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Old 16th February 2009, 13:20   #16
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Originally Posted by Samurai View Post
Fully agree, but how does it help in offroading?

Any counter-arguments to Arka's points?

Kinda depends on how you define as offroading. If by offroading, you mean the type of trails that are more like no trail whatsoever, with car size rocks, ditches, mud bogs, etc. Then I don't think IFS helps. Solid axles would be best.

If you offroading is more of rutted roads & trails then IFS may actually give you a better ride.

While I agree with Arka regarding the higher repair costs for IFS, I am not sure that I would really say that IFS is a M&M conspiracy. IFS is pretty much the natural progression to make a vehicle more appealing for the mass market.

But Arka is a serious 4x4 nutcase (like myself), so seeing M&M going to IFS is just plain painful.
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Old 16th February 2009, 13:23   #17
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Originally Posted by ex670c View Post
Hi Vinod,

Solid Axle aside, the MM540 at High speeds is unstable because of the wheel-base.

The CG will be constant in a Solid-Axle vis-a-vis IFS vehicle as the IFS tends to dive at one side while cornering.

Could be that M&M is introducing, forcing IFS 4WD down our throats because..
1) Complicated to Service and Overhaul
2) No Local Mechanics can work on it..too many variable Caster/Camber/Toe-In.
3) Result is expensive support and service bills after every OTR .
4) Obviously only M&M Garages can service these vehicles.

Conclusion - M&M is selling a vehicle which only they can service ..do the maths.

Besides I heard the IFS -Bolero Camper was not very successful in South Africa, they preferred the Solid Axle Camper & Pikup Series.

Regards,

Arka
Hi arka,
I agree with you but i doubt the intentions of M&M to increase the service costs as most manufacturers are now concentrating on how to reduce the maintenance of their vehicles for better sales. No doubt IFS is expensive to maintan compared to solid axle leaf spring but it is a trade off of what consumer is willing to spend for extra comfort. Imagine just in case if Scorpio is offered with solid axle only claiming maintenance related reasons will it sell??...(Iam sure you and i will buy it but majority wouldnt!)

With regard to S. african customers not being happy with IFS set up, i see the point here. Even in domestic market the Trax pickup is offered with a choice of non independent dead axle front and same is the case with 207 Di today. No competition to load bearing capability and cost effectiveness of the non independent suspensions when it comes to load lugging and carrying. Further there is a lot of difference between the tyre life between a solid axle Vs IFS. There comes the savings for a load hauler.

All the legendry off roaders like Pajero, G wagon , land rover discovery, LCruiser series have evolved from non independent live axle to Independent front and in some cases all independent suspension. Whether we like it or not, there has been a shift towards comfort/road dynamics factor and it is a basic hygene factor now and if it offers decent off roadability it is a plus!

For people like me i prefer vehicles like Jeep wrangler, Landrover defender that offer old world charm without compromising on off road ability and at the same time offering basic creature comforts of civilized world with acceptable on-road dynamics. i hope you also fall into the same category


with regards

Vinod
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Old 16th February 2009, 14:25   #18
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Quote:
Originally Posted by RedMM340 View Post
... If by offroading, you mean the type of trails that are more like no trail whatsoever, with car size rocks, ditches, mud bogs, etc. Then I don't think IFS helps. Solid axles would be best.

If you offroading is more of rutted roads & trails then IFS may actually give you a better ride.

...
I subscribe to the above view point. In crossing boulders/rocks, IFS may not help.

While the jungle trails & even mildly muddy/wet jungle trails would be nice for IFS.

However, from an Indian perspective, we only occasionally do the 'pure' rocks/boulder crossings and mostly it is dry/wet jungle trails. So IFS may not be soo much of a disadvantage in most of the trails that we do here.

But yes, from a pure off-roading perspective, nothing beats the plain & simple solid axle setup.
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Old 16th February 2009, 14:53   #19
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The question needs to be answered relative to what a mfg's priority is.

Lets say a mfg is attempting to offer a VFM offroader. Obviously the solid axle on account of its inherent robustness, lower cost of mfg, lower over all weight and load carrying capability is the choice. The compromise as we know is in handling (on account of higher unsprung weight).

Which is not to say that a mfg who opts for IFS remains inherently compromised vis a vis a solid axle. Combining superior on road handling with robust mechanicals a good IFS can handle almost any terrain a solid axle setup can. The down side is the considerably higher mfg costs.

Tech today can address requirements of ground clearance and articulation.

I remember I saw a video of a military truck (forget which one it was). It had a central shaft on which the IFS for wheels was hooked. You have to see the articulation on that to know what it can do. It was like a centipede snaking over undulations effortlessly.

Lower unsprung weight does have some benefits offroad too

Last edited by DKG : 16th February 2009 at 15:02.
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Old 16th February 2009, 15:03   #20
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Quote:
Originally Posted by Samurai View Post
Fully agree, but how does it help in offroading?

Any counter-arguments to Arka's points?
Samurai doing a truly wonderful job !

Quote:
Originally Posted by RedMM340 View Post
But Arka is a serious 4x4 nutcase (like myself), so seeing M&M going to IFS is just plain painful.
LOL
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Old 16th February 2009, 15:15   #21
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Originally Posted by headers View Post
Samurai doing a truly wonderful job !
I am just trying to understand both sides of the coin. I own both IFS & live axle 4x4 vehicles, therefore I have a vested interest.
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Old 16th February 2009, 15:32   #22
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For reference here is a schematic of a Hummer 2 4x4 IFS system.

a.) upper short A-arm, (a control arm)
b.) lower long A-arm, (another control arm)
c.) torsion bar
d.) shock
e.) bump stop
f.) differential
g.) axle shaft
h.) cv joint (two of them) cv = constant velocity joint, sort of like a
universal or crossover. It is covered with a rubber boot and within
the boot is a lubricant. Ripped or leaking boots can cause a cv
joint to wear and fail. This is a common and sometimes expensive
problem with cv joints. Of course, if they are well built and well
located they are no problem.

Actually, I think this schematic is labelled wrong here. The 2nd cv joint has a yellow boot and is near the bump stop.

i.) ball joint
j.) sway bar

Please dont ask me any questions about this. I do not know that much about it. I am a software guy, this is hardware.
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Old 16th February 2009, 16:24   #23
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Default Solid Axle

Some Vehicles which still remain Solid Axle Coil Spring/Leaf Spring

Toyota FJ70/80/100 Series (S.Africa/Australia) Solid Axle Leaf/Coil Spring
Jeep Wrangler (Solid Axle Coil Spring)
Mercedes G-Wagen (Solid Axle Coil Spring)
Land Rover Defender (Solid Axle Coil Spring)

Little Bigger

Mercedes Unimog (Solid Axle Coil Spring)
Mercedes Unimog Trucks (Solid Axle Coil Spring)

Question is why do these vehicles remain Solid Axle, they have better production facility and a Brand Name and a bigger budget to try and test things.
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Old 16th February 2009, 16:58   #24
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Default IFS - Disadvantages

Let me list out the disadvantages, we can then discuss each point to death.

1) Complex Construction
2) Variable Ground Clearance - Each wheel moves independently and pivot on a CV/Universal Joint.
3) Steering - Rack & Pinion - Weakest Link and wider tyres will rub on the chassis at lock-to-lock turns
4) Upgrades/Modifications - Because of the complex IFS we cannot Upgrade to Taller Tyres, Differential Ratios/LSD/Lockers, Winches.
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Old 16th February 2009, 17:09   #25
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Arka, why is rack and pinion steering the weakest link? I would have thought the CV joints were. What is a normal price for a CV joint replacement in India? Maybe we can extrapolate the cost to an off roader from that.

How do winches enter into it?
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Old 16th February 2009, 17:11   #26
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Quote:
Originally Posted by ex670c View Post
4) Upgrades/Modifications - Because of the complex IFS we cannot Upgrade to Taller Tyres, Differential Ratios/LSD/Lockers, Winches.
You have mentioned this before. If IFS rules out future winch installation, that is a serious problem. Is this only because of extra weight?

Why taller tyres are a problem? I see even Scorpio/Safari owners (with IFS) upgrading their tyres.
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Old 16th February 2009, 17:26   #27
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We would love to have an off road vehicle with solid fixed front axle. The Landcruiser 80 used to have it and was so successful. Nowdays Nissan Patrol is the only vehicle with a solid axle till they change it to become more like an armada / pathfinder clone next year.

Toyota Landcruisers 100 series come with fixed front axles only in RHD models in australia. Not in the ME. It is so much better for clearing an obstacle off road.

Back up this with a central diff lock and a rear LSD and you can climb mountains with such a vehicle.
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Old 16th February 2009, 17:48   #28
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Default Steering System for Off-Road

In a Solid Axle Steering System (Cross Over) composes of

1) Knuckle on which Wheels are mounted
2) Tie-Road Ends 4 minimum
3) Drag Links (2 -Links one for Steering and the other for connecting to each wheel/Balance rod/link)
4) Steering Box

In A Solid Axle either
1) Ball Joints will break
2) Tie-Rod End will bend/Break

The Knuckle have stoppers behind them to adjust for wider & Taller tyres, prevent the knuckles from turning to the point where the tyre touches the chassis.

In an IFS steering setup
1) Knuckle on which the wheels are mounted

Rack & Pinion Steering System consists of in one housing
2) Tie-Road Ends(2 to 4)
3) Drag-Links
4) Steering Box (Rack & Pinion)

The Result is the Steering & Load-Bearing are Linear in an Rack & Pinion System.

Drawbacks
i) Fixed Turning Radius
ii) Road Stress is directly/Linear transfer to the Rack & Pinion.
iii) Bump steer cannot be eliminated via steering Dampers.

Normally the following Damage occurs
1) Tie-Rod Ends Snap
2) Drag-Links break
3) Rack & Pinion Gears get Stripped.

What happens when Rack & Pinion Breaks --



Pics - Courtesy
ifsja.com & motorera.com

Pic1 - Cross Over Steering
Pic2 - Rack & Pinion

Regards,

Arka
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Old 16th February 2009, 18:23   #29
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Quote:
Originally Posted by ex670c View Post
Hi Vinod,

Solid Axle aside, the MM540 at High speeds is unstable because of the wheel-base.

The CG will be constant in a Solid-Axle vis-a-vis IFS vehicle as the IFS tends to dive at one side while cornering.

Could be that M&M is introducing, forcing IFS 4WD down our throats because..
1) Complicated to Service and Overhaul
2) No Local Mechanics can work on it..too many variable Caster/Camber/Toe-In.
3) Result is expensive support and service bills after every OTR .
4) Obviously only M&M Garages can service these vehicles.

Conclusion - M&M is selling a vehicle which only they can service ..do the maths.

Besides I heard the IFS -Bolero Camper was not very successful in South Africa, they preferred the Solid Axle Camper & Pikup Series.

Regards,

Arka
TRUE... and even wheel balancing becomes a pain as well, at least in my case, god know why!

Last edited by rhandle : 16th February 2009 at 18:24.
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Old 16th February 2009, 18:25   #30
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Quote:
Originally Posted by DirtyDan View Post
I am a software guy, this is hardware.
LOL, I think you are a hermit in the Himalayas!

Quote:
Originally Posted by DirtyDan View Post
What is a normal price for a CV joint replacement in India? Maybe we can extrapolate the cost to an off roader from that.
CV joints cost upwards of 4K. WInches load the steering gear if mounted up front!

Arka, dont you think R&P steering mechanism has lesser linkages and is more direct?

On the contrary, most modern day vehicles have a fixed castor. And Toe-In and Camber are not too difficult to set, nor do they change easily.

However, I do Agree that one needs good tools to measure, understand and correct them!
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