[baddy]

**Apologies/Warning for the long post.

After working as a vehicle dynamics engineer for the past decade on both passenger cars and heavy commercial vehicles, I can say with some conviction that every automobile steering system should have self-centering characteristics and from a drivers perspective too it is natural to expect positive centering of steering post completion of a turn.

What causes steering self-centering?
Mainly the steered wheel's geometry like caster and kingpin inclination and to a large extent the tyre characteristics (safe to assume, smaller the tyre foot print/wheel geometry value, lesser the self centering).
Reasons why most of the A segment cars in india would suffer from poor steering self -centering are:
1. Tiny contact patch tyres (145-155mm width) for maximising fuel economy.
2. Less wheel geometry (caster/KPI angles) for reduced steering effort and avoiding other complications like tyre wear.

Implications of aggressive wheel geometry?
Pro's
1. Positive road feel at high speeds
2. Good Self-centering at low speeds

Con's
1. Higher steering effort at low speeds.
2. Sensitive to road irregularities (steering kickback)
3. Follows road crown/camber at high speeds (vehicle pull)
4. Geometrically more forces coming to crucial steering and suspension components which means they have to be built stronger or in other words means lesser profit for manufacturer.

A Fiat Punto/Linea or a Renault Duster driver will be able to associate with the above mentioned points

Misconception associated with Type of steering assistance (HPS better than EPS?)
First of all, self centering occurs when the driver stops giving inputs to the steering wheel, which means there is no positive steering assistance forces acting on the system. So an EPS system should theoretically have lesser resistance compared to a HPS (resistance from hydraulic fluid back flow) to return back to center position. Another important factor is the ability to apply assistance characteristics specific to a large variation of vehicle speed and driver input torque with an EPS over an almost passive characteristic of a HPS.

For the same reason a well tuned EPS can have better steering feel, effort and overall quality when compared to a HPS. I explained this mainly because many car enthusiasts have a perception that hydraulic steering have better feel and feedback... This may be the fact 10 years ago, but given today's advancements in terms of electric steering system design and capability, HPS can not hold a candle.
P.S: I myself drive a 2015 fiat punto evo 90hp and love the steering feel, but hate the fact that it pulls on highways and kicks back like crazy over road bumps.


Why EPS may be better?
As mentioned earlier, The biggest advantage of an Electric Power Assistance system is the enormous programming possibilities available to enable multiple functional requirements.
Ford india launched the active centering and vehicle pull compensation feature in the updated fiesta mk6 and eco sport models quite some time ago. The system basically reduces driver intervention for road crown pull correction by applying a counter torque as well as for cross winds and help bring the steering back to 0 degree position post completion of a turn. The angle and torque sensors help the steering controller to know how and when to do this. Currently a lot of cars like the hyundai creta, kia seltos and even smaller segment cars like the nano and tiago are equipped with such systems that enable positive steering return without compromising steering feel or worrying about road crown induced pull.

In a nutshell, self centering will be good if there is sufficient wheel geometry to create it and least friction in the system to resist it. But in certain cases friction is deliberately introduced to serve two purposes:
1. Higher friction allows one to set the steering in the ideal centre position without continuous driver effort in case of a vehicle pull due to road crown.
2. The higher effort due to the friction will mask any loose feel present in the steering on centre during highway speeds.
For most beginner drivers the above two points will not even be bothersome and may rather appreciate such a feel.
The down side is the poor self centering at low speeds, leading to increased driver effort to bring the wheel manually back to center after a turn.

An ideal EPS can strike the perfect balance for all of these steering parameters if properly tuned, considering the actively variable assistance advantage.

All the above mentioned things, require substantial time, money and expertise for tuning. What some OEMs fail to understand is where to trade off performance with profitability or time to market. And from what I have witnessed, the average indian drivers requirements in terms of Ride & Handling in a car are only increasing day by day. I hope OEMs can keep up with this demand by optimising their product development route.

An interesting Incident:
In the past, one of the hcv (bus) model from the organisation i used to work for, participated in a tender for induction in the ghat section fleet for tirupati. It was turned down after the fleet test drivers complained of poor self centering of the steering. Imagine turning the steering from full lock to lock and then returning it back to center for over 40 to 50 hairpin bends. It was later found to be a tolerancing issue with the front axle, causing high friction to the steering which was then quickly corrected. I mention this to emphasise how important self centering of steering is for both driver comfort and eventually safety.

Regards,
Badri

[Sridhar K]

@badri
Thanks. The below explains the steering behavior that I see on the pre-workshipped celerio that I bought recently for my dad

In a nutshell, self centering will be good if there is sufficient wheel geometry to create it and least friction in the system to resist it. But in certain cases friction is deliberately introduced to serve two purposes:
1. Higher friction allows one to set the steering in the ideal centre position without continuous driver effort in case of a vehicle pull due to road crown.
2. The higher effort due to the friction will mask any loose feel present in the steering on centre during highway speeds.
For most beginner drivers the above two points will not even be bothersome and may rather appreciate such a feel.
The down side is the poor self centering at low speeds, leading to increased driver effort to bring the wheel manually back to center after a turn.

If I understand your post correctly and the one in the link below (explanation from Maruti engineers on a bhpians complaint about steering issues on ignis), Maruti's has gone for a passive steering geometry sometime around the early part of the last decade which has made the steering a bit tight with poor return to center action

https://www.team-bhp.com/forum/techn...ml#post4527652 (Maruti Ignis: Steering too hard & my saga with Nexa)

[PrasannaDhana]

I haven't even noticed if steering self-centers in my ciaz, in all of 5 years of usage. Guess I got used to it.

[Satish_BHP]

I had the same experience when we bought Alto K10 AMT for my wife in August 2015. The steering did not return after a turn, especially right turn at slow speeds. Wife, being a new driver, the car was hardly used at the time of the first service check of 1000 km/1month. When I complained about this, the SA told us that it will smoothen after the milage increases and advised us to take it for a longer drive on the highway.

Alto was always meant to be our city car but I took it for our next trip to Guhagar, Kokan through the Varandha ghat via winding roads of Koyana nagar MTDC. I was also new to AMT or rather any form of automatic so I was extra cautious of the steering and the AMT but I must say the car performed well on all the roads.

On return, I noticed marked difference in the steering.
After 5 years, we hardly notice any steering issues. So my impression is that it needs a bit of carefull driving in the initial months.

[sbm]

Originally Posted by baddy

**Apologies/Warning for the long post.

After working as a vehicle dynamics engineer for the past decade on both passenger cars and heavy commercial vehicles, I can say with some conviction that every automobile steering system should have self-centering characteristics and from a drivers perspective too it is natural to expect positive centering of steering post completion of a turn.
Regards,
Badri

Thanks @baddy for this wonderful post. I also believe that all cars should have self centering steering. I own a 2015 Baleno 1.2 and as you may already know, it has poor recentering characteristics. In addition to that, the steering is hard at slow speeds.

Its such a pity that the same manufacturer that made the first gen Swift which has such a lovely steering, messed up the steering of their modern cars. Whatever explanation they provide, its not acceptable.

Recently during 40k service, the tech advised to change the front suspension mount bushes which I agreed to. After that the steering effort decreased, returnability increased and there was significant improvement in the steering but still, its nowhere near what it should ideally be like. I am a member of a fb group where owner's have complained that even after changing steering coulumn, the steering behaviour is the same which implies that the whole system i.e the steering geometry and the EPS have been designed like that and changing components won't help.

Now, I have a few queries related to points you mentioned about friction in steering system.

1) As you said, friction helps the car to maintain ideal centre position and helps in countering the road crown pull. But in my case, when I'm going at speeds above 60kmph in straight line, the car tends to follow the road crown and it demands minor correction of course instead of holding the line due to higher friction in steering. Now, when I try to correct the steering slightly it offers a little resistance. It doesn't feels sticky yet its not free to move. What could be the reason for this? Is there some other issue other than the steering column which is causing such behaviour? I get wheel alignment done at every 5k kms.

2) About your point regarding friction helping to mask loose steering feel at high speeds. I have experienced it in case of the Baleno. There is no loose feel in the steering atleast till 120kmph. While in the 2018 Dzire, after 90kmph I feel that the steering has gone loose.

3) In the 2019 Baleno, the steering has been tuned in such a way that it returns to the centre very well even at low speeds. Can't maruti do retuning of the eps system in older vehicles to make them recentering? Is some extra hardware required for it?

[shancz]

Just to confirm my wagonR(VXi, 2016, K10B, ~23000kms, 155/65 R14) has the same issue. I don't think there has been any change in steering feel/behaviour since the start.
Although there is no "stickiness" and it does return to an extent but never completely. The last ~10% of the steering has to be nudged back to center even at 30-40kmph 90 degree turns or U turns.
Also second the posts that older non power assisted MSIL cars like the 800(F8D) and WagonR(F10D) didn't have this issue. And so did the non PS Matiz and Spark.

Slightly off-topic but drove a friend's Tiago back to back for comparison.
It feels as if wagonR's EPS provides a constant/passive 80-85% of the force required to turn the steering. Even if it varies the assist it isn't palpable.
Tiago's power-steering motor actively varies the assistance(as expected), provides almost 98-99% of the steering effort at parking speeds(feels like water)

In normal city roads and traffic its an inconvenience but I can see this evolving into a major irritant and a safety hazard on hilly roads with back to back turns.

Going by this thread and my experience it doesn't seem like a defect affecting certain cars/variants but has been designed as such.
Like baddy's post mentioned the steering geometry seems to be the reason, discounting the contact patch in this case as the M800/Matiz/wagonR(F10D) have similar/lesser contact patches but don't have this issue.

Whatever reasons MSIL give about it, it should be changed.

[rajendra2278]

Originally Posted by baddy

**Apologies/Warning for the long post.

Wow. Your post made sure I don't need to Google search.

Now, I understand why my Tiago steering comes back to center after a right/left/U-turn, while my cousin's Santro doesn't do that (completely).
Also, I feel little difference in steering feedback b/n these 2 cars (which I've driven extensively, and so comparing).

Coming to driving them, once I got used to Santro, I didn't feel it as a big issue. However, I've to admit, Santro driving is mostly in highways. In city, I generally take out my Tiago only.
I however feel that if we drive more in city (slower speeds), this difference might be felt most (especially for those who also drive a fully self centered car).

[Kosfactor]

Originally Posted by donjacob

At 49000 kms, there was a sound coming from the front right suspension which was diagnosed as a faulty tie end rod and was replaced under warranty.
Steering column was replaced under warranty as the centering function was not working.
Sixth paid service was done on yesterday i.e 24th Jan at 60280 kms at AVG Pala and the bill came up to 5400 which included replacing of both front differential axle boots as they had some leakages. The steering is still not centering and there is a sound when turning the steering wheel. The person who inspects the steering was not there as it was a sunday and they have promised to inspect it sometime this day.

FYI Guys.

donjacob has posted this in the baleno thread, our guy to watch out for. There has been a few things happened to the vehicle that could have potentially affected the steering when you read his entire post.

[ron178]

Originally Posted by GTO

Doesn't Maruti have ONE steering expert who can step in & fix this for all their cars?

It appears that this does not affect just Maruti's cars, but even ones sold by Suzuki globally. Here's a Mat Watson review in which he complains about the same issue in a 2017 Thailand-manufactured Celerio sold in the UK. Skip to 4:11 for details.

https://youtu.be/L_ax8yLP-E8?t=251

[baddy]

Originally Posted by sbm

Recently during 40k service, the tech advised to change the front suspension mount bushes which I agreed to. After that the steering effort decreased, returnability increased and there was significant improvement in the steering but still, its nowhere near what it should ideally be like.

Hi. I assume when you said your technician replaced the suspension bush and you were able to feel a difference in the steering, it must be the front suspension's upper mount. Because, it will naturally have an impact on the steering friction since in a mcpherson strut type suspension, the steering rotates around the entire suspension axis. Infact both the strut top mount and lower arm ball joint's friction plays an important role in deciding the steering feel. See below image for better understanding.



The next important reason for friction in eps is the eps drive motor itself. Currently most of the eps motors in the market employ a worm and worm wheel arrangement for transferring torque to the steering column. The inherent character of a worm wheel is to oppose reverse drive due to its design. Hence this will offer a lot of resistence to the self centering.



Finally, the steering rack itself. There is a rack retainer bolt on the bottom of the pinion, this usually has a nylon block placed within and between the bolt and rack to offer support and sliding friction so that unnecessary road disturbances are not transfered to the rack unit. The bolts are usually torqued at the factory with certain specifications and are not normally adjustable. Depending on the bolt torque, the friction against the rack sliding will vary.

[pavi]

I also had a very dangerous encounter with the sticky steering behaviour in my brother's Swift. Once I had to take a 180 degree turn to enter the main highway which had a higher gradient. After entering the highway I just left the steering to self center just like I have been doing in my Honda City. To my utter surprise, the steering remained in the turned position, and I had very terrifying experience. I was inching to the very end of the road, and if not stopped in time the car would have gone down to the road below. Horrifying to say the least.

[paragsachania]

Originally Posted by pavi

To my utter surprise, the steering remained in the turned position, and I had very terrifying experience.

Really dangerous! This instance itself may warrant another thread because the issue referred to here is the steering not returning to center position but not like the case you have mentioned where it doesn't turn itself from the steered position!!

Something is seriously wrong with your brother's car mechanically with the steering components. Please get this checked because even the new Gen Swift doesn't exhibit the behavior the way you have mentioned, not to the extent for sure.

Would it be possible for you to post a video of the same, perhaps from a safe stretch where someone can also record this while you are driving?

Because if it is indeed an issue, for sure this can be reproduced anyway.

[pavi]

Originally Posted by paragsachania

Really dangerous! This instance itself may warrant another thread because the issue referred to here is the steering not returning to center position but not like the case you have mentioned where it doesn't turn itself from the steered position!!

.

I would love to, but I am unable to do what you suggested. Because Swift is no more with us, exchanged it for a new Skoda Rapid TSI MT Monte carlo in red colour. Wanna make it more sweet??!! I bought the same variant Rapid in white colour.

[paragsachania]

Originally Posted by pavi

I would love to, but I am unable to do what you suggested. Because Swift is no more with us,

Hopefully the new owner gets this sorted and visits the ASC to get this fixed because the issue mentioned is not normal by any standard; steering remaining locked in the steered position is super unusual.

[Guna]

Maruti just have to replicate the tuning they had on the A-Star. I had test driven an A-Star many years back and I was thoroughly impressed with the feel, accuracy and feedback from the steering. That was in sharp contrast to the EPS on my Honda City (2nd gen) I was driving at that time.