Had an "ah ha" moment watching the Grand Am race @ VIR on Speed last night. One of the teams was talking about steering boost issues, and it came to mind that some of the complaints on a couple of other threads about the Fits handling may be caused by the use of an electric motor to boost the steering , rather than the "traditional" hydraulic method.
With hydraulic steering boost ("power steering") the fluidics isolate some road feel so you don't notice or feel as much of the imperfections in the road. With the electric boost we essentially have a manual steering box with an electric motor grafted on to decrease steering effort- no hydraulic fluid to absorb the feel of the front wheels being knocked about by groove/cracks/bumps in the road.
Thoughts???

 

Sounds like it makes sense to me.

 

Disagree. If anything, electric steering has always been derided for not offering the same level of feel as traditional hydraulic units.

The reason? Hydraulic fluid in a system is not compressible, so it adds another direct mechanical link to the steering that provides a more agreeable motion. It works solely based upon the amount of fluid moved, and provides an added level of feedback as the wheels can feed back through the system. It does not absorb anything.

Unlike an electrical system, where the level of help is determined by programming, and not directly to a mechanical system.

The perception of nervous handling has nothing to do with the power steering. It is however directly related to things such as steering ratio, i.e. the number of turns at the wheel required to move the wheels a certain amount, and suspension geometry, i.e. a lack of caster or toe to promote stability at speed. The roll center of the car, as well as the locations of its moments of inertia can also contribute.

Our cars for example, have fairly quick steering and likely have little caster and no toe, promoting a responsive front end. The CG is probably average as much of the heavy components (including gas tank) are mounted low, and the car probably has a low roll center as well. Simultaneously, it's moment is likely centered towards the front where you're seated as that is where most of the mass is concentrated, which can lead to a feeling that the rear of the car may not be tracking properly and the car is pivoting around the engine block as oppose to the center of the car. Combine that with the relatively simplistic rear suspension geometry (as attributed to the torsion beam), that does not have the ability of multilink systems to create stabalizing toe in geometry under such loads, and you can have a car that is perceived to be a nervous handler.

Or in my case, a car that provides me the sort of sensory feedback and responsiveness that puts a smile on my face and makes my commute tolerable.

If anything, be thankful that where so many manufacturers have screwed electric power steering, Honda has managed to make a system that is otherwise transparent in operation.

 

If you have ever driven a Lincoln Town car or Caddy you will have a perfect example of how hydraulic steering can be engineered to eliminate steering feel!




I 100% agree- I don't mind the "nervousness" of the handling.... I find it quite fun!!

 

I have, and you are absolutely right. Of course my response was worded in such a way to make my point. Having said that, in general, the most responsive steering setups usually are hydraulic for those reasons, while it is rare to find a great electrical one such as the one found in our cars. You agree with that, no?

It really is a great little car to drive.

 

In terms of actual stability as in through turns and maneuvers, stability could actually decrease. A roll/sway bar doesn't in fact limit body motions, it limits suspension movement.

A big misconception being that a bar prevents the body from leaning, when in fact its work is better described as picking up the inside wheel (such as in a turn). With the inside wheel lifting, the car has no choice but to roll back towards it. The perception then is, the body doesn't lean as much.

In a straight line on a freeway, perceived stability will of course be greater as the rocking motions that would be attributed to wind are lessened. Actual grip and stability however may decrease.

A rear bar of course in a front wheel drive car is added to take stability away from the rear through transient maneuvers, making the car more neutral.

This is of course, the reason I'd want one.

 

Absolutely!!

Very much so!