[stevehecht]

Could someone(s) articulate the difference between steering/road FEEDBACK vs. steering FEEL? These two seem to be closely related yet distinct. Is feedback an aspect of feel, or vice-versa, or neither?

Feedback may be more significant to Driver #1 while feel is more important to Driver #2. And while you're at it, please describe how steering HEFT/HEAVINESS relates to feedback and feel. Feel free to throw in any other major categories that you think help evaluate the steering EXPERIENCE. Inquiring minds (like mine) will be eternally grateful.

I think a lot of these disagreements are not really disagreements at all, just people focusing in on different aspects of the steering experience combined with a bit of semantic confusion.

[Sedan_Clan]

Originally Posted by stevehecht

Could someone(s) articulate the difference between steering/road FEEDBACK vs. steering FEEL? These two seem to be closely related yet distinct. Is feedback an aspect of feel, or vice-versa, or neither?

Feedback may be more significant to Driver #1 while feel is more important to Driver #2. And while you're at it, please describe how steering HEFT/HEAVINESS relates to feedback and feel. Feel free to throw in any other major categories that you think help evaluate the steering EXPERIENCE. Inquiring minds (like mine) will be eternally grateful.

I think a lot of these disagreements are not really disagreements at all, just people focusing in on different aspects of the steering experience combined with a bit of semantic confusion.

Good question. I'll bite....


...Where steering/suspension/handling/etc. is concerned, it is my opinion that feel is a component of feedback and the personal sensitivities that drive how you interpret that feedback determines your position(s) on feel (...think about the "too stiff vs too soft" arguments where suspensions are concerned).

Steering heft/heaviness is a component of feel rather than feedback, and where heft/heaviness lies on your own personal spectrum of tolerance depends entirely on personal preference (...again, much like suspension tuning). Heavy steering doesn't necessarily equate to responsive feedback and lighter steering doesn't necessarily dictate a lack thereof.

In addition, suspension components/geometry and wheel/tire choices all contribute to feedback which then contributes to feel (..example: Add wider wheels/tires on an otherwise stock car and you will immediately notice more tramlining, thus, affecting feedback through the steering wheel, etc.). Even tire pressure can affect feedback, thus feel. It's a bit of an over-simplification to suggest that the rack (..or the technology employed on the rack), alone, is the sole source of feedback and feel. They are all related. More tactile people thirst for more feel (..and as a result, feedback...), but less tactile people don't give it much thought. A really simple example lies within the well designed high-end luxury car. Soft suspension characteristics and steering systems designed with the sole purpose of making you feel like you're riding on a cloud, and insulating you from every road imperfection and/or quibble that the thoroughfare might toss your way. It's not just the rack that accomplishes that. It's the totality of all of those systems working together to produce an end result.

The F30 and E90 employ different technologies for the steering rack, but there are variances in the suspensions/track/etc. as well. All of those differences work together to produce an end result that may feel a tad different, but improve the overall abilities of the car by measurable amounts.


edit:

We can also add brake modulation into the feel/feedback discussion too.

[stevehecht]

But there seems to be a difference between steering accuracy and steering feel/feedback. Magazine writers can say that the feedback of the f30 is sub-par relative to the E9x but that steering accuracy and feel is better!

[drob23]

I'll give you the engineering perspective, which necessarily requires some background. I'm still learning about vehicle dynamics myself, but this is what I've absorbed over the last couple months.

First, understand what the steering system is. You are moving the wheel which rotates a column which drives a pinion gear against a steering rack. The rack pushes the tire rods to cause the wheels to rotate about the kingpin axis (which is virtual axis for most multi-arm suspension geometries). There is often compliance (and friction) built into this system to isolate the driver from road/tire noise.

Next, understand what the vehicle is doing. When you are moving and apply a steering input, you are generating a lateral force component transferred to the ground via the tire. Depending on the dynamic state of the vehicle (more the suspension) this can vary in complexity. For instance, a 2 wheel vehicle will "lean" into the turn (camber thrust) while a 4 wheel vehicle will twist the pneumatic tire (but can also experience weight transfer and camber thrust etc). From HS physics, we know that a constant turn requires a constant acceleration inwards, so even a constant turn requires continuous steering input (lateral acceleration).

Next, what is power steering? Well, due to packaging and gear ratios etc, it might be difficult to steer the wheels without aid. Plus, it is desirable not to require 5 turns each direction to reach steering lock. The power steering system applies a force, usually at the rack, to aid in you in wheel inputs. The requirements for assistance go down as the vehicle speed increases, mainly because small wheel angles result in much larger lateral acceleration. People are very comfortable with Hydraulic Power Steering (HPS) systems, which are belt driven pumps that operate via the accessory belt from the crank shaft. There is some fancy valving done in the pump to control how assist pressure builds as a function of engine driven RPM, similar to the bypass valve on a supercharger. Electric Power Steering (EPS) uses torque sensors + wheel angle sensors fed into an ECU to drive some motors along the rack. The motors have a lot more friction in them (analogous to dampers if you will), hence the problem many have with feedback. EPS improves fuel economy because it is a "on demand" technology, and doesn't constantly sap power from the crank like a HPS pump does. Interestingly, it also allows for the steering ECU to actually turn the wheel *without* your input, enabling features like active park or lane keep etc.

OK, lol, now to answer your question. Steering feel, in my opinion, has everything to do with how one perceives the boost curve in their everyday driving. The feel can range from "too light" to "too heavy". Issue with EPS is that the boost is determined by the ECU so may feel "artificial" in certain instances. It must vary as speed changes, and ideally makes parking easier (where you need much higher assist). In my opinion, perceived feel is highly contingent on your own experiences. Do you prefer IPA's or bud light, tube amps or DSP. People love their old sports cars (which had low assist) and now don't like light steering.

Steering feedback relates indirectly to how much friction/compliance you have in your steering system. As you are driving hard and turning the vehicle, you will generate lateral force (change torque moments at tire), hit different road surfaces, and change the dynamic state of vehicle accelerate out of turn etc. The question is how much of that gets transmitted back through the steering system. These road surface forces should be transmitted as torques at the wheel (twitches if you will). Expert drivers will know have a good internal feel for how much torque they need to apply depending on what the vehicle is doing. This is learned through much cockpit time, and again is continent on their steering assist system. I am no expert with the electric assist motors, but my guess is that the friction in the motors absorb the forces generated by the road much more than the hydraulic assist valving system. They almost act like dampers.

Well that's my $.02, hopefully made some sense and feel free to correct where I'm wrong (which is a sure thing).

[newoldbeemer]

Originally Posted by stevehecht

But there seems to be a difference between steering accuracy and steering feel/feedback. Magazine writers can say that the feedback of the f30 is sub-par relative to the E9x but that steering accuracy and feel is better!

I think that statement is spot-on. Which magazine?

[stevehecht]

Originally Posted by newoldbeemer

I think that statement is spot-on. Which magazine?

It was either C&D or MT, those are the only two I read. Maybe someone else can help out here. That opinion has also been quoted on this forum or on bimmerfest in one of the innumerable threads on this topic.

[Sedan_Clan]

Originally Posted by stevehecht

But there seems to be a difference between steering accuracy and steering feel/feedback. Magazine writers can say that the feedback of the f30 is sub-par relative to the E9x but that steering accuracy and feel is better!

There is! The car should track exactly as intended. Accuracy is pretty self-explanatory actually.

[Mak135i]

Originally Posted by stevehecht

But there seems to be a difference between steering accuracy and steering feel/feedback. Magazine writers can say that the feedback of the f30 is sub-par relative to the E9x but that steering accuracy and feel is better!

+2
If you track your F30 (especially with an instructor, who is anal about driving lines!), there is no doubt the steering is accurate. I never owned a E9X, so I cannot compare the 2.

[335BOY]

Originally Posted by stevehecht

Could someone(s) articulate the difference between steering/road FEEDBACK vs. steering FEEL? These two seem to be closely related yet distinct. Is feedback an aspect of feel, or vice-versa, or neither?

Feedback may be more significant to Driver #1 while feel is more important to Driver #2. And while you're at it, please describe how steering HEFT/HEAVINESS relates to feedback and feel. Feel free to throw in any other major categories that you think help evaluate the steering EXPERIENCE. Inquiring minds (like mine) will be eternally grateful.

I think a lot of these disagreements are not really disagreements at all, just people focusing in on different aspects of the steering experience combined with a bit of semantic confusion.

Some great interesting posts. I would simplify by saying feel relates to heft or lack thereof and feedback is affect road imperfections (and corners)have on the steering wheel.

[stevehecht]

Originally Posted by 335BOY

Some great interesting posts. I would simplify by saying feel relates to heft or lack thereof and feedback is affect road imperfections (and corners)have on the steering wheel.

Many drivers say that the F30 steering is light and lacks heft/resistance/weight (that's a "bad thing") even though they say "steering feel" is quite good. Are they as confused as I am?

[Sedan_Clan]

Originally Posted by stevehecht

Many drivers say that the F30 steering is light and lacks heft/resistance/weight (that's a "bad thing") even though they say "steering feel" is quite good. Are they as confused as I am?

I think people need to be more specific when they offer their criticisms. The E9X non-M cars didn't have modes that affected steering and chassis feel; the F3X does. So when a person juxtaposes their feelings about the E9X versus that of the F30/F32, they need to state something like this, "In Comfort mode, the F3X steering feels lighter than the that of the E9X." That's a more accurate statement than just claiming one is lighter than the other. Sport/Sport+ has heft and a nicely weighted steering feel, and arguably feels better than any non-M E9X. The funny thing is that people complained about the light steering in the E9X M3's servotronic rack, but forgave it because it was communicative (..once they adjusted to it). People have really short memories. Normal mode in the M3 wasn't to my tastes, so I always chose the heaviest of the steering modes.

[HighlandPete]

Originally Posted by Sedan_Clan

I think people need to be more specific when they offer their criticisms. The E9X non-M cars didn't have modes that affected steering and chassis feel; the F3X does. So when a person juxtaposes their feelings about the E9X versus that of the F30/F32, they need to state something like this, "In Comfort mode, the F3X steering feels lighter than the that of the E9X." That's a more accurate statement than just claiming one is lighter than the other. Sport/Sport+ has heft and a nicely weighted steering feel, and arguably feels better than any non-M E9X. The funny thing is that people complained about the light steering in the E9X M3's servotronic rack, but forgave it because it was communicative (..once they adjusted to it). People have really short memories. Normal mode in the M3 wasn't to my tastes, so I always chose the heaviest of the steering modes.

Plus wheels and tire comparisons, whether tire pressures were checked and tires warm, etc.

Seems weight and heft are the big criticism by many. Personally I don't see why it rates so highly, in gauging whether steering is up to the mark. Plus I feel suspension and chassis configurations have a major contribution to steering feedback, as fluidity of the chassis can add or detract to/from steering feel.

Isn't steering weight more a personal like or dislike? I've driven Ford, Vauxhall, Jaguar (XF) and other examples with far "lighter" steering than my E91 330d with its heavily weighted HPAS, and the other cars had similar, (or better), steering for feedback and feel. Added steering weight/heft is a preference rather than a mark of good steering, in my opinion.

I posted in the other topic that I prefer my 5-series steering in the normal mode, find the sport mode (although nicely weighted) feels damped, compared to the normal setting. I like the more sensitive feel to the steering in normal mode.

HighlandPete

[turbolag]

Originally Posted by Sedan_Clan

I think people need to be more specific when they offer their criticisms. The E9X non-M cars didn't have modes that affected steering and chassis feel; the F3X does. So when a person juxtaposes their feelings about the E9X versus that of the F30/F32, they need to state something like this, "In Comfort mode, the F3X steering feels lighter than the that of the E9X." That's a more accurate statement than just claiming one is lighter than the other. Sport/Sport+ has heft and a nicely weighted steering feel, and arguably feels better than any non-M E9X. The funny thing is that people complained about the light steering in the E9X M3's servotronic rack, but forgave it because it was communicative (..once they adjusted to it). People have really short memories. Normal mode in the M3 wasn't to my tastes, so I always chose the heaviest of the steering modes.

Don't forget, M Sport steering =/= other line steering. M Sport seems almost acceptable for an EPS system, while the noline I drove sucked. Heft was alright, feedback was lacking.

[Sedan_Clan]

Originally Posted by HighlandPete

Plus wheels and tire comparisons, whether tire pressures were checked and tires warm, etc.

Seems weight and heft are the big criticism by many. Personally I don't see why it rates so highly, in gauging whether steering is up to the mark. Plus I feel suspension and chassis configurations have a major contribution to steering feedback, as fluidity of the chassis can add or detract to/from steering feel.

Isn't steering weight more a personal like or dislike? I've driven Ford, Vauxhall, Jaguar (XF) and other examples with far "lighter" steering than my E91 330d with its heavily weighted HPAS, and the other cars had similar, (or better), steering for feedback and feel. Added steering weight/heft is a preference rather than a mark of good steering, in my opinion.

I posted in the other topic that I prefer my 5-series steering in the normal mode, find the sport mode (although nicely weighted) feels damped, compared to the normal setting. I like the more sensitive feel to the steering in normal mode.

HighlandPete

Excellent points, and all things that I've mentioned in the other thread...

[btbossman]

Originally Posted by Sedan_Clan

There is! The car should track exactly as intended. Accuracy is pretty self-explanatory actually.

Im sure you know much more about precision and accuracy than most people. Especially previously having multiple m3's(and being a cop). The last e9x 335 m sport I had to drive felt, well sluggish diving into a corner where the m3 just feels natural...I find it more like this on my f30...Its hard to describe, because the steering feel itself is mostly different, and the cars roll completely differently but they are just very precise.

I think another issue in this is suspension itself and the effect it has on our perceived "steering feel"...lets also remember in takes some time for our brains to process and analyze data, especially when constantly moving.

I have recently driven all 3 cars e92 335 e92 m3 and my f30 335... they are all vastly different from each other...the beauty in the f30 is you can have comfort and absorption, and stiffness all with a very precise steering capability. I just wish there was no roll like the e92's, I think thats the biggest factor in any issues with this car.

[stevehecht]

Originally Posted by btbossman

...the beauty in the f30 is you can have comfort and absorption, and stiffness all with a very precise steering capability. I just wish there was no roll like the e92's, I think thats the biggest factor in any issues with this car.

That's why I'm really looking forward to Dinan's Shockware release sometime in the early spring of 2014. Tighter spring rates with a thicker RSB and dampers to match should solve that roll problem I would think. We're then looking at perhaps the best (non-M) BMW 3-series ever to greet the road.

The folks at Dinan deny that Shockware will impact steering feel, but I don't believe it. (I asked a fellow there that very question...maybe he was trying to "dampen" expectations. )

[drob23]

Originally Posted by stevehecht

That's why I'm really looking forward to Dinan's Shockware release sometime in the early spring of 2014. Tighter spring rates with a thicker RSB and dampers to match should solve that roll problem I would think. We're then looking at perhaps the best (non-M) BMW 3-series ever to greet the road.

The folks at Dinan deny that Shockware will impact steering feel, but I don't believe it. (I asked a fellow there that very question...maybe he was trying to "dampen" expectations. )

The proper way to remove roll and change the understeer/oversteer margin is to swap in beefier anti-roll bars and ball joint end links (not rubber ones). I don't think the springs/dampers should be responsible for managing body roll other than lowering the COG.

[stevehecht]

Originally Posted by drob23

I don't think the springs/dampers should be responsible for managing body roll other than lowering the COG.

Right, but that is still part of the picture.

Question: Besides lowering CoG, don't stiffer springs by themselves help control body roll? Don't they in effect act as part of a stiffer chassis?

[drob23]

Originally Posted by stevehecht

Right, but that is still part of the picture.

Question: Besides lowering CoG, don't stiffer springs by themselves help control body roll? Don't they in effect act as part of a stiffer chassis?

Yea, definitely, every suspension component plays into the overall picture. But stiffening springs (lowering) or shocks will affect the ride a lot, i.e. how the car drives going straight. Changing the damper rate also won't affect body roll in steady state cornering, since dampers only affect the suspension as it moves up or down (with constant cornering you will be in a constant laterally loaded state).

The anti-roll bars on the other hand only affect the suspension when one side of the vehicle suspension compresses more than the other. They prevent this by loading up like a spring. Really stiff ARB's are bad if you hit a pot hole, in that they limit the ability of a suspension component to act independently of others. In the limit of stiff ARB's, you have a solid axle.

[stevehecht]

But specific to my question, do stiffer springs help to control roll (as part of the chassis response) outside of lowering CoG? I'm aware that struts don't play a "roll" here.

[Nedmundo]

Originally Posted by 335BOY

Some great interesting posts. I would simplify by saying feel relates to heft or lack thereof and feedback is affect road imperfections (and corners)have on the steering wheel.

That's a lot of it, but overall feel also includes linearity of response, which affects accuracy, and how effort builds and decays off center. EPS systems like BMW's and my Acura's are extremely accurate, because they respond in linear fashion to steering inputs. I notice the difference immediately when I drive our HPS Mazda, because its steering doesn't provide an even, linear response. In that respect, I prefer my Acura's EPS.

But, due to the high friction of electric motors, EPS racks simply don't respond to the road surface as much as HPS systems, which greatly reduces feedback, and also produces poor self-centering, and thus poor on-center feel unless the system is tuned to compensate. Car and Driver described much of this in an excellent article here, and their analysis matches my experience with my Acura's steering:

http://www.caranddriver.com/features...n-test-feature

In a September 2013 article, C&D measured and described the poor self-centering in the F30's steering relative to the E90's: "The slip angles producing cornering forces at the tire patches create what’s known as aligning torque—essentially, the tire trying to return to straight-ahead running. This aligning torque is fed back through the rack-and-pinion steering gear to the steering wheel. It’s part of the information the driver uses to learn what’s going on where the rubber meets the road. The K&C machine reported that aligning torque is 64 percent lower in the 328i than in the 335i. While the switch to electric power steering may improve mileage, it’s a bummer for Bimmer driving satisfaction."

http://blog.caranddriver.com/a-tale-...-so-different/

In normal driving, I actually think the weak self-centering/on-center feel is a bigger issue than nuanced feedback, because it provides a less secure sense of highway tracking. (C&D described this in the above article.) That's where I miss my old Saab's wonderful HPS the most.

I haven't driven a huge number of cars with EPS, but only the Ford Focus ST has impressed me with strong on-center feel. Ford has obviously tuned its system to provide high resistance just off-center, which doesn't provide nuanced feedback at all steering angles, but does provide a secure sense of tracking on the highway. On I-95 around Philly, it just felt totally locked in. (If you're interested, Chris Harris describes this aspect of the ST at around 7:00 in this vid:

.)

[drob23]

Originally Posted by stevehecht

But specific to my question, do stiffer springs help to control roll (as part of the chassis response) outside of lowering CoG? I'm aware that struts don't play a "roll" here.

Yes, they do. If you took the springs stiffness to infinity you would no longer have any suspension, and the car couldn't roll at all . Stiffer springs reduce body roll.