[rogerxp]

Well, you've all heard me winge on constantly about my M Sport's harsh ride being pretty much unbearable and considering a change after only 8 weeks of ownership - is it the tyres, suspension, etc?!?!?

Well, finally took it to the dealer this morning who had arranged for a like-for-like car to be there to drive back-to-back with mine. Had a mechanic come out with me for a second opinion.

Took their 330i out first. I immediately noticed the difference. Sooooo much smoother than mine. Still firm but nothing like mine. It was an '08' plate (so 2 years newer) and running on Bridgestones.

Then, went out in my 330d ('06' plate, also on Bridgestones), and the difference is massive which the mechanic concurred with. You can feel EVERYTHING in mine, from small joins in the road surface to the obvious pot-holes.

In the 330i, you can obviously feel the road under you, but in my 330d, you are bounced up and down, left and right, over most surfaces. The 330i just seemed to absorb the rough edges of the surface.

At last, someone confirmed that it's not just me, feel so relieved. You know when you convince yourself that it's your mind playing tricks...

Anyway, it's booked in on 14th July (insisted on a courtesy car just in case it turns into a big job), hence the delay. To be honest the mechanic was scratching his head a little as to what the problem could be. It wasn't localised to one corner of the car, it's the whole thing just struggles on any surfaces.

Apart from obviously being a little narked that it was sold to me in this condition (different dealer) I'm just chuffed that it's being address and I don't have to consider a change.

Thought I'd thank you all for your patience in hearing my woes and say that I'm not a 'car-hypercondriac'!!!

I'll report back in a couple of weeks once things are, hopefully, sorted.

[chrisbin]

Good stuff - interesting to see what develops!

[booforty]

Interesting that even on Bridgestones the 330i was smoother. I'm convinced the Michelins are even smoother again

[medrep]

Doesnt the more recent E90 (08') have electric steering, where the older (06') does not?

If so that may give an illusion of improved steering/handling etc?

I cannot get over the difference between my 320d with sp suspension and 18's, compared to my fathers 535dM with 19"s. They are like chalk and cheese, his car is so smooth, turns in faster, lighter steering, less bumpy yet handles so much better. Strange considering the difference in car size, wheel size etc etc. Mine is so crashy and heavy in comparison.

Hope it gets sorted anyway.

[gIzzE]

I would have put the wheels/tyres off the 08 car on yours to start with. It will be the tyres at fault I guarantee it!

[rogerxp]

I unfortunately didn't have the necessary tools on my person to make a quick switch. Could have just swapped the reg plates round except mine's Silver and the 330i was Graphite - they might have spotted that!!!

As for the steering, I didn't drive the 330i so can't comment. It can't be related to steering though as it occurs all the time, even in a straight line.

[Micky Dee]

Surely the 330d has totally different suspension settings to the 330i bearing in mind that Diesel engine usually weighs a lot more. Just a thought. Couldn't they find another 330d to compare it with?

[rogerxp]

Good point. They had a 320d but waited for a larger engined one to appear before we compared - they seemed happy with the weight comparison with a 330i - perhaps close enough for our 'un-scientific' test.

The result was what I wanted - a second opinion that backed me up and one that means it'll be up on ramps soon.

Essentially it confirmed to me that an M Sport shouldn't shake & rattle your bones during 'normal' mixed driving, no matter what guise it comes in.

[rogerxp]

Unlaided Weight Comparison -:

330d M Sport - 1610 (1625 auto)
330i M Sport - 1555 (1570 auto)

Mines a Manual and the 330i was an Auto so only 40 difference. Obviously is depends on where the weight is but I'm sure if you'd put a couple of people in the 330i it wouldn't suddenly start crashing around.

[gIzzE]

But the diesel springs are stiffer, only slightly, but could make a difference?

The latest run flat tyres are far better than the ones from even 12 months ago.

[rogerxp]

Interesting points. I've no idea how old the tyres actually are but must be in excess of 12 months; quite possibly still the ones it left the factory with if the previous owner was careful.

I suppose I could see if there are any used ones for sale at local dealers and pose as a buyer to check out an absolute match. Mmmm...

Only time will tell...

[Gibbo]

Originally Posted by gIzzE

But the diesel springs are stiffer, only slightly, but could make a difference?

The latest run flat tyres are far better than the ones from even 12 months ago.

I agree with GizzE I believe it's the tyres. Had 2 Z4s 2 years ago on 18s and the ride was rubbish. OK far different car but the tyre techology has moved on in the last 2 years. My car is 18's Bridgestone run flat and ride is no problem at all. (Apart from severe pot holes).

I would think latest generation bridgestones could solve your problem. I guess you could also try to find out from someone technical at BMW if there has been changes to the suspension settings between 06 & 08.


If you go down the tyre route make sure you get the latest spec ones fitted on 08 model yr cars.

[rogerxp]

Well, if it's the tyres (and I'm not saying it isn't) I'd be absolutely staggered that they make such a difference. Can't really see anything mechanical being wrong, especially as it's not a localised problem, it effects the whole car. It's the simplest of tests for the dealer to diagnose though.

I'd definately go for Michelin's if I'm to change tyres (now or in the future) however am tempted to try the Falkens. Obviously this is the non-RFT's route however would happily stick with RFT's if I was convinced I could live with the comfort.

[gIzzE]

This is a PM I just received from Mike who bought my PS2's (non run flats) off me and had them fitted today. He was dismayed at the ride on his M-Sport after his old E36 328i sport.
I'm sure he won't mind me posting this.

I simply sent a message saying....

"Well??"

His reply.......

One word...
Awesome!

The only way I can describe it is that the car feels like a BMW should - I now have the car I expected moving from a 3 to a 5 !!

Very quiet, smooth as anything on the motorway and grips really well - does not 'skip' round corners like it did and my fillings have not been tested.

I cannot believe that BMW put the runflat rubbish on as standard! You can't go back to runflat once you have used normal rubber and you only find out how bad they are after changing. Glad I had a BMW before so I had an idea how well it should ride and handle.

[335DJim]

More evidence to back up what gIzzE is telling you (I was here a short while back)

http://www.e90post.com/forums/showthread.php?t=131761

Read the feedback following runflat use..

Cheers

Jim

[rogerxp]

Great input guys; thanks. I'd pretty much already decided to go the non-RFT route but will see what it's like once it's returned from the garage. Seems quite a few highly recommended tyres around at the minute (obviously due to them constantly being improved) - it's getting a little like "pin the 'tyre' on the 'motor'."

[DaveC]

My guess is it's a combination of early car and early runflats. I'm on 55 plate and my car was absolutely appaling with runflats. Maybe later models have tweaked the suspension/bushing to improve the ride with runflats.

[rogerxp]

I did ask whether any 'tweaks' could have been made to the E90 between the two cars ('06-'08) but the mechanic claimed that 'tweaks' would only be made when a car is officially face-lifted. Not sure whether I beleive that or not.

Dave, I presume the only change you have made is to remove the RFT - nothing else, and you're happy with the improvement??

[alcook]

This will be academic when it's been diagnosed, but I can't tie the 'unbearable' part of Rogers complaint and the extreme consideration of actually selling the car to a simple tyre problem....

Roger describes the second car as being so much better and I can't see how a tyre can have this dramatic effect. I have RFT's om my M Sport 335D and after coming from a hard sprung Subaru, the ride is a little choppy on the corners but it's not unbearable...

My money's on a suspension issue that probably being compounded by poor tyres.. Possibly a seizing or seized shock? (this could affect the whole car and not be immediately noticeable on one side)

[DaveC]

Originally Posted by rogerxp

I did ask whether any 'tweaks' could have been made to the E90 between the two cars ('06-'08) but the mechanic claimed that 'tweaks' would only be made when a car is officially face-lifted. Not sure whether I beleive that or not.

Dave, I presume the only change you have made is to remove the RFT - nothing else, and you're happy with the improvement??

I looked up the front shocks on my car and for m sport versions (which mine isn't) there has been at least one change and realoem only has data up to the end of 2006 so BMW obviously do change things around between facelifts so I wouldn't put too much store in what the mechanic said.

Yup I changed to non RFTs and was delighted with the change - it's no limo now (nor would I want it to be) but it's a lot smoother. The whole issue of RFT vs non RFT is rather confusing as I suspect it depends on what model you have, what age, what brand of RFTs fittend and what your personal expectations/tolerances are. Nothing else can explain the wide range of opinions.

It's possible alcook is right and that it's more than a tyre problem although it should be fairly easy to walk round each corner of the car and give it the bounce test to see whats going on.

If the dealer can't find anything I'd be tempted to see if anyone on this board in your local area with similar wheels & non RFTs would mind spending an hour one saturday morning swapping the wheels over to see if it sorts things out.

[rogerxp]

Right, well I dropped my car off this morning to have the harsh ride investigated. They've just called to say that the only thing they can find fault with was a couple too many PSI in the front tyres. They have corrected this and 'claim' that it rides that same as another like-for-like car they have.

Mmmmmmm. Not too sure I beleive that a couple of PSI makes such a difference however others on this forum have highlighted the PSI 'can' make quite a difference. It has been suggested during this thread that the tyres are purely responsible; perhaps this is the case. I'll only know for sure if I physically change them.

Anyway, heading back there shortly to drive both cars to see if they can convince me!!!

As a side issue, was given a very nice '08' 320d M Sport with performance alloys on (not sure if standard or not - they have performance written on them). The ride is much better in the lighter 320d!!!

I'll report back.

[rogerxp]

Second update of the day...

Dropped off the courtesy car (a lovely drive except the start/stop freaked me out a little!!!). The PSI reading was 0.3 over on the fronts (tread 6.4 & 6.0) and fine on the rear (tread 5 & 4.5). The guy I've dealt with didn't see how that would make such a difference so told me to report back (I had done before reaching the end of the street!!!). The car to drive back-to-back with was actually a customers car being taken to the body-shop so wasn't available. Didn't make any difference to be honest; as soon as I got back in mine there was no change whatsoever.

The guy at BMW, who seems equally baffled by the firmness (only verbally as he hasn't actually been out in it), suggested I took it back one Saturday when he's working and he'll arrange to get another set of 18s M Sport alloys & tyres put on mine. At least we can then start to narrow the issue to 'suspension' or 'tyres'. Sounded sensible to me so will take him up on his offer.

The saga continues...