Land Rover Discovery Suspensions: Caster

[Scott Brady]

I am breaking the caster discussion out of the locker vs. open discussion.

I believe the information provided here is valuable.

 

[Scott Brady]

ok lets start here.

1) you can not start changing any geometry in the suspension system without looking at all factors and the affect they have on the system as a whole

Thank you for the detailed post.

 

[muskyman]

gone

 

[Mike_rupp]

Scott, I'm not the one who brought the terms "poor taste" and "offensive" into the discussion. I'm not taking things personally.

Back to the discussion

The reason that I have a hard time letting it go is that the method that Scott took to design his radius arms is exactly the same as what Rovertym did when they first started making radius arms for 3" lifts. Do you think that they abandoned that design for no reason whatsover? It is not like Scott is venturing down some new road that hasn't been previously explored. They ventured down the road, found out that there was a washout and turned around.

 

[muskyman]

gone

 

[michaelgroves]

a few reasons why its not a good idea I will touch on them one by one.

Off set bushings suck!!! they wear out and break down quickly and they dont reduce the angle of the arm at the frame so the direction of shock loads from bumps still is aimed at the passenger compartment causing a noisy ride.

Factory spec for caster angle is ok for a stock truck at a stock height but once you start lifting the truck and the center of gravity with it additional positive caster up and beyond the stock spec does alot to make the truck drive straight. being able to drive in a very relaxed manor not fighting a wandering beast is a good thing on long trips.

I'm proposing that it's possible to design a pair of radius arms to create any caster angle you want - factory spec, extra positive, extra negative. Not with offset bushings, but designed to do whatever you meant earlier when you said: "That same custom Arm should have a corrected off set built into it to allow us to return the frame end at the bushing to go through the bushing level with the bushing centerline."

If we do that, we get the caster angle we want, and we get the radius-arm bushing behaviour we want. With me so far, or am I wrong?

All that leaves us to solve is the more acute propshaft angle. If a propshaft does this reliably and without vibration, then in what sense is this a band-aid or "giving up"?

There may be lots of reasons one doesn't want to use non-standard swivels on an expedition truck, in which case you'd have to explore other solutions which maintain perfect caster.

as far as operating angle goes the DC and DDC shaft are designed to over come the running angle issues that a standard SC shaft has. since there is no up in space and drivelines need to be looked at like they are transfering torque in space. a single cardan shaft is the correct shaft when the flanges are parallel but thats where your idea goes away...the flanges are not parallel from the factory and as I pointed out before this is why the factory shaft is set up out of phase. so when you maintain the factory pinion angle and lift the truck then the angles that the shaft has to operate at become greater. this is why the best way to do this is by using radius arms to correct the pinion angle for a DC shaft. then address the resultant caster from there.

I haven't really proposed any specific type of shaft to use to overcome the shaft-angle problem "my" caster solution leaves us with. It seems likely that with a substantial lift, no propshaft could feasibly work at the very acute angles that would result. However, it seems equally likely that with a small amount of lift, managing the modest increase in angle would be feasible.

I'm not looking for a verdict, I'm looking for a chain of reasoning from people who have thought this through already. That sounds like you guys.

So I'm hoping for something like:

Michael, yes, in principle it's possible to do what you're saying, but in our experience, with any lift greater than 3 inches, the propshaft angle just becomes too great for any design of shaft to cope.

or:

No, you can't get the right caster angle with a custom radius arm, because...... So you have to modify the swivels, no matter what.


Finally, let me state again, so we don't go around in a circle: I am not arguing against the solution of caster correction by altering the swivels. I can see the wisdom of changing the pinion angle so that a DC shaft can easily manage the angle. It sounds like an excellent solution. What I'm exploring is the possibility of other solutions not involving swivel modifications.

 

[muskyman]

gone

 

[kellymoe]

Ok, on to the Costa Rica maps.

If you have the chance to go through Turrialba stop at the Hotel Americana for info on local flavor. It's also the hot bed of kayaking and rafting in Costa Rica. Lots of fun rivers in the area.

OK, back to the discussion.
I have a Detroit Locker sitting on my work bench waiting to be installed. It's my belief that with the longer wheelbase of a 130 it will reduce much of the hopping and sliding associated with a Detroit in a shorter wheelbase vehicle.
No plan to add anything to the front at this time.
There I have added something to the topic.

 

[michaelgroves]

OK, back to the discussion.
I have a Detroit Locker sitting on my work bench waiting to be installed. It's my belief that with the longer wheelbase of a 130 it will reduce much of the hopping and sliding associated with a Detroit in a shorter wheelbase vehicle.
No plan to add anything to the front at this time.
There I have added something to the topic.

LOL.. read the topic again

 

[michaelgroves]

You just dont get it...its allready out there most the guys that came to post in this thread are allready running them.

this is not a debate or a plan or a theory we all have been talking about, it is the correct best practice way to deal with this stuff. and its not new .

Scott was here making it sound like he is testing something new, you are here thinking like you are inventing the new radius arm of radius arms. This has all been sorted out long ago and we have simply been trying to share information that will save you effort getting to the best solution.

Gee, thanks, Dad! You've done all the thinking, and we just now implement whatever you've decided is best!

I'm afraid this is not the level of discussion we're used to on this forum. It's never been about the leets telling the noobs what's best. It's a community of equals sharing direct or indirect experience, providing information, discussing preferences, comparing options, and presenting coherent arguments with supporting evidence when there are disagreements about factual matters. No-one is here just to teach - even those who are real experts on some topic acknowledge that there is always something more they can (and want to) learn.

Most non-trivial decisions end up being trade-offs of one kind or another. So don't presume to tell me, or anyone else, that something you consider "best" is best for everyone. I've been around the block a few times myself.

 

[Alaska Mike]

I'd like to offer a belated welcome to all of the new members that seem to be posting in this thread. A couple notes while we're here:

• This is unlike any large 4x4 forum you've ever frequented. The key word when posting on ExPo is respect. Respect for your fellow members (no matter their experience level), respectful debate, and respect for your host.
• This forum may be more tightly moderated than other forums you're used to. This is not Pirate or DWeb. This is a family friendly site about vehicle-dependent exploration. If we feel you're out of line, we'll tell you and we'll take what we deem is appropriate action.

On a personal note:
As Scott is one of the truest friends I've ever had, I take it very personally when I feel he's attacked unfairly. Especially when I consider ExPo no different than a conversation in his living room. This is not because he requires such defense, but because I'm his friend. I know Scott can be wrong at times, and he's usually the first to admit it. I've found he's been right far more often than wrong. He's earned a vast amount of leeway with me. Your mileage may vary.

Respectful debate and questioning of his build or exploration philosophy is certainly welcome, but questioning his integrity is not. I'm a grumpy old man with no sense of humor when it comes to this subject. Please keep this in mind before you submit a new topic or reply.

Again, it comes back to respect. If you find you can't fit within the guidelines of this site, Al Gore has invented a whole internet outside of ExPo for you to explore.

 

[Hank]

Most non-trivial decisions end up being trade-offs of one kind or another. So don't presume to tell me, or anyone else, that something you consider "best" is best for everyone. I've been around the block a few times myself.

Until something new comes along, the RTE swivel mod is in fact the best option. There is no "trade off", it's just the right, or correct, way of doing this fix.

 

[kellymoe]

LOL.. read the topic again

LOL, I thought Scott combined the locker thread. My bad.

Still, go through Turrialba Scott.

 

[michaelgroves]

Until something new comes along, the RTE swivel mod is in fact the best option. There is no "trade off", it's just the right, or correct, way of doing this fix.

No, Hank - that's an opinion, not a fact. I can explain the difference, if necessary.

 

[michaelgroves]

LOL, I thought Scott combined the locker thread. My bad.

Still, go through Turrialba Scott.

Heheh, well, I think we can probably abandon this one, until normal service is resumed