Z4 Sport suspension removal

ianstones · Post by **ianstones** » Sat Jul 02, 2016 7:57 pm

Hello
I recently bought a 2015 Z4 M sport with sports suspension. I love the car but did not test drive on some of less well maintained roads I travel on regularly and find the ride very uncomfortable at times. Can the suspension been changed to normal non sport suspension.
Ian

beezernorton · Post by **beezernorton** » Sat Jul 02, 2016 8:20 pm

Yes. Put some non runflats on.

Maniac · Post by **Maniac** » Sat Jul 02, 2016 8:44 pm

ianstones wrote:Hello
I recently bought a 2015 Z4 M sport with sports suspension. I love the car but did not test drive on some of less well maintained roads I travel on regularly and find the ride very uncomfortable at times. Can the suspension been changed to normal non sport suspension.
Ian

Changing to non run flat tyres will remove the harshness. Anything is possible of course and yes you could, with a suitable bank balance, replace the suspension to normal oem or aftermarket.

techathy · Post by **techathy** » Sun Jul 03, 2016 10:52 am

^^ That! non-RFT tyres are much better especially if you've got 19" rims, also see significant traction gains.

Valor1 · Post by **Valor1** » Wed Jul 06, 2016 3:31 am

Hi. posted this in another thread. The change was so drastic that my suspension went from harsh to the point I was going to sell the car to now thinking the suspension is too soft!!!! That's how good this specific tire switch is!

When I bought my Sdrive35i (manual gearbox) she had new Bridgestone tires from the BMW dealer and ~12k miles on the clock. Mycar looks like the Z4 at the top of the forum webpage. First, I didn't care for the ultra low profile look. Then I read there was a lawsuit about these 19" wheels failing. Well, sure! Tiny rubberband tires on LA roads and the thing rides like a rock with factory recommended high pressure.

So, after much research I came up with the lightest and most comfortable high performance tires I could find. Installed Continental Extreme Contact DW tires 245/35 front and 275/35 rear. Not only does the car look better and more aggressive, but it now rides with the smoothness of my SL Mercedes. Gone are the jarring impacts and most of the creaks one hears with the hardtop up. So smooth!!!!

Pushed into a turn the car grips that much better with these fatter tires!

It's a win-win all the way around! I can't recommend this tire swap enough. I ditched my brand new OEM tires for these and couldn't be happier!

ianstones · Post by **ianstones** » Mon Jul 11, 2016 10:39 am

Many thanks for all the advise. I am going to change them ASAP.
Ian

Maniac · Post by **Maniac** » Mon Jul 11, 2016 11:43 am

You'll never lose the fact that the suspension travel is short, That's just a fact of this type of car but you can reduce the shock factor with the tyre swap. It won't help with pot holes though, they still feel like you've smashed an alloy or a shock through the turret top every time.

I noticed a spider like effect in the lacquer on one of my alloys after a recent pot hole encounter so I suspect that's gone out of round a little now. 313s are like rocking horse do dah too.

They're due a refurb for water ingress this year so I'll get them checked at the same time.

techathy · Post by **techathy** » Mon Jul 11, 2016 2:23 pm

A lot of that harshness going over pot holes is due to the poor choice of wheels which are too large for the car & thus ending up with tyres with not enough side-wall.

beezernorton · Post by **beezernorton** » Mon Jul 11, 2016 8:39 pm

Keep your runflats handy if your on a PCP or plan on trading it in back at BMW sometime otherwise you might get charged for a new set. They can't sell it as a Used Approved without them.

Maniac · Post by **Maniac** » Mon Jul 11, 2016 9:13 pm

techathy wrote:A lot of that harshness going over pot holes is due to the poor choice of wheels which are too large for the car & thus ending up with tyres with not enough side-wall.

You have small ones?

techathy · Post by **techathy** » Mon Jul 11, 2016 10:40 pm

I’m running 18” rims and deliberately running a tyre widths that are ‘square shouldered’ on the sidewalls. This really softens out the crashing bumps compared to the lower profile 19” option.

This was when I had 245/40R18 front tyres, which were great for comfort but scrubbed a little

I'm now on 245/35R18 for dynamics reason.

ianstones · Post by **ianstones** » Fri Jul 15, 2016 8:56 pm

On Thursday I replaced the runflat tyres with Dunlop Sport Maxx RT2's and it has transformed the car. Gone is the harshness I hated in the ride. The Dunlop Sport Maxx also has the lowest dB rating around so the road noise with the top up and down is greatly reduced.

Well worth the £450 cost.

Why do BMW continue to fit runflat tyres?

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