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Re:Suspension Lift and Ground Clearance?

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16 May 2020 21:45 #222362 by sniper
I'm only on 215's which are 27.5 inches tall, a very small 45mm of lift and never had any clearance issue's driving the Peaks and Lakes.

I do have to consider my line a bit more than the big tyre cars and sometimes I might have to take a second run at a step but it has always got there.

I have found that bashing the underside of the car is more to do with speed, if I take my time, very little if any, contact is made.

The upside of my suspension set up is that I can still drive like a go-cart on dry tarmac, where the car spends most of it's time..... Where 3" + lifts are weak and even unpleasant to drive, especially at speed.

Not knocking lifted cars, they look great and are off road monsters. Suppose a comfort comes from having a car that you know will make every line you choose but I get a buzz from having a modest lift / tyre size and still being able follow these monsters about.

Mostly down to personal choice, a standard car in good condition will drive 99% of the lanes out there.....

sniper
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17 May 2020 08:32 #222370 by kirkynut
This debate has taken some twists and turns and a few people have argued that Martin is wrong by saying that a suspension lift on its own without bigger tyres does not increase ground clearance.

Martin is right though when keeping it simple. The lowest point on a standard Jimny is the bottom of the diffs, closely followed by the radius arm mounts on the chassis.

Lifting the suspension will raise the radius arm mounts on the chassis but not the bottom of the diffs, which still remain in the same place, so the ground clearance under the diffs remains the same and as such, the suspension lift has not increased ground clearance.

It is true to say that the only likely time that the diffs will get caught up is in ruts. Every Pay and Play site in the UK has big Land Rover ruts from trucks with 35" tyres on. Lots of Green Lanes have, alas, deep ruts from similar trucks and tractors.

As such there seems to have been a bit of an arms race with tyre size for people not to get stuck in ruts!

Martin is clearly right here but there is a argument where just a lift with no bigger tyres can be useful, it just doesn't increase overall ground clearance.

Kirkynut

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17 May 2020 18:11 #222439 by wjamieson
Thanks to everyone for contributing to the discussion. So my understanding was pretty much correct.

I could have phrased the question slightly different with the question being as follows. Is it worth fitting a 2" suspension lift without fitting bigger wheels?

And it would appear lots of different views. Would it be fair to say that the 2" suspension lift does not improve ground clearance at the Diffs but does improve general off road capability and reduces the risk of striking and damaging the under side of your car.

So if the 2" lift did not negatively impact in any way the on road experience or add any additional mechanical stress it would make sense to do so.

it's obviously very much down to each individuals specific requirements and there is no right or wrong answer. Again thank you everyone.
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17 May 2020 18:27 #222441 by Lambert
In that case it is cheaper to armour the underside of the car and retain its driving characteristics. That way if you do get stuck it doesn't do any lasting damage.

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17 May 2020 19:00 #222442 by Busta
No, because armour decreases the ground clearance... A 2" lift will do more to protect the underside of the car than armour will do. But it's not accurate to say it has no negative impacts on the road. Even a 2" lift comes with compromises. For example, you have to choose between not having castor correction and retaining good articulation at the expense of vague steering, or fitting castor correction bushes and losing some of the articulation afforded by the factory bushes, but keeping the factory steering feel.
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17 May 2020 20:47 #222456 by X8GGY
Years ago on the Difflock discussion board there was always talk of the 'virtual lift', basically fitting bigger tyres to get the ground clearance we all seek, by cutting the body away enough to get the bigger tyres in rather that fitting a suspension lift... as Martin's monster truck picture proves, you can put a four foot suspension lift on but you're still limiting your ground clearance by how much room there is under the diffs...

Of course the problem then is gearing... bigger tyres cause gearing issues :ohmy:

Alternatives - portal axles -



or shaving the diffs -



i.e. cutting the bottom of the diff pumpkin and strengthening it...
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18 May 2020 04:30 #222465 by Lambert

Busta wrote: No, because armour decreases the ground clearance... A 2" lift will do more to protect the underside of the car than armour will do. But it's not accurate to say it has no negative impacts on the road. Even a 2" lift comes with compromises. For example, you have to choose between not having castor correction and retaining good articulation at the expense of vague steering, or fitting castor correction bushes and losing some of the articulation afforded by the factory bushes, but keeping the factory steering feel.


Except that armour actively lowers the centre of gravity even if only by a small amount as opposed to a lift which significantly increases the centre of gravity. Also depending on the amount of time spent off road armour is less of a compromise on road handling than a lift. Ok it reduces clearance but a moderately skilled driver can accommodate that with line choice. In mud guards will clog up and need more cleaning but on rocks they can protect vital parts from day finishing impacts. Ok guards might increase the risk of getting stuck in the first place but if they are well designed they can act as skids and ride over obstacles that could otherwise snag on the irregular shapes under the car. If there was a simple way of having a smooth surface under the entire vehicle including the axles I would have it but with live axles that is not an option.

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18 May 2020 08:59 #222469 by 300bhpton

mlines wrote: The thing is, that is driving position (positioning the wheel on a bank/trailer etc.). That is not clearance due to suspension lift.

Yes, it changes the ramp over angle, approach angle and departure angle as well as wading depth, but any measurement has to have a reference otherwise they have no meaning. The reference for clearance is flat ground.

Agreed. It was more meant as a demonstration that the diff ground clearance is not a static thing off road. And in many cases is a non issue, as the movement of the wheels/suspension tend to move it out of the way for the vast majority of the time.
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18 May 2020 09:01 #222470 by 300bhpton

Lambert wrote: You are right. No amount of suspension or body lift is going to have any effect on the available ground clearance of a live axle vehicle for the simple fact that you are not raising the lowest point of the vehicle. The only way to do that is by fitting bigger tyres. Which is what the lift allows you space to do.

Respectfully I would disagree.

Take a situation like this:


The underside of the vehicle is grounded, due to insufficient clearance. A suspension lift would most certainly afford more clearance here and likely prevent damage or getting stuck. As a suspension lift would raise the chassis and body (and all those bits attached like the transmission and transfer case) and prevent them grounding.
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18 May 2020 09:11 #222471 by 300bhpton

sniper wrote: I'm only on 215's which are 27.5 inches tall, a very small 45mm of lift and never had any clearance issue's driving the Peaks and Lakes.

I do have to consider my line a bit more than the big tyre cars and sometimes I might have to take a second run at a step but it has always got there.

I have found that bashing the underside of the car is more to do with speed, if I take my time, very little if any, contact is made.


Mostly down to personal choice, a standard car in good condition will drive 99% of the lanes out there.....

sniper

Off roading can depend on what type of off roading. Green lanes are technically roads. Although we normally label them as "off" road. That said, laning really should not be that challenging. If they are, then it probably isn't part of the lane. The biggest hurdle is likely deep ruts, which can cause something on smaller wheels to ground out more easily. Be it a Freelander or a Jimny.

But off roading takes many forms.

My Jimny is stock and going slowly has resulted in grounding and clearance issues off road. So I disagree it is purely a speed thing. The Jimny has a relatively short wheelbase, although still runs small tyres. e.g. an 88" wheelbase Land Rover would have had at the smallest a 205 sized tyre and more than likely a 7.50 x 16, the bigger tyre effectively increasing the ground clearance.


This was not caused by ruts/tramlines, but breakover angle:


And approach angle:


A suspension lift would help in both instances.
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18 May 2020 09:19 #222472 by 300bhpton

kirkynut wrote: t just doesn't increase overall ground clearance.

Kirkynut

Then maybe the question really is. Is there actually such a thing as "overall" ground clearance. Or simple different types of ground clearance. For instance if you had a sill/chassis rail hung up on a boulder or tree stump. Wouldn't the obvious thing to say be; it didn't have enough clearance.
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18 May 2020 11:41 #222477 by sniper
All the lanes I drive are legal and you'd be surprised how many of them are quite challenging, even impassable to your car.... YouTube Parkamoor & Gatescarth Pass, you'll see how challenging they are. Multiply that considerably in Wales, where winches are often needed. All on legal lanes.

None of the forum members that I have driven lanes with would entertain going "off piste".......Mud plugging is for pay and play sites only or if you are lucky enough to have permission to drive on private land. Cross country trials are all held on private land.

sniper
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