Land Rover Discovery Suspensions: Caster

[I Leak Oil]

Now that is well said.
And from personal experience, I agree a DC joint SUCKS to rebuild on the trail!
Jason T.

 

[Mike_rupp]

I see... if I get one thing wrong and acknowledge it, then obviously everything else I say can be disregarded?

I'll take people's word for it that you are an expert on these matters, and that therefore your proposed solution is a good one, technically speaking (despite seeing some practical disadvantages in it).

But your usefulness as a source of knowledge is at least partially offset by your inability to accept that other people's contrary views may be perfectly valid, and your resorting to ascribing those views to ulterior motives or general ignorance or stupidity.

This thread started as a discussion of lockers, and I have a strong view that a manually switchable full locker is a far better technical solution than an LSD
or an automatic locker. However, I respect the people on here enough to know that if they have a different view on what's best, then at the very least, it's rooted in their own experiences, and holds validity for them.

By all means argue the facts; just hold back on the personal jibes and innuendos.

The thing is I am no expert, by any means. That is why this is so frustrating.

Scott brought this aspect of the discussion by posting a picture of a DDC shaft, like its some shiny new piece of bling to stick on the Discovery. To me it signifies that something got messed up along the way and it was used as an item of last resort. He's been in the game much longer than I, but like I said earlier, for the life of me I can't understand why he is defending a setup that has clear disadvantages like it's his own child.


In terms of a manual locker vs. a unlocker, I agree with you. This is assuming of course that the apparatus to lock & unlock the locker is fool proof, which we all know doesn't exist.

 

[Scott Brady]

Steve,

Thank you for posting your comments. I appreciate the insight.

I promise you that I have nothing against Rovertym. I know they produce high-quality components, many of which are very appropriate to overland use. They also make many solid components for more severe recreational use.

A DDC driveshaft on a disco with a 1.5" lift is not the correct direction one should take.

For now, the only negative I have heard about the arms is that the DDC shaft is heavier. You and I both know that the likelihood of a vibration free, but slightly heavier drive shaft ruining a pinion seal or bearing is extremely unlikely within the axles service life. I love physics and geometry, so give me some hard data, some proven failures as a result of a DDC. I am all ears.

The reality is, is that functionally a DC and DDC drive shafts are used to solve the same issue, which is to compensate for the fact that the angle of the transfer case to prop shaft and pinion to prop shaft are not equal. In the case of Mike's and your preferred solution, it uses a DC on one side, where the Inland Rover's arms uses it on both sides.

I know you guys want to "prove" that your solution is correct and mine is wrong, while I am saying that your solution appears correct, and the method I am testing is under evaluation, but currently working perfectly.

Why not say "that is cool Scott, let us know how it works out after a year of hard use, and for now, we will stick with what we know works"?

If people do not test new products, and challenge the common "knowledge", how do we see if something new might work? I promise you, if these arms fail, or if the driveshaft destroys the pinion bearing or seal, I will come right on hear and say it. This is not a pride thing, or a chest thumping thing for me. I am just as happy if you are right and I am wrong as if we are both right.

 

[Scott Brady]

I am going to sign off of this discussion until either the set-up I have shows a failure mode, or some clear data is presented.

This is distracting me from looking at maps of Nicaragua

 

[Hank]

If you look at one Rovertym radius arm vs another from a year ago, they will have two different patterns. It's not a 3" vs a 2", either. It's because Rovertym changed specs about a dozen times in the last 5 or 6 years when Steve was running the show. Some are longer than other, and some are "rotated" more than others, and everything in between.

When Steve first built the 5" lift, the DDC was the only option. Steve recommended it and sold it. Steve had shafts from Arizona Drive Shaft Company, and he had Tom Woods shafts. There are also some Standard Parts Corp. shafts tossed in.

Well, Steve learned something. The DDC was not all that. Steve described the DDC to me as a limp noodle when I was in the shop one day. Both Steve and Seth told me how the DDC was just not working out.

When Steve walked away, Seth pulled the curtain back on the new Swivel ball correction RTE was about to start offering.

So, as time went on, the radius arms changed, again, and the caster corrected swivels became available. These balls have proven to be the best option to date for all the same reason already explained.

Scott,
I saw your new radius arms on the EE board. I'm sorry, man, but "elegant" is not the word.

As for Death Wobble, that sucks. I installed my lift and went for a drive. All was well until I hit a bump in the road. At 70MPH the truck shook so violently it tripped the inertia switch and the hazards came on! To solve the problem, I removed two shims from the king pin on each side.

I plan on keeping the stock radius arms and installing the drilled swivels balls on my new truck. I'll use a shim to pull the pinion back into place, if needed. I'll probably run a D2 DC drive shaft. I know the D2 shaft has only 1300 u-joints vs the 1310's in the Tom Woods shafts, but I want the shaft to be the weak link. I much rather replace a $20.00 u-joint or salvage-yard yoke than break a R&P, CV, or inner axle.

 

[michaelgroves]

Scott, I know all about ideal driveshaft geometry.

I'm all for getting the caster back to stock specifications. However, we disagree on how to get there. You somehow think its better to use the radius arms to correct the caster. I don't see the logic. In your method, you end up having a heavier driveshaft than what is needed.

Using the radius arms to correct pinion / drilled swivels to correct caster / DC shaft to correct vibrations at the transfer case end just seems to be the most elegant solution. Caster is solved, vibrations are solved, and the driveshaft is lighter than in your method. RTE took the approach that you did when they first got into business, yet when they experimented with drilling the swivels they found a solution that solved all of the problems.

It seems that your method didn't take all of the variables into account at the start. It seems that you bought the radius arms to solve one issue but then had to deal with unintended consequences.

Mike, as I see it the three steering geometry /suspension issues we are talking about are:

1) Caster angle. If the axle tube rotates (pitches) due to the lift, then the steering king-pins will be at the wrong angle. Redrilled swivels is the only way I can see to truly correct this. The king-pins must be at the correct angle, somewhere close to vertical.

2) Radius arms. Again, as the axle rotates, the bushes will bind. This can be corrected by new arms, or if the rotation is small, by offset bushes.

3) Pinion angle. If the axle rotates, then the diff pinion flange will not be parallel to the transer-box output shaft flange. (Incidentally, this is what I was alluding to with my comment about there just being one angle - they are either parallel, or they are at an angle to each other. My idiocy was in not seeing how you considered it as two separate angles).

However, if the axle isn't rotated, then am I right in saying that the caster angle issue doesn't apply? (I.e. we can keep the same swivels). In which case, is it possible to have a suspension lifting solution that keeps the at-rest position of the axle in the same orientation as standard? The only problem apparent to me, is that although the output shaft flange and the diff pinion flange would be parallel to each other, there would be a large vertical offset between them, and hence a severe prop-shaft angle to deal with.

Isn't it the radius arms and their existing bushes that keep the axle in that orientation (pitch) in the first place? In which case, just correcting the radius arms should be enough to make sure the caster remains correct. That will leave only the severe propshaft angle to deal with.

Suspension lifting is not a field I have much experience with, so I'd appreciate getting to understand these issues a bit more.

Regards,

Michael...

 

[Hank]

Isn't it the radius arms and their existing bushes that keep the axle in that orientation (pitch) in the first place?

Correct

In which case, just correcting the radius arms should be enough to make sure the caster remains correct.

Correct, sort of. But I think what has been found is that this will point your pinion too far south.

That will leave only the severe propshaft angle to deal with.

Correct

 

[Steve Rupp]

Scott, the last thing I want is a pissing match. I really do respect what you do. I think I've just been on discoweb for too many years and have heard this discussion more times than I can remember. I guess that's why I was scratching my head when I saw that you were using a that driveshaft. Anyway I hope it works for you. At least you have a white truck.

When Steve first built the 5" lift, the DDC was the only option. Steve recommended it and sold it.

This is actually not correct though. John was drilling the swivels long before Steve came around. Yes he did develop the castor corrected arms and a DDC driveshaft but before he left he was building new arms and drilling swivels. I could be wrong but that's how I remember it going down.

 

[revor]

Okay I'm on.

Like the rest pissing contests are not what I'm here for.

There are a number of folks here (in the arguement) I know personally and respect highly, I respect their opinions even if I disagree.
But I see a trend that many of of us are used to seeing on other boards that dosen't reflect the type of argument we're used to seeing on this board. That's not to say that the opinions put forth are wrong or right, it's more about the way the conversation is moving forward.

Being one who "never" gets in the middle of things I'd have to say that the experience that some of us have had vs. the exploration of new ideas by some that haven't seen, heard or experienced what we have seen needs to be taken as just that, exploration and that's okay.
As confusing as that sounds it's like me embracing the guy that wants to put a set of U Joint axles in his swivels in place of a set of CV's rather than the current CV products on the market. I KNOW that it won't work well, but in the end I have only a small amout of personal experience to draw from in this realm. Hey it could work great. ("evil twin" No it won't)

Some of these guys I speak of are some of the most Contreversial bunch I've grown to know and respect. They have opinions, and good ones based on experience. In the end they are great resources. They would say
" I wished he asked me before..." in honest tones. I am soooo impressed by the amount of tongue biting going on!!!

In the end there are many ways to skin a cat (How many? Only "Hank" and I know for sure) but some ways that aren't "the best" work fine in some situations.

We're overlanding now, it's a different world, guys that have never seen what we've seen or even worried about what we have worried about, and in many cases don't need to. As you've seen these guys that overland do a lot of homework. Some of it reflects what you would consider good tech some not.

Temper the argument with experience and good wishes (Like Hank's clear liquid) and hope for the best.

Get the Dweb out.... These guys won't play, they'll just move on.

I don't want to come off as a wuss as most of you know I'm not. It's more let it go, share experiences and let the cards fall. I don't agree with every solution but I'm interested to see how it pans out..

 

[Rovernut]

I run HD OME springs & TODDCO 2" spacers on the front of my 1988 Range Rover, with 2" longer ProComp shocks and 285/75/16 tires. I have a Truetrac installed, and I made my own bent arms getting angle measurements from an RTE set. I run the stock driveshaft with single u-joints at each end. I have NO driveshaft vibration, and I can drive my truck at 70 mph with one finger on the wheel (this was not the case before the arms).

Whether or not the caster will be adjusted to stock angles by the RTE arms will depend entirely on the amount of lift that is installed. I think that is about 3" in my experience. Less lift will make that correction too much, and more lift will cause the arms to not correct the caster enough.

I thought this thread was about lockers. That was my video. The green Range Rover is mine.

 

[kellymoe]

Get the Dweb out.... These guys won't play, they'll just move on.
.

:bowdown: Truer words have never been spoken

 

[muskyman]

gone

 

[michaelgroves]

Your comments seem to be part declaration and part speculation, and you are making them to people that have been in the land rover community a long time and spent the time and money to sort out these exact issues long ago.

I wouldn't be interested unless I believed the people had knowledge and experience! I made it clear (I hope) that I am trying to learn what the precise issues are. If I am wrong in my "speculation" or my "declaration", then I hope to be told where I am wrong, so I understand why different conclusions are being drawn.

Incidentally, I don't have a view on what solution is best - I'm not trying to persuade anyone of anything.

#1 actually the angle is not intended to be near vertical. the kingpin inclination needs to be positive. This is when the top of the king pin is rearward of the bottom kingpin.

Well, I said "near" vertical because I know it's not precisely vertical. But my point was that caster is not arbitrary, it's determined by the fact that essentially the wheels steer about a vertical axis.

#2 just correcting the arms without correcting the caster angle dose not work, incorrect caster angle will cause forces that stress the radius arm bushings under the axle housing and makes them fail in a much shorter time then if the caster is corrected.

This gets to the nub of my question. "Correcting" the arms can mean different things. If you correct them so as to point the pinion upwards towards the transfer output shaft, then you'll rotate the axle forwards, and upset the caster. But if you correct them so as to hold the axle's at-rest orientation in the stock position, then caster will remain unchanged. Yes?

#3 the pinion can also be misaligned as the axle housing moves side to side. This happens as a result of the panhard bar pulling the the housing to the driver side as the lift increases. this should not be at all a issue with a 1.5" lift as the lift gets higher different fixes can be used such as a adjustable panhard bar or relocating the mount on the axle housing.

Agreed - there are other issues affecting the lift, too. But what I am trying to do is understand the caster problem.

So far, I'm beginning to see the problem as a trade-off between bad caster angle (if the axle is rotated by the corrected or uncorrected radius arms) and the pinion pointing too far south (if the axle is kept in its original orientation).

If that's a valid analysis, then in principle there's some amount of lift that can be dealt with by simply using a propshaft that's capable of dealing with the bigger offset between the two flanges. (As well as radius arms that retain the original axle orientation, of course).

This information has past the test long ago as the correct and best way to lift a coiler land rover. when someone takes these steps as outlined here by Mike,Steve and Dan they will be rewarded with a truck that drives correctly even at high lift heights let alone a small lift like 1.5"

Thom

Yes, rotating the swivels restores the caster angle if the axle has been rotated. I can see why it's a solution that works. If the original pinion angle could be retained (i.e. the axle not rotated), would that also be a solution to the caster problem?

 

[MuddyMudskipper]

The Mother of all Hijacks

So fellas, how's that Locker vs. Open discussion going?

 

[michaelgroves]

So fellas, how's that Locker vs. Open discussion going?

LOL, this thread got hijacked long ago! But it's an interesting topic - could be snipped and put in its own thread?