Go Back   Team-BHP > Under the Hood > Technical Stuff


Reply
 
Thread Tools Search this Thread
Old 17th September 2015, 13:33   #16
Senior - BHPian
 
Join Date: Oct 2005
Location: Faridabad/Delhi
Posts: 1,594
Thanked: 439 Times
Default Re: Why are car makers abandoning independent rear suspension?

Quote:
Originally Posted by rider60 View Post
Skoda Rapid uses non-independent multi-link rear suspension. Where as its twin, VW Vento uses the independent rear suspension setup.
VW Vento does not have independent rear suspension. VW describes it as semi-independent trailing arm which is similar to what most cars in the segment use these days.
directinjection is offline   Reply With Quote
Old 17th September 2015, 13:50   #17
Senior - BHPian
 
lamborghini's Avatar
 
Join Date: Apr 2004
Location: Mumbai
Posts: 4,636
Thanked: 1,262 Times
Default Re: Why are car makers abandoning independent rear suspension?

Quote:
Originally Posted by rider60 View Post
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.
This is actually news to me too! I always thought both the Rapid and Vento were identical, and the Rapid is actually marginally better.
Are you talking about the Jetta and Octavia, where the Jetta uses an independent suspension is marginally more comfortable and better handling?
lamborghini is offline   Reply With Quote
Old 17th September 2015, 18:33   #18
Senior - BHPian
 
rider60's Avatar
 
Join Date: Mar 2007
Location: Bhagyanagaram. (A.K.A. Hyderabad)
Posts: 1,619
Thanked: 47 Times
Default Re: Why are car makers abandoning independent rear suspension?

Quote:
Originally Posted by directinjection View Post
VW Vento does not have independent rear suspension. VW describes it as semi-independent trailing arm which is similar to what most cars in the segment use these days.
So, this means they are marketing vento at a much higher cost even when they have this modern conventional dependent suspension?

And, in such a case why does rapid's cabin space and boot space take a marginal hit? approximately 50 litres of lesser boot space and slightly lesser cabin space.

Quote:
Originally Posted by lamborghini View Post
This is actually news to me too! I always thought both the Rapid and Vento were identical, and the Rapid is actually marginally better.
Are you talking about the Jetta and Octavia, where the Jetta uses an independent suspension is marginally more comfortable and better handling?
No, lamborghini, I am not talking about Jetta and Octavia. Its vento and rapid. That is how I understood from their websites.
rider60 is offline   (1) Thanks Reply With Quote
Old 17th September 2015, 20:02   #19
Senior - BHPian
 
dark.knight's Avatar
 
Join Date: Apr 2013
Location: India
Posts: 1,115
Thanked: 2,960 Times
Default Re: Why are car makers abandoning independent rear suspension?

Quote:
Originally Posted by rider60 View Post
Can someone please elaborate on the following?
Like most cases it depends on type & preference, both of end user & manufacturer. There are some variables here, its a lot easier to design the suspension for the wheels that are not receiving the torque of the engine. In this case both Vento & Rapid are front wheel driven.

The 2 types of suspension as you've mentioned, are independent & dependent. Easiest explanation first, the dependent suspension is where there is a connection of both the rear wheels by a single axle based mostly from coil-springs though certain MUV's have leaf-spring. Now independent suspension is where the wheels are sprung independently. Most modern cars have the front setup as MacPherson strut with stabilizer bar, here there will be a slight camber variation when the tyres are stressed during turns/bad patches. There is a more expensive independent suspension called double wishbone used mostly in high end cars, they offer maximum handling advantage. I checked that Vento has a semi-independent trailing arm suspension which can to some degree deflect the disturbances from the other wheel but will still lead to more camber changes on vertical movement compared to double-wishbone.

Bottom-line is that semi-independent suspensions may cost a bit more to produce & assemble though nowhere to the tune of 60k. Most of it maybe for the VW brand which is clearly positioned as above Skoda. On Indian roads the difference in driving between these 2 models may be perceived but negligible. As far as boot capacity goes can you specify what the exact difference is? If its minor like 5-10 litres it may come down to something as simple as extra padding/cladding on any 6 sides of the boot or higher floor level to accommodate spare/tools. The difference cannot be any more than 5 litres since both are badge twins with identical shell. Purely independent link in most cases does liberate space.

Last edited by dark.knight : 17th September 2015 at 20:08.
dark.knight is offline   (2) Thanks Reply With Quote
Old 17th September 2015, 20:04   #20
Senior - BHPian
 
itwasntme's Avatar
 
Join Date: May 2007
Location: BANGALORE
Posts: 2,268
Thanked: 1,330 Times
Default Re: Why are car makers abandoning independent rear suspension?

Quote:
Originally Posted by GTO View Post
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?
Also factor in that IRS tends to need more 'maintenance' in terms of alignment and is more prone to damage on our terrible roads. Classic example is the stalwart Indica which launched with IRS and has/ had an excellent rear seat ride quality. However it's very common to see Indica cabs with totally messed up rear suspensions.

Net net non-IRS is a more robust technology for the third world.
itwasntme is offline   (2) Thanks Reply With Quote
Old 17th September 2015, 20:11   #21
GTO
Team-BHP Support
 
GTO's Avatar
 
Join Date: Feb 2004
Location: Bombay
Posts: 47,705
Thanked: 89,159 Times
Default Re: Why are car makers abandoning independent rear suspension?

Quote:
Originally Posted by itwasntme View Post
Also factor in that IRS tends to need more 'maintenance' in terms of alignment and is more prone to damage on our terrible roads. Classic example is the stalwart Indica which launched with IRS and has/ had an excellent rear seat ride quality. However it's very common to see Indica cabs with totally messed up rear suspensions.
Naah, I don't think the Indica is a good example. You see them with messed up suspensions because of the poor quality of components.

Independent rear suspensions are becoming increasingly commonplace today. Even if they cost a little more at the time of an overhaul, they're definitely worth the small $$$ premium. You just had to ride in a Duster AWD with an independent rear, or compare the Octavia independent vs non-independent back to back, to feel the difference.
GTO is offline   (4) Thanks Reply With Quote
Old 17th September 2015, 20:41   #22
Distinguished - BHPian
 
Join Date: May 2005
Location: KL
Posts: 4,680
Thanked: 3,507 Times
Default Re: Why are car makers abandoning independent rear suspension?

Quote:
Originally Posted by GTO View Post
Naah, I don't think the Indica is a good example. You see them with messed up suspensions because of the poor quality of components.
I wanted to say the same. Indica is not the ideal example even the early non-taxi private Indicas had messed up rear suspension.

Maruti 1000/Esteem (has IRS) has been on the roads for longer than the Indicas and have never seen one with Indica level messed up rear.
Sankar is offline   (1) Thanks Reply With Quote
Old 17th September 2015, 21:13   #23
BHPian
 
anky's Avatar
 
Join Date: Apr 2006
Location: Mumbai
Posts: 395
Thanked: 92 Times
Default

I owned an indigo dicor for 6 years and the back seat ride was very comfortable , also I never had a problem with the rear suspension , but the front suspension gave up quite regularly on our roads .
Tata engineers at Concorde motors worli , were never interested in servicing my car properly in all the years I went to them . An excellent car let down by the casual and uninterested attitude of the service personnel .
Sorry for being slightly OT .
anky is offline   (1) Thanks Reply With Quote
Old 17th September 2015, 21:58   #24
Senior - BHPian
 
rider60's Avatar
 
Join Date: Mar 2007
Location: Bhagyanagaram. (A.K.A. Hyderabad)
Posts: 1,619
Thanked: 47 Times
Default Re: Why are car makers abandoning independent rear suspension?

Quote:
Originally Posted by dark.knight View Post

Bottom-line is that semi-independent suspensions may cost a bit more to produce & assemble though nowhere to the tune of 60k. Most of it maybe for the VW brand which is clearly positioned as above Skoda. On Indian roads the difference in driving between these 2 models may be perceived but negligible. As far as boot capacity goes can you specify what the exact difference is? If its minor like 5-10 litres it may come down to something as simple as extra padding/cladding on any 6 sides of the boot or higher floor level to accommodate spare/tools. The difference cannot be any more than 5 litres since both are badge twins with identical shell. Purely independent link in most cases does liberate space.
the difference in boot space is approx 50Litres and rear part of the cabin is also slightly cramped compared to vento. Vento is more spacious in comparison both boot and cabin
rider60 is offline   Reply With Quote
Old 17th September 2015, 22:36   #25
BHPian
 
narendra.vw's Avatar
 
Join Date: Apr 2010
Location: Bangaloru
Posts: 291
Thanked: 401 Times
Default Re: Why are car makers abandoning independent rear suspension?

-With the rear Torsion beam Suspension, major advantage I can see is that, beam also acts as a Stabilizer rod for better rear road grip. VW has mastered it right from MK1.
-Less moving parts means less serviceable parts.
narendra.vw is offline   Reply With Quote
Old 17th September 2015, 22:54   #26
Senior - BHPian
 
dark.knight's Avatar
 
Join Date: Apr 2013
Location: India
Posts: 1,115
Thanked: 2,960 Times
Default Re: Why are car makers abandoning independent rear suspension?

Quote:
Originally Posted by rider60 View Post
the difference in boot space is approx 50Litres and rear part of the cabin is also slightly cramped compared to vento. Vento is more spacious in comparison both boot and cabin
Fifty seems to be way too much, has the recent Vento update resulted in any increase in cargo volume? I just checked a 2011 TBHP review of Rapid, & that shows a 20L difference. In any case I also made a miscalculation in the last post.. I assumed a semi-independent trailing arms due to its triangular layout might occupy more space than full-independent but that's not so. Irrelevant to the current topic however.

As far as your question is concerned & if the gap is indeed 20L + a slightly better rear space, its still a mystery nonetheless considering all other things remaining constant which in this case it is. Wheelbase is identical as well. Can I hint at the main reason of product positioning by making the Vento seem better in these 2 areas hence more luxurious? I'd assume lifting the trunk false-floor about 2 inches should do it (just speculation). I've even looked into tyre/spare sizes, overall width, length (Rapid is longer by 2mm!) and everything is same hence it doesn't make sense.

Last edited by dark.knight : 17th September 2015 at 23:01.
dark.knight is offline   Reply With Quote
Old 18th October 2015, 18:03   #27
BHPian
 
aerohit's Avatar
 
Join Date: Aug 2007
Location: India
Posts: 877
Thanked: 576 Times
Default Re: Why are car makers abandoning independent rear suspension?

According to wiki, manufacturer saves €100 per car by not installing multilink in the rear. Not sure if this is too much or too less.

It would have have been nice if they had incorporated independent suspension in the rear on cars like S-cross and Creta.

If you mentally picture the torsion movement it would feel that both side wheels will move when one wheel goes over a pot hole. But thats not the case because there is a flex, though very little.

Illustration below is exaggerated -

(didnt attach the image as it would break the animation)
aerohit is offline   Reply With Quote
Old 18th October 2015, 19:28   #28
BHPian
 
aerohit's Avatar
 
Join Date: Aug 2007
Location: India
Posts: 877
Thanked: 576 Times
Default Re: Why are car makers abandoning independent rear suspension?

click here to view GIF animation
aerohit is offline   Reply With Quote
Old 18th October 2015, 20:59   #29
BHPian
 
Join Date: Aug 2008
Location: bangalore
Posts: 263
Thanked: 392 Times
Default Re: Why are car makers abandoning independent rear suspension?

Quote:
Originally Posted by mithun View Post
Is the cost cutting the sole purpose ?
This great post got me doing a google search.

http://www.volkswagen.co.uk/technolo...ear-suspension

The torsion beam rear suspension has proved to be the most economical layout for non-driven rear axles. Two trailing arms are linked by means of a cross member, which also serves as an anti-roll bar. The advantages of this layout are good directional stability when cornering and a compact design, making for convenient use of space at the rear.

http://www.worldlibrary.org/articles...ear_suspension

ADVANTAGES

Low cost
Can be durable
Fewer bushes than multi-link suspension that are less stressed and less prone to wear
Simple
Neat package, reduces clutter under floor
Fairly light weight
Springs and shocks can be light and cheap
No need for a separate sway bar the axle itself performs that function

DISADVANTAGES

Basic toe vs lateral force characteristic is oversteer
Since toe characteristics may be unsuitable, adding toe-control bushings may be expensive.
Camber characteristics are very limited.
Not very easy to adjust roll stiffness
Welds see a lot of fatigue, may need a lot of development
Not much recession compliance - can be poor for impact harshness, and will cause unwelcome toe changes (steer effects)
Wheel moves forward as it rises, can also be poor for impact harshness (this can be negated by designing the beam with the mounts higher than the stub axles, which impacts on the floorpan height, and causes more roll oversteer)
Need to package room for exhaust and so on past the cross beam
Camber compliance may be high
keroo1099 is offline   (1) Thanks Reply With Quote
Old 19th October 2015, 12:02   #30
Senior - BHPian
 
alpha1's Avatar
 
Join Date: Apr 2007
Location: P00NA
Posts: 1,625
Thanked: 965 Times
Default Re: Why are car makers abandoning independent rear suspension?

Quote:
Originally Posted by aerohit View Post
click here to view GIF animation
you have linked to the t-bhp attachment - there is no animated gif file.
alpha1 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Is Independent Front Suspension (IFS) good for offroading? Samurai 4x4 Technical 142 18th March 2014 12:06
Mahindra Thar - *Converted* Independent Front Suspension to Solid Axle Jaskirat 4x4 Technical 72 10th October 2013 14:01
Recession in Dubai leading to migrants abandoning cars @ airport & fleeing country!!! supremeBaleno Shifting gears 31 27th April 2009 13:43


All times are GMT +5.5. The time now is 22:43.

Copyright 2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks