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Old 10th September 2007, 18:36   #1
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Default Why are car makers abandoning independent rear suspension?

I wonder if members have observed this trend.

Just take a look at some of the car model replacements that have occured lately or are in the pipeline:
  1. Honda used to make the Old Honda City which sported independent suspension at the back. Honda replaced the car with NHC which has beam type, non-independent rear suspension.
  2. Suzuki used to make the Baleno which had independent rear suspension. Its replacement, the SX4 has beam type non-independent rear suspension.
  3. Esteem (or the old Swift in Europe) had/has independent rear suspension. Its successor, the new Swift has beam type non-independent rear suspension.
  4. Hyundai Accent had/has independent rear suspension. Its replacement/successor Verna has non-independent beam-type rear suspension.
  5. Our humble, home-grown Indica has independent rear suspension. It is the only car in its category in India (and probably even the world) to have this feature. Its successor, the upcoming new Indica has twisted-beam non-independent rear suspension.
  6. Indigo has a three-link independent set up at the rear, a feature much advertised by Tata at the time of the car's launch. Its successor, the new Indigo will sport non-independent rear suspension derived from the new Indica's, as reported by this month's Autocar India.
It is well known that cars with independent rear suspension (IRS)offer better ride quality, comfort and handling, especially on rough roads that are by and large the norm in this country. When Bajaj introduced IRS in its autos in early 1980s, the resultant improvement in ride quality was nothing short of dramatic and soon all three wheeler makers introduced the feature that is now regarded as obligatory.

Given this background, I'm curious to know why car manufacturers are giving up IRS even as they otherwise improve their cars? Is it because IRS costs more to manufacture? Or is it because the protruding struts of IRS reduce space availability inside the car - the reason, according to Autocar India, why Tata gave up IRS in the new Indica? Don't the benefits of IRS outweigh the disadvantages of higher cost and lesser space which in any case aren't significant? It can be argued that ride quality does not depend solely on rear suspension and factors like wheelbase, tyres, chassis stiffness, etc. also play an important role and so ride quality can be taken care of by working on those other factors. But wouldn't ride quality be still better if IRS was retained even as the other variables were improved? After all, all expensive cars still feature IRS.

I wonder what members have to say about this emerging trend of car makers abandoning IRS in the lower segment cars. I for one am not too happy about it.
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Old 10th September 2007, 19:22   #2
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Well for the SX4 & Swift the comapny website says semi-independent torsion bar with coil springs.

Not sure if semi-independent = non-independent.
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Old 10th September 2007, 19:30   #3
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Independent suspensions are more expensive to manufacture, and sharing of components across platforms becomes diffcult as the models progress.

Independent suspensions are no doubt better than non-independent, especially in case of RWD's. But as time progresses, non-independent suspensions would become standard for all sub-C segementers, and all-independent would be restricted to the D segementers. Much to our dismay.

Last edited by veyron1 : 10th September 2007 at 19:47.
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Old 10th September 2007, 21:42   #4
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Quote:
Originally Posted by directinjection View Post
Given this background, I'm curious to know why car manufacturers are giving up IRS even as they otherwise improve their cars? Is it because IRS costs more to manufacture? Or is it because the protruding struts of IRS reduce space availability inside the car - the reason, according to Autocar India, why Tata gave up IRS in the new Indica? Don't the benefits of IRS outweigh the disadvantages of higher cost and lesser space which in any case aren't significant? It can be argued that ride quality does not depend solely on rear suspension and factors like wheelbase, tyres, chassis stiffness, etc. also play an important role and so ride quality can be taken care of by working on those other factors. But wouldn't ride quality be still better if IRS was retained even as the other variables were improved? After all, all expensive cars still feature IRS.

I wonder what members have to say about this emerging trend of car makers abandoning IRS in the lower segment cars. I for one am not too happy about it.

Your observation is correct except for the GolfV platform, which has switched from twist beam to twist blade type(IRS).
The nonindepent that you refer to is a twist beam with is really a semiindependent unlike a solid axle. The ride is pretty good but there are some issues with toe control for which you need a toe control bushing. Toyota has really gone to town with twist beam on its small cars although some OEMs execute better than others. Fiesta for eg has great ride and handling with twist beam.
For B-seg and below its a pretty good option and like ACI mentioned, frees up interior room.
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Old 11th September 2007, 10:43   #5
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Excellent thread, directinjection! There isnt a doubt that IRS is superior to Non-IRS and all things alike, it offers better ride and handling behaviour.

But IRS comes at the price of packaging space and additional cost, at a time when value and space are fierce differentiators in this market segment. Also, the maintainence costs of IRS would be more than non-IRS?
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Old 11th September 2007, 11:10   #6
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IRS is any day better compared to non-IRS. Have both in the family can have experienced it over extremely bad roads, the difference is very apparent.

I guess as said before cost cutting is the main culprit...
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Old 11th September 2007, 16:23   #7
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Quote:
Originally Posted by veyron1 View Post
Independent suspensions are more expensive to manufacture, and sharing of components across platforms becomes diffcult as the models progress.

Independent suspensions are no doubt better than non-independent, especially in case of RWD's. But as time progresses, non-independent suspensions would become standard for all sub-C segementers, and all-independent would be restricted to the D segementers. Much to our dismay.
Is the cost cutting the sole purpose ?
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Old 11th September 2007, 16:42   #8
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I think the trend is only in small/compact cars globally. Its not new.
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Old 11th September 2007, 16:50   #9
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1. Save on costs.
2. Save on space.

In that order.
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Old 11th September 2007, 16:54   #10
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What are the cars still with IRS, available today in the market?

Also, NHC specs say about Suspension:
Front Suspension: McPherson Strut with Stabilizer, Coil Spring
Rear Suspension: H-Type Torsion Beam Suspension, Coil Spring

Which type it is?
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Old 11th September 2007, 21:06   #11
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Quote:
Originally Posted by diabloo View Post
What are the cars still with IRS, available today in the market?

Also, NHC specs say about Suspension:
Front Suspension: McPherson Strut with Stabilizer, Coil Spring
Rear Suspension: H-Type Torsion Beam Suspension, Coil Spring

Which type it is?
non-IRS. i honestly don't know if the money saved is worth the handling loses incurred.

if i remember correctly richard hammond says "imagine you had to run around with your both shoe laces tied together..... yup...there are better way of getting around.....!!"
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Old 12th September 2007, 00:00   #12
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Quote:
Originally Posted by flipsyde View Post
if i remember correctly richard hammond says "imagine you had to run around with your both shoe laces tied together..... yup...there are better way of getting around.....!!"
Yes I remember too. He was talking about Ford Mustang.
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Old 12th September 2007, 09:47   #13
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Quote:
Originally Posted by Mpower View Post
Your observation is correct except for the GolfV platform, which has switched from twist beam to twist blade type(IRS).
.
Quote:
Originally Posted by Rtech View Post
1. Save on costs.
2. Save on space.

In that order.

Apparently, the current rear suspension set up is bleeding VW margins. They make very little profit on the Golf V and this is their best seller!!!! VW are relooking at this for the Golf VI
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Old 12th September 2007, 11:50   #14
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Well the US press made a lot of hue & cry about the current Mustang's rear-end suspension but fact is it sold well enough (mainly on looks) to let that not be a factor. Hence, nobody really bothered but if a competitor, let's say the Camaro (due next year) comes up with an independent rear-end & is substantially better in most respects then you could see Ford & the others rethinking.

But, point is (as US mags highlighted then) the price difference for Independent & Non-Independent is not much to the company, especially in larger vehicles. I guess in the end it's the bean-counters call rather than the engineer's & also the aim to make as much money as possible.

Quote:
Originally Posted by ajmat View Post
Apparently, the current rear suspension set up is bleeding VW margins. They make very little profit on the Golf V and this is their best seller!!!! VW are relooking at this for the Golf VI
And on top of that having the most expensive car to produce in the segment doesn't help the margins much, does it?
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Old 17th September 2015, 06:54   #15
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Default Re: Why are car makers abandoning independent rear suspension?

I have a question.

Skoda Rapid uses non-independent multi-link rear suspension. Where as its twin, VW Vento uses the independent rear suspension setup.

In this case, the Vento has better boot space in comparison. But, costs 50-60K more in comparison.(prices vary according to state/place)

Can someone please elaborate on the following?

As per Google, non-independent suspensions occupy lesser space, ensuring more space in the cabin/boot. It is reverse in this case. please elaborate.

And as per Google, independent suspension set-up costs more, now is this true in the above case or is VAG just trying to price vento higher for Brand and other reasons?

Also, from Googling, I understood independent suspensions are better handlers, which is already said here too. So, is it working paying that extra 60K for a vento instead of a rapid?

Tech gurus?

Correct me if I am wrong, this is what I could understand from their websites.

Last edited by rider60 : 17th September 2015 at 07:14.
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