portal axles

[bob10]

There was a thread on the forum about some members wanting to fit portal axles, and there was some talk about whether they are legal in Aus..In the latest 4wd action mag., they have an article on a Patrol fitted with portals, and they say it is street legal.Mind you, 4wd action also advertises H.I.D. "blue" lights, and lights fitted to roof bars, and it has been argued both are illegal on Aus. roads. So, are the portals legal, or not?cheers, Bob

[uninformed]

Hi Bob,

all depends on how deep your pockets are and who you know.....No im not joking. It will also depend on what state you are in, as currently the rules are different from state to state

cheers
Serg

[Johnno1969]

Are those HID "Blue" lights those horrible bleeding things I keep seeing in oncoming night traffic that burn out my retinas on sight and make my brain hurt? Crikey I hopethey are bloody illegal. Lights that bright don't help anybody at all; they're really dangerous. I'm not long back from years overseas, and I used to see those lights in developing countries and think "At least when I get home the powers that be will have had the sense to make sure that the damned things don't get sold in Queensland...."

Maybe I was a bit optimistic.

[CJT]

There was a thread on the forum about some members wanting to fit portal axles, and there was some talk about whether they are legal in Aus..In the latest 4wd action mag., they have an article on a Patrol fitted with portals, and they say it is street legal.Mind you, 4wd action also advertises H.I.D. "blue" lights, and lights fitted to roof bars, and it has been argued both are illegal on Aus. roads. So, are the portals legal, or not?cheers, Bob

You can legally fit Portals, check out Marks 4wd Adapters. They do the kits for Nissan and Toyota.

I spoke to them about leaglity in QLD and they have approval for them here but with only a maximum 50mm increase in wheel track and maximum 33" tyres on a Patrol. This meant having to have rims custom made with a huge backspace to keep them in far enough.

I believe that they have approval for them in other states with 35" tyres but possibly not with any kind of suspension lift etc. Not that you need that given the extra clearance from the portals.

[Bush65]

You can legally fit Portals, check out Marks 4wd Adapters. They do the kits for Nissan and Toyota.

I spoke to them about leaglity in QLD and they have approval for them here but with only a maximum 50mm increase in wheel track and maximum 33" tyres on a Patrol. This meant having to have rims custom made with a huge backspace to keep them in far enough.

I believe that they have approval for them in other states with 35" tyres but possibly not with any kind of suspension lift etc. Not that you need that given the extra clearance from the portals.
I hope you are right, if so I owe you!

[isuzurover]

I hope you are right, if so I owe you!

John - AFAIK Mal Story still has 1 or 2 (QLD) registered vehicles on portals. Serg/Uninformed knows the details and is in contact with Mal every so often.

[wagoo]

I hope you are right, if so I owe you!

Do you still have the Volvos John? The 50mm track increase allowance which is the same that Vic Roads allow on normal beam axles anyway would make a landRover track width the same as a Volvo at 60.5''. With Volvo axles you would be allowed to go to 62.5'', in which case you might just be able to squeeze in a disc brake conversion and remain within the regs.

Although I agree with the track increase restriction from a structural engineering perspective,it does present an issue of stability for anyone adding Maxidrive or Tibus portals onto their vehicles.Perhaps you could apply your engineering skills to clearing up any misconceptions to the following?
I had originally thought that if you raised a vehicle 1'' and widened the track by 1'' then original centre of gravity would be maintained.This works wth a cube of constant density material,Eg a cube will overbalance once the gradient exceeds 45 degrees. But, and I'm not sure how it was calculated, and can't recall where I read it (probably Pirate),and I think it would have to vary between different vehicles, but the commonly believed equation seems to be, if you raise a vehicle 1'', then the track width should be increased by 2'' in order to maintain the centre of gravity at original levels.If that is true then if Maxidrive/Tibus portals raise the vehicle roughly 5'',and 35''dia tyres an additional 1.5'', then a Defender for example would need to have its axle housings widened out by 13'' to give a track width of 71.5'' to restore the centre of gravity to original specs.
Wagoo.

[uninformed]

I agree Bill,

not sure of the exact whys??? but have also read you need a greater track width increase than height increase.....regardless I cant understand how the DOT would allow a 5 inch portal with only a 50mm or 2 inch track width increase??? after all arnt all the rules and regs primarily based on safety???

[Slunnie]

As I understand it (from a NSW perspective) the 50mm change in track relates to the axle used, not to the vehicle which the axle is in.

[wagoo]

I agree Bill,

not sure of the exact whys??? but have also read you need a greater track width increase than height increase.....regardless I cant understand how the DOT would allow a 5 inch portal with only a 50mm or 2 inch track width increase??? after all arnt all the rules and regs primarily based on safety???

I think the D0T 50mm limit relates to the stress placed on the axle housing due to the extra leverage from the portal gear cases height and width;equivelant to fitting 42'' dia tyres vs 32'' and about 3'' less backspacing on the rims.On those numbers i'm surprised they allow any track width increase at all.
The extra king pin at the bottom beefs up the swiveI housings but not the axle housings, which would require reinforcing to cope with a bigger track increase;If I were an engineer that had to sign off on a portal conversion I wouldn't permit a bigger track increase either, unless it was done by widening the axle housing before the swivel balls and appropriately reinforced.This would be much easier to do on a LandRover with their bolt on swivel housings and firms making aftermarket 24 spline front and rear halfshafts,and steering rods than it would be for a Nissan or Toyota.

Wagoo.

[uninformed]

As I understand it (from a NSW perspective) the 50mm change in track relates to the axle used, not to the vehicle which the axle is in.

which would be a problem for LR axles using MD??? I do wonder if they have the acception if laminating/strengthening the axle case???

[uninformed]

I think the D0T 50mm 1imit re1ates t0 the stress p1aced 0n the ax1e h0using due t0 the extra 1everage fr0m the p0rta1 gear cases height and width;
The extra king pin be10w beefs up the swiveI h0usings but n0t the ax1e h0usings, which w0u1d require reinf0rcing t0 c0pe with a bigger track increase;If I were an engineer that had t0 sign 0ff 0n a p0rta1 c0nversi0n I w0u1dn't permit a bigger track increase either, un1ess it was d0ne 0n the ax1e h0using bef0re the swive1 ba11s and appr0priat1ey reinf0rced
S0rry,a few keys 0n my keyb0ard have g0ne 0n strike again;
Wag00;

what about reinforcing the stock housing and using the likes of MD portals and a stock LR rim???

dont worry Bill, after all, all this computer stuff is just 0's and 1's

[wagoo]

what about reinforcing the stock housing and using the likes of MD portals and a stock LR rim???

I'm certainly no mechanical engineer Serg, but if that was my profession I would be a real barsteward to get approval from:) and say that your proposal is not acceptable due to scrub radius concerns. See my edited post below. I fixed my keypad with a hammer:o
Wagoo.

[Slunnie]

which would be a problem for LR axles using MD??? I do wonder if they have the acception if laminating/strengthening the axle case???
IIRC as I read it ( a while ago), if you narrow or extend the axle width then the track alters for the axle by the amount of the extension or shortening. MD will fall under this. I would assume that the spirit of the guideline relates to maintaining geometry and bearing loadings.

Also, if you narrow then you cant lift.

[slug_burner]

Do you still have the Volvos John? The 50mm track increase allowance which is the same that Vic Roads allow on normal beam axles anyway would make a landRover track width the same as a Volvo at 60.5''. With Volvo axles you would be allowed to go to 62.5'', in which case you might just be able to squeeze in a disc brake conversion and remain within the regs.

Although I agree with the track increase restriction from a structural engineering perspective,it does present an issue of stability for anyone adding Maxidrive or Tibus portals onto their vehicles.Perhaps you could apply your engineering skills to clearing up any misconceptions to the following?
I had originally thought that if you raised a vehicle 1'' and widened the track by 1'' then original centre of gravity would be maintained.This works wth a cube of constant density material,Eg a cube will overbalance once the gradient exceeds 45 degrees. But, and I'm not sure how it was calculated, and can't recall where I read it (probably Pirate),and I think it would have to vary between different vehicles, but the commonly believed equation seems to be, if you raise a vehicle 1'', then the track width should be increased by 2'' in order to maintain the centre of gravity at original levels.If that is true then if Maxidrive/Tibus portals raise the vehicle roughly 5'',and 35''dia tyres an additional 1.5'', then a Defender for example would need to have its axle housings widened out by 13'' to give a track width of 71.5'' to restore the centre of gravity to original specs.
Wagoo.

If you raise a vehicle the width of track does not impact the CoG as such unless you add weight down low as a result of the wider track. The raising of CoG and increase in track may keep a triangle of CoG to trackwidth constant which is a stability measure.

[wagoo]

If you raise a vehicle the width of track does not impact the CoG as such unless you add weight down low as a result of the wider track. The raising of CoG and increase in track may keep a triangle of CoG to trackwidth constant which is a stability measure.

As I get a bit older I get a bit thicker. I read this last night when sleepy and could not understand it. I had another go this morning, Ditto!:o
https://www.aulro.com/afvb/images/imported/2011/08/1128.jpg Anyway, I did a simple drawing of an exact 50mmx50mm square mounted on a 45degree side slope,and placed the COG at the centre of the square.(centre of balance).
I then moved the COG higher up by 5mm and discovered that I had to widen the base by 10mm to restore the centre of balance.
Thing is, if I place the COG 10mm below the centre of the square and find the angle at which point of balance is reached, and then move the COG back up 10mm I find that I must widen the base by 14mm to restore stability on that angle. Now I'm really confused :confused::confused::confused:
Wagoo.

[Bush65]

Do you still have the Volvos John? The 50mm track increase allowance which is the same that Vic Roads allow on normal beam axles anyway would make a landRover track width the same as a Volvo at 60.5''. With Volvo axles you would be allowed to go to 62.5'', in which case you might just be able to squeeze in a disc brake conversion and remain within the regs.

Although I agree with the track increase restriction from a structural engineering perspective,it does present an issue of stability for anyone adding Maxidrive or Tibus portals onto their vehicles.Perhaps you could apply your engineering skills to clearing up any misconceptions to the following?
I had originally thought that if you raised a vehicle 1'' and widened the track by 1'' then original centre of gravity would be maintained.This works wth a cube of constant density material,Eg a cube will overbalance once the gradient exceeds 45 degrees. But, and I'm not sure how it was calculated, and can't recall where I read it (probably Pirate),and I think it would have to vary between different vehicles, but the commonly believed equation seems to be, if you raise a vehicle 1'', then the track width should be increased by 2'' in order to maintain the centre of gravity at original levels.If that is true then if Maxidrive/Tibus portals raise the vehicle roughly 5'',and 35''dia tyres an additional 1.5'', then a Defender for example would need to have its axle housings widened out by 13'' to give a track width of 71.5'' to restore the centre of gravity to original specs.
Wagoo.
Volvos sold to another member here. I was concerned with gearing (with low revving diesel) and disc brake conversion, while being registrable (wheels and tyres). Replaced by Marks GU Nissan portals.

AFAIK Marks had their portals engineered for 35" tyres and wheels with 50mm offset (inward) to achieve acceptable scrub radius. Off hand I can't remember what track increase this gives, so will have to check.

As slug_burner stated, COG height will increase with lift, but is not changed by track change. What does change with track is the allowable side slope for stability - increasing height of COG reduces the allowable side slope, which can be increased by increasing the track. As side slope increases the COG is moved toward the down hill side - as the COG approaches a position vertically above the down hill tyre contact the risk of overturning increases (remember some margin for dynamic upward loading is required).

Marks strengthen the axle tubes, provide a third (lower) "king pin" / swivel pin bearing, and strengthen (using webs) the neck of the swivel balls to compensate for the larger track change and hub offset. The final stub shaft and spindle diameters are also increased.

[CJT]

This is some information I recieved from Marks 4wd a while ago, seems that it is easier to make the Toyota portals compliant in QLD compared to the Nissan that need custom offset rims.

"We have been granted provisional approval on the portal axles, we have to make some changes to comply in QLD.
The biggest change is the track width cannot increase by more than 50mm over standard. The Land Cruiser portals have been changed to comply with this and we can run off the shelf rims from the 100 series IFS vehicles.
After the Land Cruisers are finished the Nissan's will be redesigned to comply. With the redesign there will be added benefits of upgrades, GVM upgrade, air operated hubs from inside the cabin and brake upgrades.

For QLD transport the portals will only be approved running 33 inch tyres as they will not approve 35 inch tyres under any circumstances. Running the 33 has many advantages over the 35 including weight, scrub radius closer to standard, cost, availability, brakes don't need to be ungraded, etc. You only loose 1 inch of diff clearance, the clearance is the same as running 41inch tyres."

[wagoo]

As slug_burner stated, COG height will increase with lift, but is not changed by track change.

Thanks John, but this is where my understanding runs off the rails a bit.:confused:
Surely COG must be lowered by an increase in track width?
Disregarding lift for now, A standard Defender has a track width of 58.5''.If I were to widen the axles out so that the track width now measures 70'' then surely the vehicles COG is lowered? Maybe lower COG is not the correct term and I shoulld just say the wider track just increases stability. But in the context of this discussion this is just semantics and distracts from the supposition that fitting portals will result in a less stable truck, unless quite drastic measures are taken to compensate for the height increase by an appropriate increase in track width.
Wagoo.

[slug_burner]

This image is exaggeratted but it serves to illustrate the point.

https://www.aulro.com/afvb/images/imported/2011/08/375.jpg

track width increases the base of the stability triangle i.e., you will need a bigger side slope to take the centre of gravity outside the track width for the same CoG height. You can see this by how much you would have to rotate the vehicle about the point at the edge of the track.

CoG is a point in space where the centre of all the mass can be though of as being present for the purposes of further analysis (usually static analysis). The only way I can change the CoG is by redistributing the mass. to lower the CoG I have to place more of the overall mass down lower. Increasing the track width will not significantly redistribute the weigth/mass.

a definition

"The point in or near a body at which the gravitational potential energy of the body is equal to that of a single particle of the same mass located at that point and through which the resultant of the gravitational forces on the component particles of the body acts." probably not much good unless you already know what it means.

Here is a better/simpler one
"The center of mass or mass center is the mean location of all the mass in a system"

[wagoo]

Thanks Slug Burner.I now have a clearer understanding of what Centre Of Gravity actually means.
But as I stated earlier, for the purpose of this excercise we are getting hung up on terminology, and in relating trackwidth to Centre of gravity, probably should use a term such as 'centre of balance' or 'centre of stability'.
Wagoo.

[LowRanger]

Thanks Slug Burner.I now have a clearer understanding of what Centre Of Gravity actually means.
But as I stated earlier, for the purpose of this excercise we are getting hung up on terminology, and in relating trackwidth to Centre of gravity, probably should use a term such as 'centre of balance' or 'centre of stability'.
Wagoo.

Bill
I think the term that you are looking for is Centre of Mass,and changing the centre of mass can be offset by changing the vehicle track width.
Have a look at this page Weight transfer - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Load_transfer) .I bring your attention to the section marked Cause: and the last paragraph in that section.
There is much interesting reading to be found by also looking here Vehicle dynamics - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Vehicle_dynamics)

And yes I agree with your assumptions Bill,but explanations come back to terminology

Wayne

[wagoo]

Bill
I think the term that you are looking for is Centre of Mass,and changing the centre of mass can be offset by changing the vehicle track width.
Have a look at this page Weight transfer - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Load_transfer) .I bring your attention to the section marked Cause: and the last paragraph in that section.
There is much interesting reading to be found by also looking here Vehicle dynamics - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Vehicle_dynamics)

And yes I agree with your assumptions Bill,but explanations come back to terminology

Wayne
Thanks for the links Wayne.
I also found an interesting article this arvo on the Jeepaholics Anonymus website, Center of Gravity and Roll-Over Angle - Jeepaholics Anonymous (http://www.jeepaholics.com/tech/cog/) Titled 'Determining centre of gravity and roll over angles of your vehicle' that explains a few things fairly clearly in laymans terms.
Wagoo.

[slug_burner]

Thanks Slug Burner.I now have a clearer understanding of what Centre Of Gravity actually means.
But as I stated earlier, for the purpose of this excercise we are getting hung up on terminology, and in relating trackwidth to Centre of gravity, probably should use a term such as 'centre of balance' or 'centre of stability'.
Wagoo.

Yes I agree that we can get hung up on what appears to be technicalities of the terminology. However in a highly textually based discussion forum, words mean everything i.e., they carry all the meaning. We don't have facial or hand gestures to elaborate the points we are trying to get across and what I think I am writing may not always get the point across. I find pictures either photos or simple graphics can convey much meaning. There is a great advantage to actually have the stuff in front of the people involved in the discussion as there is nothing like seeing and touching I find. Earlier in the "130 on portals thread" when discussion went to anti dive and scrub angles etc. The terminology was something I had limited prior exposure to and I certainly was not confident of the exact meaning but google helped with finding a few diagrams or definitions which would probably would have been more difficult to do if it wasn't for the use of commonly accepted terminology.

Anyway this is getting away from the original intent of this thread. I'll sit back and try and absorb the ideas that you more experienced people discuss and pipe in with question or three when it is all getting a bit beyond me.

Thanks for making this place an enjoyable and interesting place.

[wagoo]

Thanks again Slug Burner.I'm also very much a layman when it comes to engineering and terminology.and similarly,as Rick 130 once admitted,"I know just enough to be dangerous''.
Wagoo.