Outer Limits 4x4 Board

RED60 wrote:

grimbo wrote:

nastytroll wrote:

Dozoor wrote: Now Explian to me all you "know all " suspension gurus ,
how will the tire spin more by not being loaded up by the suspension ?

Common come get some !

Not being a smart a$$ but I'm also curious, you could read it as if you fit limiting straps it woud improove drivability. Sounds alittle strange to me.

all I can say is what I said. i have seen some very flexy, very light vehicles just spinning all 4 wheels on an obstacle not going anywhere whilst a less flexy rig crawl through by lifting a wheel. So from that I surmise that the contct pressure on the flexy one is less than the wheel lifter. Yes it is strange but that is what I have seen. Never said that flex is bad or whatever else you want to try and read into it, just seen that

How about this.... a vehicle weighs 1000kg... with all 4 wheels on the ground and with the weight evenly distribured there's 250kg on each wheel..... if we drive that vehicle onto uneven ground we may end up with 400kg each on 2 of the wheels and 100kg each on the other 2... if we were in a bad traction situation having 1 of the wheels with 100kg on it, lift of the ground the weight it was supporting is transfered to the other wheels giving them more traction, possibly enough to get it out of the stuck position... while this is a simplified version of what happens, the principal is the same....

The forrest rover is wild tho I doubt it's a big flexer...

it's only 250kg on a tared road only because it's level and the friction is the same across all 4 tires.

goto a un-level road, which is river gravel for example and the weight but also the frioction on a surface will change as well.

you can only move forward or backwards if your tires are rubbing against something (friction) if the surface also moves then your friction will also reduce by so much.

Sand would be a classic example of having either plently of friction as in you move but don't get stuck or no friction and suddenly your stuck and your tires will happily spin all day long.

then you have the drive train which gives all the power to the wheel of least resistance so having 1 wheel up in the air will be given all the power no matter how much weight is on the wheels.

that flexing truck would have all wheels to the ground but anything you have not nailed down will also help to tip over the front or back end of the truck, the shifting of weight won't be great.

in those pics I'd hate to be the driver of that tip truck because if you kept going forward you'd dump half the load of dirt out the side of the tray and probably flip the whole truck over as well, simply due to the sway of the dirt pulling the whole lot over as well.

I think it's one of those "it's a super great concept but as a real life truck it simply doesn't work as it was meant to on paper" and I think people forget about the other details like shifting of weight etc.

you could stop some of the side turning but it'd put extra stress on the split part.

same deal for the wagon truck just think of all those tools (extra side G/weight) banging around from side to side everytime you go over a bump then speed will increase the problem.

Ice wrote:

Tom0 wrote:

Gheto_Modz wrote:I will be keeping the 10 00 20 wheels on it...

That's a hell of a lot of wheels.
How can you afford all the tyres?

Gwagen? Is this one?

Who let Canada out in a Bikini again!!!

Back on topic, Tatra is a vehicle manufacturer in Kopřivnice, Czech Republicis. they make cars and trucks. tata is a little indian thing haven't seen much of them except their little 4wd things

Tatra 815 kolos, most of the ones you see in the truck challenges are 813's

815



813


404 mog next to an 813 tatra

And Tatra also build those amazing rear engined aircooled V8 sedans.

Dozoor wrote:

RED60 wrote:
How about this.... a vehicle weighs 1000kg... with all 4 wheels on the ground and with the weight evenly distribured there's 250kg on each wheel..... if we drive that vehicle onto uneven ground we may end up with 400kg each on 2 of the wheels and 100kg each on the other 2... if we were in a bad traction situation having 1 of the wheels with 100kg on it, lift of the ground the weight it was supporting is transfered to the other wheels giving them more traction, possibly enough to get it out of the stuck position... while this is a simplified version of what happens, the principal is the same....

The forrest rover is wild tho I doubt it's a big flexer...

Red60 I don,t agree with this in your senario you have effectivley removed
25% of your tread edges from the ground reducing the ability gain traction .

While I have removed 25% of the POSSIBLE traction from the vehicle, if that wheel was spinning and doing no effective driving any way, I haven't actually removed any EFFECTIVE traction. If by lifting that wheel, I transfer that weight to other wheels that are slipping and only need more weight to supply EFFECTIVE traction then the vehicle MAY get out of the situation. I'm not saying that in avery case by lifting a wheel you will drive out. What I am saying is is some situations it is possible for a vehicle with only 3 wheels on the ground may in fact go further than a flexy vehicle with all wheels on the ground.... Anyway, we're getting off the thread topic.

I know what you are saying zagan about the tipper and the tools in the service body but without the swivell they wouldent have gotten near where they are on the obstical.... I think the "falling "side on into an obstical is to blame for many rollovers as the momentum plays a great part, where as if you split the chassis and have it snake up and over obsticals it removes the already rolling aspect and in most cases the front or the rear are in a not bad position when the other part is all twisted up.
I think the key to making it work at its best is to keec centre of gravity in the middle of the vehicle, as much as possible, and low as possible. Ive seen the salt lake racers usually have a balast of some sort... maybe I run a heavy 6mm skidplate on the underside of the chassis keeping weight in and low...
Mark

RED60 wrote:
The forrest rover is wild tho I doubt it's a big flexer...

It is only limited by the guards and what you can do with LR leaf springs. 1 m of travel each end would be quite easy, with slightly modified suspension and guards that were attached to the axles rather than the body.

Mark - sounds good - I am keen to see pics. But it sounds from your post that you aren't even 100% sure if you can get it registered... But I will be following the thread very closely to see if you can manage it.

As for the hub reduction, you can get axles with 7-9:1 gearing without hub reduction, which would be sufficient and easier - but not quite a roadless (forest) rover replica. That is what I was planning to do.

Im as sure as I can be about getting it on the road... Ive done all the preliminary question asking and Im confident enough to spend 6-7k on this thing to give it a shot... Look the way these places go I guess you cant be 100% until you have the plates... But Im 97%

I hope to get a start on it real soon ... if nothing else this post has given me the fuel to get it cracking...


Watch this space...

i havn't read the last half of this thread. but the only articulating veichel aloud on our roads are franna cranes. and if u have ever driven a centraly articualating machine at any speed u will know they are a handfull and u have to constantly steer, them . not easy and offroad it just gets harder.. allso. u will need a decent hydrolic pump to run your steering and if ur engine failed u will have no steering at all. might be worth considering that most machines like this have a rear mounted engine and geabox...

i think its a good concept but 4 wheel steer will allmost allways defeat central articualtion offroad....

good luck anyway at least u wont have any cv's to break.

or am i completly wrong and u r building a circular rotating swivel so ur trucks halfs can twist circularily independant from each other thus eliminating the need for masive wheel travel suspension?

like a volvo moxy set up.
clever.

Not like a franna the other way...
have a look at the link I posted to some pics in earlier thread..
Mark

grimbo wrote:

nastytroll wrote:

Dozoor wrote: Now Explian to me all you "know all " suspension gurus ,
how will the tire spin more by not being loaded up by the suspension ?

Common come get some !

Not being a smart a$$ but I'm also curious, you could read it as if you fit limiting straps it woud improove drivability. Sounds alittle strange to me.

all I can say is what I said. i have seen some very flexy, very light vehicles just spinning all 4 wheels on an obstacle not going anywhere whilst a less flexy rig crawl through by lifting a wheel. So from that I surmise that the contct pressure on the flexy one is less than the wheel lifter. Yes it is strange but that is what I have seen. Never said that flex is bad or whatever else you want to try and read into it, just seen that

So by what you and a couple of others have written here you are totally disregarding the factor of weight? A crucial factor in suspension setup and performance.

And NO I'm not starting yet another sh*tfight. I'm just sick of the one eyed toyota, nissan and even zuk owners carrying on like a bunch of f*ckheads everytime somebody decides to go against the grain.

I have driven a 2wd Tata turbo diesel and have no complaints, pulls like a schoolboy. (more than I can say for an overpriced, over-rated 75 series)

There is also a couple of T/D Tata 4x4s up here and they do just as good off road as anything else.

Of interest... here are a couple of pics of a haflinger based buggy with a central pivot. It was on UK ebay about a month ago.





cheers
Matt

mattc wrote:Of interest... here are a couple of pics of a haflinger based buggy with a central pivot. It was on UK ebay about a month ago.





cheers
Matt

Problem with that setup is that your seat twists as far as the front wheels, looks rather unconfortable at that flex.

Bet its heaps of fun though

clm434 wrote:

grimbo wrote:

nastytroll wrote:

Dozoor wrote: Now Explian to me all you "know all " suspension gurus ,
how will the tire spin more by not being loaded up by the suspension ?

Common come get some !

Not being a smart a$$ but I'm also curious, you could read it as if you fit limiting straps it woud improove drivability. Sounds alittle strange to me.

all I can say is what I said. i have seen some very flexy, very light vehicles just spinning all 4 wheels on an obstacle not going anywhere whilst a less flexy rig crawl through by lifting a wheel. So from that I surmise that the contct pressure on the flexy one is less than the wheel lifter. Yes it is strange but that is what I have seen. Never said that flex is bad or whatever else you want to try and read into it, just seen that

So by what you and a couple of others have written here you are totally disregarding the factor of weight? A crucial factor in suspension setup and performance.

And NO I'm not starting yet another sh*tfight. I'm just sick of the one eyed toyota, nissan and even zuk owners carrying on like a bunch of f*ckheads everytime somebody decides to go against the grain.

I have driven a 2wd Tata turbo diesel and have no complaints, pulls like a schoolboy. (more than I can say for an overpriced, over-rated 75 series)

There is also a couple of T/D Tata 4x4s up here and they do just as good off road as anything else.

no not disregarding weight hence why I said lightweight. And I'm not sure how I'm carrying on like a f*ckhead when I first said interesting build but questioned the legality of how he was first going to rego it as a Tractor then as a hot rod. Sometimes outside of the grain needs some pulling in to reality. Not sure how your comments are anything but trying to start a shit fight

thats the go.... a bit low to the ground for allowing the swivell to work but concept is the same....
BTW I might move there and get it reg if that thing is....lol

grimbo wrote:

clm434 wrote:

grimbo wrote:

nastytroll wrote:

Dozoor wrote: Now Explian to me all you "know all " suspension gurus ,
how will the tire spin more by not being loaded up by the suspension ?

Common come get some !

Not being a smart a$$ but I'm also curious, you could read it as if you fit limiting straps it woud improove drivability. Sounds alittle strange to me.

all I can say is what I said. i have seen some very flexy, very light vehicles just spinning all 4 wheels on an obstacle not going anywhere whilst a less flexy rig crawl through by lifting a wheel. So from that I surmise that the contct pressure on the flexy one is less than the wheel lifter. Yes it is strange but that is what I have seen. Never said that flex is bad or whatever else you want to try and read into it, just seen that

So by what you and a couple of others have written here you are totally disregarding the factor of weight? A crucial factor in suspension setup and performance.

And NO I'm not starting yet another sh*tfight. I'm just sick of the one eyed toyota, nissan and even zuk owners carrying on like a bunch of f*ckheads everytime somebody decides to go against the grain.

I have driven a 2wd Tata turbo diesel and have no complaints, pulls like a schoolboy. (more than I can say for an overpriced, over-rated 75 series)

There is also a couple of T/D Tata 4x4s up here and they do just as good off road as anything else.

no not disregarding weight hence why I said lightweight. And I'm not sure how I'm carrying on like a f*ckhead when I first said interesting build but questioned the legality of how he was first going to rego it as a Tractor then as a hot rod. Sometimes outside of the grain needs some pulling in to reality. Not sure how your comments are anything but trying to start a shit fight

I wasn't just talking soley about you. How many times have we seen new and/or different ideas on this site (yes I admit not all of them are great ) where people have just jumped in and slaughtered the shit out of someone for doing or attempting to do so.

Hell, ya can't even own a mitsubishi without being told off about how you should be in a hilux because they are so great and raa raa raa.

I'd really like to see if Gheto_Modz gets this build done, and especially registered. Will be even better to see how well it goes offroad too.

I was trying to stay away form this, but I do need add some stuff in here. This thread has nothing to do with hot rod plates or, what anyone else drives or whether TATA's are crap.

I'll start by saying I've been victim of a "gunna"- I was "gunna" built portal boxes for my suzuki, and I still have a couple of portal boxes from split window Combi's I have borrowed from Daddylonglegs to look into the project. I've spent quite a few hours bench racing ideas with Bill and one of the better threads on Outers ( The ultimate off road landrover thread, on the LR page) was just amazing. My portal idea was was scuttled due to the hassles of basically having to fabricate everything and I don't have the skill or time to see it right though. (And actually I'm not sure how much it would help a suzuki on 36" tyres, but that's not the point)

A) I don't give a stuff what cab a project is built around

B) I've seen lots and lots of crazy projects planned and talked up (and supported) though outers that come to nothing or pop us an unfinished projects. Even once you've spent all the time and money, you're very unlikely to concede it's a bad idea. youre more likely to confine driving it to the terrain it works in, which may well be on ramps.

C) There's no point trying to sell an idea to us on here. If you ask us "what we think" don't expect to get "you're a genius." You're going to get "you haven't thought of this" or "this has been done before" or "do a search", or something.

D) I'm not convinced, Gheto_Modz, you've thought through what you want to achieve with this project. If you want to show off by driving to the top of a ramp, you're about 10 years too late. If you want a capable trail car, I really really don't think it's going to be usable. If trailering the car out to a ramp and driving all the way to the top is what you want to do, go ahead. You only need a pivot to do this, you don't need anything else.

E) I seriously don't understand why a pivoting chassis on a two axle vehicle adds any capability at all over a well designed suspension system. More on that later.

F) to pass this pivot as safe for road use you're going to need a LOT more than a truck spindle. You'll need to do some heavy calculations on this. The stress on this joint is massive and failure would be catastrophic.

G) This idea has been tried by recreational drivers, in competition, in military vehicles and on commercial vehicles for many many years. It doesn't ever seem to have been seriously pursued on two axle vehicles.

H) Gheto_Modz, you've only taken 1/2 of the suspension behaviour of the car into account. I understand you want to force the centre pivot, and on the face of it, that's a good idea, but that implies it's going to be "set" for a given obstacle -so you can "pull" a wheel up to assist a climb, or push a wheel down to assist traction. However, the moment you force the suspension, you're basically either locking it in a given position, in which case the axle suspension becomes vital for taking out the differences between the axles and will have a big effect on power transmission (which Mercedes were ALL over with the Mog)

If it's active (i.e sprung) you'll have to deal with the effect of roll stiffness this will introduce. Generally, pivoting chassis designs (like the Gamma Goat) placed the pivot close to the roll centre of the car. from what it sounds like, you're going to have the pivot well above the roll centre of the suspension. You're going to have two roll centres and its going to suck the big one under power.

That's part of the big problem. Trucks, heavy load carrying vehicles etc run very low power and high weight and never, ever, throttle a climb. tHey're always just chugging through. To have advanced capability the suspension design has to work under power too. That's why most of these whacky designs have vanished from any form of competition. complex systems are heavy and weight is a disadvantage once you're out of traction. If you have traction, you don't need complex pivoting etc systems in the first place. It's something of a viscous cycle. As an example, from what I have seen, the massive, heavily forced suspension cars built for Tough Truck, (aus) as an example don't always show a clear advantage.

By all means, go and build it, I really do wish you the best, but you asked what we think. That's what I think.

Steve.

Put the Tata cab onto a mog chassis with your choice of engine and call it done. You still get to have a whacky suspension setup (torque tubes), but it will perform quite well.

off topic, but google image search for "tatas" doesn't pull up many photos of cars

Wendle wrote: off topic, but google image search for "tatas" doesn't pull up many photos of cars

Lol Lindsay Lohan

Wendle wrote:Put the Tata cab onto a mog chassis with your choice of engine and call it done. You still get to have a whacky suspension setup (torque tubes), but it will perform quite well.

A Mog 404 chassis has upto 11 inches of flex alone, not including the suspension...

Wendle wrote:Put the Tata cab onto a mog chassis with your choice of engine and call it done. You still get to have a whacky suspension setup (torque tubes), but it will perform quite well.

X2.

Steve.