[simianspeedster]

Does this option change the weight or feel of the steering, or just the ratios?

[mfear]

tightens it up.

[pcbrew]

Are you sure, I thought it just changed the steering ratio after > 90deg steering input. I can see it may tighten up at >90deg but that is not really normal street driving scenario, only parking lot.

Have you driven with and without VSS and compared in Normal & Sport or have any documentation on this. If true, I may add to my order since the steering in Normal feels too light.

[stampchez]

Standard steering adds weight between comfort and sport.

[wynden]

From the 3 series catalogue on the main BMW site:

"Variable sport steering. This optional system works independently of road speed, varying the steering ratio in line with the steering angle. It includes the Servotronic function and reduces the steering wheel movement required to achieve a particular tight steering angle. This enhances comfort when parking and manoeuvring, as well as sporting agility in tight corners and hairpin bends. For small steering angles, the steering enhances precision and directional stability."

I interpret this to mean that the Variable Sport Steering and standard (Servotronic) steering are the same, other than the variable steering ratio vs constant ratio. I.e. the effect of the Driving Experience Control and speed are the same for both. Am I wrong?

[mfear]

i've driven my car.. when you switch from eco pro or comfort to sport, the steering tightens up ..still not as tight/heavy as the 335 coupe w/ sport, though..that shit is HEAVY

[mfear]

yeah, tighter, independent of speed -- unlike Mercedes benz which uses SPS (speed sensitive power steering), which loosens up the steering at low speed and tightens it up (as well as increases the turning ratio) at a higher rate of speed.

[Feanor]

Originally Posted by mfear

high speed/sport steering means that you have a larger ratio of steering wheel to wheel turn.. i.e., a smaller movement of the steering wheel results in a larger change in the turn of the wheels. this makes the car more responsive. think about when you watch an F1 car.. VERY tight steering, they don't have to cross their hands or turn the wheel much even going into a 90* turn.

I'm fairly sure the exact opposite applies to F1 cars. Have you ever seen an F1 driver trying to manoever the car at slow speed? Big turns in the steering wheel don't turn the front wheels much, and the cars have rubbish turning circles. I'm fairly sure that the reason F1 drivers don't cross their hands when going through tight corners is that they take a line which means that the bend isn't really anywhere near 90*. I'm pretty sure that if you were to take the same bend, with the same line, in a road car you wouldn't have to cross your hands either.

I don't see that a steering ratio that reduces the amount of steering wheel movements makes the car any more responsive. It surely just makes it harder to control precisely, as making small steering adjustments would become harder.

Think of your computer mouse. If you turn the sensitivity up too far it doesn't give you any more control - you have less because the cursor skips around everywhere. What's important to mouse control is not sensitivity but scanning resolution of the optical sensor. I see steering in the same way - it's the precision of the steering rack, motor, wheels and tyres that's important for control and responsiveness, not the sensitivity (or at least, not beyond the optimum point of sensitivity, which was surely found years ago).

[pcbrew]

The idea is when you are already putting in a lot of steering input, you get more steering effect.

BTW, this is analogous to how your mouse behaves. Most(all) computer pointing devices have acceleration effect so that the more you move the mouse, the faster it moves. This makes it more natural feel when moving longer distances - say across the screen.

http://en.wikipedia.org/wiki/Mouse_(computing)
Moving the pointer a long distance: When a practical limit of mouse movement is reached, one lifts up the mouse, brings it to the opposite edge of the working area while it's held above the surface, and then replaces it down onto the working surface. This is often not necessary, because acceleration software detects fast movement, and moves the pointer significantly faster in proportion than for slow mouse motion.

[E90Fleet]

Originally Posted by pcbrew

Fleet - really appreciate all your inputs here, but this is one place when I am pretty sure this is backwards.
Steering is same as non-VSS from 0 to roughly 90deg turn of the wheel, then, additional steering input results in proportionally more turn on the actual wheels.
The idea is that you get more responsive steering when maneuvering in parking lots & such. You really don't want increased sensitivity at high speeds when steering wheel angles are low.

Ok, 1am postings may be allowing some confusion to creep in
From the technical documents.:

Standard steering has 1 ratio from 0-359 degrees

Sport starts the same as standard at 0.
But from just after 0 it changes very quickly all the way to 90.
From 91-359 degrees the ratio does not change anymore

The change from 0-90 is that the ratio becomes more and more direct. meaning less turns of the steering wheel are needed to get the road wheels to turn.

The sport steering is always more direct than the standard, except in the center position. the amount that is is more direct by changes till 90 degrees then stays constant.

So for a slight maneuver the sport steering requires slightly less steering wheel movement, but for a big maneuver the sport steering needs a lot less steering wheel movement. The amount less steering wheel movement needed is variable up to 90 degrees then becomes constant.

The sport steering always needs less steering wheel turn, but the amount less needed changes from 0-90. ( hardly less at 1 Degree, a lot less at 90 Degrees)

[E90Fleet]

Originally Posted by mfear

yeah, tighter, independent of speed -- unlike Mercedes benz which uses SPS (speed sensitive power steering), which loosens up the steering at low speed and tightens it up (as well as increases the turning ratio) at a higher rate of speed.

You are talking about a totally different system

BMW has the same system, its called Servotronic and is in the F30.
As speed increases it makes it harder for the driver to turn the steering wheel.

Going into sport mode makes the steering harder aswell.

Both Standard and Sport Variable steering get Servotronic


The variable sport steering we are talking about is the gear ratio of the steering, not how hard it is to turn the wheel.

[E90Fleet]

Originally Posted by pcbrew

Are you sure, I thought it just changed the steering ratio after > 90deg steering input. I can see it may tighten up at >90deg but that is not really normal street driving scenario, only parking lot.

Have you driven with and without VSS and compared in Normal & Sport or have any documentation on this. If true, I may add to my order since the steering in Normal feels too light.

If you want the steering wheel harder to turn you need to go into sport mode. there Servotronic will make the steering feel harder.

Variable sport steering will feel just as hard to turn in normal or sport mode as standard steering in those modes, but the amount of steering wheel turn angle needed to make the turn will be less with the Sport Variable. How much less depends on how steep the turn is as explained before.

[pcbrew]

Originally Posted by E90Fleet

If you want the steering wheel harder to turn you need to go into sport mode. there Servotronic will make the steering feel harder.

Variable sport steering will feel just as hard to turn in normal or sport mode as standard steering in those modes, but the amount of steering wheel turn angle needed to make the turn will be less with the Sport Variable. How much less depends on how steep the turn is as explained before.

Thanks for clarifying. That was my understanding as well.

[pcbrew]

Originally Posted by E90Fleet

Ok, 1am postings may be allowing some confusion to creep in
From the technical documents.:

Standard steering has 1 ratio from 0-359 degrees

Sport starts the same as standard at 0.
But from just after 0 it changes very quickly all the way to 90.
From 91-359 degrees the ratio does not change anymore

The change from 0-90 is that the ratio becomes more and more direct. meaning less turns of the steering wheel are needed to get the road wheels to turn.

The sport steering is always more direct than the standard, except in the center position. the amount that is is more direct by changes till 90 degrees then stays constant.

So for a slight maneuver the sport steering requires slightly less steering wheel movement, but for a big maneuver the sport steering needs a lot less steering wheel movement. The amount less steering wheel movement needed is variable up to 90 degrees then becomes constant.

The sport steering always needs less steering wheel turn, but the amount less needed changes from 0-90. ( hardly less at 1 Degree, a lot less at 90 Degrees)

Thanks for the detail. This and your response on the level of effort should be added to the FAQ sticky.

[Snow King]

Originally Posted by wynden

From the 3 series catalogue on the main BMW site:

"Variable sport steering. This optional system works independently of road speed, varying the steering ratio in line with the steering angle. It includes the Servotronic function and reduces the steering wheel movement required to achieve a particular tight steering angle. This enhances comfort when parking and manoeuvring, as well as sporting agility in tight corners and hairpin bends. For small steering angles, the steering enhances precision and directional stability."

I interpret this to mean that the Variable Sport Steering and standard (Servotronic) steering are the same, other than the variable steering ratio vs constant ratio. I.e. the effect of the Driving Experience Control and speed are the same for both. Am I wrong?

Also how is this different than the Active Steering on the E9x cars? I have on my e93 and really like it.

[r3dbimmer89]

Originally Posted by pcbrew

Thanks for the detail. This and your response on the level of effort should be added to the FAQ sticky.

+1

[lbahoshy]

Originally Posted by E90Fleet

Ok, 1am postings may be allowing some confusion to creep in
From the technical documents.:

Standard steering has 1 ratio from 0-359 degrees

Sport starts the same as standard at 0.
But from just after 0 it changes very quickly all the way to 90.
From 91-359 degrees the ratio does not change anymore

The change from 0-90 is that the ratio becomes more and more direct. meaning less turns of the steering wheel are needed to get the road wheels to turn.

The sport steering is always more direct than the standard, except in the center position. the amount that is is more direct by changes till 90 degrees then stays constant.

So for a slight maneuver the sport steering requires slightly less steering wheel movement, but for a big maneuver the sport steering needs a lot less steering wheel movement. The amount less steering wheel movement needed is variable up to 90 degrees then becomes constant.

The sport steering always needs less steering wheel turn, but the amount less needed changes from 0-90. ( hardly less at 1 Degree, a lot less at 90 Degrees)

Thank you E90. I was contemplating adding the Variable Sport Steering and now I think I will.

A question though, does the BMW Variable Sport Steering work on a similar principal to the variable steering that comes standard on the Porsche Boxster/Cayman/911 ??