[Bluestu37]

Evening all!
I bought a 2007 335i convertible a few weeks ago, and I have to say I’m struggling with the really firm ride. Any little bump in the road and the car really feels it.

It’s on Bridgestone run flats, could this be the cause? I’ve never driven a car with run flats before.

Thanks in advance!
Stuart

[snedanator]

Yes! The runflats are the problem, and especially the bridgestone runflats have very stiff sidewalls. Do u have 19 inch alloys as well?....if so if u wanted to make the comfort slightly more comfortable..i suggest buying non runflats but going up a profile in the rear.....ie from a 255/30/19 to a 255/35/19.....and for the 225/35/19 front go slightly wider to add more side profile to a 235/35/19. Or even better drop down to 18" alloys for an even more improvement in comfort. But the most noticeable diffrence will be going from the runflats to non runflats and the other suggestions will only make a small but noticable difference. And it's not just ur car, the whole 90x series all have the same crap suspension.....And that would be ur next step if the comfort level u are looking for doesn't happen with changing the tyres or alloys and tyres.

[snedanator]

Or go the whole hog and buy new shocks n springs and new non runflat tyres.....it's a good chance ur suspension is needing refreshed depending on the mileage? Bilstein B12 kit is a great starting point....amongst other setups.....koni etc....

[Jackma119]

Originally Posted by snedanator

Yes! The runflats are the problem, and especially the bridgestone runflats have very stiff sidewalls. Do u have 19 inch alloys as well?....if so if u wanted to make the comfort slightly more comfortable..i suggest buying non runflats but going up a profile in the rear.....ie from a 255/30/19 to a 255/35/19.....and for the 225/35/19 front go slightly wider to add more side profile to a 235/35/19. Or even better drop down to 18" alloys for an even more improvement in comfort. But the most noticeable diffrence will be going from the runflats to non runflats and the other suggestions will only make a small but noticable difference. And it's not just ur car, the whole 90x series all have the same crap suspension.....And that would be ur next step if the comfort level u are looking for doesn't happen with changing the tyres or alloys and tyres.

+1

[therealdb1]

Good choice!

Yes ditching the RFT's is the first job on the list. That will transform the ride of your car.

Do this and try it for a while before you start throwing money at smaller wheels or new suspension components.

My 2007 335i has perfectly acceptable ride on 19" rims and 30 profile rears with stock suspension but then again it does only have 36,000 miles on the clock.

In fact only last weekend I changed the original from new front brake pads and discs! I'm still running it in really

[RajB]

I personally wouldn't start changing the rear profile without doing the same with the front to ensure the front/rear ratios stay consistent.

Definitely swap the tyres to non-RFT's and perhaps go up a tyre size (so 235/35/19 & 265/30/19). Just swapping the RFT's out will improve ride greatly. Then depending upon how you get on you can start to consider suspension etc.

[Bluestu37]

Thanks chaps!
I will start with changing the tyres

[RajB]

Originally Posted by Bluestu37

Thanks chaps!
I will start with changing the tyres

No problem. Let us know how you get on.

[old grey steve]

Mainly what the others like RajB (Hi Raj by the way long time) but the one thing that is 100% worth doing is tailoring the alignment on the car to suit(and that will mean moving the settings out of the standard BMW's standard set up and to get this perhaps spot on might mean you'll need someone with some common sense doing the job)

I had 19's on my old 335i went no run flats had a Blistein B6/Eibach Pro kit and EiBach front/rear roll bar set up with front camber plates on mine and drove the car in stages the same day as bits went on through the build, to test/verify(this was done for a magazine feature) but the one thing I felt that made a marked difference after all this was tailoring the alignment to suit what had taken place, it made the car ride better over expansion joints/over undulating roads rutted roads it simply rode over these type of obstacles better, plus it made a difference to tyre wear(inner shoulders on the rear outer/inner shoulders front) as I saw better tyre mileage overall more even wear better ride as I explained I'd say the car may have been oh so slightly quieter as well on certain surfaces(though this is if present a very small difference and only a sensation I felt was taking place) but it made the car over all with the mods I had more rewarding to drive/own.

Of course you don't need to have all the suspension type things I had on my car done to yours, you could if a re fresh is needed just replace springs/shocks for instance but the standard set up on the suspension side, let alone the parts used on these cars IMO doesn't work overall for these cars in this country, its too hard too crashy, enough people have asked the same questions re ride quality both in the press and on forums like this and the only plausible answer seems to be either live with it and the issues known or go for the mods suggested as people have tried/tested them and its their opinion you'll be reading but for me the alignment was one thing on the posts so far written that wasn't mentioned.

Re the issue same goes for 5 series and especially X5's the difference can be night/day

Hope this helps