Retarder caused skid!

[Stormtrooper1909]

I was going about 110km/h on the highway to Poznan, and a toll was up ahead, so I put full retarder, and something that has never before happened, happened. It seems that my wheels seemed to have locked up or something, I went into a skid and hit into a roadworks barricade. I am extremely lucky that today the damage system wasn't sensitive for some reason, and I only took 1% damage from hitting a barrier at 90.

What could have gone wrong? It was pretty scary.

[Wolfgang]

You were going too fast, that's what was wrong.

[[GER] TM]

That happens in reality as well, especially on wet or icy roads.

[Stormtrooper1909]

Originally posted by GER TM:

That happens in reality as well, especially on wet or icy roads.

That's it actually, I have the rain probability quite high. Thanks

[Briannospam]

Originally posted by Stormtrooper1909:

What could have gone wrong? It was pretty scary.

The retarder only brakes the truck itself, not the trailer.

Due to its inertia, the trailer will therefore try to keep both its speed and direction and push on the rear of the truck.

If you then turn just slightly, the trailer will push the rear of the truck out to the side so that you lose control.

As @TM correctly mentions, the risk is greatest on surfaces with poor grip, and in addition, the weight of the trailer is also important as there is more inertia in heavy loads than in light loads.

By the way, you can risk the same with a powerful engine brake, as the engine brake only acts on the truck's traction wheels (which is usually one of the rear wheels if no differential lock is used)

[[GER] TM]

Originally posted by Briannospam:

Originally posted by Stormtrooper1909:

What could have gone wrong? It was pretty scary.

The retarder only brakes the truck itself, not the trailer.

Due to its inertia, the trailer will therefore try to keep both its speed and direction and push on the rear of the truck.

If you then turn just slightly, the trailer will push the rear of the truck out to the side so that you lose control.

As @TM correctly mentions, the risk is greatest on surfaces with poor grip, and in addition, the weight of the trailer is also important as there is more inertia in heavy loads than in light loads.

By the way, you can risk the same with a powerful engine brake, as the engine brake only acts on the truck's traction wheels (which is usually one of the rear wheels if no differential lock is used)

Actually its the same for the retarder. Only the drive axle is affected.

[Briannospam]

Originally posted by GER TM:

Originally posted by Briannospam:

By the way, you can risk the same with a powerful engine brake, as the engine brake only acts on the truck's traction wheels (which is usually one of the rear wheels if no differential lock is used)

Actually its the same for the retarder. Only the drive axle is affected.

Thank you very much for that information. :)
- I had the feeling that it is like that, but I did not know for sure as I do not think this is very clear to me on this page:
https://en.wikipedia.org/wiki/Retarder_(mechanical_engineering)

I can maybe have overlooked / misunderstood certain information on the page due to language difficulties, English is not my main language.

[metpei]

Retarder is basically made for downhill driving with heavy loads to prevent brakes overheating. Heavy trucks need to control downhill speed not to increasing drastically.
Retarder is very powerful, also it has 3-5 steps to adjust, see in game settings.
Like said above, retarder affects only to drive axles and should not to use suddenly specially with overspeeding.
I think something similar situation you did, like this: What you think about driving with VW Golf pulling 4000kg trailer on 160kph and you pull handbrake suddenly as hard you can...

[Calico-Jack]

Originally posted by metpei:

Retarder is basically made for downhill driving with heavy loads to prevent brakes overheating. Heavy trucks need to control downhill speed not to increasing drastically.
Retarder is very powerful, also it has 3-5 steps to adjust, see in game settings.

I kind of feel engine braking isn't modelled correctly though - it should have a more noticeable effect on limiting downhill speed for example, which actually I find myself getting from adjusting cruise control up or down more than gears. The following is quoted from a lorry driver's forum where the OP was asking about dealing with hills and gear shifting while driving a fully laden 27 ton tanker:

To answer the most important bit first (seeing as keeping full control of an artic on descents is fairly important :) ) you should definitely be doing both on downhill runs, although how much downshifting you do will depend on the road itself. On long motorway descents if you're driving something fairly new with a half-decent exhaust/engine brake you can regulate the speed mostly with that, provided you get the revs right. For instance in a Daf CF/XF with an engine brake a gear and a half down will put the needle at around 2300rpm if you're travelling at 90kh/h, which is where the engine brake gives optimum performance. On a descent like Portishead bank (M5) you'll probably wouldn't need to even dab the footbrake as the engine brake will hold the rig back at 90km/h. On a steeper, nastier drop like Fish Hill (A44) it's more a case of combining both the exhaust brake and service brakes to descend safely. On this hill there's no escaping the fact that it's got to be done slowly, or at least the first part, meaning maybe even dropping into low range and keeping the revs in the blue sector on the revcounter (but obviously don't let it go into the red :shock: ). Of course a few cars may have to slow up behind you but forget about them, your job is to get down the hill safely without cooking your brakes. I don't know what truck you're driving but the safe speed for going down hills will be partially determined by how efficient your exhaust/engine brake is (keep the needle in the blue for best exhaust braking) - the main thing though is to err on the side of caution: better too slow than too fast!

As for the traction problem up hills; try to plan your gearchanges in advance. If it's obvious that the truck isn't going to make the climb in 6th make the change a little earlier, and don't be afraid to block change on steep hills as trying to make single shifts on a steep climb is like trying to bail out a boat with an egg cup ... darned hard work. Make the shifts a little earlier, think about what the gradient is doing, and keep the truck in the power (top of the green rev sector) if the hill's a steep one.

link to orginal thread[www.trucknetuk.com]

[metpei]

Originally posted by Calico-Jack:

I kind of feel engine braking isn't modelled correctly though - it should have a more noticeable effect on limiting downhill speed for example, which actually I find myself getting from adjusting cruise control up or down more than gears. The following is quoted from a lorry driver's forum where the OP was asking about dealing with hills and gear shifting while driving a fully laden 27 ton tanker

That 27 ton tanker is only 3 axle rigid truck without trailer(!?), so very light and he was talking engine brake only. What he said is correct as engine brake is most efficent in very high rpms.
When you use engine brake in game with auto transmission, it changes smaller gear possible to keep rpms high but not too small what would damage engine. Naturally if you drive manual you need to change smaller gear yourself in game and rl. This works fine.

Engine brake is not old and it's powerful compared to older exhaust brake. I'm not going to try explain more with my bad english, you find easily nice visual videos for that.
Retarder is in transmission and in game engine brake and retarder works with same button, that is very minor issue, but result is very sudden drive axle brakeing, as in game retarder is full power by default. So you need to bind 2 keys in settings to adjust retarder stick just like wipers and animation works in cabin nicely too.

See Volvo truck D13 values here for example:
https://www.volvotrucks.co.uk/en-gb/trucks/trucks/volvo-fh/specifications/powertrain.html
Volvo uses Voith retarder:
http://voith.com/corp-en/braking-systems/retarders-trucks/voith-retarder-3250.html
More Voith:
http://voith.com/corp-en/braking-systems/retarders-trucks.html

Edit: VEB is Volvo Engine Brake