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mike. Mud Obsessed
Joined: 03 Nov 2005 Odometer: 4010 Location: wirral
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Posted: Mon Oct 05, 2009 7:33 pm Post subject: suspension design
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got to the point where i need to settle on a suspension setup for the project.
plan is a custom chassis riding on hilux axles shod with 38's pushed by a trooper 2.8td... road legal (hopefully)
originally thinking of 3 link with the a-frame at the bottom on the front to allow for clearance for the motor.
been looking through the custom builds and now i'm leaning towards radius arms front and rear for ease and simplicity.
thing i'm struggling with is do i make my own or use disco2 or toyota ones with the eyed bushes at the chassis end?
does anyone have any pics of setups?
was thinking of buying a set of disco 2 bushes and making my own arms to mount to the inside or top of the axle.
do they have to be parallel or do they need to track in or out at all?
any guidance would be much appreciated,
thanks,
mike.
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big_patrol Mud Obsessed
Joined: 10 Sep 2006 Odometer: 2620 Location: Rossendale
1998 Nissan patrol
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Posted: Mon Oct 05, 2009 8:49 pm Post subject:
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Hey mike you could not have used an a frame on the front anyway due to steering not having the same arc. ie you need a panhard rod for this reason.
If your going to the trouble of making your own set up the using restrictive oe radius arms is in my opinion a waste of fabrication. Why not use 3 or 4 link with a panhard.
Saying tis if you are not after mad flex the radius arms will fit the bill but judging by the rest of the ingredients in your cocktail i though extreme was the direction your looking at.
Another route would be the fabbed radius arm like fat_zuke uses i can get pics if your havent seen it or cant remember it from other posts.
The binding you get from the radius arms from hevier trucks will make flex very difficult to achieve but road manners will be nice.
And yes they are meant to be parallel.
Course there is always the good old 1 link which works vey well.
I think if you go down the 3 link route you have mentioned but use a link arm not an a-frame in the middle it will work well.
Hope this helps
Danny
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mike. Mud Obsessed
Joined: 03 Nov 2005 Odometer: 4010 Location: wirral
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Posted: Mon Oct 05, 2009 9:11 pm Post subject:
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thanks danny,
i'm not looking for massive amounts of travel, this time i'm looking for simplicity, strength/reliability and making the vehicle a pleasure to use and drive on road aswell as off.
looking through some of the trucks, radius arms should give enough flex for me. there's also traction aids in each axle.
a good point with the radius arms being made for heavier trucks, i would have to make the axle bushings very close together to force any flex out of them if i were to use the disco bushings.
3 or 4 link would give great offroad results but if i get it slightly wrong it'll be a pig onroad. it would also put constraints on the chassis design.
seeing SPAM zukes design would be very helpful.
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andyb66 Just got MTs
Joined: 18 Jun 2004 Odometer: 236 Location: Ferndown, near Bournemouth
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Posted: Tue Oct 06, 2009 8:57 am Post subject:
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I am not familiar with the hilux axle, but if the rear (at least) has a diff lock then loads of axle travel is not really needed, just enough to cope with normal undulations.
With that in mind, I would use a standard setup with standard arms, simply for avalibility of parts and bushes etc. It will also retain it's road manners.
__________________________________ Andyb
http://www.challengemotorsport.com
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mike. Mud Obsessed
Joined: 03 Nov 2005 Odometer: 4010 Location: wirral
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Posted: Tue Oct 06, 2009 11:20 am Post subject:
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auto locker in rear and torque biasing in the front, both aftermarket parts than went in with the re-build.
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mike. Mud Obsessed
Joined: 03 Nov 2005 Odometer: 4010 Location: wirral
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Posted: Tue Oct 06, 2009 3:48 pm Post subject:
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andyb66 wrote: |
With that in mind, I would use a standard setup with standard arms, simply for avalibility of parts and bushes etc. It will also retain it's road manners. |
if i were to build my own set and incorporate a set of disco 2 bushes then i'd be laughing. the arms themselves seem hard to come by but the bushes i can get from paddocks.
would like to see how someone else has done them 1st though and what materials were used.
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d86 Articulating
Joined: 27 Aug 2008 Odometer: 635 Location: bath,somerset,u.k.
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Posted: Tue Oct 06, 2009 7:07 pm Post subject:
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not knocking you danny but you can use a a frame on the front.
the auverland a3 has one.
tony
__________________________________ if at first you dont succed,give up and get somone else to do it.!! |
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ScottieJ Guest
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Posted: Tue Oct 06, 2009 8:10 pm Post subject:
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how is the steering set up on the auverland? surely it would give you really bad bump steer with a traditional drag link steering set up as the axle wont follow the same lateral plane as the steering like it would with a panhard rod set up.
Edit: I just noticed in those pics that i cant see the a frame on the front, just on the rear??
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burko_uk Off-Road Guru
Joined: 21 Oct 2005 Odometer: 1017
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Posted: Tue Oct 06, 2009 9:15 pm Post subject:
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The first pic of the three is the front a-frame by the looks of it... I'd agree about the steering mind you.
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big_patrol Mud Obsessed
Joined: 10 Sep 2006 Odometer: 2620 Location: Rossendale
1998 Nissan patrol
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Posted: Tue Oct 06, 2009 10:46 pm Post subject:
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I stand corrected but i still think its a bad idea. Im not sure how the auverland ever passed any safety test as it must have steered like a pig. Body roll would result in constant steering changes as you cornered could aven result in a pitching effect and cause a roll.
If you look at the pic there seems to be another rod coming from the general area of the axle mount od the a frame, i wonder if there is more to the set up than meets the eye.
Danny
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d86 Articulating
Joined: 27 Aug 2008 Odometer: 635 Location: bath,somerset,u.k.
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Posted: Tue Oct 06, 2009 10:53 pm Post subject:
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from what i can remember the steering set up is pretty much the same as a suzuki.
the top b/w pic is the front.
if you have never seen one in action have a look on you tube.key word auverland.
they are french,used by a few europen armys.there use to be a supplier (new) in long ashton bristol.
dont know why but i have always wanted one.
dave lovejoy off here did a write up review a few years back...do a search on google still loads about.
they make some wicked trucks now..
tony
__________________________________ if at first you dont succed,give up and get somone else to do it.!! |
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big_patrol Mud Obsessed
Joined: 10 Sep 2006 Odometer: 2620 Location: Rossendale
1998 Nissan patrol
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Posted: Wed Oct 07, 2009 5:39 am Post subject:
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I know what you mean as a kid when i used to watch my dad trial there were two guys who owned a dealer ship and the used to trial them they were very capable. I always loved them.
I had completely forgot that they had a frame front ends til you said, mind i was only 7 when they trialed.
They had great well balanced flex and because the engine and box was so far back they are very stable.
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mike. Mud Obsessed
Joined: 03 Nov 2005 Odometer: 4010 Location: wirral
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Posted: Wed Oct 07, 2009 7:37 am Post subject:
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would it not make a difference with the a-frame mounted infront of the axle?
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big_patrol Mud Obsessed
Joined: 10 Sep 2006 Odometer: 2620 Location: Rossendale
1998 Nissan patrol
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Posted: Wed Oct 07, 2009 7:41 pm Post subject:
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not really as it would still be a central pivot
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mike. Mud Obsessed
Joined: 03 Nov 2005 Odometer: 4010 Location: wirral
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Posted: Wed Oct 07, 2009 7:48 pm Post subject:
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cant get my head around that (another reason to go for radius arms).
so can anyone suggest how heavy i need to build them? 1 1/2" thickwall do it?
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Roger Mud Obsessed
Joined: 25 Feb 2008 Odometer: 2050 Location: Redditch Worcestershire
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Posted: Mon Oct 12, 2009 8:17 am Post subject:
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ScottieJ wrote: | how is the steering set up on the auverland? surely it would give you really bad bump steer with a traditional drag link steering set up as the axle wont follow the same lateral plane as the steering like it would with a panhard rod set up.
Edit: I just noticed in those pics that i cant see the a frame on the front, just on the rear?? |
Bump steer can be created by changes in caster angle as you would get with trailing arms moving in an arc and the front axle moving East / West in response to suspension movement, if the system is fitted with a panhard rod.
As the Auverland was fitted with an "A" frame on the front, which would inhibit the East / West movement, and bottom control arms that with the "A" frame would reduce caster changes, surely bump steer would be all but absent.
As I don't remember any adverse comments in the press regarding bump steer and Danny's comments re: there abilities in trialling would also appear to rule this trait out, I am confused as to why the subject as been brought up.
Please don't take this as a criticism of what has been said, it's just that it doesn't jell with how I view it.
Roger
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big_patrol Mud Obsessed
Joined: 10 Sep 2006 Odometer: 2620 Location: Rossendale
1998 Nissan patrol
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Posted: Mon Oct 12, 2009 10:03 pm Post subject:
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roger the way i see it is that in vertical movement the axle will not move from side to side how ever for the steering to match this the link from the box to the hub would have to change length to compensate for this.
Bump steer is what occurs when the hub your steering is attched to does not move in an arc about its lenght hence panhard rods having to be equal in length and running parallel to the steering arm.
No i suspect the auverlander was never subject to any big problems due to them being rare and there for not getting treated to lifts. By this i mean at standard the steering arm will be sat nice and flat so the move stands the best chance of causing probles as its length changes would be minimal, thats why i was saying that body roll would effect the steering moor than bump steer.
If however you did choose to lift one and then you lengthened your steering arm to suit your problems would start.
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Roger Mud Obsessed
Joined: 25 Feb 2008 Odometer: 2050 Location: Redditch Worcestershire
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Posted: Tue Oct 13, 2009 9:03 am Post subject:
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Danny.
There is a fine line here.
I have just been reading an article in the Nov. '09 edition of 4x4 Australia.
This article compares live axles to independent.
Under the pros and cons for the live axle they say,
"The act of one wheel affects the other on the same axle, causing bump steer - bad for on road use."
This would imply that whatever the suspension system, with a live axle, you will get bump steer.
To my mind bump steer is when anything adds to the steering movement when the suspension moves.
If you drive through a bend on a perfectly flat road, you should not get bump steer, whatever type of suspension you have, because the suspension will be stable.
Trouble is, we don't have perfectly flat roads.
With the panhard rod system, as used on my own Toyota and your Nissan and I believe all the other live axle jobs apart from the Auverland, any vertical axle movement will move the axle in an arc left to right but as the steering box will remain stationary, this will promote bump steer.
The shorter the panhard rod, the worse the bump steer, so the toyota is as long as it's practical to make it.
I have never experienced any bump steer in the Toyota that I would claim to be bump steer but this could well be due to the relatively flat way in which the motor corners.
Since removing the anti roll bar I do get more roll---to be expected---but it is predictable and not dangerous.
It would appear that the only way to completely eliminate bump steer is to have the steering box mounted on the axle but as this would create numerous problems whilst only solving one, we must accept the problem as is.
I agree with much of what you have said but I believe that the problems associated with the front "A" frame may not be serious enough to warrant abandoning the system.
Although sales of Auverland vehicles was low is this country, I believe that they were common enough in France.
We will just have to wait until someone builds and tests a system.
Roger
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clbarclay Off-Road Guru
Joined: 22 Oct 2006 Odometer: 1779 Location: Worcesterhire
1987 Land Rover Range Rover
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Posted: Thu Oct 15, 2009 9:56 am Post subject:
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Quote: | If you drive through a bend on a perfectly flat road, you should not get bump steer, whatever type of suspension you have, because the suspension will be stable. |
As well as a lack of flat roads, this could only if the vehicles centre of gravity is on the suspension roll axis, which is both practically impossible with a 4x4 and also for other handling reasons undesirable. Also that would induce roll steer, not bump steer.
There are ways of significantly reducing or even eliminating body roll during corners, but anti roll bars can cause handling problems if they are too stiff and then your getting into the realms of active or semi-active suspension systems.
Most manufacturers of vehicles with steered live axle do a good job of reducing bump and roll steer to a negligible level by making the drag link as near the same length, parallel and located close to the Panhard rod.
Bump and roll steer are significant problems in independent as well as dependant suspension systems. Get the steering links the wrong length or in the wrong place and it can be just as bad. Also given the wide spread use of anti roll bars, there are relatively few vehicles on the road with true independent suspension.
Glossy magazines like the internet and news papers are not ideal sources of information. That is not to say they don't contain good accurate information, just that its not unlikely for the information in them to be dumbed down, misinformed, distorted or in some cases just lost in a see of faeces.
__________________________________ The Lord helps them as helps them selves
and the Lord help them caught helping there selves. |
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