Self Levelling Unit for RR Classic

Quote:

---

Originally Posted by wagoo

I agree that your vehicle is sitting level in the above photographs, but your words above suggest that you just removed the boge unit and retained the original springs. So why is it not dragging its bum? Because you fitted polyairs to compensate.Not the same effect as central springing for offroad ability.
Wagoo.

---

My argument is/was that you need to be able to adjust the ride attitude for the load. I don't like the idea of a self leveling unit mounted on the a frame (Boge unit) because IMHO it can act like a central pivot.

I use Poly airs (for Bearman = little air bags fitted inside the standard coils) to increase the load capacity of the coils when you have a load.

In theory, you could use twin Boge units (mounted outboard either side), but I would assume that arrangement would definately limit your articulation. You could also swap coils to suit the current load. But how many pair would you have to carry! :confused:

Everything outside full air suspension is going to be a compromise and full air has reliability issues.

I bet there are a lot of Land Rovers out there that have inoperative Boge units but the owners don't realise. In which case you are better not having it and adjusting manually.

ADDIT: yes I too have had to replace the Polyairs, also the tubing sometimes kinks inside the top rubber, but I also think that I once rolled my RRc because of the instability of the Boge. After that event, I would prefer the occasional inconvenience of the Polyair maintenance.

However it all comes down to personal preference and that's fine.

I won't get involved in the technical angles of this, but I know mine works, and I like it - I have actually tested this with 500Kg of bricks, so I know it works, and it always ends up level, no matter what I put in the back, or what I tow. After you unload it, it ends up high until you drive it again, then it's back to where it should be - brilliant, and no adjustments needed by my lazy arse. I like the way it rides, so I don't want to make the suspension any stiffer than it hs to be.

It also works fine off road - I don't do any double diamond runs or anything like that, but for medium to hardish tracks, I have had no problems - it still puts my mates Trihard to shame, which is all I really care about... :D

I am aware of what Polyairs are, I used a set for several years in my 110 after my Boge unit died but went back to the Boge unit after 1 Polyair disintegrated and having separate airlines 1 was still loaded and the other cactus ( from rubbing inside the spring ). Result was a substantial lean to one side. Not good if you are carrying a load when it happens. I am of the opinion that the Boge leveller is the best and most comfortable ride you can get especially on undulating surfaces.

Quote:

---

Originally Posted by Lotz-A-Landies

I bet there are a lot of Land Rovers out there that have inoperative Boge units but the owners don't realise. In which case you are better not having it and adjusting manually.

---

Yes Diana, but the contributors to this 'Technical' discussion are in the main, enthusiasts who ARE interested in whats going on underneath their steeds, and some of us place offroad ability fairly high up on the priority scale.
Discounting the fitting of difflocks,offroad traction is dependant on keeping wheels firmly planted,and it is my belief, based on studying almost 100 years of real cross country vehicles and their development, that a centrally pivoted and sprung suspension on at least one end does a better job of doing that than most any other passive,non electronically controlled system that I can think of.
Wagoo.

So the question begs......how do they work?

My second question regards balance: with regards to a balanced suspension front to rear, and looking at the original RR, would the soft coil/compliant rear be working more than the front RA set up? Givin that they early thinner RA,s and their appropriate bushes are more flexable than the later, would the boge set up be better used with these? Basicly how do we get the front end to work in balance with such a good rear design

Quote:

---

Originally Posted by uninformed

So the question begs......how do they work?

My second question regards balance: with regards to a balanced suspension front to rear, and looking at the original RR, would the soft coil/compliant rear be working more than the front RA set up? Givin that they early thinner RA,s and their appropriate bushes are more flexable than the later, would the boge set up be better used with these? Basicly how do we get the front end to work in balance with such a good rear design

---

Within the constraints of what you can legally modify in QLD, there isn't much you can do with RAs to make them articulate more.Holey bushings give a bit more if you don't mind replacing them every so often.The only way you can have a F/R balanced system with RAs up front is to restrict the rear end. But then you might as well get a Commadore and a winch.:)
Wagoo.

Quote:

---

Originally Posted by wagoo

BTW, does anyone have a working boge unit lying around in their shed that they can measure how far the shaft protrudes from the units body? I'm reasonably sure it should be greater than the 12cm I measured on the dead one.I vaguely recall in the past having to disconnect both rear dampers and jacking the chassis up to the max and even put a bottle jack between the axle and the chassis to relieve enough load on the shaft to remove the unit from the vehicle
Wagoo

---

Hi Bill,
Without taking things apart, mine measures 13.5cm from end of strut body to the lever casting (when held with faces parallel) as shown:
https://www.aulro.com/afvb/images/im...011/08/411.jpg

Quote:

---

Originally Posted by wagoo

Yes Diana, but the contributors to this 'Technical' discussion are in the main, enthusiasts who ARE interested in whats going on underneath their steeds, and some of us place offroad ability fairly high up on the priority scale.
Discounting the fitting of difflocks,offroad traction is dependant on keeping wheels firmly planted,and it is my belief, based on studying almost 100 years of real cross country vehicles and their development, that a centrally pivoted and sprung suspension on at least one end does a better job of doing that than most any other passive,non electronically controlled system that I can think of.
Wagoo.

---

I do agree with you there, and your comment "keeping wheels firmly planted" is crucial however I am not completely convinced that articulation per se necessarily equates to traction, particularly when the suspension system is disarticulated. But in this area you are most certainly far more expert than I.

Diana

Thanks for measuring that for me Mark. It's not much different to the one on the Rangey, considering 110s are meant to be longer. But the way they are positioned, the shaft doesn't telescope much through out the articulation range of the suspension.The gas pressure inside must be enormous.
Wagoo.

Quote:

---

Originally Posted by Lotz-A-Landies

I do agree with you there, and your comment "keeping wheels firmly planted" is crucial however I am not completely convinced that articulation per se necessarily equates to traction, particularly when the suspension system is disarticulated. But in this area you are most certainly far more expert than I.

Diana

---

I'm not sure, but I may be going to do a bit of a back flip here.I'll make it up as I progress through this post.:)
It is entirely possible that I misunderstood and have misrepresented the operation of the boge unit. Because the early RangRovers had a load capacity of 1500lbs I originally assumed that this was the downforce that was constantly applied by the Boge unit, but that is not accurate. It would appear that they are designed to maintain the shaft at a certain extended length, and any load in addition to the empty weight of the rear of the vehicle, that compresses the suspension to shorten the shaft length will allow more gas pressure to enter the piston chamber to restore the preset shaft length .ie no load no extra downforce. So what we have is a device that attempts to maintain a constant distance between the centre of the axle and the chassis, that can apply a downforce of up to 1500lb depending on load carried.So if all that is correct, then the axle is only centrally sprung when a significant load is carried. When vehicle is travelling unloaded cross country, articulation is afforded by the soft springs only,with the boge supplying little extra downforce to the drooping wheel. But then again, having a functioning boge unit in place does allow the use of soft springs, where as indicated by my comparison between the Range Rover and the Hybrid, stronger springs do in easily measurable terms, inhibit articulation and traction.

Diana. By ''disarticulated'' i assume that you mean dislocated. A drooping wheel on the same side as a dislocated spring will still have a certain amount of downforce, whch is the product of the leverage that the opposite wheel transfers via the fulcrum, that being the spring on the compressed side. The closer the spring spacing the greater the conversion of upforce on the compressed side into downforce on the drooped side.
Wagoo.