Run flats

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   I have owned a 440i M sport + Coupe for over 5 years. Throughout that time, the ride and handling has concerned me. I have some questions that someone may have some answers to.

The current, original tyres are Good Year run flats, has anyone driven a 4 series with non run flat tyres on 19 inch wheels, if so does it improve the ride and handling?

The suspension is quite harsh and jiggles around a lot, this is a known issue. Birds BMW sell a suspension kit to compensate for this. Does anyone have any feedback on this system? I wish to increase the comfort and predictability. I do not wish to make it stiffer or lower.

There is nothing wrong with any of the current parts, the car has only covered 22k miles. It's their performance that is the issue.

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
Pegasus800 Members Profile Send Private Message Find Members Posts Add to Buddy List Club Member Joined: 18 Jan 2025 Location: Wiltshire Status: Offline Points: 5	Post Options Post Reply Quote Pegasus800 Report Post Thanks(0) Quote Reply Topic: Run flats Posted: 18 Jan 2025 at 12:42pm
	I have owned a 440i M sport + Coupe for over 5 years. Throughout that time, the ride and handling has concerned me. I have some questions that someone may have some answers to. The current, original tyres are Good Year run flats, has anyone driven a 4 series with non run flat tyres on 19 inch wheels, if so does it improve the ride and handling? The suspension is quite harsh and jiggles around a lot, this is a known issue. Birds BMW sell a suspension kit to compensate for this. Does anyone have any feedback on this system? I wish to increase the comfort and predictability. I do not wish to make it stiffer or lower. There is nothing wrong with any of the current parts, the car has only covered 22k miles. It's their performance that is the issue.

Sponsored Links

Tony Members Profile Send Private Message Find Members Posts Add to Buddy List Club Member Joined: 12 Dec 2008 Location: United Kingdom Status: Offline Points: 210	Post Options Post Reply Quote Tony Report Post Thanks(0) Quote Reply Posted: 21 Jan 2025 at 1:26pm
	Well, the M-Sport probably has stiffer/lower suspension than the non-sport version...and runflats do by their nature have a stiffer/heavier/thicker sidewall to cope with being driven on when flat. Strangely I have a F31 335xD M-Sport Touring that has recently replaced my F31 320D M-Sport Touring, and on exactly the same 19" Goodyear runflats the 320D ride better (less harsh jiggles over bumps). Whether that is due to a lower weight or suspension tuning I don't know. I cured the 320D issue by moving to 18" non-run flat Continental AllSeasonContact tyres last winter and have left them on for over 12 months, but that may not suit a more powerful model. I'll do the same on the 335xD once I've fixed the non-responsive TPMS on the 18" wheel set that I've lived with for 12 months.
	2006 Z4MC Individual Ruby Black, Extended Champagne, Piano Black trim 2016 335xD M-Sport Touring Estoril Blue, Black Dakota Leather, M-Performance carbon/alcantara trim

Pegasus800 Members Profile Send Private Message Find Members Posts Add to Buddy List Club Member Joined: 18 Jan 2025 Location: Wiltshire Status: Offline Points: 5	Post Options Post Reply Quote Pegasus800 Report Post Thanks(0) Quote Reply Posted: 21 Jan 2025 at 2:29pm
	Thank you Tony. I don't see why all season tyres would be a problem. I have all season tyres on my Porsche Cayenne 4.2 V8D That has just short of 400 bhp and 850 nm of torque. I will probably go for non run flat, Michelin Pilot Sport tyres on the BMW.