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Old 11th January 2006, 10:28   #1
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Arrow Steering Designs

Hai BHPians,

Ford adds announce that they have ONE of the best steering systems in the world and my Fusion turns lock to lock in 2.5 turns. A few thoughts in my mind:

1. If the turns are more than 2.5 what are the consequences? Obviously the riding comfort and strain will be less; other than that any other technical imlications?

2. What about other popular cars, do we have to do more than 2.5 turns lock-to-lock?

3. Are there any cars with less than 2.5 turns, lock to lock?

4. I read somewhere, most driviers like to FEEL the feedbaks and that connects them with the tarmac. Are there cars which DOES NOT give any feedback AT ALL to the driver?

Thanks in advance for the inputs.

--Ramky.

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Old 11th January 2006, 11:47   #2
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Quote:
Originally Posted by ramkya1
Hai BHPians,

Ford adds announce that they have ONE of the best steering systems in the world and my Fusion turns lock to lock in 2.5 turns. A few thoughts in my mind:

1. If the turns are more than 2.5 what are the consequences? Obviously the riding comfort and strain will be less; other than that any other technical imlications?

2. What about other popular cars, do we have to do more than 2.5 turns lock-to-lock?

3. Are there any cars with less than 2.5 turns, lock to lock?

4. I read somewhere, most driviers like to FEEL the feedbaks and that connects them with the tarmac. Are there cars which DOES NOT give any feedback AT ALL to the driver?

Thanks in advance for the inputs.

--Ramky.

=====================
It depends on what you mean by 2.5 turns. Now that you raised the question I realized that I never counted the turns of the steering so precisely. I believe for both Santro and Indica it is something similar. However I think that 2.5 turns must be from the dead-center to one side lock. Are you sure it is lock-to-lock?!! Because if it is from one side wheel lock to the other in just 2.5 turns it works out to little over 1 turn of the steering from dead center to the wheel lock position. Sounds a bit too optimistic. Moreover won't that lead to oversteer problems?

About the turns in other cars, what is more important is how big is the steering wheel, a bigger wheel will mean lesser turn in comparison to a smaller steering wheel but of course the effort will be more. Also, in city conditions the important thing is whether your car can take a 180 degrees turn (U-turn) comfortably? That is how small is the turning radius of the car rather than the number of turns to lock the front wheels?

Personally I feel Feedback is something about how well you are in control of the car. A steering system with good feedback will have no understeer or oversteer problems. If I give it a minor twitch of say 2degrees and I can feel the car changing course immediately by that much angle I would say the feedback is great. The steering should not feel vague or with any play.
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Old 11th January 2006, 12:28   #3
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Arrow Steer Lock To Lock?

Quote:
Originally Posted by Zappo
It depends on what you mean by 2.5 turns. Now that you raised the question I realized that I never counted the turns of the steering so precisely. I believe for both Santro and Indica it is something similar. However I think that 2.5 turns must be from the dead-center to one side lock. Are you sure it is lock-to-lock?!! Because if it is from one side wheel lock to the other in just 2.5 turns it works out to little over 1 turn of the steering from dead center to the wheel lock position. Sounds a bit too optimistic. Moreover won't that lead to oversteer problems?
Hai Zappo,

All the adds of Fusion and other cars on their websites talk of 2.5 turns or 2.7 turns etc., from lock-to-lock. I'll physically count the turn today and let you know. Yes..... the bigger the wheel the lesser the turns......... but there must be some trade-offs?

--Ramky

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Old 12th January 2006, 11:18   #4
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[quote=Zappo]It depends on what you mean by 2.5 turns. Now that you raised the question I realized that I never counted the turns of the steering so precisely. I believe for both Santro and Indica it is something similar. However I think that 2.5 turns must be from the dead-center to one side lock. Are you sure it is lock-to-lock?!! Because if it is from one side wheel lock to the other in just 2.5 turns it works out to little over 1 turn of the steering from dead center to the wheel lock position. Sounds a bit too optimistic. Moreover won't that lead to oversteer problems?

=========================

Checked out the fusion wheel; lock to lock 2.7 turns, from centre to full right and full right around 1.5 turns. I think the rack and pinion assembly ratios also have everything to do with the number of turns needed........

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Old 12th January 2006, 12:43   #5
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Tata indica lock to lock is something like 3+. Thats from one side to other, I tested it on mine
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Old 12th January 2006, 12:46   #6
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The BMW 5 series E60 with active steering is 1.5 turns lock to lock!! its awesome..

Last edited by Maverick5490 : 12th January 2006 at 12:49.
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Old 12th January 2006, 12:50   #7
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I guess having a lesser lock-to-lock-turn improves the steering response. Just a little turn of the steering is enough to make the car turn properly. This looks logical. But one doubt I have is, will the turning radius increase because of this? I am yet to measure the lock-to-lock turn of Palio but I know it is pretty small, as in Fusion. But the turning radius of Palio is large. Is there a connection?
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Old 12th January 2006, 17:24   #8
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having a smaller lock-to-lock movement on the steering wheel would definitely make driving on the highways a pain...even dangerous for the reason mentioned by deepak (feels strange mentioning my own name)...i.e that a small movement on the steering wheel would translate into a greater movement of the tyres. I remember long time ago, the santro zipdrive ads also claimed lock-to-lock in just 1.5 turns of thw steering whjeel. But i doubt thats true...or maybe i cant remember properly.

Another thing is that having less turns required to turn the wheels would also mean that more effort is required to turn the steering wheel. I guess manufacturers would increse the power assistance to compensate for that.

Most cars i've driven/travelled in have had at least 2.5 turns from lock to lock.
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Old 12th January 2006, 18:10   #9
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Quote:
Originally Posted by Deeps
having a smaller lock-to-lock movement on the steering wheel would definitely make driving on the highways a pain...even dangerous for the reason mentioned by deepak (feels strange mentioning my own name)...i.e that a small movement on the steering wheel would translate into a greater movement of the tyres. I remember long time ago, the santro zipdrive ads also claimed lock-to-lock in just 1.5 turns of thw steering whjeel. But i doubt thats true...or maybe i cant remember properly.

Another thing is that having less turns required to turn the wheels would also mean that more effort is required to turn the steering wheel. I guess manufacturers would increse the power assistance to compensate for that.

Most cars i've driven/travelled in have had at least 2.5 turns from lock to lock.
Exactly! the point I raised... won't it lead to oversteer problems? You will always have to keep that at the back of the mind... and in panic situations it can get ugly. That is when people give the steering a mighty big heave!
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Old 12th January 2006, 19:15   #10
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if by oversteer you mean the tail snapping out then...not it wont happen due to a smaller lock to lock turns.
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Old 12th January 2006, 21:22   #11
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Lock to lock on the OHC Vtec is 3.6 turns.

A lower LTL ratio gives you more turning capacity per degree of steering angle. But, this can only be true if the car you're comapring it with, has the exact max-wheel-turning angle.

It's way too complicated to come to any conclusion, as to which is better.

Shan2nu
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Old 12th January 2006, 21:35   #12
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You're right. Its hard to compare 2 cars based on LTL. But it is a good rough comparison and car mags always do it.
What you need is something called steering ratio which is anywhere from 13:1 to 17:1. Its the ratio of the steering wheel to the road wheel.
The BMW active steering keeps its around 12:1 for painless parking and slows it down to 17:1 for autobhan speeds
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Old 12th January 2006, 21:49   #13
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Quote:
What you need is something called steering ratio which is anywhere from 13:1 to 17:1. Its the ratio of the steering wheel to the road wheel.
Yup, steering ratio is the more accurate way of determining the turning capabilty of the vehicle, per deg of steering angle.

13:1 comes to around 3.25 turns for every 90 deg change in road-wheel angle. 17:1 goes up to 4.25 for the same given road-wheel angle.

Another thing i've noticed is that on some sports cars
(Noble M400), the point where the steering joins the steering rod, isn't at the center of the steering wheel. Which means that the steering axis isn't centrally positioned.

One reason could be that this design helps steer the car with less effort as it increases the leverage when moving the steering.

Shan2nu

Last edited by Shan2nu : 12th January 2006 at 21:54.
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Old 15th January 2006, 20:10   #14
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Quote:
Originally Posted by Shan2nu
Another thing i've noticed is that on some sports cars
(Noble M400), the point where the steering joins the steering rod, isn't at the center of the steering wheel. Which means that the steering axis isn't centrally positioned.

One reason could be that this design helps steer the car with less effort as it increases the leverage when moving the steering.
Interesting thought, but are you sure the boss on the wheel is really offcenter??

cya
R
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Old 15th January 2006, 20:39   #15
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Quote:
Interesting thought, but are you sure the boss on the wheel is really offcenter??
Yup, i'm pretty sure about it. Coz when Vicki turns the steering, you can see one section of steering move up n down. This is only possible if the axis is offcenter or if the steering is not a proper circle. What ever the reason, it does improve leverage.

If any off you guys have the Noble M400 vs the Mitsu Evo VIII FQ400 test video from 5th Gear, check it out.



Looking at that pic, it does seem as if the steering is an oval, doesn't it. Maybe the steering axis is centered but the steering is surely not a circle.

Shan2nu

Last edited by Shan2nu : 15th January 2006 at 20:46.
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