Changing from 16" Runflats to 18" Normal - Ride Quality

[sbhumphrey]

Looking for some advice. I have been driving my 2003 2.5 Z4 on 16" runflats and the ride is pretty harsh. Seems the best way to reduce this is to fit non run flats but if I do that I am tempted to go for bigger wheels (18") too as I like the look. My question is will changing up wheel sizes negate the benefit of fitting the non run flats and be just as firm? If that is the case I may just stick non run flats on my current 16" wheels. Any help would be appreciated.

 

[sars]

I went from 17" RFT's to 18" conventional, ride is slightly firmer and you notice it on uneven road surfaces, however the handling and feedback have improved

 

[sbhumphrey]

I was hoping to reduce the firmness of the ride. Sounds like I need to stay with the 16" wheels but just get rid of the RFT's

 

[johnbmwboy]

I've driven a zed on 16" normal (non run flats) tyres and the ride was very compliant. In fact I liked it a lot. Very little body roll and soaked up the bumps and camber changes. Go for it.

 

[Adamski]

With wider 18s you may end up with tramlining, however it will be less extreme if the 18s are on non run flats.

If you want a softer ride, change to non run flats on 16s

 

[sars]

How about going for 17" with conventional tyres as a happy compromise

 

[sbhumphrey]

17" with conventional tyres might be an option. I so like the way the larger wheels fill the arches. Does anyone know if the conventional tyes are taller?

 

[Mrsbrown]

Went fom 16 rft to 18 vredestein's....ride quality is massively improved...

 

[sbhumphrey]

What profile were the vredesteins?

 

[Adamski]

On 18s the fronts are 225/40 18s, rears are 255/35 18s

 

[Shooter]

On my previous 2.5i, i changed the original 16" rims with Bridge RFT to 18" rims with GY F1A tyres, ride quality was significantly improved.

 

[bcworkz]

17" with conventional tyres might be an option. I so like the way the larger wheels fill the arches. Does anyone know if the conventional tyes are taller?

There's always some variation between manufacturers, but for a stated size, they should be more or less the same. When you go with larger wheels, you normally go with a lower ratio, so the overall height is about the same. You may get away with a slightly higher ratio, but that size may be harder to find, may rub, makes your final drive ratio taller, and your speedometer will be off.

So a bigger wheel normally doesn't physically fill the arches more, only visually, since in a way you don't 'see' the shorter rubber.

 

[WizzEssex]

Hi all- I did exactly the same a month or so ago- changed the 16" wheels with RFT to 18" 108's and Pirelli PZero tyres- amazing difference- better ride quality - 'zero' tramlining and much more responsive steering. Was amazed- despite the fact everyone here told me it would happen!!