Why did you buy Nav. or Active Steer?

[dick w]

Thinking about it, I wonder if the 3.0->3.0/16->18 discrepancy is to account for the amount it can "unwind" the steering for stability yaw compensation and, thus, the 18 end of the ratio is only effective when it is doing so?

[Vaaaan]

Originally Posted by dick w

Thinking about it, I wonder if the 3.0->3.0/16->18 discrepancy is to account for the amount it can "unwind" the steering for stability yaw compensation and, thus, the 18 end of the ratio is only effective when it is doing so?

I'm thinking that with AS the wheels just don't turn as far at high speeds.

Even if they only turn 30 degrees at full lock (18:1 @ 540 degrees = 30 degrees) instead of 33.75 (16:1 @ 540 degrees = 33.75 degrees), that's still plenty more than the car's chassis/tires could handle at 100+ mph.

I would guess that something inside the steering wheel - like the airbag clock spring, or radio/phone button wires, maybe even a manual stop - prevents it from being turned greater than 3 full turns, AS or not. But seriously, when was the last time you went full lock on the highway anyway?

[dick w]

Originally Posted by Vaaaan

I'm thinking that with AS the wheels just don't turn as far at high speeds.

Could be. But there has to be a fail safe mode for when the AS fails. That would set the limits.

[dick w]

Originally Posted by Vaaaan

Even if they only turn 15 degrees at full lock (18:1 @ 270 degrees = 15 degrees) instead of 16.875 (16:1 @ 270 degrees = 16.875 degrees), that's still plenty more than the car's chassis/tires could handle at 100+ mph.

Imagine the size of the skid pad you'd have to be on!

[Vaaaan]

Originally Posted by dick w

Could be. But there has to be a fail safe mode for when the AS fails. That would set the limits.

I'm not sure if I understand what you're saying, but failsafe mode just locks the active part of the active steering. So if it dies at the highest ratio, whatever normally prevents the wheel from turning more than 3 turns would still function, and if it dies at the lowest ratio, the lock to lock would be limited by length of the rack itself.

This video briefly explains the failsafe at 0:42-0:58 if anyone's interested

Originally Posted by dick w

Imagine the size of the skid pad you'd have to be on!

That would be fun


I just realized I was doing the calculations with 270 degrees which would be 3/4 of a turn, not 540 or 1 1/2 turns, the idea is still the same though... previous post edited.