Ha ha. Rover brakes need to be a lot better. [It's a bug actually]

[cephalo]

I understand that driving a rover in a reckless manner ought to be dangerous. The real lunar rover had a top safe speed of about 3 m/s because of the Moon's bumpy terrain. However, I'm pretty sure that rover had much better handling than any deathtrap you can make in KSP.

Here's the issue: Driving over a cliff on the Mun or Kerbin should be not much different than driving off a cliff on Earth; however even on a gentle slope with the brakes full on, you're going to hit 30ms(70mph!) and nothing is going to stop you until the next bump sends you tumbling through the air in an entirely unsurvivable manner. I think we all know this is very, very wrong. I'm quite sure this is also highly unrealistic in addition to being highly unsatisfying. We should be able to drive downhill in a controlled manner with nothing but wheels and brakes.

Hey, funny related story. My solution to this problem was to put Verner RCS controls front and back to assist with speed control. I made a big, beautiful science bus that absolutely drives like a dream all over the Mun. Problem solved right? Then I realized that in driving 10km I used about 3000 delta-v in fuel!

Edited May 28, 2015 by cephalo

[Robotengineer]

The problem is gravity, on the Mun you have less gravity, thus when you go fast, you tend to soar rather than drive, making braking difficult because your wheels aren't actually touching the ground.

[regex]

The real lunar rover had a top safe speed of about 3 m/s

You just answered your own problem. Had you approached the cliff and went over it at 3m/s there would have been no issue keeping the speed down on the slope. Also, lower gravity means your brakes work less efficiently because you can't grip the surface as well as you can on Kerbin (for instance). Using fuel to push your craft into the ground will help immensely.

[Docsprock]

I hear ya! I took a 30 km jaunt on the Mun and it took about 7 hrs of real-time to complete. Coasting down hills can get quite white-knuckled in a hurry. I also used RCS, but I used the uni-directional ones on the front for braking. Also having a couple pointing up helps keep your rover grounded.

[cephalo]

You just answered your own problem. Had you approached the cliff and went over it at 3m/s there would have been no issue keeping the speed down on the slope. Also, lower gravity means your brakes work less efficiently because you can't grip the surface as well as you can on Kerbin (for instance). Using fuel to push your craft into the ground will help immensely.

No, no. That's not even true on Kerbin. Try stopping a rover on the slope that leads from the runway to the KSC. You can't. I've designed two rovers so far, one small and one large, and it doesn't matter how slow you are going on a slope. Nothing will stop you except powerful, wasteful RCS.

[Feradose]

My 20 ton 8 ruggedized wheel truck on mun can drive up 80° slopes and come down 10° slopes safely, there is something fishy

[cephalo]

My 20 ton 8 ruggedized wheel truck on mun can drive up 80° slopes and come down 10° slopes safely, there is something fishy

That gives me hope. I'm still using the orange wheels. Perhaps my issue is with these.

[regex]

No, no. That's not even true on Kerbin. Try stopping a rover on the slope that leads from the runway to the KSC. You can't.

Sure I can. I don't even need to prove that. All I need to do is slow down before the slope and go over it slowly. You don't go barreling off a hill IRL unless you intend to do some stunts, same thing applies to KSP. Now, if your rover is built strangely you probably will have some problems, but I never have.

[Murph]

There's a bug at the moment, where the brake torque isn't being set correctly. It's ok for a newly installed wheel, but as soon as you open the right-click menu it's getting set to a fraction of what it should be, in some cases to 10% or less than what it should be by default.

If you know what you are doing, edit your save file and you'll find that you have cases of "brakeTorque = 30" on some rover wheels. Set that to a more appropriate value, e.g. "brakeTorque = 300". You can check the default values in the cfg files in GameData/Squad/Parts/Wheel, it's different for each wheel:

$ grep brakeTorque GameData/Squad/Parts/Wheel/*/*.cfg
GameData/Squad/Parts/Wheel/roverWheelM1/roverWheelM1.cfg:		brakeTorque = 300
GameData/Squad/Parts/Wheel/roverWheelS2/roverWheelS2.cfg:		brakeTorque = 180
GameData/Squad/Parts/Wheel/roverWheelTR-2L/roverWheelTR-2L.cfg:		brakeTorque = 500
GameData/Squad/Parts/Wheel/roverWheelXL3/roverWheelXL3.cfg:		brakeTorque = 200
$ 

It will break again as soon as you right-click the wheel, but should stay at the correct value if you don't touch them. The culprit seems to be brakeTorque_UIFlight's maxValue, so you can also set that much higher, which I believe should prevent the value getting clobbered (untested, not sure if setting a higher value there actually sticks). Each new craft will launch broken, these things only fix it for craft already in flight. I've not tried actually fixing the part cfgs themselves.

If the above made about as much sense as a novel written in a random mixture of Dutch and Chinese combined, you probably shouldn't be messing with your save file (or at least don't complain to me if it all goes horribly wrong for you).

Edited May 28, 2015 by Murph

[cephalo]

Sure I can. I don't even need to prove that. All I need to do is slow down before the slope and go over it slowly. You don't go barreling off a hill IRL unless you intend to do some stunts, same thing applies to KSP. Now, if your rover is built strangely you probably will have some problems, but I never have.

Here's what's happening to my rovers. I can start with the landing struts down and brakes on, and once I raise the struts, movement starts and gains pace. How can this happen? If my rover is too heavy down RCS should make it worse, if it's too light, it should certainly need much less friction to stay still. It doesn't make any sense. Maybe some of the later wheels are better, but the orange ones really need to be better.

These are on gentle slopes by the way. I've had driveways steeper than these slopes.

- - - Updated - - -

There's a bug at the moment, where the brake torque isn't being set correctly.

Aha, that must be the whole issue. The thing is, you have to right click to set steering or no steering. That can be important.

[Murph]

Aha, that must be the whole issue. The thing is, you have to right click to set steering or no steering. That can be important.

Steering should be enabled by default for the rover wheels, I believe (or maybe it's just some of them, not sure without checking).

[The Yellow Dart]

Sure I can. I don't even need to prove that. All I need to do is slow down before the slope and go over it slowly. You don't go barreling off a hill IRL unless you intend to do some stunts, same thing applies to KSP. Now, if your rover is built strangely you probably will have some problems, but I never have.

He isn't making this up, I have seen this problem mentioned several times since 1.0 and it is now even part of Claw's Stock bug fix mod.

+ ModuleWheelFix (Plus) (18 May 15) - (STATUS: Minor Updated Release) - Description: Rover wheel brakes are rendered ineffective and traction is low.

- Fixes bug with brake torque not working on rover wheels (changes tweakable range to 0 to Max Torque for that part)

- Improves wheel grip for all rover wheels

-- (removed) Also adds tweakable "grip" multiplier (from 1 to 3x)

Edited May 28, 2015 by The Yellow Dart

[regex]

He isn't making this up, I have seen this problem mentioned several times since 1.0 and it is now even part of Claw's Stock bug fix mod.

Pardon me, haven't experienced it. Any time I've crashed it's been due to excessive speed.

[cephalo]

Pardon me, haven't experienced it. Any time I've crashed it's been due to excessive speed.

Nah, speed is not the problem. It's the sudden stop... (My stepdad used to tell that joke every week) Without brakes though, speed is a real problem.

[problemecium]

Nobody seems to have mentioned the new tweakable brake torque so far. If you haven't, try increasing the torque on the rover's wheels' brakes. More on the back than on the front will help keep it stable.

[SelectHalfling0]

I build low riding wide rovers for low-g worlds. That way I dont have to worry about high speeds (also 6 wheels tweaked so that the middle ones are motors and brakes, but dont steer) helps alot. I can cover 30 km in 30 minutes with this.

This design was made in .23.5, and I still use it today.

[cephalo]

Nobody seems to have mentioned the new tweakable brake torque so far. If you haven't, try increasing the torque on the rover's wheels' brakes. More on the back than on the front will help keep it stable.

Actually that is where the bug lies. If you try to do that with the orange wheels it will max out at 30 instead of 300. I had no reference for how brakes were supposed to work because I wanted front wheel drive on my first rover, and my second rover was a big bus with many wheels where the center ones had their steering locked. All my tweaking broke them both.

[Temeter]

I build low riding wide rovers for low-g worlds. That way I dont have to worry about high speeds (also 6 wheels tweaked so that the middle ones are motors and brakes, but dont steer) helps alot. I can cover 30 km in 30 minutes with this.

http://i.imgur.com/cOIPp7B.png?1

This design was made in .23.5, and I still use it today.

Nice design, built like a true sports car. My last moon rover i used for a 80km voyage consisted of a 2.5m truck with very low wheels, that thing was more surfing than driving.^^'

[samstarman5]

For one thing, this isn't Need for Speed. We are designing rovers, not sports cars. With the equipment we have there should be zero expectation of any real awesome performance. That would be where mods can come in if you actually wanted to drive a humvee or lamborghini on the Mun.

[Slam_Jones]

An option for atmospherically-bound rovers is to put some AIRBRAKES on it. Haven't done it personally, but from what I've heard they should at least make up some of the missing brake torque.

[Archgeek]

Sure I can. I don't even need to prove that. All I need to do is slow down before the slope and go over it slowly. You don't go barreling off a hill IRL unless you intend to do some stunts, same thing applies to KSP. Now, if your rover is built strangely you probably will have some problems, but I never have.

Heheh, that or you fully intend to hover over the crater and land softly on the other edge, like my silly Puddle Jumper rover.

He isn't making this up, I have seen this problem mentioned several times since 1.0 and it is now even part of Claw's Stock bug fix mod.

I was wondering why I've not experienced this issue. N cheers for the Claw-erator!

for(int i = 0; i < n; ++i){puts("Herp derp, huzzah!"); if(i < n) puts("\n");}

[Motokid600]

The real issue is the fact that all surfaces in KSP act like ice. Hoping Unity5 can fix that.

[T.A.P.O.R.]

I've found that (on my installation anyway) the large wheels have no brakes and will not stop my rovers from hurtling down hill to their fiery doom.

That is even from a standing start, gently lowered from landing legs.

[anarkhon]

The real issue is the fact that all surfaces in KSP act like ice. Hoping Unity5 can fix that.

No way,the problem is the stock wheels,its like the stock water and clouds.

Here is the cure:

Delete them and isntall a modded one like Zwheel or RollKage.

some pics:

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.

[panzer1b]

That gives me hope. I'm still using the orange wheels. Perhaps my issue is with these.

The best generakl purpose are the medium grey ones, they seem to have decent braking and then at least feel grippier. That said, IRSU gives infinite fuel, rocket rovers tend to be the new thing these days, rover around one spot, then fly to the next interesting area (driving anything more then 20km is excrutiatingly painful on most planets right now even if you are going 50m/s and somehow dont die after flying off a cliff)