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      11-27-2012, 09:40 AM   #23
MaestroAl
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And a puppet president with Goldman Sachs pulling the strings
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      11-27-2012, 03:12 PM   #24
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Quote:
Originally Posted by MaestroAl View Post
Going from 15:1 to 14.5:1 != "a much sportier rack" so it's just marketing calling it sporty. There are only a handful of humans who would notice the difference and the feel would be identical since it's the Servotronic element that stiffens the steering up in the various adaptive modes.

You also then went on to say that Servotronic makes parking easier which, yes it kinda does because it makes the steering lighter at slow speeds, isn't what you're referring to, I don't think, since VSS is the topic. And VSS makes parking easier by allowing you to turn the wheel through fewer degrees to achieve tight turning angles so that's not a function of the Servotronic bit.

The reality is that the only benefit anyone will get from VSS is easier parking. That means that calling it Variable Sport Steering is misleading and therefore marketing BS




-edit- You can do the maths easily enough on the steering angles we're talking about here. At 90* of lock, which is a pretty tight, relatively slow turn, the difference in steering angles between Servotronic and VSS would be 3*. Could anyone notice 3* difference in the lock on their wheel? Really? And that's the absolute maximum difference in normal driving. obviously it's much more in parking but that's kinda my point At a normal 0 to 45 degree steering input which is where most of us spend our lives, even on spirited B-road driving, you're talking between 0 and 1.5 degrees of difference in the steering angle. It's bugger all and I'd maintain that a 3% difference in steering input does not a "sporty" rack maketh In fact, it's barely even visible.
So nothing I said is actually wrong then. The rack ratio is not 14.5:1, that is just mid point. The overall ratio is much faster than the standard rack.

I know which steering system I'd perefer up here, driving some of the twisty stuff, the VSS with a faster rack (overall ratio). Much easier to throw the car though 90-degree turns and hairpins.

BTW, I'm not confused with how servotronic works. It is the ability of servotronic to give the 'comfort feeling' with a faster ratio, that makes parking with a faster rack possible. Otherwise it would be very heavy with the speed of the rack towards lock. At speed in the twisty turns you have fast reactions with sensible weighting.

For me it is a 'win, win' piece of kit. A little faster mid position, faster on the turns, junctions, and twisty road driving. Easy parking thrown in.

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      11-27-2012, 03:16 PM   #25
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No. The overall ratio is not much faster. That is where you are mistaken
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      11-27-2012, 06:00 PM   #26
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Quote:
Originally Posted by MaestroAl View Post
No. The overall ratio is not much faster. That is where you are mistaken
I think this whole issue of what we term fast or slow, depends on what you expect in an average BMW road car.

I see a steering system that gives just 2.2 turns lock to lock, with an average ratio ~12.2:1, as much faster than the standard 2.7 turns, with a 15:1 ratio, in this same application.

E92 M3 has 2.4 turns lock to lock, (again variable) with an average (overall) ratio of 12.5:1, so the F30 with VSS is not doing too bad is it?

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      11-27-2012, 06:22 PM   #27
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Quote:
Originally Posted by HighlandPete View Post
E92 M3 has 2.4 turns lock to lock, (again variable) with an average (overall) ratio of 12.5:1, so the F30 with VSS is not doing too bad is it?

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I had an E92 M3, I thought the steering was perfect. So, I ordered my F30 with VSS
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      11-27-2012, 06:33 PM   #28
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Hi everyone,

Thanks for the remarkable number of responses. I feel a bit guilty in nearly starting a small war on this ... Peace, we all love driving beemers :-)

Thanks especially to HighlandPete and johnbmw6 for your helpful replies and dropper99 for the useful link. I wasn't expecting the kind of steering feel you get in a 997 911 (utterly fabulous) from the VSS - just a bit of an improvement in feel and involvement.

I've read around a fair bit on this and, barring a few negative comments (mostly coming from the theory angle), the overall feedback seems positive, especially from people who have driven both systems.

Anyway, I'll come back when I finally get my car mid-December and I'll post a mini-review of the steering compared to the three none VSS F30s I drove, good or bad :-)

Thanks all for your thoughts!

Dave

PS Is there a drug I can take that will put me into a deep and restful sleep until 15th December?
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      11-27-2012, 07:46 PM   #29
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Quote:
Originally Posted by HighlandPete View Post
I think this whole issue of what we term fast or slow, depends on what you expect in an average BMW road car.

I see a steering system that gives just 2.2 turns lock to lock, with an average ratio ~12.2:1, as much faster than the standard 2.7 turns, with a 15:1 ratio, in this same application.

E92 M3 has 2.4 turns lock to lock, (again variable) with an average (overall) ratio of 12.5:1, so the F30 with VSS is not doing too bad is it?

HighlandPete
But it's not linear. You can't say it has an average lower than the "standard" Servotronic because in normal driving, as I've said a bazillion times, it's nigh-on identical. From 0-100 degrees there is a maximum of 3% difference in the driver's steering input to achieve the same angle at the wheels. That's identical in anyone's book. Just because it suddenly goes much faster from 100 degrees to full lock does not make it a more sporty rack. It's not even a quicker one To all intents and purposes it's exactly the same.

The only time you actually benefit from the faster lock is when you're parking and manoeuvring since that's the only time you ever apply more than 100 degrees of lock. Sorry if I'm repeating myself but it's a very simple process to understand
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      11-28-2012, 02:44 AM   #30
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Is the difference between VSS and 'vanilla' servotronic just this rack/teeth thing or are there other differences, e.g. the electronics/assistive bit? (Sorry if it's a dumb question, not very tech savvy on such matters).
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      11-28-2012, 08:24 AM   #31
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Yes the VVS is just the same steering rack as standard except it is machined different at the bottom, so to make it less turns lock to lock.. So it costs BMW the exact same to manufacture but cost Joe punter an extra 250.. why than you!! (information supplied from my friendly BMW sales person who was shown both on a training course)
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      11-28-2012, 09:01 AM   #32
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I suspect there will be software differences too. It'll require more power assistance to provide the same level of comfort at slow speeds and high steering inputs

Still a rip-off and a marketing con though Just glad we Eeeeengleesh can order M Adaptive without VSS unlike our poor Yankee cousins who get shepherded into buying both

Quote:
Continuously adjusts the steering ratio and steering force to suit the changing driving situation. The steering ratio is adjusted depending on the steering movement.
(/chortle)
That's at best dishonest and at worst a down-right lie.
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Last edited by MaestroAl; 11-28-2012 at 09:07 AM.
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      11-28-2012, 09:02 AM   #33
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PS Is there a drug I can take that will put me into a deep and restful sleep until 15th December?[/quote]

If there is can you get me some to see me through to the 10th December.
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      11-28-2012, 10:28 AM   #34
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So if the two racks are so similar (except a little machining of the teeth), why is it that:

1) a number of folks (including myself) who have driven both say that VSS has better feel [when both in Sport or Sport+ mode] during normal driving, not just parking lot maneuvers (subjective, but not an uncommon observation); and

2) of the many complaints on this forum about "steering wheel vibration", only one of those complaints comes from someone with VSS?

I suspect there are more differences, software and/or hardware, between the two.

My .02,
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      11-28-2012, 10:41 AM   #35
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1) Placebo. It's something you paid for so it must be better?

2) I don't think the evidence supports that claim
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      11-28-2012, 11:14 AM   #36
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Quote:
Originally Posted by MaestroAl View Post
1) Placebo. It's something you paid for so it must be better?

2) I don't think the evidence supports that claim
1) Or "it's not what I have, so it can't be better." Equally valid argument.

2) Not a "claim", I'm stating an observation: only one of the many reports in the lengthy "2012 F30 Steering wheel vibration" thread indicates that the car has VSS. What "evidence" are you referring to?
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      11-28-2012, 11:19 AM   #37
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I just thought that it was across the board in the Steering wheel vibration thread. Granted I've not read the thread for a few weeks but it gets a bit dull after a while My memory could easily be wrong there though Even if that is the case, it might be a harmonic resonance on a 14.5:1 rack that's not present on a 15:1 rack. Perfectly reasonable conclusion
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      11-28-2012, 11:42 AM   #38
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Quote:
Originally Posted by Irnbrukid View Post
Yes the VVS is just the same steering rack as standard except it is machined different at the bottom, so to make it less turns lock to lock.. So it costs BMW the exact same to manufacture but cost Joe punter an extra 250.. why than you!! (information supplied from my friendly BMW sales person who was shown both on a training course)
A variable rack is much more difficult to manufacture and to package, so to say it costs the same is ridiculous. If it did it would be standard fitment across the range. Tip: never ask a salesman for highly technical information, some are technically minded most aren't.

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So if the two racks are so similar (except a little machining of the teeth), why is it that:

1) a number of folks (including myself) who have driven both say that VSS has better feel [when both in Sport or Sport+ mode] during normal driving, not just parking lot maneuvers (subjective, but not an uncommon observation); and

2) of the many complaints on this forum about "steering wheel vibration", only one of those complaints comes from someone with VSS?

I suspect there are more differences, software and/or hardware, between the two.

My .02,
Because they aren't 'just a little machining different'. The two racks are significantly different. Maestro is correct in saying the ratio's are not that different up until 90-100 degrees of lock, but the mechanism is different, so the overall feel is different too.
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      11-28-2012, 12:32 PM   #39
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Quote:
Originally Posted by MaestroAl View Post
1) Placebo. It's something you paid for so it must be better?

2) I don't think the evidence supports that claim
Just drove the Luxury 330D touring today whilst mine was in on the computer, it had STD suspension NO VSS, NO brake upgrade, got back in mine and way better all round and the brake feel was just great, what a difference.
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      11-28-2012, 12:41 PM   #40
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My impressions are that the VSS does make a difference.

I spend most of the time on the motorway so I don't notice it then but once off the motorway and on the twisting and turning roads home it comes into its own. It does seem to have more directness and the turns feel easier when you're having to go round those tighter bends.

I had a loan car a few weeks ago without VSS and it did feel different. The car didn't seem to go into those bends with as much purpose. On the way back home then in my car it was back to best
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      11-28-2012, 02:04 PM   #41
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MaestroAl. Have you actually driven both cars with and without VSS - so your comments are 1st hand? Or are you just taking a guess that VSS is a waste of money and pointless based on whatever you have read?

Seems you are the only person on here that thinks its a waste of time.
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      11-28-2012, 05:14 PM   #42
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Quote:
Originally Posted by NISFAN View Post
A variable rack is much more difficult to manufacture and to package, so to say it costs the same is ridiculous. If it did it would be standard fitment across the range. Tip: never ask a salesman for highly technical information, some are technically minded most aren't.


How is it much more difficult to manufacture.. Afterall is it just not machined to different dimensions, is the rack made of a different material? Maybe a little extra time machining it but i cant see it to be honest.

Why isn't it standard fitment, maybe because if you put a few letters and marketing on the end the sheep will purchase it..

True what you say about salesmen, but he would never try and sell me something for the sake of it. He actually laughed when he asked if i'd like to spec it.. tells you all you need to know.
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      11-28-2012, 05:48 PM   #43
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Quote:
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How is it much more difficult to manufacture.. Afterall is it just not machined to different dimensions, is the rack made of a different material? Maybe a little extra time machining it but i cant see it to be honest.

Why isn't it standard fitment, maybe because if you put a few letters and marketing on the end the sheep will purchase it..

True what you say about salesmen, but he would never try and sell me something for the sake of it. He actually laughed when he asked if i'd like to spec it.. tells you all you need to know.
Well to compare we would need to understand the 'normal' rack first. It has a relatively small pinion gear running along a rack. Teeth on both are matched to the same pitch and tooth size. The pinion can rotate more than one revolution in either direction. Typically you can turn the wheel over 2 times lock to lock.

In a system with variable geometry, you can't just change the pitch of the rack teeth either side of centre because the pinion would run out, the gear would not mesh.

Soooo.....a variable system has a large pinion, big enough to cover the full rack movement, and has matched varying pitch. The rack and pinion are made as a matched pair. The differing ratio is machined into both the rack #and the pinion to maintain meshing. This system has to be carefully aligned to start with, etc. so quite technical and orders of magnitude more complex than a straight rack. The important feature is the pinion cannot rotate more than 360 degrees like it does on a normal system.

Coming back to what your salesman advised, as it has a similar ratio in the centre as Maestro explained it won't behave much differently, although the large pinion would require less assistance, so could 'feel' different depending on the electronic assist programming. Also in normal driving you rarely use more than 90 degree steering wheel angle where the tighter ratio kicks in, so you are unlikely to feel this action in normal driving, only low speed manoeuvres. Again as Maestro explained hardly a sporty experience on it's own, but with advanced assistance might feel significantly different to matter.
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      11-28-2012, 05:56 PM   #44
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Great explanation - makes complete sense!
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