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Old 24th May 2011, 23:21   #166
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Lightbulb Re: Composite Fibre Leaf Springs: Can they be used for off-roading?

maybe, it will help clarify things, if we consider it from two perspectives :
  • minimum ground clearance (height of diff. housing from ground) , which can only be increased by putting in bigger tyres.
  • overall ground clearance (height of the body lower edges from the ground).
Though the minimum GC remains the same with increasing the number of leaves and spring arching, the overall GC gets better, and definitely has advantages in tackling some types of obstacles.

Last edited by Blue Thunder : 24th May 2011 at 23:33.
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Old 25th May 2011, 14:10   #167
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Default Re: Composite Fibre Leaf Springs: Can they be used for off-roading?

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Originally Posted by Blue Thunder View Post
  • minimum ground clearance (height of diff. housing from ground) , which can only be increased by putting in bigger tyres.
  • overall ground clearance (height of the body lower edges from the ground).
Though the minimum GC remains the same with increasing the number of leaves and spring arching, the overall GC gets better, and definitely has advantages in tackling some types of obstacles.
GC is a technical spec that refers to minimum distance from the ground from the lowest point. What you are referring to is useful clearance which often has no connection to GC at all.

I had mentioned it else where before: https://www.team-bhp.com/forum/india...ml#post2150850

Since there is no definite way to measure useful or overall clearance, there is no technical term for it.
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Old 25th May 2011, 14:24   #168
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Default Re: Composite Fibre Leaf Springs: Can they be used for off-roading?

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Since there is no definite way to measure useful or overall clearance, there is no technical term for it.
Hi Sharath,

I think ADR Angles can qualify as a "technical term" to measure useful clearance; are improved by a suspension lift, especially Ramp-Over/Break-Over Angle.
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Old 25th May 2011, 14:45   #169
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Default Re: Composite Fibre Leaf Springs: Can they be used for off-roading?

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Hi Sharath,

I think ADR Angles can qualify as a "technical term" to measure useful clearance; are improved by a suspension lift, especially Ramp-Over/Break-Over Angle.
Arka, I guess it partially covers it.

Also, I want to add that sprung clearances are no way absolute. Let me give an example from Avalakonda.

Generally, I can easily judge what rock my Jeep can clear, and what it can't and should be avoided. On the second day I was the lead Jeep, and Sreeni was showing the way. And I started repeatedly scraping the bottom on rocks I didn't expect to even come near the bottom. Sreeni asked me to pay attention to the trail as he thought I was distracted and didn't notice the rocks. But I was feeling stupid for scraping on rocks like that, and I didn't think I was careless. At first I thought that the rock formations were very deceptive, but that logic didn't make much sense when I remembered I didn't scrape any on the previous day on the same trail while UBS was riding with me.

Little later, I parked and looked back, and suddenly understood what happened. The CFL suspension in the rear is very soft. That is why I have a very good sedan kind of ride in my Jeep.

The rear of my Jeep was filled with food/water for the entire Sreeni's team and two of the volunteers were sitting on my rear storage trunk. Whoa! That would bring the body down by 4-5 inches in the rear, thanks to my soft CFL setup. That was the reason why I was scraping every rock like a noob.
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Old 26th May 2011, 22:32   #170
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Default Re: Composite Fibre Leaf Springs: Can they be used for off-roading?

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GC is a technical spec ...
The technical spec is always 'minimum Ground Clearance'.

Quote:
Originally Posted by Samurai View Post
...Since there is no definite way to measure useful
or overall clearance, there is no technical term for it.
, really ?
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Old 27th May 2011, 01:25   #171
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Default Re: Composite Fibre Leaf Springs: Can they be used for off-roading?

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The technical spec is always 'minimum Ground Clearance'.
No, sorry. Not always, may be sometimes. But mostly it is mentioned as Ground Clearance. You might google and find some Minimum GC, but I am sure I can find more instances of just GC. And it always means the same thing, the lowest point to the ground, except for tyres and may be mudflaps. So let's not split hair here, the GC value doesn't mean much in offroad parlance as much as ADR value.

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, really ?
Sigh! Yes, really. As Arka rightly pointed out ADR does give some idea about useful clearance. But the underside of a vehicle is hardly uniform, and the layout varies from from vehicle to vehicle. Even terrain type, load, articulation and suspension can influence what you can clear and can't clear in a given vehicle. As far as I know there is no number to define all that.
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Old 27th May 2011, 12:12   #172
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Default Re: Composite Fibre Leaf Springs: Can they be used for off-roading?

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... the GC value doesn't mean much in offroad parlance as much as ADR value....
"the minimum GC value doesn't mean much in offroad parlance as much as ADR value " : that , I wholeheartedly agree .
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Old 11th June 2011, 16:25   #173
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Default Clearances

Dear All,

I have done a few modifictions to my Bolero DI 4wd for increasing the ground clearances.

The modifications are

1. Fitment of 31-10.5-15 Yokohama Geolander AT-s
2. Recambering of the leaf springs
3. Fitment of longer shackles plates

The ground clearances before and after the mods are given below.

Regards

Vinshad Aziz
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Old 11th June 2011, 17:20   #174
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Default Re: Clearances

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Originally Posted by vak View Post
Dear All,

I have done a few modifictions to my Bolero DI 4wd for increasing the ground clearances.

The modifications are

1. Fitment of 31-10.5-15 Yokohama Geolander AT-s
2. Recambering of the leaf springs
3. Fitment of longer shackles plates

The ground clearances before and after the mods are given below.

Regards

Vinshad Aziz
Dear Sir, Please post pictures for 1, 2 and 3 stated above: Thanks..
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Old 16th June 2011, 21:30   #175
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Default Re: Clearances

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Originally Posted by headers View Post
Dear Sir, Please post pictures for 1, 2 and 3 stated above: Thanks..
Dear Headers,

Was busy with work. uploading few pictures. In the first picture we can see the difference in height of my moded Bolero when compared with an OE Bolero SLX. My Bolero stands 4 to 5 inches heigher.
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Old 17th June 2011, 06:27   #176
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Default Re: Clearances

Quote:
Originally Posted by vak View Post
3. Fitment of longer shackles plates
Can anyone explain the pros & cons of these ? Scientifically ?

Many are doing it & many not .

I am personally against it , once I had to use longer shackles from another model , due to lack of availability of OE. The ride/handling was notably BAD . When I fitted the original ones , all the mess was sorted out ( this is about the Land Rover )

Haven't tried it on Jeeps though

Also how much longer shackles ( over standard ) can go with a standard MM 540 ( up to 1995 ) or with a 340 classic

Sudarshan
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Old 17th June 2011, 11:09   #177
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Default Re: Clearances

Quote:
Originally Posted by Sudarshan View Post
Can anyone explain the pros & cons of these ? Scientifically ?

Many are doing it & many not .

I am personally against it , once I had to use longer shackles from another model , due to lack of availability of OE. The ride/handling was notably BAD . When I fitted the original ones , all the mess was sorted out ( this is about the Land Rover )

Haven't tried it on Jeeps though

Also how much longer shackles ( over standard ) can go with a standard MM 540 ( up to 1995 ) or with a 340 classic

Sudarshan

Hi Sudarshan JEE,

I will try to explain in a non-scientific manner.

Advantages of Shackle Lift

i) Cheapest alternative to lifting a vehicle 1-2inches over stock. (Compared to Taller Leaf Springs/Suspension Lift)

ii) Does not require drive train modification (compared to SPOA)
a) Steering
b) Prop-Shaft Angles
c) Re-Orientation of the Front Knuckle

iii) Allows the Leaf to flex more, thereby allowing better articulation

Disadvantages

i) Steeper Steering Angles

ii) Higher Chances of Bump Steer

iii) Reduced Steering re-centering (Slightly to very obvious)

iv) Noticeable Axle Wrap (Slightly to very obvious).

iii) Increased body roll as the chassis and Body sit Higher.

iv) Ride Quality may improve or become worse. The shackle acts as a pre-load on the suspension/Leaf Spring.

In some case, when the vehicle is carrying passenger/goods (ideal Weight), the ride is much better, than without weight.

In some cases when the vehicle is overloaded, the suspension/leaf spring cannot take the weight and results in a very harsh ride.

Imagine the suspension as a rubber band looped around your thumb and index finger, if it is slack you cannot sling it. If it is stretched to tight, even then you cannot sling it, worse, it will break.

The Ideal pre-load/stretch for the rubber band will depend on its length/circumference, thickness, elasticity and how far you want to throw the paper pellet.

Shackle Lift is suitable for terrain, where the general going is slow, like crawling and articulation type of obstacles.

Regards,

Arka
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Old 17th June 2011, 11:50   #178
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Default Re: Clearances

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Originally Posted by ex670c View Post
Hi Sudarshan JEE,

I will try to explain in a non-scientific manner.
As long as you are sharing knowledge , everything goes

Quote:
Advantages of Shackle Lift==
Quote:

iii) Allows the Leaf to flex more, thereby allowing better articulation.
I doubt this , I have compared two jeeps ( 540 ) having different shackle length in two OTRs doing same obstacle ( Kunal's & Kishoreda's ) . I found the longer shackled one at disadvantage -- articulation & Roll wise

Quote:
Disadvantages
Quote:

ii) Higher Chances of Bump Steer
Death Woble ? yes its horrible at some speed even at 40 kmph

Quote:

iii) Increased body roll as the chassis and Body sit Higher.
Yes seen it

Quote:
iv) Ride Quality may improve or become worse. The shackle acts as a pre-load on the suspension/Leaf Spring.
Surely this IS THE lead to be looked in to deeper to think of the effects


Quote:
Shackle Lift is suitable for terrain, where the general going is slow, like crawling and articulation type of obstacles.
I doubt this , because the notable body roll could be dangerous & lack of articulation will worsen the situation

Another thing is the Prop shaft cross bearings will be the first casuality as the prop shaft angle is aught to change

Thanks for your thoughts & sharing it

Sudarshan
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Old 17th June 2011, 12:10   #179
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Default Re: Raising a Jeep's ground clearance : Options?

Another simple advantage that drove my choice of dogbone shackles was that when you upsize tires, the longer shackles compensate for the reduced gap between tyre and fender.

@Sudarshan bhai,

Also, how did longer shackles result in a disadvantage articulation-wise?

Last edited by AVR : 17th June 2011 at 12:16. Reason: added "tires"
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Old 17th June 2011, 13:07   #180
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Default Re: Raising a Jeep's ground clearance : Options?

@ Sudharshan JEE

I tried longer shackles on my gypsy - The difference was:

1. Steering felt disconnected.
2. The front of the vehicle was loose
3. The longer shackles did not make the leaves do their job effectively [could be a bad shackle design too - I copied the AL tippers rear shackle design partially]

I reverted back to stock shackles purely because I need steering feedback to know where i place the front wheels!!

Scientifically, I am lead to believe that the anchor points of the leaf changed that resulted in the suspension not doing their job optimally / correctly. The steering vagaries is because of the change in steering drive train angles!!
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