- Ideas about other sorts of anti-wrap setups

[XtremeMarineInc]

Very nice, FF. Your truck just keeps impressing the ****e out of me. I am looking at doing similar with my truck, after the SOA is complete. Planning on using this:

http://www.spidertrax.com/s.nl/it.A/id.1204/.f

For the rear. Then converting another one hopefully for the front. If I can't , then I'll go something like your route.

[bill van snorkle]

So far I've done a couple of steep but firm climbs (on dry grass), Sunday I'm taking it off-road properly so will test it then.

With the swinging shackle arrangement it should be quite easy to do a series of definitive tests on set obstacles with the bars alternatively attached and disconnected.

Bill.

[FridgeFreezer]

I thought I'd revisit this for some more detailed design thoughts (from you guys, not necessarily from me!) - after a year of use & abuse, including this year's Ladoga run, the front bushes are well knackered. Now, that's not unreasonable as the thing's had a hell of a beating, but I'm pondering the front setup and wondering if, in fact, there is a bit of adjustment to be done of the geometry.

Unfortunately I don't have any Lego or Meccano here to play with as I am struggling a little to work out in my head where everything is trying to move when things are happening.

Basically, I suspect the looong front shackle is fighting the arc the axle is trying to take when the suspension cycles. Maybe. I also think the short front arm may not be helping the problem as it doesn't have the leverage of the longer rear arm. Possibly the front arm wants to swap and point forwards like the rear one, I can't decide if that removes the spring shackle from the equation or not. Anyway, now my brain hurts.

Does anyone have any thoughts, or perhaps some modeling software / toys they can mock this up on?

It's not the function of the setup - it kills spring wrap, no question there. It's the effect it may be having on the rest of the suspension.

[bill van snorkle]

I don't think the anti wrap bar assembly's geometry would conflict with the arc of movement dictated by the leaf springs. The bars swinging shackle should easily accomodate the for/aft movement of the axle as the springs compress and droop.

Unfortunately Land Rover spring bushings are a bit too small to expect a reasonable service life on a suspension system that regularly sees articulation movement in excess of the standard design limits. Longer shackles can help a bit as there are fewer degrees of bushing twist for a given amount of suspension travel,but larger diameter spring eyes and bushings are what's really needed. Problem is that civilian front spring hangers provide insufficient clearance for the extra compliance of larger bushings,unless the wrapper leaf is deleted.

Whilst I agree that the antiwrap bar addresses one of the major flaws of the LandRover front leaf suspension,without the need to reinvent the wheel, it doesn't alter antidive/antisquat characteristics or provide the more positive linear link from the axle to the chassis that the reversed shackle setups of Toyota Landcruisers, Jeeps , Suzukis etc do.Try any of these vehicles on a ditch crossing or climbing a vertical offroad obstacle where a leafprung LandRover hops around and tinkles about and you can see and feel the difference.It is also my belief that the superior overall abilities of Defender type LandRovers when compared to Series vehicles is mainly due to antisquat/antidive geometry and positive linear location more than the different type of springs employed.

Bill.

[FridgeFreezer]

Good points Bill - the bushings on the anti-wrap are coiler trailing arm ones, not massive but should be up to it I have the Gone2far spring plates on the front so if I want articulation I can open those. I may refit the revolvers to the rear to see what happens too.

I still can't decide if the front anti-wrap is actually going to bind up on flex (or just travel) or not, I still think the shackle is too long in proportion to the spring shackles. Is there an adult with a CAD program out there?

I'm seriously considering reversing the spring shackles as an experiment, if I can engineer a nuts-n-bolts way to do it I'll definitely try it.

[MECCANO]

Probably not much use, but i looked at a ARB on the rear of my 88 due to the wobbly 2 leaf paras. It took ages to measuring to get an idea of the location. As your probably aware, your not only contending with the arc of the leaf but the extension caused by its flattening. After all that, for a perfect pivot point, with no shackle. I would be looking at having needed pivoting mount near the rear of the seat box.

[Daan]

I hate to say this Fridge, but I think the reason your bushes are finished is because the geometry of the anti tramp bars is indeed fighting the suspension movement. Basically, when your axle goes in bump, the axle moves upwards and backwards, but does not rotate. While the trampbars dont stop the movement backwards or upwards, they do force a rotation on the axle, and are trying really hard to flex the leafsprings that way.

If it were me, I would make a link from the top of the diff housing to a crossmember, ponting forwards. That would stop axle tramp without forcing the system too much. The link would have to be half the length of a leafspring and the same angle, as far away from the leafsping as you can. Of course, you will not be able to stop the figthing of the links completey, because you leafsprings are really a set of flexible suspension links.

another option could be to allow the axle to rotate freely in the springseats, basically have bearings in the connection between the axle and the springs. It would be complicated to do, but it would work. One thing your current setup does provide is anti dive. The axle rotation is exactly oposite of their drive reaction, causing you to have good traction when you apply beans, like you mentioned.

Daan

[landroversforever]

could to not get away with only a single attachment to the axle, at the top?

[LEAFERS RULE!!!]

Look at the front axle on a toyota hi lux single bar, single bush both ends and thats from factory

[Snagger]

I think you're right to use the bushes on these bars, but also agree with the others that the geometry is what's probably caused the failures.

The axle moves around a fixed point, and that point is the front spring bush - the distance from that point is almost unchanging, but the rear end of the spring moves fore and aft and also vertically (hence the use of shackles). Since the bottom of the axle is connected to that fixed datum, the top of the axle also needs a fixed datum on the same side with the same relative displacements. To avoid torque forces on the axle, the anti-tramp bar needs to form a parallelogram between the vertical extent of the axle, the longitudinal locator (radius arm or the front half the of the leaf spring) and the chassis. I think the best results will be achieved if you can make anti-tramp arms that run parallel to the front half of the leaf springs (measured from the spring bolt to the axle seat, ignoring the curvature), with the front end of the arms pivoting at a point the same height above the spring bolts as the rear end is connected above the spring/axle seat. The use of a rose joint on one end of each arm will also help with cross-axle articulation.

[Chicken Drumstick]

Very interesting, is there any more info on this?? Have there been any changes to the setup at all Fridge?

[FridgeFreezer]

A minor update of sorts, it's all still in and working OK.

Daan and others are right, it does bind slightly especially when the car is fully loaded and towing - it sits high on the side of the anti-wrap bars and you can feel the effect over bumps in a similar way that you can feel things move about under a coiler. We lengthened the front arm and shortened the shackle & moved it back a bit recently which cut down the binding at the front a bit, it's by no means bad but it's not quite right, you can see the shocks on the "high" side don't move quite as far as the ones on the other side.

I'm mulling over the geometry of the setup, it obviously needs something but it's working out the best (read: most simple) way of doing it. A single link as has been suggested would be great if it could be made to work in the available space, or it could just be a case of fine-tuning the arm & shackle lengths to match the spring's movement more closely.

As has been said, quite a few leafers from other manufacturers use straight arms with a single bush in each end, but I need to work out the maths of making a fixed link that doesn't bind up when working next to a leaf spring which effectively gets longer & shorter.

More pondering to be done methinks - in the meantime if anyone has any useful links on the subject I'm all ears.

[nicks90]

i think the single bar method would be much simpler and i dont think the issue of spring lengthening and shortening would be too much of a problem. I bet there is no more than a few mm difference in spring length throughout its range of flex.

a simple rear radius arm matching length to the spring would probably have enough movement in the genuine LR bushes to compensate for that.

plus if you're going to the trouble doing all this - why not lengthen the front dumb irons a bit, move the rear mount back a bit and fit some 88" rear leafs up front? Loads more flex and you'll even out the suspension front to rear nicely. With your big tyres and portals, not like oyu have to worry to much about the front leaf mounting points being 6" further forward and digging in on steep hill climbs.

[tony109]

Axel tramp really isn't that much of a problem on my vehicle, thats with 9.00 tyres and parabolics. When climbing loose steep inclines there can be an element of hop but nothing that would make the inclusion of anti tramp bars necessary..

I assume 'fridge' has portal axels fitted.. Is this a portal hub, added to the landrover axels or are these portal axels off a volvo 303 or similar? With Portal axels there will be additional leverage around the spring seat leading to a more noticable amount of tramp.

I made new axel seats, as the original axel seat edges had started to 'Round', so even with the U bolts tight, play could still take place potentially allowing the axel to roll slightly.

Firstly with standard landrover axels/parabolics I do not see the need for anti tramp bars.. Even with 35" tyres on mine it has not been a problem.. If you fit Portal axels and 37" tyres as 'Fridge' appears to have, then this mod would be more of an issue..

If you dispenced with the "anti wrap" bars completly and went for slightly wider axel/spring seats would this be enough to reduce the spring wrap effect?

If you really want to go the anti tramp bar route, the amount of fore and arft movement the axel makes can be conciderable especially when fitted with longer spring shackles.. Standard shackles will reduce this effect, so you could get away using two straight tubes pivoting from the axis of the front spring eye, then back horizontally to the top of the axel case, using the spring plate mountings to give you a solid fixing point and if you used a shock eye arrangements with bushes, any changes in geometry could be allowed for.

There must be many arrangements easily found on the net

[FridgeFreezer]

Tony, to answer your post:

- It's difficult to say whether the springs are wrapping or not from inside the truck, hopping is a symptom of it but only when traction is poor. As I've said previously, now I've started watching other trucks off-road I can see that other Series with parabolics also do it.

- Yes I have Volvo portals and ~37" tyres which does greatly increase the leverage in the system compared to normal axles & smaller tyres.

- Wider spring seats were something I considered but ultimately they will either be ineffective or limit the movement of the spring.

To answer other posts:

I have no great desire to change ends with my shackles, fit longer springs, go SOA, convert to coils, smoke crack and worship satan, etc. etc. This is about using the standard suspension setup, which despite being imperfect in many ways does work. The only issue I want to address here is axle wrap, and TBH the setup I've got kills it dead, albeit with a small amount of binding which is what I'm hoping to tune out here.

Having spent all of this evening reading up to the point of going cross-eyed on anti-wrap/tramp bars/bam bars and general leaf spring geometry I have found a few leads:

- The single-mounted link solution is not as good as an "A" type one as it relies on the spring as the missing link, compressing or tensioning the spring along its length. The general consensus seems to be that it can "sort of work" for setups with flat springs, minimal wrap, or massively beefy springs but is not really as effective as an A-type link.

- The Bam-bar (vertical setup) does prevent wrap but has other drawbacks in its geometry and, for me at least, in the space it takes up. And IMVHO it's fugly.

- The vast majority of people running anti-wrap setups seem to be running basically the same thing as me with no issues. This leads me back to my thought that the basic design is sound but the geometry of link and shackle lengths and angles needs to be tweaked.

- The intelligence of most people on the net is inversely proportional to their insistence that they know what they're talking about

I have found a few actually-useful-looking bits of tech on the subject so I'll read up when I've had more sleep (and coffee) see if I can come up with some sort of coherent tech... Don't hold your breath

[oddballrovers]

Hi Fridge

Welcome back to the "plain" kind off life

I have a plan, had it for a long time, will some day be made one "the kitten" wich with the 2 leaf TIC paras has loads off axle warp.

Plan is like this:

Use trackrod ends, Abar from flush off bottom off axle casing and from somewhere on the top, goes together so the center off the 3 end is lined up with the end off the spring not horisontal but vertical.

That end is then attached to a shakle with same length as the spring ones, this shakle is made off a stering arm welded to a tube with same id as springs then you can use std spring bush or poly something, for bar you can use trackbars.

It has not been done yet but principle has been tested with a wood muck-up and it looked right, one big issue is however to get room for it.

This set up will as far as I can figure give the least bind, be cheap to make so what more to wish for, erhm does it work IRL!!!!! will the rod ends hold up the for the wear anyway they are cheap.

To make it even less work why not use end cut off steering arms and weld those to the axlecasing with some reinforcement.

Regards

Ole

[Jon White]

As fridge can vouch for, my series on parabolics with 33" tyres and series axles tramps and spring wraps something rotten, especially on the front axle, and its most visible on steep climbs.

I believe things may be different with the longer wheelbase of a 109, but on my 88" its certainly a problem.

And needless to say I still havnt got round to doing anything about it yet!

Jon

[bill van snorkle]

The British Motor Corporation when in the early 1960's completely redesigned the suspension of the Austin Gipsey from all independant Flexitor suspension to LandRover style solid axles and leaf springs, fitted a tramp rod on each side, mounted a couple of inches above the leaf spring at both the axle end and the spring hanger end. The spring hanger roughly resembled that of the UK Military LandRover 109's. Australian Military 88'' also had these deeper hangers. I have fond memories of the old 1964 LWB Gipsey I once owned. The absense of axle tramp and the difference in front end traction compared to a 109 LandRover on steep loose rocky surfaces was like chalk and cheese. IIRC the spring bushings were significantly larger than LandRover ones, which when combined with the two bushes on each tramp rod had enough compliance to absorb the effect of any conflicting geometry between the rods and the springs.

Bill.

[discomikey]

what if you disconnect the top bar from the bottom and attach it seperately to the X member, paralell to the bottom link, this would still stop the rotation, but let the axle travel more freely up and down, i agree with the polybushes on the axle end though, this setup would save the bushes as well as perform how you want it to. ill put a quick picture up of what i mean.

mikey

[discomikey]

cant upload it

grr

mikey

[larryowner]

i think the single bar method would be much simpler and i dont think the issue of spring lengthening and shortening would be too much of a problem. I bet there is no more than a few mm difference in spring length throughout its range of flex.

a simple rear radius arm matching length to the spring would probably have enough movement in the genuine LR bushes to compensate for that.

plus if you're going to the trouble doing all this - why not lengthen the front dumb irons a bit, move the rear mount back a bit and fit some 88" rear leafs up front? Loads more flex and you'll even out the suspension front to rear nicely. With your big tyres and portals, not like oyu have to worry to much about the front leaf mounting points being 6" further forward and digging in on steep hill climbs.

I have spent some time looking into the causes and possible cures for front axle hop/tramp. I have taken a lot of measurements of the front axle movement on my series one.During its travel from full droop to full up(against stops). The axle moves vertically app 130mm, but also reawards app 40mm (80mm at shackle). I found it was not possible to fit a single bar without a bind at some point of the axle movement. With the bar fitted horizontally to the top of the axle case facing rearwards and a pivot on chassis or cross member, as the axle lifts the bar gets shorter scribing a circle around its rear pivot, so far so good.But I have not been able to find a bar length or pivot point which shortens and lengthens the bar to match the axle movement as near as dosn't matter.

[Gremlin]

We have had this discussion on another tread with bill, i am going with a single rod running forward to the bumper, basically a rear coiler rod shortened, and a doughnut bush like the raduis arms at the chassis end. This should allow enough movement in the rubbers to let the axle move back and forth. I am in the process of fabrication, so pics soon.

G

[DaveSIIA]

Having seen the pictures of the worn bushes, the failure mode seems to be similar to that of the front arms of Defender/RRC/Disco. Movement of the chassis end of the arm is constrained, so the axle end bushes get twisted severely as the suspension flexes - particularly in cross axle situations.

For the anti-wrap bar, would the chassis end link be longer lasting if designed like the anti-roll bar links for Defender/RRC/Disco? Basically a ball joint / track rod end at one end and an eye that takes a pair of Series shock absorber bushes at the other. Probably TRE to the chassis mount and rubber bushes to the anti-wrap bar.

I suspect the axle moves away from square to the chassis as the leaf spring flattens on compression. One wheel up, other down and the chassis end of the anti-wrap bar would want to move laterally as well as trying to pitch up/down. The anti-roll bar type link would allow more freedom of movement in lateral or longitudinal axes, while resisting vertical loads of the anti-wrap bar.

A bracket suitable for a TRE could be chopped off an old RRC axle case to save machining a bush with an internal tapered hole. Alternatively, a pair of hefty rod end bearings would do the job but the lack of compliance would probably transmit additional noise/vibration to the chassis.

[Soren Frimodt]

This is how I did it. Definetly not rocket science, and most likely not the best solution, but IMHO it worked a treat! No more noticeable axle movement/tramp than a defender. And dirt cheap and simple to fabricate. Heim Joints at both ends, mounted center axle and center to the pivot point of the spring in the front. And to avoid binding the vertical distance from center axle to center of the joint on the axle, was the same as center from spring bush to center of frame joint.

[FridgeFreezer]

Having seen the pictures of the worn bushes, the failure mode seems to be similar to that of the front arms of Defender/RRC/Disco. Movement of the chassis end of the arm is constrained, so the axle end bushes get twisted severely as the suspension flexes - particularly in cross axle situations.

Do you mean my dead bushes? If so, you're on the wrong track - the heim on the end of the bar can rotate on its threads if needed so there should be no binding due to rotation. The fact that the shackle bushes stay good but the axle end pair wore out suggests to me the force that wore them out is the binding trying to wrap the axle due to incorrect shackle/arm geometry.