Axle wrap/tramp control

[Snagger]

Thanks for the tip, Bill. I'll be fitting the two-piece bush - over enough time, the flexing will wear the broken ends and that could cause more trouble. I think the smooth joint between the ends of the two-piece bush will wear less and last longer, especially since they'll also allow oil in better.

[bill van snorkle]

Back to the 'cowbelly' shaped trackrod for a minute. If you flip the cowbelly so that it is above the horizontal diff, then it won't interfere with the r/hand leaf spring when turning left, although I am not sure whether or not the r/hand chassis rail would be an issue

[Snagger]

Believe me Bill, I looked at just about every permutation before settling on leaving the axle axis alone and using taller saddles and retaining the vehicle height by fitting a third leaf to the springs to bolster their camber. There are other solutions, but this was the best fit for my parabolics and 1-ton chassis and shackles. I spent two whole years mulling it over, fiddling with this, researching that...

[dirtydiesel]

Believe me Bill, I looked at just about every permutation before settling on leaving the axle axis alone and using taller saddles and retaining the vehicle height by fitting a third leaf to the springs to bolster their camber. There are other solutions, but this was the best fit for my parabolics and 1-ton chassis and shackles. I spent two whole years mulling it over, fiddling with this, researching that...

Your method of fitment has reduced your ground clearance by raising your axle case this has ultimately led to the problem you have now.

Having the track bar at the back is doing nothing for your ground clearance either.

The rangerover swivels have so little Ackermann in them I'm sure you would barely notice moving the track bar to the front.

[FridgeFreezer]

Seems a little spurious to argue against having the track bar in front as that's where it is on Series... and it's not like anything with a green oval has laser-sharp handling at the best of times.

[discomikey]

if anyone would be interested, my mate has a gopro thingy,

i thing it would be interesting what actually happens under a leaf sprung vehicle where tramp is concerned, i get the concept etc, but nobody really knows by how much in general

im on RM parabolics, and atm only have rear wheel drive, but it would still give us more of an idea

[dirtydiesel]

Seems a little spurious to argue against having the track bar in front as that's where it is on Series... and it's not like anything with a green oval has laser-sharp handling at the best of times.

But the OP read a book, and the book said it was bad!!

[Snagger]

The Ackerman angle is pretty significant on RR axles at full lock, and given almost all of my driving is on road, I'm not willing to have it reversed. As for the argument that because the Series axle had it track rod in front, that the coiler axle can be set up the same way, that's not right - the angle between the axle and steering arms has to be set up correctly; if I remember rightly, they have to be convergent in front of and divergent behind the axle, so swapping the swivels from side to side won't work, and nor will using a lhd swivel on the rhs.

As for your comments, dirtydiesel, my ground clearance has not been lost - the third leaf has given it a very small rise of about 1/2" despite the taller saddles. I also had no choice about the saddle height as the diff sits further outboard on coiler axles, with the neck over the spring - this means the saddle has to be taller. The diff housing is actually touching the top of the spring with the saddle formed around it; the saddle height is the absolute minimum for the axle case to fit, regardless of steering systems. The contact problem is more because of the overlooked lower engine mounting, not directly because of the axle mounting solution. You don't know the vehicle and haven't read my posts properly, so, why the attitude?

[dirtydiesel]

The Ackerman angle is pretty significant on RR axles at full lock, and given almost all of my driving is on road, I'm not willing to have it reversed. As for the argument that because the Series axle had it track rod in front, that the coiler axle can be set up the same way, that's not right - the angle between the axle and steering arms has to be set up correctly; if I remember rightly, they have to be convergent in front of and divergent behind the axle, so swapping the swivels from side to side won't work, and nor will using a lhd swivel on the rhs.

As for your comments, dirtydiesel, my ground clearance has not been lost - the third leaf has given it a very small rise of about 1/2" despite the taller saddles. I also had no choice about the saddle height as the diff sits further outboard on coiler axles, with the neck over the spring - this means the saddle has to be taller. The diff housing is actually touching the top of the spring with the saddle formed around it; the saddle height is the absolute minimum for the axle case to fit, regardless of steering systems. The contact problem is more because of the overlooked lower engine mounting, not directly because of the axle mounting solution. You don't know the vehicle and haven't read my posts properly, so, why the attitude?

Excuse my attitude its a reflection of your total confidence that you've found the "only" solution.

How have you not lost ground clearance by lowering the spring seats? Drive down a set of deep ruts and see how much your U bolts dig in!

The axle casing can be notched on the o/s/f to get the spring perches as high as possible,

And without experiencing the neutral Ackermann that using a lhd swivel and the track bar at the front gives how can you absolutely dismiss it?

I have read your posts, including the bit where you thought the tyres were slipping on the wheels.

And whilst I haven't seen your vehicle, I have built and driven a few series on rangerover axles though.

[Snagger]

The spring plates are slightly lower than before, but still higher than they would be with standard leaf springs - parabolics are much thinner in the middle. As for notching the axle, I really didn't fancy weakening it like that. Given that my 109 is mostly used as a family runabout and camping vehicle with the ability to do expedition work, but is not set up for rock climbing or deep mud pay and play site use, losing about 1/2 clearance under the springs compared to before makes little difference - the diffs are still by far the lowest points. As for the Ackerman issue, it's basic physics. On a mostly road going vehicle, it's a benefit to have it, otherwise it wouldn't be incorporated in the design of cars. I don't need to experience neutral Ackerman to know it's not a good idea, just like I don't need to experience jumping off a cliff to know that's a bad idea too. You still haven't explained your attitude.

[dirtydiesel]

I drove quite a few miles in my brothers 2a with rangy axles and the track bar up front and I honestly couldn't tell any difference in the steering compared to a standard series.

I think your book may have been exaggerating if it compared neutral Ackermann to jumping off a cliff!

[bill van snorkle]

Snagger, I have bumped the thread titled '' RangeRover Classic Ackerman Angle'',on the International Forum, and refer you to post # 10, where I reprinted an excerpt from the tech book titled ''New Directions in Suspension Design" This book offers a different view on the benefits or otherwise of true Ackerman angles to the American book that you have read. What this proves is that even qualified automotive engineers disagree as to the true value of Mr Ackermans principle. There is a rebuttal further down the page of that thread by Rick at post #13, who has had some racing experience. American book or British book, whose opinion is valid? The only point I make is that for many many years, Britain had been or maybe still is the home of racing car engineering.Even Ferrari formula 1 cars were built in the UK for a time, and American Indy car teams almost exclusively bought their chassis from Lola in the UK.

Dans and my own positive personal experiences with reverse Ackerman angles also suggest that one can't go too far wrong with what LandRover have given us to work with.

[Snagger]

The point I was making about the book was apparently unclear - I was making the point that not everything in print is accurate and that not everything on sale works. Sorry that point wasn't clear. I was also trying to point out that I did try to carefully look into how to do my axle swap, looking closely at what others who had already done it, both on here and other forums, in the club I'm a member of, and by reading a couple of books about it, including said inaccurate US book. Part of my problem was not realising how much the diffs move on leaf springs through axle wrap and overlooking the fact that I had already fitted a Defender engine, which means that rhs mount is much lower than normal for a SIII. This was not an issue for others as those I had seen didn't have that combination, so didn't come up in my research.

I don't object to what other people have done, but I do object to Dan jumping down my throat for no reason, regardless of his experience. A reversed Ackerman is clearly be little problem for what you use your vehicle for - off road, on relatively straight roads or at speed, I'd agree that it probably makes little difference, but with the roads in this little island being so twisty, the the towns having so many tight corners, and using the 109 to commute, parking in tight car parks, the Ackerman angle becomes a little more important; a large part of the reasons for swapping axles in the first place was to improve the turning circle, and it frequently gets used at full lock. While the angles aren't adjustable, they are at least a close approximation, which not only reduced loads on the wheel bearings and swivel pins, but also reduces loads on my arms! I'm probably one of the few people who has such a widely modified and heavy 109 and still retained the original steering...

[dirtydiesel]

I apologize Nick for jumping down your throat and poking fun at your expense.

But, and its a big but. You need to realise that other less experienced users of this forum will read your posts and likely take your views and opinions as the gospel truth, rather than speculation and conjecture (however well rationalized).

I'm taking nothing from your modifications on your vehicle, as you have it seems near completely achieved your goals as you set out to.

What I picked up on, is the manner in which you completely disregarded other methods of achieving your goals that could prove to be more advantageous for others following in your footsteps. This and you being absolute in you statements without any practical experimentation to support your statements

I strongly believe that this forum's sole biggest asset is its core members practical nature, to put "book" knowledge before hard won empirical knowledge is ridiculous and undermines the fabric of the place.

Again I apologize for my terse comments and the tone I delivered them in.

[Snagger]

I wasn't trying to thumb my nose at anyone's solutions - there would be little point is asking for others' input if that was the plan, and it certainly wouldn't help get a response next time I need advice. I didn't understand the fitting of the ladder bar system properly, and that book was partly responsible having shown them fitted horizontally, hence why I thought they'd cause wrap from articulation while stopping it from torque reaction. Like I said, there was a lot of carp being pedalled in that book, like leaf springs with over 18" camber, shackles nearly 12" long and spacer blocks under the springs up to 6" with SOA conversions - a lot was of it was real red-neck stuff and I'm disinclined to do most of what I saw in there and prefer to learn from you lot. But, at the same time, I want to retain the standard LR attributes where I can, minimising the alterations from standard. I'm not en engineer, but I have had plenty of technical training and can easily visualise where stresses act and how they affect components, which is why I have been less keen on some solutions than others; while most people will get away with certain things, they have a way of biting me in the arse - it always seems to be me that gets the problems, even when doing exactly the same mod a hundred others have done before without issue!

Maybe I perceive the tone of some posts incorrectly, but I think Soren took some stick too for his 88, but while his bar may not be pretty, I still think it was a smart solution - he found it works well, and hasn't caused any problems despite his concern that it might wear the rear bushes. I thought it unfortunate that his idea was so readily dismissed. I did get some very useful information, including photos, by PM, and I can only guess at the reason it was sent that way.

[Gremlin]

Nick that book you mention sound very much like that web site (who remembers it)........the scary steering page.........sadly it seems to be defunct or i just cannot find it!

G

[Snagger]

It looks like that site has been taken down. Shame - it was as entertaining as it was horrifying! That book was OK in many respects - it showed a lot of different suspension schemes used by 4wd manufacturers, (all US), some of which seemed quite bizarre but entirely reasonable. Where it went awry was in showing off-the-shelf modifications. Everything was very glossily painted in bright primary colours, looking pretty and neat on first inspection, but much of it was clearly unstable or unworkable, looking from an engineering perspective like many of the red-neck crates on that site. It was worth the read, but demonstrates that you have to be careful to get information from more than one source.

By the way, I was in and out of MLA this morning, Grem - I've never seen it looking so green!

[bill van snorkle]

There has been a 'Scary Steering' thread on Pirate for a few years, but you may have to use their confusing 'search' function to find it. IMO any steering system that uses Heim joints with parrallel shank bolts in place of proper tie rod ends is also a bit on the scary side on a vehicle that is occasionally used on public roads , regardless of how well the geometry was thought out.There is a lot of that on US self built offroaders,aside from the purely competition rigs that are trailered to events. Heims or Rose joints are OK for high end racing cars where everything is replaced after each event,or for offroad trucks that don't see public roads. but heims and parrallel shank bolts wear and work loose too quickly compared to sealed,greasable self adjusting tie rod ends. That is probably why they are illegal for steering and suspension systems on road going vehicles in Australia, where it is possible to cover several hundred kilometres of corrugated roads at relatively high speed in one session.

[FridgeFreezer]

Nick - this is possibly the politest I have ever seen Dan, so don't knock it!

I'm impressed you managed to find a recent book about leaf springs, I suppose it would have to be American as they're the only ones who still fit them to anything. Unfortunately they do have a unique approach to engineering. Last time I was there I crawled under quite a few vehicles and it wasn't good. The (factory) rear-steering chevy pickup was quite a surprise too.

[Snagger]

I think some Japanese vehicles still use leaf springs too, at least on the back end. Like I said, it was an interesting book for the first half - the different manufacturer systems were quite clever, from live beam axles to independent suspension, with a curious middle ground of a scissor-like axle pivoting in its centre. A few of the mods in the second half were OK, but some were clearly risky - leaf springs with so much camber they were literally semi-circular (you can imagine how stiff they'd be, and how much aft movement of axle you'd get as the springs compress; the bushes would last no time at all and the shackles had to be over a foot long, which was highly unstable), but combined with a SOA conversion with 8" or more of raising blocks between the axle and spring and U-bolts 2' in length, and you get the general idea. Plenty of heim joints in steering components, and drag links with 45 degree bends set at 30 degrees or so to the axle. All that good stuff!

I know what you and Bill mean about Heim wear - the longitudinal link between the base of the selector lever and shaft on a Roverdrive uses Heim joints, and while they take very little force, over the space of a year they became loose enough that the flange of the joint rotates on the ball easily enough to rattle against the arm of the lever pivot to which the ball is bolted. They're free of slop for actuation, so the fix was an o-ring between the arm and flange, around the outside of the pivot ball, just to sop the rattle. I wouldn't want to use them on critical parts, but figured that anti-wrap bars would be non-critical, providing an advantage but not of great consequence if they wore a bit. Of course, if one failed outright, it could rather ruin your day being so close to the steering system...

Serious question, guys: am I just making my life more difficult by worrying about this? You don't hear of many front two leaf parabolics failing (not the good brands, anyway) unless used hard on triallers, so with the three leafs I have, used almost entirely for routine road driving, is it worth the effort? I can see how it's technically beneficial, but is it going to be practically beneficial to me or am I just over-analysing again?

[FridgeFreezer]

As I said, I have heims on my anti-wrap and they work but they do wear and I wouldn't want them on my steering. The situation they're in it's not a problem if they have a little play.

Serious question, guys: am I just making my life more difficult by worrying about this? You don't hear of many front two leaf parabolics failing (not the good brands, anyway) unless used hard on triallers, so with the three leafs I have, used almost entirely for routine road driving, is it worth the effort? I can see how it's technically beneficial, but is it going to be practically beneficial to me or am I just over-analysing again?

Depends if the problem really exists - maybe 1st job is to work out what's really happening? Strap a camera under the car, put some paint markers, blob some blu-tak or whatever to work out how things are moving and why. No point fitting anti-wrap if the real answer is to clock the axle tube round to lower the diff angle.

On the flipside, spring failure or lack of is not proof that wrap is or isn't happening - as Bill says, you can watch it on Series vehicles and sometimes see the dents in the shocks (my early ProComps had this, that was with 7.50's and Rover axles... the TIC parabolics are still going strong!) From an engineering point of view, wrap is not just bad for springs but the rest of the driveline too, and doesn't help the off-road ability of the truck either.

[bill van snorkle]

Another point to consider. Is the propshaft universal joint contacting the engine mounting, preventing the axle from going to negative castor under heavy braking? Floppy springs and Negative castor during heavy braking creates an unstable situation,especially if you happen to be rounding a high speed curve at the time, so If you modify the engine mounting to provide clearance, you may still require some form of wrap control to prevent that occurring.

[Snagger]

Makes sense. I'm not sure how much of the gap between prop ad mount is closing up from spring compression and how much from wrap, though both will be a factor. I ask because every time I make a mod now, it has knock-on consequences to do with other mods. You can make a few changes, it seems, without too much difficulty, but you can get to a point where is becomes a cascade of side effects, and while I can't see any negatives from fitting anti-wrap control if kept away from the steering components, it doesn't mean that there won't be new issues. I would think that the new axle has less wrap than the original purely because of that third leaf being added at the same time. I'll see if I can rig up a camera like yo suggest.

[Gremlin]

Oooooohhhhh tell me about the cascade effect............... But i seem to have found a happy meduim now, although i get all sorts of new ideas which will involve more mods to the mods i have already done!!!

Anyway, yes ideally you should try the camera thing, it would be interesting to watch, or find someone willing to let you loose on a rolling road, although i doubt it wil be enough to simulate what is happening.

G

PS, yes nick its as green as can be, not for long, heat is starting to kick in!!!

[Snagger]

I'll be coming down there for a week in October with the family, Grem. Get the sprinklers on in September, will you?