Run flat 16s for normal 18s

[Timmo478]

Hi all. Will changing from standard bmw 16 inch 5 spoke alloys with Bridgestone run flats. To normal rubber, staggered 18 or 19 inch alloys be much more of a softer ride. First Z4 so have no experience to compare although the ride at the mo is shockingly hard.

 

[kis]

I went from 18” runflats to 16” runflats and noticed an improvement in comfort.

When I went from 16” runflats to 17” NON runflats I noticed the most improvement in comfort.

I then later went from 17” non to 18” non and didn’t feel too much of a difference.

In my opinion the best trade off is 18 with non run flats. If you go 19 with such a reduced sidewall you’re going to be sacrificing some of the comfort element.

Also be worth noting that your suspension will probably be really old and tired. So that will be attributing to the comfort and ride quality element

 

[skelters]

Bin the runflats or sell them and the wheels.

18" will be best with Goodyear or Michelin or Pireli etc.

19" might be a bit too harsh over the bumps depending on the suspension.

 

[Timmo478]

Thanks all. Gonna sort some 18s out then sell the old ones on.

 

[tee.gilding]

19's look perfect to fill the arches but the ride is fairly harsh. 18's are probably the perfect size for cosmetics/practicality. 17's are probably the most comfortable without looking tiny.

 

[MattZCars]

19's look perfect to fill the arches but the ride is fairly harsh. 18's are probably the perfect size for cosmetics/practicality. 17's are probably the most comfortable without looking tiny.

I think TG sums it up pretty well. I have a facelift 2.5 SE so its the lowest power 2.5 and I've changed from 16" with runflats to 17" with proper tyres. The difference in ride, handling and steering is huge! It's really like driving a different car. I think the wheels and tyres are somewhat dependent on your car and how you drive it. For me comfort and handling balance are more important than cosmetics. Others will of course have different priorities.

For a standard 2.0, 2.2 or 2.5 my view is that 17's are enough from a purely driving point of view. A 225/45 tyre is more than enough for the power. If you're going to 18's to me these models would be a bit over tyred with 255/35 on the rear.

For a 3 litre I think 18's with 255/35 (or possibly 245/40) are about right, especially facelift Roadsters and all coupes as they have to N52 with a bit more power than earlier 3 litre's.

 

[Mr Tidy]

18s with non-RFTs sounds like a good plan OP.

19s might look better but if you go up a profile on the tyres 18s will fill the arches better - alternatively you can add spacers to the mix.

Or maybe look at E89 18s as they have different offsets and sit much further out in the arches. (I've got E89 staggered 295s on my car and love how it sits on them).

Seeing as we all love photos!

 

[paulc_bkk]

I went from 16s with runflats to 19s on non runflats

Ride was a bit softer afterwards, but since adding coil overs ride is not much different from before I changed to be honest





As others have concluded, 18s might be be best compromise