Tyre pressures

[Rickg3]

Trying to find tyre pressures for my 17inch wheels with almost new none rf goodyear tyres that will give me a comfortable ride without damaging the tyres. Although I have my moments, I'm a bit old for tearing it up all the time and just enjoy cruising around the lanes of Suffolk with the top down listening to the burble of that lovely 6 cylinder engine.
And if anyone has tips on softening the suspension that would be great.

 

[matsmith749]

Which car / year is it Rick?

I'm asking because on 17s with non runflats (goodyear what exactly?) you seem to have the plushest options.

Maybe tired suspension (depends on age / milage) - when you say 'softening' do you mean firmness, or do you have banging / clattering over bumps?

This link rates the current options out there for comfort - might be worth a look?

Tyre Reviews

https://www.tyrereviews.com/Tyre-Type/Passenger-Car-Summer-Max-Performance-Tyres/

 

[brillomaster]

standard tyre pressures are what, 36psi front, 39psi rear? does seem rather hard for big sidewall 17s. standard pressures on a E85 z4 is 33psi/36psi, i'd give that a go.

 

[B21]

standard tyre pressures are what, 36psi front, 39psi rear? does seem rather hard for big sidewall 17s. standard pressures on a E85 z4 is 33psi/36psi, i'd give that a go.

 

[Rickg3]

Mat Smith - hello again Mat. I have Goodyear Eagle F1 Asymmetric 5 all around. Done about 2000 miles. There doesn't appear to be anything wrong, after reading a few reviews etc I've come to the conclusion the ride on a Z4 is just firm.
Tyre pressures I have been using are 32 front 34 rear.
I think I have been driving Jag's for too long!

 

[javis20]

This is from the manual.

 

[matsmith749]

Hey Rick - those assymetrics are well regarded for comfort, looks like you have it as good as you will get unless you fancy changing out the suspension.

You didn’t mention what car this is, but if you have the msport version it is a little stiffer than the standard car.

If it is approaching 10 years old or has >50k miles, you might see a good improvement in ride quality with a shift to one of the bilstein shocks range for about a grand. Might be worth considering?

Ride quality is a combination of tyres, wheels, shocks, all the joints & linkages. This all ages over time & miles.

Another tip - think about filling in your car details in your forum signature, takes a lot of the guesswork out of giving as helpful answer going forwards.

 

[Rickg3]

Morning Mat when I think back over the years I've had a Z3 and a couple of convertible 3 series, both had stiff suspensions compared to the 5 series that I normally ran.

The car is a 2009 sDrive23i auto with 104000on the clock. Has full history and runs beautifully. Unfortunately I don't know if or what parts have been replaced, so you may have hit on the my problem. IF the shocks are original that could well be the problem. I will get them checked out. Thank you

 

[matsmith749]

At 13 years and 100k miles, you will see a transformation in the ride from a new set of shocks. It will not be subtle.

Let us know how you get on.

 

[Busterboo]

This is from the manual.

Hard love, but true.

 

[matsmith749]

The manual is showing tyre pressures for the oem runflats.

Not the non-runflats.

General consensus is to go 3-4 psi lower front/rear on non run flat tyres, and there is no official pressures available from BMW.

 

[javis20]

Tire pressure should be the same for run flats and non run flats.

I had ask this question to Mike MIller, BMW CCA Roundel Technical Editor. His response was as follows.

Subject: Re: Tire Air Pressure RFT's to non RFT's

"There are the tire pressure specs on the sticker in the driver's door jamb. These specs are for U.S. only. And then there are the specs in the owner's manual. I use the owner's manual specs no matter if run flat or normal tires. "

 

[B21]

Tire pressure should be the same for run flats and non run flats.

Incorrect…tyre pressure is determined by required pressure relative to the load factor of the tyre..if you require the tyre to carry more load then you need to increase pressures..most non run flat tyres fitted have load factors way above that required for a relatively light car on relatively large tyres..

Dynamic loads increase the actual loads so higher speeds, more aggressive driving requires higher pressures…

Based on that logic tyre pressures starting around the 26-28 psi are from a safety viewpoint acceptable..if you are poodling around..

As an example the G29 with wider tyres has advisory pressures in the 30-32 psi area..

The OE runflat is a way way obsolete design..to say that a modern design tyre of different design and construction needs the same pressures as a tyre ranked bottom (67 th) of all sports tyres tested by one tyre review entity is no basis for a recommendation….IMHO

 

[matsmith749]

BMW Z4 owners group suggests a bit lower for non-runflats, as do many users that have tried both.

Your milage may vary I guess, as non runflats are officially not a supported option.

 

[Busterboo]

I nearly had an accident yesterday afternoon. Coming out of a roundabout on a 2-lane by-pass at some speed in Sport+, the 35iS fish-tailed.

I know the road very well, it was dry, both front & rear Pirelli P Zeros are completely legal, Sport+ adapts power, suspension and steering efficiently and the car has never behaved like this before.

So, it's entirely possible, of course, that the cause was the twat who was driving. However, it now occurs to the same twat that he hasn't checked the tyre pressures for longer than usual. This morning, I shall. I'll post the figures later today.

 

[Busterboo]

OK, so tyre it probably was. The nsr was 7psi off its normal 42. The Tyre Monitor, however, although active, had said nothing.

 

[flybobbie]

I have run on 18 inch 40 rear with even wear, 42 the crown wears more. If i go less the back end feels a bit wobbly.
Front i go 38, the steering on these is already compromised with electric steering.

Now with GY asymetric 5, i think. I found the earlier 2's a better tyre. 5 seem harder wearing thus a bit more unstable on bumpy country lanes.

 

[Marcoose]

it's entirely possible, of course, that the cause was the t**t who was driving.

You've got this right, Buster.
oke:
:rofl: :rofl:

 

[Busterboo]

You've got this right, Buster.
oke:
:rofl: :rofl:

One way or the other, I think I have.

 

[Phoenixboy]

OK, so tyre it probably was. The nsr was 7psi off its normal 42. The Tyre Monitor, however, although active, had said nothing.

42 in the rear!
Must be like driving on concrete blocks.....