[sandman69]

Hi,

I have a 2021 330i xdrive and live in a pothole ridden state. With rough roads and potholes, I plan on changing the stock RFT 225/45-18 to non-RFT 225/50/18 because I prefer the additional sidewall over 245/45/18. I also figure the additional sidewall will provide a softer ride than the current firm RFTs.

I’d like to know if there is any rubbing or other issues with the 225/50-18 setup? I know rule of thumb is +3.0% overall diameter and the setup proposed here is +3.5%. So it’s veeery close!

[SLGrassoPA]

I would say more than the tires, consider getting the suspension components changed to something similar to the Adaptive M option from the factory. That will drastically improve your ride quality over bumps, etc... it may cost a bit more than 4 new tires, but well worth it, especially if you live anywhere in the northeast where the roads are mostly terrible.

[sandman69]

Since I may change RFT to non-RFT anyway, how much will 225/50-18 improve the ride comfort? Will the tires perform without rubbing?

I've driven a 2023 430i Grand Coupe for a week and I love the soft suspension especially for my sciatica and back issues. I'd consider suspension parts but don't want any lowering, only ride comfort enhancements (ie: goal is similar suspension feel to the 430i or 5-series double wishbone). Does anyone have suggestions for suspension parts/model numbers?

[SLGrassoPA]

https://www.bmw-m.com/en/topics/maga...-fahrwerk.html

[G30M]

i kinda did this to my subaru, went from 225 45 18 that was too harsh, to 235 45 17 for more sidewall

the car now is very bouncy like a pogo stick. but hey the ride less harsh!

[Gaviatrix]

Originally Posted by sandman69

Hi,

I have a 2021 330i xdrive and live in a pothole ridden state. With rough roads and potholes, I plan on changing the stock RFT 225/45-18 to non-RFT 225/50/18 because I prefer the additional sidewall over 245/45/18. I also figure the additional sidewall will provide a softer ride than the current firm RFTs.

I’d like to know if there is any rubbing or other issues with the 225/50-18 setup? I know rule of thumb is +3.0% overall diameter and the setup proposed here is +3.5%. So it’s veeery close!

You could just consider ditching the runflats. It would make quite a difference, depending on what you're on now. To misquote the old ad, tyres aint tyres. Research your choices carefully with an emphasis on comfort if that's what you're looking for. You might find a touring tyre like a non-RFT Michelin Primacy 4+ or Bridgestone Turanza T005 or similar are a big change if you're currently on a sport RFTs.

[sandman69]

You’re thinking is like mine. Currently on the car are the Pirelli P7 RFT. The best non-RFT noise and comfort tire in the Grand Touring All-Season category are the Pirelli P7 AS PLUS 3 followed by the Michelin Primacy Tour A/S on TireRack.

I want to go a step further and add the extra sidewall by going 225/50-18. A lot of potholes in my region and every cm of sidewall will be great.

The question is if there will be rubbing? Tire comparison shows tire diameter will increase from 660mm (stock 45-series tire) to 683mm (50-series tire).