How to get the unstable rovers fixed:

[Tiron]

Alright, after two versions with this problem without so much of a peep, well, I'm tired of this being treated as a minor issue and pushed aside. The terrain/suspension problem on rover wheels makes all rover use a crapshoot at best and futile at worst, as it *will* go tumbling down a hill and break sooner or later as a result.

Squad don't seem to grasp how big of a problem it is, since the most recent bugtracker report (with the best reproducibility I've seen on one yet, complete with a save file) has been downgraded to 'Low'. It's not 'Low', it's a major issue that's seriously affecting an entire core game function.

So do all of us a favor: If you're ever experienced the problem where the suspension on your rover jacks up, resulting in the rover losing traction and bobbling about and/or flipping over, please add a comment on your experiences in this regard to this bugtracker report:

http://bugs.kerbalspaceprogram.com/issues/1141

We need to show them that this is a major, widespread problem that causes serious gameplay issues, and not just some minor niche thing that a couple of people are experiencing occasionally.

Edited August 16, 2013 by Tiron

[Echostatic]

It has made driving my two seater on Laythe a nightmare... Terrain change causes it to jitter and lose control, next terrain change gives control back, next terrain change loses control, etc etc... Lots and lots of quicksaving/loading.

[Tiron]

It has made driving my two seater on Laythe a nightmare... Terrain change causes it to jitter and lose control, next terrain change gives control back, next terrain change loses control, etc etc... Lots and lots of quicksaving/loading.

Exactly. I just don't think Squad realizes the scope of it, so how do we fix that? Bring it to their attention.

[hugix]

Do you drive in docking mode (I believe that's the name). It disables the roll controls which helps you not to flip over the rover. I'm having little problems with my rovers. And the problems I'm having I can solve myself by editing the designs.

[SkyRender]

The problem is not the driving mode, the problem is that the suspension on stock rover wheels doesn't have nearly enough flexibility for the terrain. To the point that being one pixel off in placement of wheels can cause your rover to bounce around like a crazy thing on a flat surface, and even perfectly-designed rovers will get jostled by any terrain discrepancies at all.

[Tiron]

Do you drive in docking mode (I believe that's the name). It disables the roll controls which helps you not to flip over the rover. I'm having little problems with my rovers. And the problems I'm having I can solve myself by editing the designs.

Actually, originally I just moved the rover controls over to IJKL. My latest attempts moved them back and used docking controls so that I could experiment with active ASAS use. Which helped some on flat terrain but at one point seemed to actually lift the rover off the side of a hill, causing it to go tumbling down the hill and break.

There's lots of things that help rover stability in general, and this isn't about any of those issues: This is about terrain segments that cause your suspension to lift your rover partially off the ground, removing almost all traction and control ability, and have a severe tendency to send you rolling down a hill if you're on one when it happens.

Because right now, even with good design, lots of testing, and every other assistance measure, this bug still ends up flipping you over if you drive in hilly terrain (and massively slows you down if you don't).

The problem is not the driving mode, the problem is that the suspension on stock rover wheels doesn't have nearly enough flexibility for the terrain. To the point that being one pixel off in placement of wheels can cause your rover to bounce around like a crazy thing on a flat surface, and even perfectly-designed rovers will get jostled by any terrain discrepancies at all.

Actually, what happens is that Unity's wheel suspension system responds to invisible deviations in the terrain mesh: it thinks the terrain is in a different spot than it looks like it is, and tries to move according to where it thinks the terrain should be, instead of where the wheel is actually sitting. This causes the suspension to either harmlessly push the rover down or lift the rover up. The latter causes problems because it seems to actually be able to exert force on the rover, and tries to pull it right off the ground. The problem is that it partially succeeds, resulting in instability and lost traction.

Even TT's Multiwheels, which work far better than the stock wheels in many cases, have this problem.

Edited August 17, 2013 by Tiron

[Tiron]

...why did it make a new post instead of editing the previous one... *confused*

And more importantly, where'd the delete button go!

[Echostatic]

I have noticed that when I get this bug, the wheels are all the way out on their suspension. The whole rover goes rigid and it just jitters along until it reaches a change in terrain or flips over and makes me quickload.

[SkyRender]

I wouldn't be the least bit surprised if this particular problem is related to the "phantom force" bug. (This bug is easily seen by building a craft consisting of an OKTO2 core, an FL-T200 below it, 8 M-Beam 200 I-Beams in radial symmetry attached to that, and an FL-T200 at the end of each of those.) The basic symptoms are pretty similar, if less exaggerated.

[Tiron]

I have noticed that when I get this bug, the wheels are all the way out on their suspension. The whole rover goes rigid and it just jitters along until it reaches a change in terrain or flips over and makes me quickload.

Yep. I'm pretty sure the suspension is actually the cause, and is exerting actual force on the rover to try to lift it off the ground.

But seriously: Don't just post about it here, go on the bugtracker, and post it there by hitting the 'Update' button. This is the most recent (and best) bugtracker item on the subject:

http://bugs.kerbalspaceprogram.com/issues/1141

[RocketPilot573]

Yes, this is indeed a huge issue, my Tylo rover was completely undriveable (it crashed every 30 seconds).