CLS 250 wheel downsize

[molgrips]

Hi, I've just got a CLS 250 with AMG sport suspension and 19" staggered. They're too rough but also pretty noisy particularly on the back with Pirelli P-Zero. Tyres have around 6mm of tread so they aren't that old.

I want to down-size the wheels to either 18 or 17 - both are specified in the manual and on the tyre pressure plate - but I can't decide which one. I don't particularly care about looks, I want quietness more than anything else (but I also don't want to trash my wheels on a pothole). I'll keep the 19s and put them back on when I come to sell, probably in a couple of years or so. I hope someone's done this and has experience on this car:

- Are 17s going to be noticeably quieter than 18s?
- Are 17s going to be significantly more comfortable than 18s?
- I know the handling will be a bit less sharp on 17s and I never really push a car - I just appreciate a bit of flow sometimes - but is the squishier rubber going to be really weird or somehow mis-match the sport suspension.

My other current car is a Hyundai and I did not expect it to be much more comfortable and quiet than a Mercedes...

 

[dry run]

Strange, I don't find the 19" wheels and P-Zero tyres on my AMG line CLS 350d noisy at all?? Previously had 18" with Michelin Pilotsport on a E350 and found those tyres quieter than the Conti Contact 5's. Maybe changing the tyres would be a cheaper (and nicer looking) alternative? Not sure 17"s will suit a CLS

 

[JBell]

Tyre size does not dictate noise, tyre brand and model does, all tyres have a dB rating on, so look for a low number - probably around 69

Drop the pressures by 2psi

Stick a set of Dunlop SportMAXX tyres on it they are the quietest and most pliant tyres around ATM, Pirelli are quite hard and do have stiff sidewalls

 

[molgrips]

The tyre pressures are already at 32/33 which is the number on the plate.

I'm not sure that tyre size doesn't affect noise. Most of the options for my large wheels on black circles are around 74 or 75dB, whereas most of the 17" options are 70dB with some even lower. There is a definite correlation - and that's just the drive-by noise not in-car noise.

I have to say the appearance of my car is very low down the list of things I care about. I might spend many hours driving it but I only spend a few seconds looking at it when I get in or out!

 

[JBell]

The tyre pressures are already at 32/33 which is the number on the plate.

I'm not sure that tyre size doesn't affect noise. Most of the options for my large wheels on black circles are around 74 or 75dB, whereas most of the 17" options are 70dB with some even lower. There is a definite correlation - and that's just the drive-by noise not in-car noise.

But you can buy a tyre the same size as you already have from a different brand with a lower noise rating therefore it is quieter, every 3dB drop is half the noise, that is for drive by noise and in car noise.

For example the front tyre on your car is a 255/35 R19, the Pirelli has a dB rating of 73 and the Dunlop SportMAXX RT2 69dB and on the rear the Pirelli is 74dB and the Dunlop is 70dB

The Dunlop is also a much more compliant tyre overall, you will find the Pirelli gets noisier the more worn it gets.

18"

Front Wheels: 8.5Jx18 ET34.5 fitted with 255/40R18 99Y XL
Rear Wheels: 9.5Jx18 ET48 fitted with 285/35R18 101Y XL

17"

8.5Jx17 ET34.5 fitted with 245/45R17 99Y XL all round

 

[Gazwould]

 

[dry run]

A CLS is a strange choice of car for someone who doesn't really care what their car looks like IMHO.

 

[molgrips]

A CLS is a strange choice of car for someone who doesn't really care what their car looks like IMHO.

I care, but not as much as I care about refinement and ride quality!

It's a long story but I had to get a car immediately, and the only choices were this or a Kia Sportage (old model) and they were the same price...

 

[JBell]

A Kia Sportage (old model) and they were the same price...

You did make the right choice

 

[molgrips]

For example the front tyre on your car is a 255/35 R19, the Pirelli has a dB rating of 73 and the Dunlop SportMAXX RT2 69dB and on the rear the Pirelli is 74dB and the Dunlop is 70dB

Hmm yes.. although those Dunlops (Sport Max Race on blackcircles.com) are 71dB and are rated F on fuel which is pretty poor, and only C on wet grip so you seem to be sacrificing other areas. One would assume that they are quiet because they are soft and hence would wear fast.

You did make the right choice

I know I said I didn't care about looks but I mean.. there is a line I won't cross

 

[SmartAmg]

Nooooo, don't do it, 19s suit the CLS so well, if you MUST do it go for 18s, personally I think 17s will look a bit lost.
I don't see the problem at all with 19s or even 20s for that matter, but s'pose that's just me.

 

[molgrips]

I don't see the problem at all with 19s

I could put up with the ride, but I don't want to risk a smashed rim and the noise is annoying.

The benefit of 17s would be that the rims (if I can find them) would almost pay for themselves, and given the extra fuel economy points and my assumption that as less sporty tyres they'd last longer they'd probably come in significantly cheaper over the long term.

Having said that the 18" tyre sizes listed in the book (255/40 front and rear I'd go for) aren't too bad, and they do non-performance tyres which I'm assuming are going to be more comfortable such as the Bridgestone Turanza T005 or the Goodyear Eagle F1 Asymmetric which is A on fuel and 69dB.

I'm aware though that the noise I'm hearing is rumble which is transmitted through the car, and probably not the same noise that the tyre tests are measuring outside the car. But the only way to figure out what tyres are quieter is to either fit them and hope, or find someone who has them in the same car and try them out.

Seems like the only place I can get these rim sizes used is from a German eBay store - prices are good but there's Brexit tax on top of that and big delivery so it'd be £700 or so probably. Any tips on getting used rims? It's not a rare size but most examples are from I think E or C classes and they have a different offset.

 

[molgrips]

Looks like going to the non-staggered setup with 8.5 on the back instead of 9.5 gives a lot more options with regard less sporty tyre models.

Re looks, I think that all the wheel combinations result in the same actual diameter, you just get more black and less silver. I don't think it'd affect the stance of the car that much.

 

[JBell]

Hmm yes.. although those Dunlops (Sport Max Race on blackcircles.com) are 71dB and are rated F on fuel which is pretty poor, and only C on wet grip so you seem to be sacrificing other areas.

Fronts, A for Rain and C for fuel here:

Dunlop Tyres / Car / Dunlop SportMaxx RT2 P Dunlop Sport Maxx RT2 - 255/35 R19 (96Y) XL MFS TL Fuel Eff.: C Wet Grip: A NoiseClass: 1 Noise: 69dB Car Tyres - MPV Tyres - People Carrier Tyres - 19" R19" - 255/35/19, 255/35R19

Buy online cheap Dunlop Tyres / Car / Dunlop SportMaxx RT2 P Dunlop Sport Maxx RT2 - 255/35 R19 (96Y) XL MFS TL Fuel Eff.: C Wet Grip: A NoiseClass: 1 Noise: 69dB

www.camskill.co.uk

Rears, A for Rain and E for fuel (I wouldn't expect a tyre that wide to be a C for fuel!!)

Dunlop Tyres / Car / Dunlop SportMaxx RT2 P Dunlop Sport Maxx RT2 - 285/30 R19 (98Y) XL MFS TL Fuel Eff.: E Wet Grip: A NoiseClass: 1 Noise: 70dB Car Tyres - MPV Tyres - People Carrier Tyres - 19" R19" - 285/30/19, 285/30R19

Buy online cheap Dunlop Tyres / Car / Dunlop SportMaxx RT2 P Dunlop Sport Maxx RT2 - 285/30 R19 (98Y) XL MFS TL Fuel Eff.: E Wet Grip: A NoiseClass: 1 Noise: 70dB

www.camskill.co.uk

One would assume that they are quiet because they are soft and hence would wear fast.

There is always a trade off between wear and noise, the Dunlop is a softer tyre hence it is more pliant, quieter and by all reviews gives a great ride

 

[JBell]

The benefit of 17s would be that the rims (if I can find them) would almost pay for themselves, and given the extra fuel economy points and my assumption that as less sporty tyres they'd last longer they'd probably come in significantly cheaper over the long term.

The fuel use difference is minimal, you would need to be doing 10's of thousands of miles a year. Less sporty doesn't mean they last longer the composition of the rubber determines how long they last for

There is no way you would recoup the cost of a £700 set of wheels in the added fuel economy.

You don't have to put OEM wheels on it, you just need a set of 8.5x18" ET35 wheels that will fit (the problem is the rear that will sit a Looooong way in the arch)

Having said that the 18" tyre sizes listed in the book (255/40 front and rear I'd go for) aren't too bad, and they do non-performance tyres which I'm assuming are going to be more comfortable such as the Bridgestone Turanza T005 or the Goodyear Eagle F1 Asymmetric which is A on fuel and 69dB.

Steer well clear of Bridgestone, terrible things, the GY Assy 5 is superb and loads of rim protection

But the only way to figure out what tyres are quieter is to either fit them and hope, or find someone who has them in the same car and try them out

@s5tuart on here with the cleanest CLS in the world is using the Dunlops, I am sure he would give you real world opinions

 

[molgrips]

There is no way you would recoup the cost of a £700 set of wheels in the added fuel economy.

Not on its own no.

17" wheels on the German eBay place are about 600 € with delivery, so probably £500 if I have to pay VAT. Hankook Ventus S1 Evo 2 in the 245/45/17 is currently £111 on Black Circles which looks good with being quiet and decent on fuel. If I were to stick with 19s, out of the current list on BC I would get the Goodyears as above at £135 and probably the Goodyears again on the rear but at £230 in that size. That's a total of £730 for a full set given my criteria vs £444, so currently £286 more expensive. Those tyres are all C rated (better than what I have now and actually not that bad) so by my calculations assuming a current 45mpg that's an extra roughly 1.75mpg which means an extra er... £11 in fuel if you do 10k miles.

Ok so that's not a lot BUT in my past experience energy saving tyres last FAR longer than non-energy saving; however these days they appear not to be advertising specific energy saving version. But surely wide high performance tyres are softer compound and will last less well than efficient tyres?

In any case you still make half the cost of the new rims back at tyre purchase time alone, which is significant, even if they didn't last any longer.

 

[JBell]

Hankook Ventus S1 Evo 2 in the 245/45/17 is currently £111 on Black Circles which looks good with being quiet and decent on fuel.

Which one?? there are loads

Car Tyres - MPV Tyres - People Carrier Tyres - 17" R17" - 245/45/17, 245/45R17

www.camskill.co.uk

 

[Blobcat]

You could put your car details into “MyTyres” website - you can buy rims and tyres suitable. It’s a German site and do some good deals - I bought my 16” winter wheels and tyres from them
I’d also go for 17’s as it’s nicer driving than sitting looking at it…