Four turns lock to lock?

[Boston Boy]

Since the vehicle has power steering, and I assume it was designed to be robust, why could they have just changed the gearing to, say, three turns lock to lock and depended on the power steering's assistance to keep the steering effort reasonable? I am not a steering gear designer (and don't play one one tv as the old ad said), with the many complaints about the number of turns, why could that not be a solution for future builds?

 

[DaveB]

Since the vehicle has power steering, and I assume it was designed to be robust, why could they have just changed the gearing to, say, three turns lock to lock and depended on the power steering's assistance to keep the steering effort reasonable? I am not a steering gear designer (and don't play one one tv as the old ad said), with the many complaints about the number of turns, why could that not be a solution for future builds?

Because it is designed for off road use not on track sports

 

[bigleonski]

Without being flippant though, is there a mechanical reason due to design for the higher number of turns?

 

[DaveB]

Without being flippant though, is there a mechanical reason due to design for the higher number of turns?

It is mainly based on the gear ratios selected and the diameter of the steering wheel.
Although the length of the pitman arm can also have an impact.
The Grenadier has a fairly small diameter steering wheel.
Change it to a larger one and obviously there will be less turns lock to lock.
Change to a higher ratio gearing and there will be less turns lock to lock, but less feeling and more kick back offroad and on bad roads.
Turning circle is also often setup with different wheel/tyre combinations in mind so they can fit within the wheel arches.
I have seen a lot of 4wds that rub tyres on wheel arches.

 

[DenisM]

It is mainly based on the gear ratios selected and the diameter of the steering wheel.
Although the length of the pitman arm can also have an impact.
The Grenadier has a fairly small diameter steering wheel.
Change it to a larger one and obviously there will be less turns lock to lock.
Change to a higher ratio gearing and there will be less turns lock to lock, but less feeling and more kick back offroad and on bad roads.
Turning circle is also often setup with different wheel/tyre combinations in mind so they can fit within the wheel arches.
I have seen a lot of 4wds that rub tyres on wheel arches.

Number of turns lock to lock is independent of the diameter of the steering wheel....
A larger steering will however provide increased mechanical advantage...less effort required (well known in the days before power steering!).

 

[DaveB]

Number of turns lock to lock is independent of the diameter of the steering wheel....

Poor choice of words on my part
The size of the wheel makes the number of turns feel different but as you say the number of turns on the steering shaft doesn't change.
Just the distance the wheel rim travels for the same effect