End stop can't exceed overall force strength, pros and cons

Hey all,

The devs said earlier about having the bumpstops stronger than overall force:

“Not possible, as the strength slider controls the servo drive amperage level too. Switching this around (it actually was that way very early in Simucube 1 firmware development) results in less fidelity to FFB.”

Personally I want my end stops to be hard, and I feel the only way for an end stop to feel is hard, because its supposed to be a physical end of travel.

There is even a possible risk from this because say with iRacing:

  • I want hard bumpstops so I run overall force 100% and bumpstop force 100%
  • I tune the FFB way down on the Miata or Skip barber in iRacing so I feel perhaps 8Nm torque max
  • When I hit the end stops it can go up to 25Nm, I am happy!
  • If I crash or get weird online lag, I can get unexpected FFB spikes of 25Nm which can hurt.

In the case above, running overall strength 100% but limiting the in game setting so I only feel perhaps 33%, there is a loss of fidelity there as you only use a small range of forces.

Is that loss of ‘fidelity’ not identical to setting the motor amps to 100% for the bumpstops, but then scaling the game output to 33% on the servo drive?

I really feel pretty strongly about having strong end stops as you can see here… :wink:


Hi Niels,

and thanks for the feedback. For some reason which I can’t remember anymore, the early Simucube 1 beta testers (before the first public release) said that there was indeed a notable difference in FFB smoothness when the final scaling step was changed so that it was done on the servo drive. However, it can be experimented with again for sure.

If the final scaling is done before sending the value to the servo drive, and user uses for example 50% of the force, the resolution is reduced in half. On Simucube 2 Pro, this would be in steps of 1.5 mNm (millinewtonmeters). So, I really wonder if it really was placebo back then…

just to note, that we definitively will not put back two sliders - one for motor amperage and one for overall strength.

Hey Mika,

Everywhere guys (or gals) get really into a hobby, the placebo risk grows fast! I have edited physics of a car, feeling changes, until I found out I was editing the wrong file and nothing was changed… :astonished: (this has happened more than once too… )

With AMS we upped the FFB rate from 90 to 360. Recently we found out the FFB is actually still limited to your framerate most likely. We had 180 and 360hz options in game, I’m sure people felt a difference, but if they ran less than 181fps, the FFB rate was most likely identical. :smile:

At 1.5mNm and 12.5Nm of maximum torque, you have 8300 steps of torque available. On a 30cm diameter wheel, those are force steps of 0.01N or 0.001kg. You breathe out more air mass than this every time you exhale. (1 liter of air is 0.012N, lung capacity about 6 liters…). I wouldn’t worry about that the slightest. :slight_smile:

Another consequence of the current approach is that the friction, damper and inertia effects are also limited when you lower the overall strength. You clearly feel this for the damper and inertia where it stops being able to ramp up much sooner when using a lower overall strength. These effects would be more consistent if they are also allowed to use more torque.

Blind tests are a bit hard as you can’t see where you’re going… :stuck_out_tongue_winking_eye: but I really doubt we would loose anything by testing this change.


Hi Niels, since you are the right man to ask, I want to ask two simple questions about AMS since a long time :
1 - is it still possible to implement the 720hz ffb setting?
2 - I am still looking for a way to have the turbo boost on classic F1 cars, like you showed on your video time ago…I installed the AMS beta just for that but no luck…has it been scrapped from the sim?
Thank you very much, from an AMS absolute fan :slight_smile:

Happy to hear you enjoy AMS. But sadly it is end of life. We looked at the force feedback code, and it is quite confusing. A lot of things happen at the requested 360hz, but somewhere the framerate, especially when you run a hard fps limit, limits the FFB update rate.