bilstein shocks and replaced the anti roll bar bushes and it was 100x better, shocks do wear and on a car that is over 10 years old they will need replacing.

I then swapped for 19" wheels when I got it feeling good again, I went with Goodyear EfficientGrips, 235 width again, and these were actually even more comfy than the Michelins even though they were now 2" bigger rims.


The ride quality should be pretty good, I have a 2013 X3 as well, and the old man has a 2010 ML350, the ML270 with Bilsteins and better tyres is more comfortable than either of those.

Having said that, my old man has just put 19" wheels with Goodyear EfficientGrips on his instead of the 20's with Pirellis and that has transformed his car too.

 

[Kenic]

What width were the rims you had with the 235.65.17's

 

[gIzzE]

8.5" on the 17s, not sure on the 19s, may have been 9".