Really uncomfortable ride quality

[Chrishazle]

I have a C220 204 estate on 17's - in my case 245/40 Goodyear Eagle F1's on the rear and now 225/45 Michelin Crossclimates on the front (previously Eagle f1's), but at 33psi. Ride is lovely, and even if I have to inflate for full load (as in booze cruise day) it's about 38psi on the rears. No way would I put 42psi in my tyres, it's way too much and would destroy the ride. My car is Elegance trim - wonder if OP's 205 in SE trim has harder suspension.

 

[markjay]

I suspect that many newer cars now run around on over-inflated tyres. This may be to achieve certain type approval/emissions figures under test by reducing rolling resistance rather than for speed/ load bearing characteristics?

My Suzuki Vitara has a defult pressure of 41psi which is labelled as 'Eco', and then the usual range of 33-36psi which is labelled as 'Comfort'.

I suspect that the cars all leave the factory with 41psi and this is also how they were tested for mpg and emissions... and then owners reduce it to 33-36psi for real-world driving.

 

[GrahamDevizes]

Morning all, well I adjusted the tyre pressures down to 34psi and it has made a big difference to the ride quality so thanks for the suggestions. Only issue now is that the dashboard warning is constantly telling me that the tyres need inflating

 

[whitenemesis]

Only issue now is that the dashboard warning is constantly telling me that the tyres need inflating

You should be able to reset to the new pressures.

 

[grober]

This will give you an idea what to do- settings etc may not be exactly the same for your car but the menu / steering wheel buttons interactions bit will likely be the similar.

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[190]

Part of the problem may be the 94 tyre load rating which is 670 Kg or 1340Kg per axle. If the load rating is higher than it needs to be then the stiffer tyre construction reduces ride comfort regardless of correct pressure. I know that my load rating should be 89 or 590 Kg which is more than enough for the max laden weight of the car so I would never exceed that when replacing tyres. The W speed rating for 168 MPH won't help either as high speed rated tyres have stronger construction to resist expansion at high speed. Again I would never choose a higher speed rated tyre than necessary.

Lastly the max pressure printed on the sidewall is almost never appropriate. Most tyres reach their maximum load rating well below this figure so it shouldn't be viewed as a target. Things have got confused with manufactures recommending higher pressures than necessary for reasons of economy. The benefit is small though with a 10% increase in pressure typically producing only 0.8% improvement in economy. At one time they would have consulted industry standard tyre load tables to derive the correct pressure for the weight of the car but now they seem to be exceeding these figures by some margin with the inevitable reduction in ride comfort.

 

[GrahamDevizes]

Thanks guys, most helpful

 

[Deletedmember130310]

Part of the problem may be the 94 tyre load rating which is 670 Kg or 1340Kg per axle. If the load rating is higher than it needs to be then the stiffer tyre construction reduces ride comfort regardless of correct pressure. I know that my load rating should be 89 or 590 Kg which is more than enough for the max laden weight of the car so I would never exceed that when replacing tyres. The W speed rating for 168 MPH won't help either as high speed rated tyres have stronger construction to resist expansion at high speed. Again I would never choose a higher speed rated tyre than necessary.

Lastly the max pressure printed on the sidewall is almost never appropriate. Most tyres reach their maximum load rating well below this figure so it shouldn't be viewed as a target. Things have got confused with manufactures recommending higher pressures than necessary for reasons of economy. At one time they would consult industry standard tyre load tables to derive the correct pressure for the weight of the car but they mostly seem to be exceeding these figures by some margin with the inevitable reduction in ride comfort.

good spot - I missed the OP referenced his tyres have a load rating of 94

 

[Gbrowncls55]

It will say run flat or RF on the sidewall somewhere if they are. On 17s the ride should be good. Reduce tyre pressures as suggested and when you next change tyres consider Goodyear F1 or dunlop MaxxRT. I have found these to be significantly quiter and more comfortable than contis or pirellis. Incidentally my car has no spare but is not on run flats (and never was). It is rather old though.

 

[Jtvgray]

Had my 2017 c220d for 3 months now and agree entirely with the OP....it’s the most uncomfortable ride I’ve ever known, particularly over bumpy roads. Tyres are set at 35 as per fuel cap but I still have little confidence in the handling, especially in the wet.

 

[GrahamDevizes]

Just checked inside my fuel cap and the only two recommended tyre pressure settings stated there are based upon three people in the car and states 42 psi all round or five people and a full load for which it suggests increasing rear pressure to 46 psi. When I use the car, it's always just me at 13 stone with a couple of boxes of light stuff in the boot, total weight in there no more than 10kg. So, a lot less weight than if I were carrying two additional people

 

[190]

Just checked inside my fuel cap and the only two recommended tyre pressure settings stated there are based upon three people in the car and states 42 psi all round or five people and a full load for which it suggests increasing rear pressure to 46 psi. When I use the car, it's always just me at 13 stone with a couple of boxes of light stuff in the boot, total weight in there no more than 10kg. So, a lot less weight than if I were carrying two additional people

Very strange that the minimum recommended pressure is that high when my W204 on skinny 195/60/R16 recommends 32 PSI. What are MB doing selling a car/tyre combination that rides so badly.

 

[Deleted member 6183]

Very strange that the minimum recommended pressure is that high when my W204 on skinny 195/60/R16 recommends 32 PSI. What are MB doing selling a car/tyre combination that rides so badly.

It helps them to be able to quote better MPG figures.

 

[Stratman]

..................................

What are MB doing selling a car/tyre combination that rides so badly.

Trying to get it in to a lower tax band or influence fleet buyers who look at things like fuel consumption to two decimal places.

 

[CaptainChaos]

Very strange that the minimum recommended pressure is that high when my W204 on skinny 195/60/R16 recommends 32 PSI. What are MB doing selling a car/tyre combination that rides so badly.

The higher the profile the lower the pressures tend to be.
Your 60 profile tyres will ride beautifully, but sadly modern fashions have pushed even the smallest car on to giant wheels and correspondingly low profile tyres. The recommendation for my rear tyres is something like 48psi!

 

[190]

The higher the profile the lower the pressures tend to be.
Your 60 profile tyres will ride beautifully, but sadly modern fashions have pushed even the smallest car on to giant wheels and correspondingly low profile tyres. The recommendation for my rear tyres is something like 48psi!

Low profile tyres are even worse than I thought. Besides the poor ride, with pressures that high all of the suspension components must wear prematurely due to increased shock loadings.

I'm quite happy not being fashionable, at least as long as there is a choice available.

 

[Rory]

Part of the problem may be the 94 tyre load rating which is 670 Kg or 1340Kg per axle. If the load rating is higher than it needs to be then the stiffer tyre construction reduces ride comfort regardless of correct pressure.

So here's a thing - it's 670kg at 2.5 bar (36psi). It's not an XL tyre (would be 98 for that).

The tyre's max pressure is 3.5bar (50psi) so no issue with running at 42 per se, but it's well beyond what's needed.