[thescouselander]

Originally Posted by Skyhigh

Is that an advantage or a disadvantage....?
Firm is what you want from a sporty car.

Maybe / maybe not. Too firm is slower on bumpy surfaces.

[MashinBenzin]

19s plus adaptive for the best big wheel/comfort combo I think. I haven't driven 18s since a couple of years before I tried the 19s , but the adaptive setup on 19s is certainly more pliant than the passive.

[Grant_7]

Originally Posted by Skyhigh

Is that an advantage or a disadvantage....?
Firm is what you want from a sporty car.

No it isn't at all! Why this complete misconception that firm is sporty?!

What you want is compliance to allow the suspension to do its job; to suspend the body structure from the road surface. This is absolute.

However the compromise comes in controlling the body movements relative to the unsprung masses and 'external factors' (forces applied to the body through its relative motion).

The nub of the issue is that there are two main factors as to why suspension on BMWs - and almost all other OEMs - is so compromised; vehicle mass and use of simple (read: cheap) dampers.

[sensible]

Originally Posted by MashinBenzin

19s plus adaptive for the best big wheel/comfort combo I think. I haven't driven 18s since a couple of years before I tried the 19s , but the adaptive setup on 19s is certainly more pliant than the passive.

Yes, happy with this combo.

[Skyhigh]

Originally Posted by Grant_7

No it isn't at all! Why this complete misconception that firm is sporty?!

What you want is compliance to allow the suspension to do its job; to suspend the body structure from the road surface. This is absolute.

However the compromise comes in controlling the body movements relative to the unsprung masses and 'external factors' (forces applied to the body through its relative motion).

The nub of the issue is that there are two main factors as to why suspension on BMWs - and almost all other OEMs - is so compromised; vehicle mass and use of simple (read: cheap) dampers.

Disagree slightly. For a sporty ride one needs best feeling for the road, which includes discomfort! Best handling is achieved in full awareness of the terrain, not in a cozy cruising comfort.

Adaptive suspension + 19" as others said: best of both worlds!

[HighlandPete]

Originally Posted by thescouselander

Maybe / maybe not. Too firm is slower on bumpy surfaces.

Totally agree.

'Too firm' on less than ideal roads doesn't help grip. A lot of the talk about poor grip from specific tyres, is not always the tyres themselves but a combination of suspension stiffness, wheel size and/or tyre.

Too big a rim diameter, the tyre with a lower sidewall height may not be capable of following road contours without loosing some grip. Downsizing wheels, getting increased sidewall height, allows a larger working envelope for maximum grip.

[Rich9600]

Originally Posted by HighlandPete

Totally agree.

'Too firm' on less than ideal roads doesn't help grip. A lot of the talk about poor grip from specific tyres, is not always the tyres themselves but a combination of suspension stiffness, wheel size and/or tyre.

Too big a rim diameter, the tyre with a lower sidewall height may not be capable of following road contours without loosing some grip. Downsizing wheels, getting increased sidewall height, allows a larger working envelope for maximum grip.

I totally agree. Comfort damper mode is better for grip on poor surfaces.

Also, counter intuitively. I find that I get better ride quality with run-flats slightly over the recommended pressure. This is to allow for temperature fluctuations and to prevent the non-compliant run-flat sidewall coming into play over the bumps. Especially during the autumn as the ambient temperature is dropping.

I know when I need to top up my tyres as the initial few miles of every journey are 'jiggly'. Once the temperature builds, the pressure comes back in range and the ride smooths out.

So, with big rims and run flats. Tyre pressure is very important.

[HighlandPete]

Originally Posted by Rich9600

I totally agree. Comfort damper mode is better for grip on poor surfaces.

Also, counter intuitively. I find that I get better ride quality with run-flats slightly over the recommended pressure. This is to allow for temperature fluctuations and to prevent the non-compliant run-flat sidewall coming into play over the bumps. Especially during the autumn as the ambient temperature is dropping.

I know when I need to top up my tyres as the initial few miles of every journey are 'jiggly'. Once the temperature builds, the pressure comes back in range and the ride smooths out.

So, with big rims and run flats. Tyre pressure is very important.

Similar findings with RFTs over the years. The tyre does require precise pressure to keep its limited shock absorbing ability, at the highest level. We want the tyre to be as 'springy' as possible. Too low a pressure is also evident by a tendency to follow the road, (like tramlining), when the two sidewalls take unequal loads. An extra couple of psi can completely eliminate the road follow behaviour, and improve comfort over small ridges and road imperfections. The same criteria applies to the tyre's ability to follow the immediate road changes and contours, helps keep an evenly loaded footprint, giving the best grip levels available.

[thescouselander]

So what are the best pressures to use? Are the recommended pressures ok or would some other pressure be better?

[Rich9600]

Originally Posted by thescouselander

So what are the best pressures to use? Are the recommended pressures ok or would some other pressure be better?

I bought a half decent pressure gauge and tend to go for 0.05Bar over the recommended pressures when tyres are stone cold at the coldest time of day I can reasonably manage.

[Grant_7]

Originally Posted by Skyhigh

Disagree slightly. For a sporty ride one needs best feeling for the road, which includes discomfort! Best handling is achieved in full awareness of the terrain, not in a cozy cruising comfort.

Adaptive suspension + 19" as others said: best of both worlds!

You're still confusing a firm ride for feel. My suggestion would be to try something that is properly setup; Lotus / high-end Porsche / Alfa Quadrofolgio (yes, really!). Compliant suspension but fabulous body control. Cars like this give a glimpse into what can be done with proper suspension.

And on that note, and in difference to your belief that discomfort is 'sporty', think about things like Rally or Dakar cars. Massive amounts of suspension travel and compliance to absorb severe impacts, but they aren't rolling around like battleships on a rough sea.

As I've said, you'd be amazed at what can be achieved by correctly valved dampers with matched springs.

[HighlandPete]

Originally Posted by Grant_7

You're still confusing a firm ride for feel. My suggestion would be to try something that is properly setup; Lotus / high-end Porsche / Alfa Quadrofolgio (yes, really!). Compliant suspension but fabulous body control. Cars like this give a glimpse into what can be done with proper suspension.

And on that note, and in difference to your belief that discomfort is 'sporty', think about things like Rally or Dakar cars. Massive amounts of suspension travel and compliance to absorb severe impacts, but they aren't rolling around like battleships on a rough sea.

As I've said, you'd be amazed at what can be achieved by correctly valved dampers with matched springs.

It is going to be interesting to see how the G20, with its form of 'selective' damping works out in a 3-series. We need a bit more technical detail, but from the media pre-release description it does appear something like the ZF Sachs Vario Damper, with a stroke dependant damping rate.

[Skyhigh]

Don't confuse racing on tracks with sport driving on roads with a variety of imperfections!

Stiff is much better than soft for that sake.

[davethefish]

wow!
It's been a while since I was on here last,
And I can't believe this topic is still up there...

Runflats are crap, end.

No one who puts normal tyres on, ever goes back. (me included)

M3 = normal tyres.... you know why...

Would you ever catch an F1 car with runflats...?

[Rich9600]

Originally Posted by davethefish

wow!
It's been a while since I was on here last,
And I can't believe this topic is still up there...

Runflats are crap, end.

No one who puts normal tyres on, ever goes back. (me included)

M3 = normal tyres.... you know why...

Would you ever catch an F1 car with runflats...?

Ok, so your F3# is a pure drivers machine?

My F31 is a family car and work transport, that is also a bit fast and a bit fun to drive. I willingly accept the compromise of runflats. A puncture at 1am on motorway re-adjusts your priorities in this area.

Don't get me wrong, I wish runflats were better! Though, they now work much better than on my first Runflat equipped E90. The implementation has vastly improved in the 10 years I've been running them.

I can't see an F1 car with a baby seat in the back or a dog in the boot. So, not a real comparison in my eyes. Also, BMW won't make an M3 estate...

So, what I'm saying, is it's horses for courses. BMW do offer a go-flat tyre and 18" wheel option from the factory. Even on here, a driving enthusiasts forum, not many choose it... So, the wider world bulk of owners will take the convenient safety net of runflats.

[HighlandPete]

Originally Posted by Rich9600

Ok, so your F3# is a pure drivers machine?

My F31 is a family car and work transport, that is also a bit fast and a bit fun to drive. I willingly accept the compromise of runflats. A puncture at 1am on motorway re-adjusts your priorities in this area.

Don't get me wrong, I wish runflats were better! Though, they now work much better than on my first Runflat equipped E90. The implementation has vastly improved in the 10 years I've been running them.

I can't see an F1 car with a baby seat in the back or a dog in the boot. So, not a real comparison in my eyes. Also, BMW won't make an M3 estate...

So, what I'm saying, is it's horses for courses. BMW do offer a go-flat tyre and 18" wheel option from the factory. Even on here, a driving enthusiasts forum, not many choose it... So, the wider world bulk of owners will take the convenient safety net of runflats.

Well put across. Quite a few of us reason a similar way.

Many know from my posts over the years, I criticised RFTs from first fitting to the E60/61 models. Got into discussions with my dealer, BMW and Bridgestone, even had a Bridgestone Field Engineer come up to the Highlands to discuss the issues and ride in my E91. He gave a running commentary of the way the tyres and the E91 chassis were working on my roads. He summarised my typical driving roads as "extremely challenging". I changed the damping and found the RFTs worked much better. Non run-flats were obviously better, but with the compromises of not having a spare. Using valuable boot space to carry a spare when in remote areas and/or away from home.

I've lived with RFTs on my F11 for almost 6-years, nothing like the negatives of the earlier RFTs. They are not perfect, but not causing any of the issues the 3-series had. I replaced 'like for like' when new summer tyres were needed for the run-on-flat benefits.

I ride in a few other cars, non of which are on RFTs, my car is far smoother riding over the same roads.

[cfm56d7b]

Originally Posted by Grant_7

You're still confusing a firm ride for feel. My suggestion would be to try something that is properly setup; Lotus / high-end Porsche / Alfa Quadrofolgio (yes, really!). Compliant suspension but fabulous body control. Cars like this give a glimpse into what can be done with proper suspension.

And on that note, and in difference to your belief that discomfort is 'sporty', think about things like Rally or Dakar cars. Massive amounts of suspension travel and compliance to absorb severe impacts, but they aren't rolling around like battleships on a rough sea.

As I've said, you'd be amazed at what can be achieved by correctly valved dampers with matched springs.

Could not agree more with the above. That's why mixing and matching springs with shocks never designed to work together leads to mediocre outcomes. One of the best examples of suspension designed for compliance with exceptional control can be found in Ohlins R&T coilovers.

[MashinBenzin]

Originally Posted by Rich9600

Ok, so your F3# is a pure drivers machine?

My F31 is a family car and work transport, that is also a bit fast and a bit fun to drive. I willingly accept the compromise of runflats. A puncture at 1am on motorway re-adjusts your priorities in this area.

Don't get me wrong, I wish runflats were better! Though, they now work much better than on my first Runflat equipped E90. The implementation has vastly improved in the 10 years I've been running them.

I can't see an F1 car with a baby seat in the back or a dog in the boot. So, not a real comparison in my eyes. Also, BMW won't make an M3 estate...

So, what I'm saying, is it's horses for courses. BMW do offer a go-flat tyre and 18" wheel option from the factory. Even on here, a driving enthusiasts forum, not many choose it... So, the wider world bulk of owners will take the convenient safety net of runflats.

This is all true. My F36 on MSport adaptive and 19s is absolutely streets ahead of my previous E90 SE on 17s. That's for ride quality. Something has been lost at the front end, but hard to tell if that is just the over-light steering that just doesn't respond as quickly or something related to the suspension/tyre tuning.

In my E90 days I was always happy with the compromised nature of runflats as I was on the motorway on my own for 50 miles a day, the majority of which in the morning was way before 7am and frequently the evening return was past 11pm.

Much as I like the sound of even better ride, traction and handling, I wouldn't bother changing from runflats on the F36 either. Like yours, it's a family and commuting workhorse and i would rather have the knowledge that every journey will be completed - or at least that tyres won't play a part in that not happening.

[Skyhigh]

Guys, how often in your entire driving experience have you had a flat tire (not caused by a more serious damage that would prevent further drive anyway)!?

In my case: 0!

In my other car, I carry a 300g. set for repair of flat tires. Yes, it will not help with a seriously damaged tire, but I like the chances...

[Watsey]

Originally Posted by Skyhigh

Guys, how often in your entire driving experience have you had a flat tire (not caused by a more serious damage that would prevent further drive anyway)!?

In my case: 0!

In my other car, I carry a 300g. set for repair of flat tires. Yes, it will not help with a seriously damaged tire, but I like the chances...

In >30 years of driving I've had one tyre instantly and irreparably damaged - at night, hit a waterlogged manhole cover around which the tarmac had been cut-back for resurfacing. It cut through the tyre wall.

I've had several slow punctures (Michelin PS2 were dreadful on one of my E46s), all of which have been slow (i.e. nail/sscrew in tread) and could be managed with TyreWeld or, my preferred option having used it on my brother-in-law'd Macan, a 'sticky string' repair. Having got the hang of the string I could plug a tyre in around 5 minutes now. BiL drove it for several days, and the return trip from Devon to London, with zero loss of pressure.

Running regular tyres and no spare is a slight risk, but a small one. For me, the benefits in ride and handling outweigh it massively.

[MashinBenzin]

Originally Posted by Skyhigh

Guys, how often in your entire driving experience have you had a flat tire (not caused by a more serious damage that would prevent further drive anyway)!?

In my case: 0!

In my other car, I carry a 300g. set for repair of flat tires. Yes, it will not help with a seriously damaged tire, but I like the chances...

In 28 years of driving, three times. Although all of those were in the first 20. Plus one on my wife's car in the last five. Couple of slow punctures too.

All of the above on non run-flats.

[aquazi]

I remember seeing this debate as 16 vs 17 on the 2k forum.

Then 10 years later on z4 forum was 17 vs 18.

Now its 18 vs 19’s.

Maybe in another 10 years it will be 20 vs 21’s on a road car.