[HighlandPete]

Originally Posted by Jon D

Pete,
I can understand how larger rims might help in alleviating the on-centre vagueness; presumably the lower tyre profile would result in less sideways flexing, thereby reducing the tendency to wander.
If my assumption is correct, I would have thought that non-run flats would take you back to square one in that they have more flexible sidewalls.
I'd appreciate any further enlightenment - thanks,
Jon

Personally I sense very little difference between the poor F10/11 examples with EPS, than my 330d with hydraulic power steering, with run-flats on a bad day. Hence my speculation that it may not be the EPS, but wheel/size and run-flat issues.

From experience in various 3-series with different wheel sizes I'm not sure there is a progressive relationship with steering precision and wheel sizes and/or aspect ratios, when it comes to run-flat's.

I personally believe there is something going on which is not clearly understood. A 'cause and effect' scenario. Whether it is the higher profiles needing stiffer sidewalls to support the car at low to zero pressure, and/or the aspect ratio and rim width, but in the 3-series 17" wheels don't seem to be the best for following poor road contours and road crowns. (I have some theories as to why the 17" could be less precise). We appear to get situations where either the L/H sidewalls (of each tyre) are taking the loads, or the R/H side sidewalls, so we get a resulting tug to either side. The transition between alternating loadings seems to be where the inprecision comes in. In my experience it translates to light and a 'darting' side to side feel. Sometimes as if the steering is loose and not connected, at other times tugs or pull. Or a 'cogging' feel as if the rack and pinion is loose (backlash) or the opposite, running too much preload, can be either feeling. We can have this sensation in other wheel sizes, but it seems more amplified with 17" wheels.

I'm wondering if the 5-series has a more extreme issue on 18" wheels. Not everyone will sense it, roads we use can as I say amplify the conditions where this vague/loose feeling displays itself. Tyre pressuees also effect the severity of the loose feeling, as does ambient and tyre temperature.

For me the simple change to non run-flat tyres sorted the situation, teaching me it wasn't the steering itself, but tyres. To show the concerns I had, twice I jacked the car and went through all the components looking for where the loose part(s) were.

When I did my first F10 'back to back' tests in April and finding an 18" shod car was so different than the 19" model, I was alerted to the fact we could have this same scenario all over again in the F10/11. I'm yet to be convinced we don't have a tyre issue.

This was my first comments on the internet, the same day.

This example was running 18” wheels and Dunlop RFTs, they worked well and at first it didn’t feel like they were run-flats, ambient temperature about 10-degrees. Steering did seem a bit light, but well connected. But once on the motorway I started sensing the steering was not as precise as I’d choose, in fact over some road imperfections it seemed to go a little vague in mid position, also some vibration was coming back through the wheel, but not matching the road. “I’ve been here before”… some frequencies just don’t cancel out, but get amplified. It becomes clear the steering is not a good as I’d hoped.

Then we get on the A91, and once the surfaces go in all directions the same old run-flat feel, as on my 17” wheels comes to the fore, the front wheels are fighting for the line and makes the steering feel very light and imprecise, as the car is wanting to dart about. I get my wife to also lightly touch the wheel, to feel the road vibrations and strange feedback. Which confirmed, a RFT issue, our car doesn’t do it on normal rubber.

If my experience and a bit of thinking ouside the box is correct, it could explain why there is a difference of opinion. There's a stack of variables, some will not even sense any steering issues, others will be hitting the conditions which mess the steering feel quite regularly.

HighlandPete

[stickypaws]

If tossing the RFTs seems to 'solve' the problem, that's good for consumers to know. But the issue is that BMW designed this car to be used with RFTs. And so the bigger question is why doesn't it operate the way it was apparently meant to (according to your theory that by not using RTFs on this chassis it makes it a better drive)?

If BMW is selling the car with RFTs (and promoting the idea of using RFTs), then why don't they just design the car to run the best it can on RFTs instead of making owners even have to think about switching to conventional tires? This car should be perfect right out of the box without the buyer having to deal with these sorts of attempts at modifying the ride.

[nectarine712]

i thought my steering was a little bit a little bit too stiff. but then i drove my wifes car honda accord and now realize that the bmw steering is pretty precise and good.

[bm323]

Originally Posted by stickypaws

If tossing the RFTs seems to 'solve' the problem, that's good for consumers to know. But the issue is that BMW designed this car to be used with RFTs. And so the bigger question is why doesn't it operate the way it was apparently meant to (according to your theory that by not using RTFs on this chassis it makes it a better drive)?

If BMW is selling the car with RFTs (and promoting the idea of using RFTs), then why don't they just design the car to run the best it can on RFTs instead of making owners even have to think about switching to conventional tires? This car should be perfect right out of the box without the buyer having to deal with these sorts of attempts at modifying the ride.

BMWs are not "designed" for RFTs. Check your stuff before you troll your usual nonsense. A forummer was correct, your posts should be disregarded.

[stickypaws]

Originally Posted by bm323

BMWs are not "designed" for RFTs. Check your stuff before you troll your usual nonsense. A forummer was correct, your posts should be disregarded.

I'm not sure why you seem to think I'm trolling.

I've been on this forum a lot longer than you. You have no idea of my intentions here. Perhaps I've been waiting for the F10 for a while now and have plans to purchase one. Perhaps I've been waiting for the M5 to appear.

I own a BMW and have owned them for many years, long before you were probably even born. I'm a huge fan of the marque. However, I am also critical of it just like I'm critical of a lot of things. People who use their minds and don't simply look at the surface are critical. As in critical thinking or critical analysis.

I pose my question again. BMW uses RFTs. They come on the car. I have to assume the chassis was designed with RFTs in mind. Why are they on the car?

I'm sorry that I hurt your feelings and put you on the defensive. That was not my intention whatsoever. But I will say what I think, right or wrong. These are cars, not human beings. I'm not being critical of you as an individual or anyone else.

Rather than making assumptions like you are doing, why not educate me and help me out here. That would certainly be a lot more helpful, don't you agree?

[pharding]

Originally Posted by bm323

BMWs are not "designed" for RFTs. Check your stuff before you troll your usual nonsense. A forummer was correct, your posts should be disregarded.

The F10 is in fact was designed for RFT's. The E60 initially was not and that impacted the ride initially.

[HighlandPete]

Originally Posted by stickypaws

I pose my question again. BMW uses RFTs. They come on the car. I have to assume the chassis was designed with RFTs in mind. Why are they on the car?

BMW have used the statement "designed for run-flats" or something similar. I've come to the conclusion and from an engineering point of view, it's more like "compromised for run-flats". Nothing wrong with that in itself, as suspension and steering tuning and feel are a set of compromises anyway.

From my investigations (and experience) it is clear that the working parameters of the run-flat are to a much tighter envelope than conventional tyres. When we recall that a tyre is also a spring element in a suspension system, we have a different animal to deal with, at a basic level.

The performance is affected in a much more critical way to setting pressures, temperature, road surfaces and particularly to cambers and road crown. There seems to be issues when running on uneven surfaces where one side wall per tyre causes the 'cone effect' that takes away directional stability. Very understansdable as the tyre is not as flexible, cannot follow the road form as easily, and the slip angles are different than conventional tyres.

BMW have certainly improved things in six or so years, but are we really through the issues? That's why I suggest we could still have tyre performance in this steering debate. Why some won't find the critical areas where the envelope is pushed to the limits, others will be finding the limitations, but perhaps not thinking tyres are a part of the issue. I personally find there are similar problems for run-flats on a hydraulic assisted steering, so don't see it just as an EPS issue.

I'd love to take an F10/11 where I feel the steering slackness and try different wheel sets, including non run-flats and see how the steering changes.

HighlandPete

[stickypaws]

Originally Posted by HighlandPete

BMW have used the statement "designed for run-flats" or something similar. I've come to the conclusion and from an engineering point of view, it's more like "compromised for run-flats". Nothing wrong with that in itself, as suspension and steering tuning and feel are a set of compromises anyway.

From my investigations (and experience) it is clear that the working parameters of the run-flat are to a much tighter envelope than conventional tyres. When we recall that a tyre is also a spring element in a suspension system, we have a different animal to deal with, at a basic level.

The performance is affected in a much more critical way to setting pressures, temperature, road surfaces and particularly to cambers and road crown. There seems to be issues when running on uneven surfaces where one side wall per tyre causes the 'cone effect' that takes away directional stability. Very understansdable as the tyre is not as flexible, cannot follow the road form as easily, and the slip angles are different than conventional tyres.

BMW have certainly improved things in six or so years, but are we really through the issues? That's why I suggest we could still have tyre performance in this steering debate. Why some won't find the critical areas where the envelope is pushed to the limits, others will be finding the limitations, but perhaps not thinking tyres are a part of the issue. I personally find there are similar problems for run-flats on a hydraulic assisted steering, so don't see it just as an EPS issue.

I'd love to take an F10/11 where I feel the steering slackness and try different wheel sets, including non run-flats and see how the steering changes.

HighlandPete

I tend to agree. And perhaps more like "designing a suspension yet utilizing existing RFT technology."

Since BMW doesn't design tires themselves (although I'd venture to say that they certainly work with tire engineers while developing the suspensions), there certainly have to be compromises here and there. Despite whether it's EPS or hydraulic, there seems to be issues with RFTs that appear in various guises. Or, 'raise their ugly heads' to be blunt about it.

I guess my hope was that since BMW has said (or at least implied) that the suspension of the F10 is designed with RFT in mind, that there should be no reason to have to consider switching out tires, or even think about it as we had to in the past with the early RFT adoption by BMW.

[bm323]

Originally Posted by stickypaws

I'm not sure why you seem to think I'm trolling.

Check out posts #4 and 5 http://f10.5post.com/forums/showthre...88#post8090988

[HighlandPete]

Originally Posted by stickypaws

I guess my hope was that since BMW has said (or at least implied) that the suspension of the F10 is designed with RFT in mind, that there should be no reason to have to consider switching out tires, or even think about it as we had to in the past with the early RFT adoption by BMW.

I do wonder whether the more complex front suspension is used, at least in part, to try and get run-flats to work better. I'm sure the working envelope is getting bigger, but that can still mean some of us will notice the limitations in our normal use.

The work done by Bridgestone with the 3G run-flats and the blurb put out by BMW and Bridgestone when the first tests were given public release, told me that BMW are very well aware of the limitations of current run-flat technology. Sort of shot themselves in the foot. We'd been told for several years run-flats were not a faulty product, any complaints were trivial. Lost all credibility from my perspective. Run-flat tyres should be an option, IMO, until they have virtually no impact on driving dynamics.

HighlandPete

[bm323]

Originally Posted by pharding

The F10 is in fact was designed for RFT's. The E60 initially was not and that impacted the ride initially.

Originally Posted by HighlandPete

BMW have used the statement "designed for run-flats" or something similar.

Maybe I'm mistaken then. The F10s of course come with run flats as standard and I understand that there is a sensor for punctured run flats, but where is it stated that the F10 (presumably its suspension etc) was designed for run flats?

Further, my E90 comes with run flats as standard and there is a sensor for punctured run flats. Is the E90 also designed for run flats when clearly non run flats gave a better ride and handling when the E90 was introduced and now?

------
Quote "BT: Many people see run-flat tires as one of the biggest faults in riding comfort. What do you think about this?

JvS: There has been a lot of development in the past and without a doubt the first run-flat tires had some issues with comfort levels. The Run-Flat tires offered today are way better and we even made some blind tests with some of our developers and with normal customers to see if they can tell the difference between run-flat and regular tires. And, they usually can’t.

So the normal customer will hardly notice any difference with today’s tires.

BT: So will run-flat tires present an interest to BMW M for their future cars?

JvS: Thats a bit of a philosophical question and it also depends on how you are positioning a car. There are some things that are very important for the M GmbH, but not for every BMW. For example, they are using other tire sizes and they want as few unsprung weight as possible, so run-flats are not very attractive for their purposes." http://www.bimmerpost.com/2010/04/01...by-lead-tuner/

------------------------------

Not mentioned in these articles either, run flats are used by BMW more for the drivers' convenience and as a "green" choice
http://www.bmwblog.com/2010/09/01/bm...un-flat-tires/
http://www.autoweek.com/article/2010...NEWS/100839977

[bm323]

I'm mistaken. Just read this, quote "All of our vehicles that use Run-flat technology have their suspension and braking components set up to accommodate Run-flat tyres. Should you decide to change to non Run-flats, it may alter the driving and handling characteristics of your vehicle. It is for this reason that this modification is not recommended by BMW as a manufacturer."

http://www.bmwblog.com/2009/03/12/re...s-on-your-bmw/

[HighlandPete]

Originally Posted by bm323

I'm mistaken. Just read this, quote "All of our vehicles that use Run-flat technology have their suspension and braking components set up to accommodate Run-flat tyres. Should you decide to change to non Run-flats, it may alter the driving and handling characteristics of your vehicle. It is for this reason that this modification is not recommended by BMW as a manufacturer."

Yes, that's the sort of comment we find all over the place, BMW will state the same sort of comment in any reply email, if asked about removing run-flats.

Obviously we end up with a different set of compromises with any alternative tyre.

Then that begs the real question, which is the optimum size run-flat for the F10/11 cars? Is it the same for all models and/or different suspension systems?

Try and get BMW to answer that one. I'm sure they will say the standard OEM fitment. All others are a further compromise....

HighlandPete

[grimlock]

Originally Posted by HighlandPete

Yes, that's the sort of comment we find all over the place, BMW will state the same sort of comment in any reply email, if asked about removing run-flats.

Obviously we end up with a different set of compromises with any alternative tyre.

Then that begs the real question, which is the optimum size run-flat for the F10/11 cars? Is it the same for all models and/or different suspension systems?

Try and get BMW to answer that one. I'm sure they will say the standard OEM fitment. All others are a further compromise....

HighlandPete

Having made the switch from runflats, the difference is less than I would have imagined. This leads one to believe that BMW has made many changes to allow the runflats to fit in better with the car, but which would also mean making the change is less rewarding.
Personally I would have prefered if they didn't make this switch/compromise, as I feel I have the tires+wheels set up properly, but now the car is wrong! :

[bm323]

Originally Posted by grimlock

Having made the switch from runflats, the difference is less than I would have imagined. This leads one to believe that BMW has made many changes to allow the runflats to fit in better with the car, but which would also mean making the change is less rewarding.
Personally I would have prefered if they didn't make this switch/compromise, as I feel I have the tires+wheels set up properly, but now the car is wrong! :

Meaning the non run flats are still better?

[grimlock]

Originally Posted by bm323

Meaning the non run flats are still better?

they r still better, but i think the need to change is less pressing than say on the e60 (from what i hear), cuz its less bad with runflats, and less good with them off

btw, can i ask you how do u find the suspension setup on the 535i? any comment on the front/rear sway bars? cuz im looking to upgrade mine, the 535 front standard sways r the 528M ones .. so im trying to decide between those and the 535M ones

[bm323]

Hi, mine's with adaptive drive and I find the anti-roll bars work fine, just that the car is not as tight as I would like. I may change the springs later on, but will wait for more info on this issue when more F10s are tuned.

[grimlock]

Originally Posted by bm323

Hi, mine's with adaptive drive and I find the anti-roll bars work fine, just that the car is not as tight as I would like. I may change the springs later on, but will wait for more info on this issue when more F10s are tuned.

Hi, sorry i thought u had normal susp...
yeah not much u need to change with Adaptive.. with the springs the concern is matching spring rate with the electronic dampers right?
In sport+ is the car still not tight enough for your preferences? overall, or anything specific wrt 1.springs 2.damper 3.antiroll ?
Can u feel the damper and antiroll vary dynamically over different road conditions/speeds/turns while on the same (passive) setting?
very curious about the dynamic abilities of Adaptive drive..

[stickypaws]

Originally Posted by bm323

Check out posts #4 and 5 http://f10.5post.com/forums/showthre...88#post8090988

Thanks for posting that. Did you follow through and read the rest of the thread and see other people's responses towards the end (and my other posts, too)? Look at the posts after those two: 11, 14, 15 and 17. Or are you simply selecting out two posts to try to prove something?

Again, I believe what I believe and being critical is far from trolling. Anyway, this thread has turned into a very informative thread.

I'm surprised as someone from Singapore that you would be so adamant as to cut off any sort of dissent. If someone speaks out against the government is it the appropriate response to shut them down and quiet them? That's where it gets scary, imho.

If I say that the F10 is more couch-like than the E60 (yet if that's what one is looking for then all is good), what is trolling about that? It's simply making an opinion. The fact is, I'm not the only one who is concerned about the F10 suspension versus the previous E60 suspension. Are the car magazines simply trolls? Is Consumer Report trolling? Are people who post negative reviews here all trolls?

You have to be critical about things in life otherwise you are simply rolling over and playing dead. Without criticism, then no progress can ever be made.

The bottom line (for me) is that as a potential consumer of the F10, I'm concerned/upset/nervous (call it what you will) that the F10 has been turned into more of a couch-like comfort car similar to other luxury cars out there. I personally like the "E60 style" suspension and am worried about EPS and the cushioning up of the F10. But I'm no troll.

If you can't take criticism, then look the other way. But please don't attempt to shut people up. Especially by using misinformation (ie, that the chassis isn't designed for RFTs and I don't know what I'm talking about, etc..) That borders on fascist thinking and cuts off all dialogue.

This thread is an informative one, btw. And a new one has even appeared today about RFT and chassis dynamics of the F10.
EDIT: here's that new thread for anyone who's interested:http://f10.5post.com/forums/showthread.php?t=441975

[bm323]

Originally Posted by stickypaws

Thanks for posting that. Did you follow through and read the rest of the thread and see other people's responses towards the end (and my other posts, too)? Look at the posts after those two: 11, 14, 15 and 17. Or are you simply selecting out two posts to try to prove something?

Again, I believe what I believe and being critical is far from trolling. Anyway, this thread has turned into a very informative thread.

[/URL]

Bing critical and analytical about the suspension, handling etc is perfectly right eg as in other posts pointed out. But the below is clearly trolling, not being critical and has nothing to do with you being old or having owned BMWs for 50 years. It's clear that you are the one selecting a part of your post to justify your feigned "innocence".

Originally Posted by stickypaws

Once you buy a car you pretty much have to convince yourself all is okay. What other choice do you have?

And my reply, in case you have forgotten:

Originally Posted by bm323

And I presume you have been buying your cars first and check out whether it's ok after that

The definition of trolling is "In Internet slang, a troll is someone who posts inflammatory, extraneous, or off-topic messages in an online community, such as an online discussion forum, chat room, or blog, with the primary intent of provoking other users into a desired emotional response[1] or of otherwise disrupting normal on-topic discussion.[2]" http://en.wikipedia.org/wiki/Troll_(Internet)

Or in your view, the definition of a troll would be the following: "Being a prick on the internet because you can. Typically unleashing one or more cynical or sarcastic remarks on an innocent by-stander, because it's the internet and, hey, you can." http://www.urbandictionary.com/define.php?term=trolling

[stickypaws]

Originally Posted by bm323

Bing critical and analytical about the suspension, handling etc is perfectly right eg as in other posts pointed out. But the below is clearly trolling, not being critical and has nothing to do with you being old or having owned BMWs for 50 years. It's clear that you are the one selecting a part of your post to justify your feigned "innocence".



And my reply, in case you have forgotten:

The definition of trolling is "In Internet slang, a troll is someone who posts inflammatory, extraneous, or off-topic messages in an online community, such as an online discussion forum, chat room, or blog, with the primary intent of provoking other users into a desired emotional response[1] or of otherwise disrupting normal on-topic discussion.[2]" http://en.wikipedia.org/wiki/Troll_(Internet)

Or in your view, the definition of a troll would be the following: "Being a prick on the internet because you can. Typically unleashing one or more cynical or sarcastic remarks on an innocent by-stander, because it's the internet and, hey, you can." http://www.urbandictionary.com/define.php?term=trolling

Well, I guess we just won't see eye to eye then. When I said, "Once you buy a car you pretty much have to convince yourself all is okay. What other choice do you have? " And put a smiley emoticon next to it, I was being light-hearted. When I've bought cars that I later question their reliability or performance, I tend to not bring that up and try to not think about it. We all are human and that's part of human nature. If something isn't working out the way we had hoped then we convince ourselves all is really okay. I mean, seriously, what other choice do we have?

It wasn't sarcastic but simply poking at myself, and at all of us as human beings. For the record I own three German cars (BMW, Porsche and Mercedes.) All three have faults. None are perfect. And in the end they are simply cars and have no reflection on me or anyone else as individual human beings. Do not let your choice of car have any bearing on who you are. You are much more important than the car you drive.

If we take it all too seriously then the world becomes too dark (at least for me.)

Cheers.

[Goodchip]

FWIW, to quickly answer the question posed in the thread title: "How does you steering feel?".
My answer is "Just fine thanks".
No hard driving enthusiast here, Just a fifty something suburbanite empty nester who keeps trying to figure out what all the fuss is about.
I think I understand one thing...for the auto park to work you need EPS, right? I think the auto park function is pretty darned amazing. Which is what you would expect from a fifty something suburbanite empty nester who simply enjoys driving a nice car.